United Airlines Flight 553 Midway Airport December 8, 1972

NATIONAL TRA.~SPORTATION SAFETY BOARD Bureau of Aviation Safety Washington, D. C. 20591

Report of Examination of Altimeters and Air Data Computers

Recoyered from B737 UAL Flight 553

8 Dec. 1972 Midway Chicago, Ill.

Docket No. SA-435 Exhibit No. 9-C

REPORT OF EXAMlliATION OF INSTRUMENTS

RECOVERED FROM UAL - B737 - Registry N9031U

Midway - Chicago, Illin.ois

I Exa.:m.ination conducted at:

a) United Airlines Maintenance Base, San Francisco, California

18, 19, 20 Dec. 1972

b) Kollsman Instr_ument Company, Elmhurst, New York

8, 9 , 1 0, Jan. 197 3

c) Kollsman Instrument Company, Syosset, New York

25 January 1973

d) Kollsman Instrument Company, Elmhurst, New York

26 January 1973

II Persons in Attendance

Mr. Wm. Weston NTSB Washington, D. C.

C. Tomasso FAA Des Plaines, Illinois

0. E. E. Anderson UAL San Francis co, California

W. Robertson ALPA Des Plaines, Illinois

J. Angus Kollsman Elmhurst, New York

P. Redmond Kollsman Syosset, New York

At times, others supplemented the above group:

J. Cincotta FAA San Francisco, California

F. Dilts UAL San Francis co, California

K. Humphrey UAL San Francisco, California

KOLLSMAN INSTRU1viENT CORPORATION -1-

III Accident:

UAL Flight 553 B737 N9031 U

Date:

Place:

8 Dec. 1972 2:28 P.M.

Approach to Runway 31L Midway Airport Chicago, Illinois

Elevation of site - 620 ft. MSL(approximately).

Reported Altimeter Setting - 3 0. 05 In. Hg abs

IV Identification of Equipment reportedly recovered from the accident

aircraft and studied in this examination.

A. Altimeters

Identification data was obtained from UAL maintenance records.

1. Gaptain 1s Altimeter

KI Type B38689 10 015, Serial No. 745A

2. First Officer 1 s Altimeter

KI Type B38689 10 015, Serial No. 492A

These are identified as -

UAL Type MR41101-121 UAL Type MR41101-52

Captain1 s Altimeter First Officer's Altimeter

UAL reported dates of last servicing -

22 Sept. 1972 1 Feb. 1971

Captain's Altimeter First Officer 1-s Altimeter

KOLLSMAN INSTRUMENT CORPORATION -2-

B. Air Data Computers

Identification of installation position supplied by UAL records

KI Type KS-200-117 Serial N9 1123 Captain 1s C~WC

KI Type KS-200-117 Serial No. Kl003 First Officer 1s CADC

These are identified as

UAL Type MR 41113 Serial No. 1165 Captain 1s

Serial No. 1004 First Officer 1s

UAL reported dates of installation are:

5 Nov. 1972 Captain1 s Unit

16 Feb. 1971 First Officer1 s Unit

v A. Altimeters

1. Captain 1s Altimeter

The outside case paint was severely burned.

The nameplate, an adhesive backed foil, was missing.

The cover glass was cracked but not separated.

The baro setting noted at SFO was 30. 36 In. Hg.

No loose parts were noted when the altimeter was gently

shaken.

Moisture was present on the inside of the cover glass.

Testing was conducted as follows:

a) Integral lighting operated

b) Integral vibrator operated

c) As soon as servo power was applied to the receptacle,

the fuse in the test equipment failed.


d) The pressu~e mechanism was tested for operation

as follows:

1) (a) Baro set 30. 36 as received

(b) Due to excessive case leak attributed to

burned gaskets, cracked cover glass, etc.,

the instrument was placed in a bell jar. The

bell jar was tapped externally to remove friction.

The motion of the pointer was irregular indica-

ting a higher than normal level of friction.

(c) The pressure was adjusted to position the pointer

in 200 foot steps from 0 to 2000 feet. A

barometer was read to determine the actual

test pressure in the altimeter

Altimeter Measured Equivalent Feet Set Altitude Pressure for Me

The data for conversion of pressure altitude is based on

the U.S. Standard Atmosphere 1962.

To determine the instrument errors the QNH values were

computed based on the indicated value of an altimeter set

at 30. 36 and exposed to the pressures determined in the

above test.

Test QNH Reading Test Altimeter Test Altimeter Pressure for 30. 3 6 Baro Reading Error

30. 250 In Hg abs +100 feet 0 feet -100 feet

30. 045 +288 200 -88

29.795 520 400 -120

29.517 777 600 -177

29.289 993 800 -193

29;110 1162 1000 -162

28.900 1361 1200 -161

28.699 1553 1400 -153

28.547 1698 1600 -98

28.264 1971 1800 -171

28.005 2223 2000 -223

v A. 1. d) 2) The baro setting was then adjusted to 29. 92

In. Hg. Standard pressures were set into the

altimete.r and the altimeter error was noted for

increasing and decreasing altitudes behveen

0 and 2000 feet.

KOLLSMAN INSTRUMENT CORPORATION -5-.

v

Set Pressure Altimeter Error Altitude Increasing Alt. Decreasing Alt.

0 feet -9 0 feet

-80 feet

200 -120

-100

400 -llO

600 -120

-110

800 -130

1000 -155

-130

1200 -130

-120

1400 -100

1600 -130

-120

1800 -160

2000 -160

-140

A. 1. e) Resistance measurements were made to determine the

conditions of the servo elements.

Receptacle Pin Measured Resistance Nominal Resistance

J-K 40 ohms 38 ohms

J-H 40 If

H-K 40 It

A-Y 18 ohms 18 ohms

A, Y to case 5 megohms

H, J, K to case .>s megohms

Other paths open or short at the case receptacle.

Note: The recepticle was packed with a foreign material which had to be remove.cl a~d each pin brushed clean to obtain electrical contact.

KOLLSMAN INSTRUMENT CORPORATION ~ -o-

~-i

v A. 1. f) The altimeter was then placed in a bell jar with a

supply of Silica Gel for the purpose of drying the

entrapped moisture in the unit. This was done over-

night (period of approximately 17 hours). After

removing the altimeter from the bell jar, the altimeter

was placed in an oven at +72C for approximately 8

hours to continue the drying operation.

g) The investigation of the pne.umatic operation of the

Captain's altimeter was continued at Kollsman in

New York on 8 Jan. 1973. The altimeter was placed

in a bell jar where the internal vibrator was wired to

an externally controlled source of 28V DC. In addi-

tion a separate vibrator,external to the instrument

but inside the bell jar, was included. At each pressure

setting the instrument was read three times:

1) as the instrument settled out without vibration,

2) after the instrument internal vibrator was excited,

3) after the bell jar vibrator was excited.

The baro setting was 30. 05, the reported value set when

the instrument was recovered. The pressures set in

for each test point were standard QNE values based on

the U. So Standard Atmosphere 19 62.


B38689 10 015 Captain 1s Altimeter Baro Set 3 O. OS

Indicated Errors Readings Increasing Readings Decreasing

Standard Test Alt. No Vib Int Vib Ext Vib No Vib Int Vib Ext Vib

-lOOOft -120 ft -80 ft -70 ft +80 ft +20 ft -10 ft

0 -100 -35 -20 +125 +40 +20

+ 500 -130 -80 -55 +80 +30 +10

1000 -130 -100 -75 +110 +60 0

1500 -115 -60 -45 +45 +20 - 5

2000 -140 -80 -70 +125 +10 -15

2500 -165 -95 -75 +105 +40 +10

3000 -270 -120 -105 +550 +550 +550

4000 -555 -540 -540 -440 -440 -440

5000 -1440 -1440 -1440 -1440 -1440 -1440

The altimeter pointers stopped operating at +3400-feet, therefore, the increase

of pressure altitude was stopped at +5000 feet. The same values were taken for

descending readings as had been taken for ascending values.

The total friction values determined from the above test data are shown below: The normal friction tolerance in this area is 7 0 ft.

Friction Test Alt. Increasing Decreasing

,...1000 ft 50 ft 90 ft

0 80 105

+ 500 75 70

+1000 55 110

1500 70 50

2000 70 140

2500 90 95 3 000 165


-....

INCll\ ">

Kl:"lJfflt.I. ti. tSi;.\:!R C:u. -.

~

v A I. h} At this point it was decided to conduct a detailed exami-nation of the mechanism by removing it from the case.

1) The rear cover was removed and the electronics

which are attached were noted to have been subjected

to high temperatures which discolored the electronic

parts, the circuit board, the internal connector.

Several capacitors nexploded 11 Subsequently, three

typical capai:::Ttors (same part number) were placed

in test tubes and exposed to two hours of heat at

300, 350, 361, 400, 425F. At 361F the

capacitors showed visible signs of deterioration.

One unit was left in the oven and when 425F was

reached it exploded.

The.re was notable contamination in the back of the case

and at the rear .of the mechanism. It appeared that

most of this contamination came from the electronics

assembly which deteriorated with elevated tempera-

ture exposure.

The mechanism assembly was then removed from the

case for further examination. The contamination of

of the mechanism consisted of corrosion products on

the aluminum casting and shafts, on the brass parts

of the links and capsules and on the steel pinions

and shafts.


v A. l. h) 1) continued

Very little corrosion existed forward of the mount-

ing plane of the mechanism.

The solder, on the lip of the capsule closest to the

internal connector, showed evidence of melting for

approximately 1200 of the capsule lip. This solder

melts at 361F. The fact that this solder melted

but the capsule did not leak {pressure) indicates

that the temperature-time exposure must have been

just at the meltl.ng temperature for a short period

of time. A check was performed on the capsule

loading to determine if the capsule might have

a partial loss of vacuum. Under nominal conditions

the load is -500 ft. and +1800 feet. This unit

measured -570 feet and +i600 feet which are well

within the normally expected variations. The

questionable joint is on the capsule with the negative

load which is further assurance of no leak.

DC resistance measurements of the motor were made.

The control phase measured 320 ohms (nominal is

328 49 ohms). The fixed phase was open, however,

this phase contains a series circuit for temperature

compensation which was open. The measurement

of the inotor inside of this circuit was 485 ohms

(nominal is 426 64 ohms).


.. _.

v A. 1. h) 1) continued

Further examination of the mechanism centered on

why the indicator stuck at +3400 feet during the test

performed in Para V. A. l. g. Microscopic

examination of the gear train showed deposits of

contamination to be sitting in between gear teeth

of the intermediate pinion of the altitude gear train.

By analysis it was determined which teeth would be

in mesh at 3400 feet altitude. Moving the gears to

an accessible position, and using a 30-power micro-

scope and a fine sewing needle, the contamination

was ejected from the gear teeth. The altimeter

was placed in the bell jar and using vacuum the

altimeter smoothly passed thru the 3400 foot point.


v A. Altimeters

2. Fir st Officer rs Altimeter

Severe impact and fire damage was noted. The entire

flange and cover glass assembly was missing.

The right half of the case was missing. The case and

mechanism below the mounting plane was mis sing. The

display was damaged but the following parts were present:

Main dial Baro dial 100 ft. pointer 1, 000 ft. pointer 10, 000 ft. pointer Flag (Servo On/ Off)

The display altitude had to be verified but the positions of the

pointers were such as to indicate a loss of synchronization

between the three pointers. To verify this, a separate altimeter

of the same type was photographed by adjusting the display

using the baro setting system. Several photos were taken so

that each photo would have one pointer set the same as the

corresponding pointer of the F /0 Altimeter. Examination of

the photos indicates that the pointer positions on the F /0

altimeter are un-coordinated. The disc pointer was free to

rotate on its shaft. The 100 ft. pointer and the 1000 ft. pointer

are geared together by means of a small gear located inside the

front mechanism plate. This gear is secured to the hands ta

(100 ft. pointer) inside the gear box. Inspection of the hand-

staff assembly inside the main mechanism showed an endplay

of O. 025 inches to exist due to the impact damage. This


v A. 2. continued (First Officer's Altimeter)

excess play could result in a disengagement of the pointer

gear drive thus permitting the pointers to desynchronize.

It was noted and photographed that a diamond shaped shadow

corresponding roughly to the 1000 ft. pointer was present

on the disc pointer.

The altimeter dial had been shifted upward and slightly

to the right due to the heat and forces present on the dial.

The baro setting was 30. 035 In. Hg.

.,

KOLLSl\.t1AN INS.TRUMENT CORPORATION -13-

v. A.

. . ,

.,

Servo Monitor Function

UAL supplied a separate three-pointer servo pneumatic

altimeter, of the same type, to demonstrate the failure

monitor and limiter action. Tests were conducted show-

ing the effects of:

a) Trip out assuming no change in elect;rical transmitted

data while the pneumatic pres sure to the altimeter I

static port is changing.

,b) Trip out assuming constant pnelitnatic pressure to

the altimeter static port while the el~ctrical trans -

mitted data is changing .

KOLLSMAN INSTRUlviENT CORPORll.TION -14-

.a}

.. ''"":''

~

SERVO MONITOR TESTS

Pr'.,e,.,S-s11.re Alt. at AlthoiiJer Static Port

0 "ft.

+100

+200

. +300

+400

+440

0 ft

-100

~zoo

,..300.

-395

Transwited Synchro D9'ta frthn-GADC

0 0

9.2 100

14.4 200

20 278

0 0

-7.2 ~100

-14-:.14 . .~.... . -200

.....

. { ~ ..

...,LS ,

-347

Transmitted _Synchro Data from cADc

0

0

0

0

0

0

0

0

0

Pressure Alt.

0 ft

0

0

0

0 ft

0

0

0

KOLLSMAN INSTRUMENT CORPORATION

Altimeter Indication

+ 0 ft

+ 5

+10

+20

+40

+60 Tripout

0 ft

- 5

-15

-25

-70 Tripout

Altiineter Indicati.on

0 ft

+100

+187

+zzs Tripout

0 ft

-90

-182

-295 Tripout

-15-

v. B. Air Data Computers

The covers were removed to provide access to the individual

modules. The procedure followed was:

1. -Measure the electrical position of the output devices

(synchro or potentiometer) in the received condition.

This was done by supplying only the necessary power for

each element or section by using individual pin connections.

The synchros were connected to an angle position indicator

(API).

The potentiometers were connected to voltage ratio read-

out units.

The encoders were measured by a Simpson meter from

each leg to common.

2. The altitude sensor was electrically disconnected from

the servo system.

The sensor was then connected to an angle position indicator

(A. P. I.) and it was run through the pres sure altitude range

from -1000 ft. to +2000 ft. and return. The relative friction

was also determined by tapping the unit after the initial

reading was taken. The difference between the two values

is the friction level present.

3. The sensor was then electrically connected to the altitude

module and a readout was made of the fine synchro that

drives the servo pneumatic altimeter with standard pressure

applied to the sensor.


v B. Air Data Computers - continued

4. The encoder correlation to the fine synchro was checked by

adjusting the pressure until a t_ransition just occurs and

. then reading the fine synchro position. This should corre-

spond to a 50 foot offset from the reported code value.

5. A servicable servo pneurriatic altimeter was then connected

to the altitude module output synchro, the static ports from

the altimeter and the module were connected together.

Standard pressures were set into the sensor and altimeter ,

before reading the altimeter {in servoed mode).

6. It was then decided to check the turn-off slew coast by

subjecting the unit to 2500 ft. /min. descent and then turning

off both the pneumatic and servo power simultaneously at

1000 ft. This was repeated for a descent rate of 1000 ft. /min.

The descent rate was controlled by maintaining the altitude

rate output voltage at the standard value during descent.


r l.

Output Readings in 11As Received State 11

A. Encoders (AlOl) Equiv. St'd Press. Tol. 1 Bit (100 ft.)

ADC Unit Pin

5-13 6-13 7-13 8-13 l-13 2-13 3-13 4-13 9-13

12-13

Code Channel

A1 A2 A4 B1 B3 B4 C1 C2 C4 D4

Captain

0 0 0 0 1 0 0 0 1 0

700 ft.

B. Fine Synchro #1 (B 104) Tol. l. 15 ( 15 ft.)

Static Reading Equivalent Altitude

46.95 652 ft.

C. Fine Synchro #2 (BllO) Tol. i.150 (15 ft.)


47.38 658. ft.

D. Coarse Synchro #2 (Blll) Tol. 2 (750 ft.}


E. Cabin Press. Pot. (RlOl) Tol. o. 0015

2. 1 o0

787 ft.

First Officer

6 0 0 0 1 0 0 1 1 0

600 ft.

43.080 598 ft.

42.80 594 ft.

0.87 326 ft.

0. 9417 VR 0. 9442 VR

F. TAT/EPRL {Rl51) Tol. o. 0018

G. Airspeed Sy:hchro Tol. - 2 KTS

,/\/ 6 8 0 ft. ~ 6 3 0 ft.

O. 326 VR .,,..._.,, 660 ft.

331.13 57. 55 KTS

0. 0331 VR ,.,.,...,666 ft .

337.87 66. 6 KTS

K 0 L L S lv1 A N I NS TR U ME N T C 0 R P 0 R A TI 0 N -18-

1. H. . Resistance Readings of Output Devices

Captain F/O Fine Synchro #1 Stator 24-2S 9 8-1/2

2S-26 9 8-1 /2 24-26 9 8-1/2

Fine Synchro #2 Stator 71-72 42 so 72-73 43 50 71-73 44 so J

Coarse Synchro #2 Stator 4-5 14 15 5-6 14 15 4-6 14 15 Airspeed Synchro

Resist. Stator 30-31 15 lS 31-32 15 15 30-32 15 15

-..... ..


2. Altitude Sensor Fine Synchrotel Reading (API)

Altitude Input Pressure Alt. Capt. F/o

-1000 ft 298. 85 . 300. 35 - 800 306.2 307.75

600 >:< 313.5 ~:< 314. 9 - 400 320.85 322.25 -

200 328.2 329.4 0 335.5 >:< 336. 55

+ 200 342.9 343.8 400 ~:< 35 o. 2 350.9 600 357.45 357.9 643 F/O 360.0 671 c * 360. 0 800 4.7 5.6

1000 11. 9 12.7 1500 30.3 30.7 2000 48.6 48.55 2000 48.85 48.8 1500 30.5 31. 1 1000 12.1 13. 05 800 5. 0 6. 0 636 F/O 360.0 666 c * 360. 0 .,_ ,,. 600 357.7 358.5 400 350.5 351. 3

+ 200 343.1 343.95 0 335.7 336.7

-200 328.45 329.3

- 400 321. 1 322.1 -

600 313.8 314.7 -

800 306.45 307.4 -1000 299.15 300.0

Note 1. lo = 27. 78 ft.

2. readings are taken without vibration except for reading of friction,

:{

3. Pressure Altitude to Altitude Sensor. Altitude Module Servo Connected, Measured Fine. Synchro #1 Output

Note 1.

2.

3.

St 1d Press. Alt. Captain 1s F/O No.m.

-lOOOft 287. 03 284.46 288. o0 - 800 301. 77 299.25 302.4 - 600 316.51 313.58 316. 8 - 400 330.72 328.16 331. 2 - 200 345.21 342.40 345.6

0 359.48 356.66 360.00 + 200 14.00 10.80 14.4

400 28.35 24.76 28. 8 600 42.61 38.88 _,_ 43.2

--800 56.88 52. 90 57.6 1000 70.93 67.36 72.0 15.00 106.98 103.24 108.0 2000 147.84 139.24 144.0 2000 143.38 139.96 1500 107.66 104.28 1000 71. 62 68.28 800 57.60 54.5

--600 43.26 39. 94 .. -4P,-O 29.20 2.5. 64

+ 200 14.72 11. 42 0 0.22 357.16

- 200 345.96 342.70 - 400 331. 36. 328.46 -

600 317.00 313.68 -

800 302.22 299.20 -1000 287.51 284.58

1 O = 13 8 9 ft {3 O = 4 2 I)

readings are taken without vibration,

reading of F / 0 unit at special test point>!< (sensor null as received) In. Hg ABS Fine Synchro Rdg.

2 9 2 3 1 41. 8 8 Inc r.

29.231 43. 02 Deer.

?: O L L S ::.,f A ~; I l'T S T R U :,\1 .2 N T C 0 R P 0 R A. T I 0 :0T - 2. 1-

4. Encoder Tra:.nsitiori to :F'ine synchro

Transition Captain's F/0 Norn.

-10 o 291. 8 291. 6 to

- 9 291. 3 . -

8 -

7 305.8 306.2 306.0 -

6 -

5 319.9 320.0 320. 4 - 4 - 3 334.1 334.2 334.8 -

2 -

1 348.8 349.0 349.2 0 + 1 3.2 3. 3 3.6

+ 2 + 3 17.4 17.2 18.0 + 4 + 5 31. 7 31. 7 32.4 + 6 + 7 46. 0 46.1 46.8 + 8 + 9 60. 8 61. 4 61. 2 +10 +11 75.2 75.5 75.6 +15 +16 111. 1 111. 7 111. 6 +20 +21 147.2 147.7 147.6 +21 to +20 147.0 147.6 +16 +15 111. 0 111. 7 +11 +10 75.0 75.4 + 9 + 8 60.6 61. 2 + 7 + 6 45.8 46.2 + 5 + 4 31.6 31.7 + 3 + 2 17. 1 17. 1 + 1 0 3. 1 3.3

-1 - 2 348.7 348.9

-3

- 4 334.0 334.2 -

5 - 6 319.2 319.9 -

7 - 8 305.5 306.1 - 9 -10 291. 1 291. 5

Note 1. lo = 13. 89 ft.

2. readings are taken without vibration

3. normal tolerance 1. 15 = 15 ft.

- - ,-, r -Z2-

~~ .,,, . ,_.., .. ~. :- '. -

,5, .81;~;;,o,d Pr~s~.~i~k1~;~rfi~'s. & SPA, SP:. is Servo Mode: St 1d Press. Altitude Captain 1s F/O

-lOOOft .,,_ -1055ft -

- 800 ::I:: - 850 600 .,,_

645 -.- -400 .J.. --

- 200 --

- 445 -- 250 -0 .,,_ -.-

+ 200 ..... 55 -- + 140 400 .,_ -.-

340 600 * 540 800 .,_ ..,..

735 1000 _,_ ..,..

935 1500 .,_ ,,. 1430 2000

---.- 1935 2000 2000 ft 1945 1500 1500 1450 1000 1000 955 800 800 755 600 600 555 400 405 360 + 200 210 1.60 0 + 10 40 - 200

- 190 - 240 400 390 435 600 585 640

- 800 - 790

- 845 -1000

- 995 -1045

Note l. readings taken without vibration

2. Tolerance 15 1 ADC

3. >:

6. Cm;i.st Test

Rate -1000 ft./ min.

Power Off TE

Reading of Fine Synchro #1

Coast

.Rate -2500 ft. /min.

Power Off Value

SPA reading

Coast

KOL=."s:vt . .;.N INSTRT;:::AEST CORPOR/',_TION

Captain's

46.70

46.20

0.5Q0 = 7 ft.

1011 ft.

1013 ft.

-2 ft.

F/O

42.98

42.97

0. 01

1014 ft.

975 ft.

39 ft.

7. CADC Monitor Checks

The computer chassis was connected to the computer test console. The

altitude module was removed from the computer chassis and connected

back to the_chassis using a jumper cable with intermediate means to open

the fixed phase of the altitude module servo motor. This would disable

the motor such that as the pressure altitude changes the servo will not

follow. When sufficient error signal has been generated, the monitor will

trip the failure relay which removes the reliability signal. The normal

tol~rance is l 00 15 feet.

F. 0. Unit - Alt. Module Monitor Trip

+ 135 ft. increasing alt. + 133 ft. returning -110 ft. decreasing alt. -110 ft. returning

F. O. Before this test it was noted that the connection tube at the/altitude module

to chassis connection had a white flaky deposit in and around the static

port. This material was removed and stored in a container for further

analysis.

Capt 1 s Unit - Alt. Module Monitor Trip

+ l 05 ft. increasing alt. + 105 ft. returning -118 ft. decreasing alt. -112 ft. returning

During this test the Captain 1 s CADC A/S reliability signal and associated

reliability signals tripped out and then came on. This was repeated

several times until it was isolated to the A/S module. The servo has a

spring return in the gear system. When po\.ver was off the spring would

return the unit to a position of approximately 50 knots. when power \Vas

turned on the monitor lights would be off indicating a monitor trip_


At the same time the A/S servo would slew upscale until the reliability

signal is latched, the lights would go on; however, the servo was at the

high end of the airspeed system. The cond:ltion was isolated to a gear

and sector (~on-linear) which had become disengaged. This allowed the

output shaft to assume a high airspeed position regardless of the value

of input airspeed.

Examination of the mechanism showed side stops on the gear to be in place

and HI and LO stops to be in place. The data taken following re-engagement

of the airspeed gears is shown on the enclosed data sheets and is also

shown in graphical form.

A shock test was performed to determine if the gear disengagement could

be duplicated. The Captain 1 s airspeed sensor was positioned to an output

equivalent to 120 Knts and was subjected to 20 g 1 s three times and the 25

g 1 s three times in the fore and aft direction. Before and after each shock

run, the a.irspeed sensor was tested for operation through the range of

SO to 250 Kts and spot checked at 100, 120 and 200 Kts for any direction

of change in output. No disengagement occurred and no change was

observed.

KOLLSMAN INSTRUMENT CORPORATION -2 6-

""" "'..) ~ fl\.) !:.')

~{,~E ;~ ~u :!1~Ji-~;Ht: lNCH ~~ 11~ ~:~ ~ KlHJP"Ft::t. ll. li'SSER C'O,

-"'4 ~ ~ ~ - . ~ ~ ' - ' ' ' ~ ' ~ ~ '~ ~' ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~. ::,,--1-'.:r:-:-:~,nr~:1 :ir""1rr;lf -1 l ... -.. -11n ii: ~: : . . - --~ ~- ....... .. -- .: .. ~-- ~: .... rr1.i ., in-: j''! i1i-r ~~

! : : . . I . : 'I . I '! : I: I . I ! I I ~ I< ~ . ~ . . ~ . ~. I< ' ! 11 I 1 ! i:: . ; i 1 ! I .. " 1 , . . 1 ',.. . , . ,. . - .. , .. ,.... - -- . - ~ . . . . . . . - . . - . '1 I - -.-' ' - + -;i: :::::'ii;:;. i:::: .~ 11 . - I . - I - - : . . - .: .. : - ::.:: - ~ :_:: _-_ - - . I I~ _- 11

; . : 1 t ! i .. I; .. ' ... j : ' .... 1 ,. ~- I . - --. . - --- - . -- - - . - -- - . -- .. .,....-~r ... _ ... :--,..,. ~61" r ,. ... -., :t?-; ~ tf ~ . . . I :1!'.1i:! ;!;: :1:: il:': ; '.'.!! . : :: .:: _-- : :: ::: : - .. : - - - - - - . . ::: .. ::: :i:;l\i:: .!J :! ,:: ii 1 > . : - - -- - :: ": __ :_: ::: __ :: -' 'c, .. : .. I,_~.-- .. --,.-~ ~-' 't- ' iTf -~1-: " : ; \ : ' ) i .;: ' l l ( ! : f : : ! l ._ _ -: -- - - - ' - ~ --. . . .. . - . . ~, , :Lt,i~ , ";ilJ ,~ i . j _JI - , t - -I , : - : - - -_ . - :: -:_-.: - -: :::- . . . - I n , -~~]~''I' . 111!11LLLD.LLLLJ +

I ' J ' . +!-i~.J-. I . I ' 'ITT . I . . - - . - - . - .. . - - . - - - I ....___,,, .. :. 1 ,11 .. 1, '" 11 I~ ~ j - - - - --- - - --- - -- --- - -- rt r r11 . : : ~ : .. : i ~~: ~ -!~ii ~;:.j~' .L~: : : ! : ! I_ - . : -_ . . . . . . - . . - - - - . : - . - - . : : - - - :. - - - : _ - - : : : : - - : . -- - - . ~ T - : - . . . . . --- I ~ ---~ --~~-:..:.~ :2.).;. ~~ ' . .,J.:...:: t - I : . - - -- ..::.. - - - i I _ ill. . ~ . . . .. i, :ii , .. ; 1 . . . , I . - - - - .. - . - - - - -- ..

1

ir ; .. .: "J "ti.;. ,.11 .. ; Ii JI I - .f 1! - ' -~ ---- r 1l .. ,_,L.,., .. ,11Li-r1~ .. ,., .. ; ; ' . '.: : : ; 1 I : ; : l I ' ! ' . I I . : : . -. - - - -- -: - :: . : : - : : -- : . - . - . i' I I I I I . i , : : . , : ' 'I' , ; : : : : : : . ; 11 I ' - - - . : . . - .. - r. -.. : . . . . -- - ' 11 . ~ I , ' I : ' I 11 .;: ~ :.;': ; ":::i1 ,,JI I: "Iii I I -,1 - - ... - --. - - . . .. - -- -- - I! : ;! !::11,1 ' ~,., . :-r' c-~ ' : " :i--rrT tl!f n 1rr1 1~r . .. - r . 1 1- T"t" - " . ...J +11rl-i- t 1 : : ! ' : : . . i : l : ; : : : . I : I l i . . ... ' ~ . . . :. . . . . : . . . .. . . . : . - . . : .. . I I 11; ~ I \ I II I . I I ' / ' I ' ' . ; ! ' . I ' I - . . -. . -. . . . I I . I I I ! I . I ' . ' I ' 1 ' . ' ' I . . . . . . - - - I I I I ' ' i ' , .. ' . ' . _. I ' .. I . .. t" 1-1 r I lr I -- - . -. . -. -- - ~ h .. -;- . - -' L., r. ,. . ,.! 1 1 , . f - - . r

1'., r... . . , 1 . ! , , I - . . - - - - . - . .. I .. I , ,, I , .. 11 , 1 v .i:1 : :! .::; .:;; . : : : il I . . , : . - - - .... . : . . 1 1 ~ jyl;;:1 :r+rn~-:;f1:-:n.' 1-t\rr~ ._. ..: ., : j r _- - : -__ - . - ; _::: _- - 11I11'11 tl1-'nl IJ,1-:11' 11' t ! : ! ' ! ' : I I ! ; 1 1 J ; 1 ! ~ 1 I : J 1 : : .. - ~ : - - - I / r I : I i 1 ~ ': !~,: : .. ., r,f,_.,. ,.,~t r1' '--, - - . - - . - - . - .... I - - . 11..111 f1~II11' l~jt 1 ~ , I \ . , , , .\!I . 1 , '1 , ~ 1 t' 1 . r - - - 1 , 1 1 . 1 \: '; ,,. . . I I .. I . ' '. ' I I ''I . . . . ,. - . - - 1, . ' I I

- . 'I ' . . : ; : . ' ': ! . I I 'i I i 'I I ' . - ~: . . . I 1 I I, I I : ! I I i ., - i'\" ,, .. .,.., .... :- .. .,.,.-rl -,-ly t+ m t 'fl . ' nl I j j I ...,._f l -- . ., .. I I,.._ ,, ... , "" 1. I ' - I ..... ~ -- . I ,,I :r-;-tt. I'",,. 't'" .1 .111 I ' ! I I i I I I . . . . . "' - I 1111 ,, I/ I ' '! .. ,,, I I I ' I . - - . -- . . I . I I

"-.... i".. "1 , i ' ; ' .. 11.I ' ' I - - - - ......... - .. - " "I ,, I I ' I ,; 'I I' . . I I I I ' 11 . I ' . i I . - .. - . . - - . -. . I I I ' . I' I I ~- !'; \..),:.!'';' 1\:1, I"} ! - ..... :: - ..... -- r~- - _: - I I I j1,: j 1 I

( . -, r,' ::~.,. rr--: . ;T r-:-:~ ".- h ,.~ 1-/ I I I - - - - . - - . - - . - - 1'1 I I '1" lT-rr 111 I \' \J I ' ' ' ' I I . i I ' ! . I . ~'J ' IX ' ,.,; I . . I i . . . - . ~ - - I I ! ' ' I 1 I ' : ' '- _J I J -....! ~ '1 I . ., I ; ". ' .. ' : I'. '.;' . I 'N ., ' - - .. . ..... - ~ - - -.. ... .. - . . I I' I I I I 11 I

"' l ~ I ! . ! ! : i '. I . i l ~ : !"I : : : . : i . I I N l . . . . : .. . - . . .: . . . . . . . . . . : . . . . . . - I l I I \ ' .. . . I ., ; .. l I HI .;.. . , ... : . ' ' ~ i . rr . -~ I . l. 1J - 1 - . . . . - - . . 11 t ff r If ~:1.,- 1 r "f I~ 11r1 . 1-.1\ I . ,I ' : l i i I j I . i I : " i I ; ; I N. ' I I I - . - . - - - .. - . - .. . -. . . : ... - -- . : . I 1 ! ' J I ' I I ! I ' I

:i ' ' : ' ; . I 1" i , ; : ' : i ' ', I ~ . - - - - I - . - .. - . - - I I I I I I ' 'I I I I, I' . ' ' . '. I I 'I '.I ' H . . . I' ... "" I ' I , ! I I e'-1--. "- ,-- rn: -~--- ~t--.- N .:- j n ~ t), H H . - . f-l-1-~r~+ 1...- ;r 1 r~.J. n ~-1,.. . . ' I . . . .. ' I ! I '!I I . - . ~ - . - I ti I 11 .. I ' I 1 'I '"li!.,; ..... 1 .,., 1 1 , I - ... " . .. i'ilq'1/. 1 11, ; \ ! -r11'~-1-: "I . I I ' . . I . I I ' ' '\ I ~ I I . -- . I I I' I ' 11 ~ I I " . I ~~

. ; ! ii ., : Ii . I I Ii I I I . - - . - - . ~ - I 'I ' I I! I ' . I 'I' ! 'I 'I:: : I ; I:' . . ' : i I I . ~ : I 11 1 I ; . . . .. ... :.n . -",+ fl.IT "'1 . ., . . -Nt '+ 1 -- . - . -. . - I+ f'X.j I;...... I H1+ -n-1+

,. : . ' ''II I I I ' ~}!. I I -. - ... I: -1 I. I I I I II Hil '!.. 1 1 ' II I I: : : . ; . 'I .. '' . : '! . . j I -- - . - -- -. . . . -. - - - -T .I I. ... ~Mr+'~ iW +1i $~ fi .I. !1 T . H . . - .. - . -....... . 11 I 1,!,'l t:lt -~~ ~l-j-1m, r ' :rii iL:; :i ["i~I :':: :i" ~.:i .. ;'1"" Tl' - . .. r -. - - Ii 1 ,. - .... - . - - ... . - . - . i, 1 11JI/!11;: i11 r:11 :11! -111. '.l ! I '. I i ! . i I 11 ! ! ! ' I ~ : ! ' \ -..,,; I 1 j ! I ! j I ' I :11 . I I l : n I ! I ! I I !~, I I 11 : Irr : 11 I . 'j I . 11 I ' ; ' . . . ,\, 11 11 I I I I I ' I I 1 I ' JI I ' ' " I 1 , 1, " I ' 11 I I 1. ' 1 1 : 1"' 1 r 111 , ' ,,, 1 , .. ,,,. :t "1 -+ ' .... ;. .. n I r' ~. T .. . . - ,_;.l . . . ., - m -r n--+--1-r ., .... T .. I -' ' Ii ' I : . : " I ' . -. ~ I I I I I I . -. - I I I I ! I I I I ' I I ' 111 I I : ' : ; : i : : ' ! i i ' ; I: I 11 . I ! I . ; I/ ! I il!i GU: 11:1 llli J Ii 1 I 1 i - IT l ml ll -- . . .--. - . 1 fr r If l1c:11 lr111 11111

......

l I t"- -.,

....

Subject l ype 1'46.

Remarks

; ,r1 _,1 ; /0

,--- ,

} / / ....

1[)_

,- 3 !'

, ./ .

. 7['

-- , .. /_,.'

.... r~-/ ; .;- ..

.. ./

7/

~\ D 0 i oO

PERFORMANCE DATA

-....- ( i'.J.J lief -~

7 &J-17 J ,.,,

--; . c: ..) I. : U

/.f ~-&/ t. . (I ......

7

PERFORMANCE. DATA Subject Date

( 1ype No. .. Job No.

Remarks ..

Signature

/{ '/ - n C7 /.JJ_Jc:) ;FJ.rf-0 / S.J. :It' /J3JT tj Y-0 /-57 9'2- I .J7."!'-- -/7 /cf /..5/(/ / ..>7'.: ~ 9'?0 /b/ ?O /6 / 2;-- /{ / tZ3 /t I~ YO' t-7 .r:z:::: c&f: 'fJ /G 't / ,;-. /. /6S-12_ /CJ~or

-/;-~ /i ,;; ..?" - /jf.?7 / > 'i. 90 . (,.,- ..... //, 9C~ /? "?1 / 1- -'""" , I I? tA-. d.-J L---

"Y-//(' r..:Y /70' /!) I

l

:\D-0160 Kollsman lnsfrum.ent Corporation ::\h

8. Altitude Sensor Ac~.eleration Sensitivity

A fixture was made to mount the altitude sensor from each CADC and

individually subject the unit to accelerations greater than one g in the

normal, longitudinal and the half way positions (in between normal and

longitudinal positions).

A Schavitz Acceleration Table was used to perform this test. In this test

the output of the sensor Synchrotel was brought out of the acceleration

table and monitored on an A. P. I.

A sensitive altimeter was used to monitor the pressure to the sensor. It

was agreed to use 500 ft. altitude as the test value and observe variations

about that value. In each position the altitude would be set at 500 ft., a

reading of the API taken, the table would then be rotated to a value computed

to obtain the necessary acceleration bn the test sensor, the pressure

altitude would again be stabilized, a reading of the API taken, the table

would then be allowed to come to rest; the pressure stabilized and the

reading of the API again taken. A test run was demonstrated using an

overhauled Kollsman sensor. In all three positions .the maximum devia-

tion of the model sensor was i 0 (27 feet) for accelerations from 0 to 10 g 1s.

This test was repeated using the two sensors from the aircraft CADC units.

K 0 LL S MAN INS TR U MEN T C 0 R po R A TI 0 N -27-

Case 1 Sha,ft end of Sensor out (Equivalent to deceleration force when

aircraft is slowed from flying speed to zero velocity.)

G Level Captain 1 s First Officer 1s

0 18.09 17.32

1 18.48 17. 37

0 19. 90 17.41

4 17.67 17.37

0 17.75 17.42

4 17.61 -----

0 17.55 -----

10 17.23 17. 18

0 17.52 17.21

Ca.se 2 Normal Acceleration (wing loading)

G Level Captain'~ First Officer 1 s

0 18.09 17.93

1 18.36 17. 74

0 18.01 17. 9 0

4 18.78 16.60

0 17.91 17. 74

10 15.98 14.50

0 17.82 17.73

10 16.22 -----

0 16.78 -----

Note: 1 = 27.8 ;ft.

Case 3 Position 45

Based upon the data obtained with the test unit and a review of the data obtained on all three units, the 45 test "\Vas not conducted on

KOLLSMAN INSTRUMENT CORPORATION on the two CADC sensors. _28

_

: '.::>

A. Gaptain 1 s Altimeter

The primary damage was due to fire and heat. Moisture and other

:forms of contamination also caused damage. The calibration has

';,Bhifte.d negative by approximately 120 feet .

. . .r The friction has increased over the normal 30/40 feet to a level of

about 70/90 feet. A check of the preload on each capsule showed . .

the low side to be -570 ft. and the high side to be +1600 ft.,

compared to -500 ft. and +1800 ft, as nomina:Ivalues. The shift

~in scale error to values approximately -120 feet'from normal can be attributed to the heat exposure which causes a negative shift of

"'-..

. the capsules deflections.


B. First Officer 1 s Altimeter

As may be noted on the photo taken at UAL SFO, the angle between -

the #1 pointer ( 100 ft.) and the #2 pointer ( 1, 000 ft.} is approximately

26. If we assume that the 100 ft. pointer is indicating +975 feet then

26 away, the #2 pointer would be at 472 feet. This indicates a

de synchronization of the pointers. When the photo of the disc pointer

is examined for the 1rshadowtt of the #2 pointer is noted that the angle

of the shadow is 3 o0 If both pointers start at zero and move clock-

wise at 10:1 ratio, a 30 angle occurs at an altitude of 925 feet.

The disc pointer utilizes an eyelet type embossing for the center hole

to attach it to the shaft that drives it. The high heat to which the unit

was exposed would have caused the eyelet tension on the shaft to be

lost in a manner similar to that of annealing or stress relieving.

Thus, the position of the disc pointer on its hub is questionable. As

noted by the melted aluminum case, the temperature of this unit was

well over ll00F. It is impossible, based on the information avail-

able, to state whether the shadow has any significance or not

because the difference in the pointers is relative to which pointer

is considered to have moved and in what sequence. With sufficient

impact damage (pre-fire) the rockingshaft pivots usually break re-

sulting .in a ttplus 11 effect on the display elements due to the hairspring

tension.


C. Captain's C. A. D. C.

The "frozen positionrr of the outputs indicate that at the time of

power removal this unit was sensing very close to 650 feet QNE

which based on a 30. 05 baro setting would be close to 77d feet.

QNH. The turn off position of the pneumatic altitude sensor

indicates approximately 665 feet Ql\TE. This represents the post

accident condition of the pneumatic sensor which could easily have

have been subjected to 15 feet of irppact damage.

The encoder was correlated to the altitude output.

The monitor operated slightly out of tolerance on the increasing

altitude side but within tolerance on the decreasing altitude side.

D. First Officer1 s C.A.D.C.

The ''frozen positionn of the outputs indicates that at the time of

power removal this unit was sensing very close to 600 feet QNE

which ba9ed on a 30. 05 baro setting would be close to 720 feet QNH.

The turn off position of the altitude sensor indicates approximately

640 feet QNE. This represents the post accident condition of the

pneumatic sensor which could easily have been subjected to 40

feet of impact damage.

The encoder was correlated to the altitude output.

The monitor operated within the monitor tolerances.


ADDENDUM I

SPECIAL TESTS

Additional testing was conducted to ascertain characteristics which

were not previously documented.

1. Computer Step Function - In this test, the computer was taken

to some altitude by using pneumatic pressure. At this altitude h1

the servo

was deactivated by opening the motor fixed phase. This maintained all

electrical parts at their normal potential. The pressure was then

changed to a new altitude hz and stabilized. The time for the servo

to reach the second position was recorded. During this slewing

operation it was also noted if the altitude reliability signal was interrupted

and if the reported altitude was maintained or interrupted.

A. Times to Slew

Step Change Used Captain's F/O

1000 to 0 feet 3. 8, 4.3 sec 4. 8, 4. 9 sec

0 to 1000 3. 8, 3.2 5.2, 4.2

1000 to 500 2. 3, 2.4 3. 2, 3.3

500 to 1000 2. 4, 3. 1 2. 4, 3.2

800 to 600 1. 8, 1. 8 2. 3, 3.0

600 to 800 2. 1, 1. 9 3. 1, 2.5

700 to 600 2. 0, 2.3 3. 1, 3.2

600 to 700 2. 0' 2.2 3. 3, 2.2

B. Reliability Signal

On all but the 100 ft steps, the reliability signal opened. On

the lOOft step, the step was just within the trip level and no trip was noted. KOLLSMAN INSTRUMENT CORPORATION

' ' -

G. Whenever the reliability signal was lost, the encoder readout

test egpipment reverted to -1000 ft which is indicative of an open common '<

line t9 ~the encoder.

2. Computer Slew Offset - In this test, the computer was run at

high vertical speeds and it was noted on the i;est equipment at what point

the m:onitor was on the edge of tripping. This information was used to

compute the vertical speed and this data was then related to the previously

obta}:hed monitor trip data to assign the servo offset.

Captain 1s AD~ Increasing 21, 400 ft/min

Decreasing 21,400

Monitor Trip Increasing 105 ft

Decreasing 115 ft

F/O ADC Increasing 18, 100 ft/min

Decreasing 16, 200

-Monitor Trip Increasing 135 ft

Decreasing 110 ft

KOLLSMAN INSTRUMENT CORPORATION

Docket No~ SA-.435 Exhibit No. 7-A

NATIONAL TRANSPORTA~ON SAFEIJ1Y.E0Afill :SUREAJ,J: OF AVIATION SAFETY WASHING'l'ON, D. C. 2059l

.SWRUCTCJEES GROUP ~'S.FACTUAL REPORT .OF INVESTIGATION

:SY Robert J. Gordon

Docket No. SA-435 Exhibit Noo 7-A

NATIONAL TRANSPORTATION SAFETY BOARD Bureau of Avi.ation Safety

Washington, D. C. January 15, 1973

STRUCTURES GROUP CHAIRMAN'S FACTUAL REPORT

A. ACCIDENT

LOCATION

DATE

AlRCRAFT

Approxi!Dately 1.5 nautical miles southeast of Runway 31L, Chicago Midway Airport, Chica.go, Illinois. Exact coordinates were: lat. 87 42' 54" W - long. 41 45' 51" N ' December 8, 1972

United Airlines, Inc., Boeing Model 737-222., N903lU, S/N 19069 B. STRUCTURES GRCXJP

The following personswere official representatives of their respective organizations on the Structures Group:

R. J. Gordon National Transportation Saf'ety Board

R. s. Kriebel Federal Aviation Administration

U. E. Toatley Federal Avi.ation Administration

B. DeRosa United Airlines

w. P. Rushing Air Line Pilots Association

R. A. Patterson Air Line Pilots Association M. w. Ludwig Boeing Company

E. Huizinga Boeing Company

c. SUMMARY

United Airlines Flight 553, a Boeing 737-222., N903lU, crashed at approximately 1428 central standard time on December 8, 1972 while making an approach to Runway 3lL at Chicago Midway Airport, Chicago, Illinois.

- 2 -

The aircraft impacted into a residential area mainly comprised of one story brick and wood structures. The primary wreckage area was approx-imately 500 feet in length and 90 fe12t wide. Both wings and the fuselage, from just a:ft of the cockpit to the rear galley door, were for the most part consumed by the post impact ground fire.

No evidence of pre impact structural failure or in-flight fire wa.G found.

D. D~ILS OF INVESTIGATION - ACCIDENT SITE OBSERVATIONS

On December 8, l972, a Structures Group was appointed by the investigator-in-charge for the purpose of examining the wreckage of aircraft N903lU.

The chief purpose of the Structures Group was to develop all pertinent and significant evidence bearing on the nature and probable cause of the accident.

The accident occurred in the residential area of Chicago, Illinois. A total of eight houses including three garages were extensively damaged or destroyed as a result of aircraft impact and po~t irrIJlact ground fire.

The following is a resume of this damage:

l. Two houses on the north side of West 7lst Street received extensive irrIJlact damage of the roof and u;pper floor structure.

2. Two of three houses on the south side of West 70th Place received extensive impact damage to the roof and upper floor structure. The third house was destroyed as the result of aircraft impact. Two garages were severely irrIJlact damaged.

3. Three houses and orte garage on the north side of West 70th Place were destroyed as the result of aircraft and post impact ground fire.

After preliminary examination of the accident site was made, members of the Structures Group proceeded to work with the- -wrecking crew to carefully remove house rubble from around and on aircraft structure in order that the various investigative groups could proceed with their investigation.

In conjunction with the above operation, oth~r members of the Structures Group proceeded to collect the data necessary to prepare a chart of the wreckage distribution. In addition significant property and house damage was noted and charted to assist in determining the manner in which the aircraft contacted the houses and broke up.

- 3 -

Following com;pletion of the; wreckage diutribution work; the detailed exru:nina.tion of the wreckage pieces wns initiated.

The results of the GroUJ> 1 S investigation effort are presented in the following section of this report.

The wreckage of aircraft N903lU came to rest on three properties, No. 3724, No. 3722, and No. 3718, West 70th Place, Chicago, Illinois. The aircraft, with the exception of the left cockpit section, empennage,and inboard portions of the left and right wings, had been consumed by post inrpact ground fire.

The first evidence of house and property damage was noted on the south side of West 7lst Street. Numerous front roof peak shingles were found on the front lawn and the front UJ>per storm 'Window was detached on house No. 3707.

A tree, approximately 24 feet in height lqcated on the front lawn of house No. 3709, had branches broken at a height of approximately 18 feet from ground level.

A tree, approximately 20 feet in height, located on the lawn in front of house No. 37o6 on the north side of West 7lst Street, had one branch broken approximately 18 feet from ground level.

Two houses on the north side of West 7lst Street were severely damaged. The northwest upper corner of house No. 3710 was caved inward. The T.V. antenna located on the chimney was bent over. The left elevator tip of aircraft N9031U was recovered on the roof. The northeast upper corner of house No. 3714 was also caved inward. A T.V . antenna located on the chimney -wa.s bent over. A tree approximately 20 :feet in height located in the backyard and adjacent to the house had numerous branches broken.

The two telephone poles located in the alley wa:y which separates West 7lst Street and West 70th Blace were broken, Examination of the electrical cables indicated that they failed in tension. This was evidenced by the necked down condition of the cable ends.

Pole #2, as designated by the wreckage distribution chart, snapped off at a point approximately l2 feet above ground level. The pole -was found on the ground in the backyard of house No. 37U, .West of 70th Place.

Pole #3 was resting on the southwest corner of a garage at the rear of house No. 3723 West 70th Place. This pole had snapped off at a point approx-imately 3 feet 6 inches above ground level.

The garage at the rear of 3717 West 70th Place was knocked off of its foundation and the north portion of the roof was caved in-ward. A section of the left horizontal stabilizer skin, P/N 65-47536-501, and a section of the left elevator, P/N 65-47512-3, was recovered in the alley adjacent to the garage door. A section of the left horizontal stabilizer was also recovered on the ground between two small buildings adjacent to the rear of the garage and located on tb,e lot of 3719 West 70th Place.

- 4 -The roof of a garage located at the rear o:f the house and :property at

3715 West 70th Place was corrr.pletly caved in.

The outboard :portion o:f the le:ft horizontal stabilizer :from a:p:proximately Sta. 207J including the elevator, was recovered in the backyard o:f house No. 3717 West 70th Place. The house was destroyed by aircra:ft irrr.pact. Two :pieces of the a_ircra:ft, a hydraulic line and :filter, and a section o:f right wing outboard mid :fla:p, was recovered in rubble adjacent to the rear foundation of the subject house.

The right wing ti:p, from Sta. 531 outboard, was recovered at the base of the rear wall of house No. 3715 West 70th Place. The southwest corner of the house was extensively im:pact damaged. A section o:f the right wing leading edge was recovered between house No. 3715 and house No. 3717.

A vacant lot (3719) exists between house No. 3717 and 3723 West 70th Place. Numerous pieces o:f aircraft structure were :found by the Structures Grou:p :piled on the sidewalk and in the street in front of this lot .. These items were not documented at their location subse~uent to aircraft irrr.pact. These items are listed as followes:

1. Section of fla:p track including jackscrew. 2. Section o:f :fla:p track fairing 3. Mid :flap section and jackscrew 4. Oxygen :filler and gauge 5. Right hand strut door, P/N 65-52206-36 6. Strut door, P/ N 65-52201-88 7. Section of skin with stringers, P/N 65-55726-5 8. Skin and rib section 9. Section of skin "With louvre

10. Fuel tank :plate, P/N 65-46446-1 ( 2 - each)

The southern peak and east side of the roof and second floor structure of the house at 3723 West 70th Place was caved inward its :full length as a result of aircraft i:awact. Num.erous :pieces of the left wing tip light lense were re-covered within the upper attic :portion of the house.

Aircraft N9031U came to rest on the pro:perties of 3724, 3722, and 3718 West 70th Place. The three houses were destroyed by ai:r:ieraft impact and :post irrr.pact ground fire.

l. Empennage

The vertical stabilizer and rudder assembly remained intact and attached to aircraft structure. Fire damage was minimal and con:fined to blistering of the leading edge :fairings from fin Sta. 56 to f'uselage . The fiberglass leading edge :panels forward of f'uselage Sta. 986 were consumed by ground fire.

., - 5 -The right horizontaJ.. stabilizer and elevator assembly remained

attached to the aircraf't. Numerous dents and :punctures were noted on the leading edge with one gash at a:priroximately Stao 22l "Which rienet:ra.ted the stabilizer af't to the rear SIJar. A l2 inch section of' the elevator tip was missing.

The elevator tab remained intact and attached to the elevator. The right horizontal stabilizer and elevator assembly was resting on an in-verted totally destroyed automobile.

The le:ft horizontal stabilizer and elevator from a point adjacent to the outboard edge of' the elevator tab to the stabilizer ti:p was m,issing. The stabilizer f'rom ari:prox:bma.tely Sta. l30 outboard to Sta. 193 was torn ilhd bent in the upward direction.

The tail cone was f'or the most :part intact and attached to aircrai't structure. The tail cone upper surf'ace was punchured from Sta. ll56 af't to Sta. u76. The lower surf'ace at the tail cone showed considerable damage.

2. Fuaelage(Sta. 887 .Af't) The right side of' the fuselage f'rom approximately Sta. 887 aft remained

partially intact. The uri:per most portion of' the fuselage structure in-cluding a portion of' the vertical stabilizer from Sta .. 10o6 f'orward was f'or the most part consumed by post impact ground fire. The right hand fuselage interior had been subjected to ground f'ire. The af't window opening at approximately Sta. 934 b.B.d. been blocked with sheet metal and remained intact.

The window.at approximately Sta. 9l7 was severely heat damaged. The window at approximately Sta. 897 was missing. The galley area exhibited extensive post impact fire dam.age. The right galley door was f'ound in the open position.

The le:ft side of' the fuselage from approximately Sta~ 1016 forward was consumed by f'ire. The upper portion of' the pressure bulkhead at Sta. lOl6 was burned through.

3. Fuselage (Sta. 887 Forward) The :ma1iJ. body of' the fuselage from approximately Sta. 887 on the right

sideeilll1 sta. 1017 on the left side forward to approximately Sta. 334 on the left side was f'or the most part consumed by post impact ground fire. Portions of fuselage structure within these stations including system components such as primary heat exchangers, water separators, cold air units ram air intakes and associated ducting were recovered and identified. These structural pieces and system components were burried in the rubble of the destroyed homes.

- 6 -The cock.pit left side rTom a:p:proxima tely Sta. 334 forward to

Sta. 178 came to rest against a large tree located just aft and to the right o:f' the garage to the rear of the house at No. 3722 West (oth ~lace. The left cockpit structure contacted the tree at approximately fuselage Sta. 227. The structure -was on its left side at an angle of 70 and on a heading of 30~

The left hand passenger door was found in a vertical :plane within the ap:proximate center of the door opening with the forward edge o:f' the door rotated inward approximately 40. The fuselage structure aft of the :passenger door including the door surr01.md had se:parated and ro-tated rearward. The door was jal!lilled in the :partially open :position.

The le:ft cockpit seat and left instrument :panel remained in their relative positions. The pilots Nao l window was shattered and punchured. The :pilots No. 2 window was shattered and the No. 3 window re?M.ined in-tact with evidence of smoke and heat discoloration. The two eyebrow windows were intact with evidence of heat damage.

The right cockpit structure showed evidence of severe impa.ct and :post impact ground fire damage. Various :pieces of right cockpit structure 'WaS recovered from under rubble of both house No. 3718 and house No. 3722 West 70tb. Place.

The airstair assembly was recovered in the area of the cockpit wreckage and exhibited no evidence of fire damage. The nose gear' assembly was re-covered under the cock.pit weckage.

Le:ft Wing

A section of left inboard wing approximately 24 feet in length, 'Which included the landing gear assembly, inboard ground spoiler, inboard flight spoiler, inboard center and bottom fla:p sections, and engine :pylon structure was recovered under the rubble of house No. 3724. The wing leading edge f'rom approximately Sta. 254 inboard to the fUselage area vra.s missing. A 10 foot :piece of leading edge slat was also recovered in the immediate area of' the w.ing. The wing section and associated components showed evidenced of extensive im_pact a!Jll.d :post impact ground fire damage.

Two sections of the to:p outboard fla:p, a:pproximately 3 feet in length, a l2 foot section of the center outboard fla:p, and a 10 foot section of the 0utboard bottom fla:p were recovered. These flap com:ponents showed no evidence of fire damage~

The le:ft engine had separated from its pylon structure and was positioned adjacent to the left aft i'uselage structure at ap:proximately S=!;,a.. 1016.

-/'

- 7 -

Right Wing

A section of right inboard wing approximately 18 feet in length which included a 2 foot 9 inch section of the inboard center flap, a short section of leading edge slat,and the engine pylon structure,were recovered under the rubble of house No. 3718.

The follciwlng right wing flap sections. were recovered in the immediate area of' house No. 3T-L8:

l. Outboard Fla' Sections

Two top flap sections, one section 13 feet 3 inches iri length, one section 2 feet 10 inches in length.

Center f'lap remained intact.

Three bottom flap sections, one section 6 feet 5 inches in length one section 3 feet 4 inches in length., and one section 8 feet ih length.

2. Inboard Flall Sections

Two top flap sections:,; one section 4 'feet 4 inche;s in length, one section 4 feet 2 inches in length. One center and one bottom flap remained attached to each other and measured 7 feet 10 inches in length.

The right engine had separated from its pylon structure and was positioned in the front area of house No. 3T-L8.

The right main landing gear had separated from the aircraft and was recovered adjacent to the right -wall of' the garage located in the back of house No. 3T-L8.

lftf~j VQ J. Gordon

Air Safety Investigator

UNITED STATES OF AMERICA NATIONA.L TRAHSFORTATION SAFEI'Y BOARD

WASHINGTON> D. C. 20591

An Aircraft Accident Involving United Air Lin~s> Inc.

Boeing 737; N9031U Near Chicago Midway Airport

Chicago, Illinois December 8> 1972

---------------------------------------

PREHEA.RING CONFE:REI!TCE February 26> 1973

--------------------------------------

PREHEA.RING CONFERENCE OUTLII\'E

Mr. William 'R. Hendricks Hearing Officer

Mr. Hendricks will open the conference and :introduce the Members of the Board of Inquiry and. Technical Panel.

Honorable Isabel A. Burgess Chairman> Board of Inquiry

Presiding Officer Burgess will give the opening statement for the conference and introduce the spokesman for each Party.

Mr. William R. Hendricks Hearing Officer

Mr. Hendricks will review the list of witnesses for the hearing and the areas of testimony to be covered in the questioning. Other areas) if any> from the Parties will be decided. upon and the scope of the testimony will be set.

' -~ . '

WITNESS LIST AJ:ID AREAS OF TESTIMONY

L Mr . .William J. Simonini Eyewitness C~ic_ago) Illinois

(a) Observations of aircraft and weather conditions

Ex: 4B

2. Mr. Thomas J. 0 1Brien Eye~ritness Chicago) Illinois

(a) Obsenrations of aircraft and weather conditions

Ex: 4B

3. Mr. Louis Stalec EyeWitness Chicago) Illinois

., ~{a) Observations of aircraft and weather conditions

Ex: 4B

-

- 2 -

4. Mr. Marvin E. Anderson Surviving Passenger UAL Flight 553

(a) Pertinent observations made during flight and approach to Midway Airport.

(b) Post-crash observations and activities

EX: 6B

:5. Mr. Harold R. Metcalf S~rviving Passenger UAL Flight 553



Ex.: 6B

6. Mr. Harold \[. Green Surviving Passenger UAL Flight 553



Ex.: 6B

c ~. :., ...... :-!'~

- 3 -

7. Mrs. Margurite J. McCausland Surviving Stewardens UAL FLT 55~

(a) (b) (c)

(d)

Qualifications> duties and responsibilities Preflight activities and observations-Observations and activities eh route and during

approach to Midway _A.irport

Post-crash activities and observations

Ex: 6c

8. Mrs. D. Jeanne Griffin Surviving Stewardess UAL FLT 553

(a) Qualifications; duties and responsibilities (b) Preflight activities and observations (c) Observations and activities en route and during

approach to Midway Airport

(d) Post-crash activities and observations

Ex: 6c

9.. Mrs. Kathleen S. Duret Su~ving Stewardess t:r:AI:; FLT 5 53

Qualifications> duties anCi responsib:i,l:;Lt1es Preflight activities and observation:s .. Observations and activities en routeanB:.dtiring approach

to Midway Airport_

(d) Post-crash activities and observations Ex: 6c

4 -

10. Captain Arthur C. Munin

(a) , Duties and responsibilities

Chief; Hook and Ladder Coopany No. 31

Fire Department of the City of Chic~go

(b>) ~espouse and firefighting/rescue activities at .the accident scene

Ex: 6:m

11. Captain Rugh E. Mu~phy CaptainJJ)elta Airlines Flight 56'T Dec ember. 8 j-_ 1972

(a) Observations and operational conditions on apj;lroa.ch to Midway Airport; December 8) 1972

(b) Standard Operating practices and procedures utilized for .Runway 31L localizer approach to Mid_way

12. Mr. M;b;tton W. Harding Executive Pilot Air Commander N309V

(a) Observations and operational conditions on apJ?roach to Miclway Airport) December 8) 1972

13~ 11r~ George w. Kipp Executive Pilot Cessna 31.0; Nto/d-3L

(a) Observations and operational conditions on a:gproa,eh. --Do MiC!-way Airport; December 8) 1972

Ex: 2-I,, 2-J

...........

"" '-.

- 5 -

14. Captain H. R. Trimble Captain) United Air Lir~es FLT 737J December 8) 1972

(a) Observations of weather and operational conditions on approach t.o 0 1Hare Airport) DecembE;n' 8; 1972

. (b) UAL approa~h practices; procedures:; aJ:;Ld training relating to line operations in J3-737 aircraft

15. lite John J. J3aldwin

(a) Duties and responsibilities

Air Traffic Control Speciali Federal Aviation Aam.inistra-:. 0 1Hare Approach Control

(b) Radar observations) communications; and ATC services provided to UAL FLT 553

( c) Standard ATC arrival procedures for Mi'dWay Aiport

16 .. '.Mr. Jack E. Margotta Assistant Chief) Midway To;-~: Federal Aviation A&ninistr2.-:


(b) Radar observations) communications) a~d AIBa ~.e:c'v-ices provicled to UAL FLT. 553

(c) ATC services provided to aerocommand.er N309VS (d) Standard arrival procedures for Runway 3lt approach (e) Crash alert procedures Ex:: 3J3, 3C, 3D, 3E) 3F, 3G

r - 0 -

l 7 Captain John C. Aasen Flight Tr~ining Supervisor 3-7:?7 UAL :Fligh:t; Tratning Center Denver_, Colorado

l8.

. ,;-,

'~) Duties and responsibilities (b.) UAL B-73 7 flight training :program (Captain,, qp;irst Officer;

Second Officer) as related to: Descent and c;i.:pproach :procedures; crew coordination; aircraft

l9.

- 7 -

Captai.h Bobby C. Gooclr:IBn


Flight Manager UAL Flight Operations Washington; D. C.

(b) Review of flight history of First Officer Coble

(e) Line operation observations of First Officer Coble (d) Standard procedures and practices concerning cnew

coordination and crew duties for line. operation

20. Gaptain Louis N. DeWitt Manager) Flight Performance B-737 Western Airlines; Inc.

21.

(a) (b)

(c)

Ex: . .

Los Angeles) California

Duties and responsibilities

Experience relating to B~737 flight perform~nce characteristics in descent) approach and landing; missed~approach> and stall recovery configurations

WAL approach and landing practices and:pxocedures

2J> 13D

Mr. Robert P. Beatty Assistant Branch Chief; National Data Systems Branch National Aviation Facilities

.(a) .(l:t)

Ex::

Duties and responsibilities

Ex::perime:o,iJa:l_ Center Federal Aviat'.ioil"Administration

Concept> progr81llllling; capabilities and tolexanc~s of ARTS-III

3E; 3F> l3B, 130> 13D

22.

23.

.\nt ti .

8 -

Mr. William K. Howell

(a)" Duties and responsibilities (b) B-737 icing certification

B-737 AerodynaCTics E..-rigineer The Boeing.Company Seattle; W~shington

'. (c) Examination of flight profile as developed from A.."ii.TS-III data relative to aircraft configuration and thrust reg_uirements

(d) Effects of ice on horizontal stabilizer

. (e) Eogine :peformance as effected. by high angles of attack and inlet-duct icing

(:f) Effects of high angle of attack on :pitot-static system (g) Stall characteiistics; recovery technig_ue and. stick-shaker

activation

Ex:: l3A; l3B; 13C: l3D: 13E

Mr. Matson M. Lord.

(a) Duties and. responsibilities

Liason Representative Service Department Pratt & Whitney Aircraft Com.pa:::y East Hartford.: Connecticut

(b) Nominal engine :performance and response in the approach thrust engine; acceleration from idle thrust; and. factors affecting engine spool-up (inlet duct icing; Pr~2 probe icing; total engine time; etc.)

:(c) ~nti-icing bleed-air system operation

' ', ~ .

- 9 -

24. Mr. Jarrtee w. Angus


Staff Engineer Kollsman Instrument Company

~shurst) J)(e-1.;r York

(b) .Description of the B-737 altimetry system including CAW a:tJ,d the altimeter servo loop

( c} ,Fif.tdi:i:tgs of the exarrtination of altimeter system com;ponents ,. :from N903lU

( d)' DiEic11ssion of possible causes for altimeters system anomalies

25. Mr. Pa,nl Smith Chief; Pbarm8cology Biochemistry Laboratory

Civil Aeromedical Institute (CA:fl,IT) Federal A-V:iati~.:i Administration Oklahoma d:Lty; Oklahoma

(a) Aircraft fires and resultant toxicity

(h} j)iscussion of accident related deaths

/:.

UNITED STATES OF AMERICA . NATIONAL TRANSPORI1ATION SAFErY :BO.ARD

WASHINGTON) D. C. 2059l

*********************** In t)J.eMatter bf Investigation of Accident *

Exhibit No. l-A

Invb+v{.ug United Air Lines) Inc.; :Boeing 737* o('Ur1;it~q_ $tates Registry N903lU, *

D::icket No. SA-435

ChicagO.; Illinois) December 8) l972 * *~*********************

ORDER OF HE.ll..RING

A :public hearing is hereby ordered by the National Transportation

Saf'ety I)oard in connection with the above matter at a time and :place to

be dei:J.erm:i'.ned by the Hearing Officer who will hereafter be designated..

Datea. tM s 5th day of January l973.

For the :Board.

UNITED STATES OF A.i.'vfERICA NATIONAL TRA.NSFDRrATION SAFErY BOARD

WASHINGTON, D. C. 2059l

************************ In the Matter of Investigation of Accident *

Exhibit No. l-B

Involving United Air Lines; Inc.; Boeing 737 * D:lcket No. SA-435 of United States Registry N9031U; * Chicago) Illinois) December 8; l972 * ************************

DESIGNATION OF HEARING O:FFICER

Pursuant to the authority conferred by the National Transportation Safety Board; Mr. William R. Hendricks; Principal Investigation Branch; Investigation Division> Bureau of Aviation Safety; Washington) D. C.) is hereby designated Hearing Officer to conduct a public hearing on behalf of the National Transportation Safety Board; to be held in the above matter. The said Hearing Officer is authorized to set the time and place of the hearing; to give notice thereof; and to exercise_ such other :powe1s in connection with the conduct of such proceeding as authorized by the National Transportation Saf~ty Board.

Dated thi-, 5th day of January 1973.

FOR THE BOARD

.,....---, I . it Cv:' tu,Jiu C. O. Miller Director; Bureau of Aviation Safety

UNITED STATES OF AMERICA NATIONAL TRANSPORTATION SAFEI'Y BOARD

WASHINGTON, D. C. 20591 .

* '* * * * * * * * * * * * * * * * * * * * * * * I'i\, :tlie.. Matter of Investigation of Accident *

Exhibit No. 1-

Irtr/'o1ying United Air Lines) Inc. ):Boeing 737 * J):x~ket No. SA-435 of United States Registry N9031U * Ch:i,ea'.io;, Illinois) December 8, 1972 * ************************

NOTICE OF REA.RING

Notice is hereby given that an Accident Investigation Rearing on

the a~ove matter will be held commencing at 9:30 a.:m.) (local time) on Fclb:tttiiry 27) 1973, at the Sheraton - 0 1 Hare Motor Hotel; Rosemont) lllfuois.

bated this 5th day of January 1973.

/!- // /)' ~ tC./d'..C.t.c

+- ~

UNITED UNITES OF AMERICA NATIONAL TRANSPORTATION SAFErY BOARD

WASfilNGTON) D. C. 2059l

******~**************** In the-Matter of Investigation of Accident *

Exhibit No. l-D

Involv}ng United Air tines; Inc.) Bo~ing 73T~ of Uhit.~d States Registry N903lU) *

Docket No. SA-435

Chic

UNITED STATE3 OF AMERICA NATIONAL TRANSPOfilATION SAFErY BOARD

WASHINGTON, D. C. 2059l

STU.ARI' ROOM SHERA.TON-0 1H.ARE MOTOR HOTEL

ROSEMONT, ILLINOIS FEBRUARY 27, l973

RJBLIC HFARING

An Aircraft Accident Hearing United Air Lines, Inc.

Boeing 737, N903lU Near Chicago Midway Airport

Chicago, Illinois December 8, l972

BOARD OF INQUIRY Honorable Isabel A. Burgess Member

National Transportation Safety Board

Washington, D. C. CHAIBMAN, BOARD OFINQUIRY

Mr. Bernard C. Doyle . . . . Chief, Investigation Division Bureau of Aviation Safety National Transportation Safety

Board Washington, D. C.

Mr. John M. Stuhldreher Senior Attorney Office of the General Counsel National Transportation Safety


Mr. William R. Hendricks . . Senior Hearing Officer Investigation ~ivision Bureau of Aviation Safety National Transportation Safety

Board Washington, D. C. HEARING OFFICER

Mr. William L. Lamb

Mr. Martin A. Speiser

- 2 -

TEJHNICAL PANEL

. . Senior Air Safety Investigator Investigation Division

. . . . . . . . . . .. .

Bureau of Aviation Safety National Transportation Safety

Board Washingtion, D. c. INVESTIGATOR IN CHARGE

Air Safety Investigator Technology Division Bureau of Aviation Safety National Transportation Safety


Mr. William. G. Laynor . . Aerospace Engineer Technology Division Bureau of Aviation Safety National Transportation Safety


Mr. Matthew M. McCormick Air Safety Investigator Technology Division Bureau of Aviation Safety National Transportation Safety

Board Washington, D. c.

---------------------------------------

Mr. Brad D.inbar . . Deputy Director, Office of Public Affairs National.Transportation Safety


- 3 -

HFARING OUTLINE

1. Honorable Isabel A. Burgess . :.' . . . . . . Chairman, Board of' Inquiry

Member Burgess will give the opening statement of' the public

hearing.

2. Mr. William R. Hendricks . . . Hearing Of'f'icer

Mr. Hendricks will identify and receive into the record the

f'ollowing:

Exhibit No. 1-A Order of' Hearing 1-B Designation of' Hearing Of'f'icer 1-C Notice of' Hearing 1-D Designation o:f Parties to the Hearing

3. Mr. William L. Lamb . Investigator in Charge

Mr. Lamb will report for the record, the notification of' the accident and the organization o:f the investigation. He will review the investigation activities and submit all exhibits to be entered into the public record o:f the accident.

Exhibit No. 2-A Operations Group Chairman 1 s Factual Report 2-A-l Simulator and flight test report 2-B 2-C 2-D 2-E 2-F 2-G 2-H 2-I 2-J

- 2-K

UAL FLT 553 Dispatch Documents Training Records - Captain w. L. Whitehouse Training Records - F/O W. O. Coble Training Records - S/O B. J. Elder Excerpts f'rom UAL B-737 Flight Manual Excerpts f'rom UAL Training Manual Excerpts from UAL Flight Handbook Statements from pilots flying in Chicago area 12/8/72 Jeppesen Approach Charts and Chicago Area Chart Cockpit visibility diagram B-737

- 4 -

Exhibit No. 3-A Air Traf'f'ic Control Group Chairman's Factual Report 3-B Statements, ATC Bersonnel 3-C ATC Transcript (Approach Control) 3-D ATC Transcript (Midway Tower) 3-E Aerocommander N309US Q::-:-ound Track Chart

plotted f'rom orHare Radar ARrS III Computer Readout 3-F UAL Flight 553 Ground Track Chart - plotted from

orHare Radar .ARI'S III computer readout

4-A Witness Group Chairman's Factual Report 4-B Witness Statements 4-C Witness Location Chart

5-A Weather Group Chairman's Factual Report 5-B Surface Weather Observations - Midway 5-C Aviation Weather Sequences 5-D Surface Weather Charts 5-E Upper Air (850 mb. & 700 mb.) Charts 5-F Weather Radar Log - Chicago 5-G National Weather Svc., Inst:rument Checks - Chicago 5-H Instrument Location Chart - Midway 5-I National Weather Service and FAA Tower Visibility

Reference Charts 5-J Portion Electro-writer Record, Nat,ional Weather

Service, Midway 5-K National Weather Service Observer's Statements 5-L TeletYJ?e-Pilot Reports 5-M National Weather Service Forecasts (Area and

Tenninal Forecasts and SIGMETS) 5-N Upper Air Data 5-0 Pseudo-adiabatic Charts, Peoria & Green Bay 5-P National Weather Service Briefing Statements 5-Q United Air Lines Forecasts

6-A Hum.an Factors Group Chairman 1 s Factual Report 6-B Passengers Statements 6-e Flight Attendants Statements 6-D Civil Aeromedical Institute (CAMI) Reports 6-E Chicago Fire Department Operations Report 6-F United Air Lines Galley Study 6-G FAA, Office of Aviation Medicine Report: Carbon

_ Monoxide and elyanide Hazards~ in 'Air Transport Accidents accompanied by f'ire

7-A Structures Group Chairman's Factual Report 7-B Wreckage Distribution Chart 7-C Photographs

Exhibit N~8-A 8-B

-8-c

~9-A 9-B 9-C 9-D 9-E

- 5 -

Power:plant Group Chairman's Factual Report Photographs Engine Bleed Air System Schematic

Systems Group Chairman rs Factual Report Photographs Kollsman Report on Altimeter System Kollsman Report on Air Data Computer Excer:pts f'rom B-737 Instruction Manual re: PitotStatic System

10-A Flight Data Recorder Specialist'~ .Factual Report lO-B Photographs of FDR and Para.meter Traces 10-C Report of FDR Examination

ll-A Maintenance Records Group Chairman's Factual Report ll-B Excerpts from Flight Log ll-C Deferred Item Sheets

12-A Cockpit Voice Recorder Specialist1 s Factual Report

13-A Flight Performance Group Chairman 1 s Factual Report l3-B Automatic Radar Tracking System (ARIB) Computer

Printout 13-C Aircraft Performance 1)3.ta Plot Developed f'rom. ARTS III

Data. 13-D Approximate Flightpath Prof'ile as 1'eveloped f'rom ARrS III

1)3.ta and CVR Transcript 13-E Excerpts of' B-737 Certif'ication 1)3.ta

- 6 -

WITNESS LIST

1. Mr. William J. Simonini

2. Mr. Thomas J. 0 1Brien

3. Mr. Louis Stalec

4. Mr. Marvin E. Anderson

5. ML Haro:_Ld R~ Metcalf'

6. Mr. Harold W. Green

7. Mrs. Margurite J. McCausland

8. Mrs. D. Jeanne Grif'f'in

9. Mrs. Kathleen S. Duret

10. Ca:ptain Arthur C. Munin

ll. Captain Hugh E. Mur:phy

12. Mr. Milton w. Harding

13. Mr. George W. Kipp

14. Captain H. R. Trimble

15. Mr. John J. Baldwin

Eyewitness Chicago; Illinois

Eyewitness Chicago, Illinois

Eyewitness Chicago, Illinois

.Passenger; UAL FLT 553 South Holland; Illinois

.Passenger; UAL FLT 553 Tinley Park; Illinois

.Passenger; UAL FLT 553 Park Fa.rest) Illinois Stewardess; UAL FLT 553 Reston; Virginia

Stewardess; UAL FLT 553 Silver Spring) Maryland

Stewardess, UAL FLT 553 Alexandria; Virginia

Chief') Hook & Ladder Company No. 31; Fire Department of' Chicago; Chicago; Illinois

Captain., Delta Airlines North Redding) Massachusetts Executive Pilot Vincennes; Indiana

Executive Pilot Ft. Madison; Iowa

Captain; United Air Lines Arlington) Virginia Air Traffic Control Specialist Federal Aviation Administration O'Hare Approach Control Chicago; Illinois

- 7 -

l6. Mr. Jack E. Margotta

l 7. Captain John C. Aasen

l8. Captain Donald K. Holman

l9. Captain Bobby C . Goodman

20. Captain Louis N. DeWitt

21. Mr. Robert P. Beatty

22. Mr. William K. Howell

23. Mr. Matson M. Lord

24. Mr. James W. Angus

25. Dr. Paul W. Smith

Assistant Chief', Midway Tower Federal Aviation Adm..inistration Chicago, Illinois

Flight Training Supervisor B-737 UAL Flight Training Center Denver, Colorado

Flight Manager UAL Flight Operations Was!\ington, D. C.

Flight Manager UAL Flight Operations Washington, D. C.

Manager, Flight Performance B-737 Western Airlines, Inc. Los Angeles, California

Assistant Branch Chief' National D3.ta Systems Branch National Aviation Facilities

Elcperimental Center Federal AYiation Administration

B-737 Aerodynamics Engineer The Boeing Company Seattle, Washington

Liason Representative Service Department Pratt & Whitney Aircraft Company East Hartford, Connecticut

Staf':f Engineer Kollsman Instrument Company Elmhurst, New York

Chief', Pharmacology Biochemistry Laboratory

Civil Aeromedical Institute Federal Aviation Administration Oklahoma City, Oklahoma

--

'-;,

Docket No. SA 435 Exhibit No. 5L

NATIONAL TRANSPORTATION SAFE'l'Y BOABD Bureau of Aviation Safety Washington, D. C. 2059l

TELEI'YPE - PILOT REPORTS

f . . . ,.; .

; ! 1

. 2

' ..

' i I

'

O~ UA

UA

NNNN

UA.

f_';P~ c'."1!~

DPA UA

. ~ .. .. I i

tie .. , ~ 3er11~ u.if f~~E~ ff=~ i

\

l_-(~T Rl\A~ T\-HlJ Pl\S LYi\. } ... : .

.' ..

r I l "-fJ-0/BDr AT

0/CRD ffi64 LGT TO MDT RP. DURGO 8E1Z

ORO SP 1616 \l)Vffi3/4ZL-F 2403/004/ ;:(14RVRUov:;J+

.<

l_ ~T

Docket No. SA 435 E:x:b.ioit No. 5M

NATIONAI1 TRANSPORTATION S.AFE'11Y BO.ARD Bureau of Aviation StLfcd;y Washington7 D. C. 20591

NATIONAL WEATHER SERVICE FORECASTL~ (AREA AND TERMINAL FORECASTS AND SIGMETS).

DCA PP 021240 13Z fRI-01Z SAT

DEC 8 1S72

OHIO A9J GRTLK WVA MD JSL VA ~~ ~S CSTL WT~S HGTS ASL U~L~SS NOTE~

SY:~s. RDG OF }-{I ?~ES ALS r:STL SECS OF" FA A~ef\ 1.,rJT'! s1.fl.Y ::-Lo :"'\:LPG F"RT~!-: i 1 WK LO P:1ES IN ~10 A!1E/I 1.!JLL vov [:1,.1;) T':J:) OHIO \/LY P.::. ''Cf''~ DVLPS IN S~LY ~LO AND S?RDS NEWD.

srs:~ET. OHIO ADJ G;;'TLI\ l . 1\/(1 hit~~.) ! IP-XCP S-H JVH 1~ 1 Ji~N OHIO. EL;-;1,7 OVl Ol!IO C35-5r~-:v~"S'.l'::J3-5Z1-I?-:'-'.C? S- C\11 N PT~l hJIT11 :OCT9 Cl1-'.3'!rvic9 Forecast Office, Washington, D.C. / (Suitland, Ma) / /.. . .:;

. . y ./ _,..,-:.. 1'.'.1-:.V~~~

DC/\ lS>Z

;;fl OG 1 :;11 Cr /IR I - 07Z :. ,\ 1

T;: (;'f _..,... .... ~--i i. 7 -1 i.il l.

T-. r-.-; ~ \.' I I

S IGi::_:T. "' ..... ~. ~ ~ l ..:. 1 4 I :

DEC 8

1. I

~JV;. v.:;;

oc.:. ~L

1972.

; :'I.I"( J/\\ . .,,I

tJL '{ T ~~

l r."''="l:f'r' f'., !H.-:; s. CT :.,11 ~nt:?" t"f !( l '. :.-!: fl .~~ ... ~: -~~ 1 .: '~.:i,.c!hf'r ,Sqr/h"e

l-\:r'"!!c~l fln.:c,,, WG.s.bi..ugti>:i, D.C.

, .

.:J>J . c:: ::;::. u:~-:::J1 -r~::~;.c :~;_,J 1'.JGo ..:.. c;;~ :::L_:; .. :J ~- UII .L:J::L .. 1 rL:~_,~; . .-;LC: i~--~,. v;~x:. .~.;,)rJ u~: .. lL;( : . .:\/,~i ,,.-1 :.\~: !J~'t ~-;::u i~L~ .j:;) ::.:c

CIC}~ :i~~.T :.n.;:-: 1 T::.~~.: {,~:L1 ~j~-~ \l;_L.)"{ ;}]..Jt.0i :_. l;~~ :;.~:,~uc; ~~\.~D uv;~ l~i:r~~ 11:~.:.:\ ~_;y c.~;:~. ;:J 2D --;::-: ~.~~...:T o~~~cr .. f"T l\ r ..... ~ ... :-

1,_ ,,

r :""'

Z~;-T 1::> ., .. , . ., , l l_J l .. _, ~ .,,_; .......

T ~ -> u , .. \ ~.

l~J ...

,.,.,,... -...~J ,....., ".J,;'

ft. .. 1

fl""" . , ... : .

LI~- Ii)- l l L.. ~ :;_:i .. : ::!J L::: \.l\l1\ :~; : _;::,i; .. i. ST ; : ~; T :J ... ': T 0 2 t~ Ci 0 \/I{ TO c4-c_1-~;>;.- ~"'."ii! :;c;:_-'.~!iZ. o I '

-, ;~er :t("'I !IV

...... ,,. ....

"'"\ ..

...f Il .. "'TI

:::./

;\:: lJ TIL

.: :.-.-(.. ... :....__..

' I\ --Jiu i' l 2 IL.

, .... - t \,.,.: I ' ' ~

'.iT . . .... :~ ! , \)

., . '" u .... ,_'\_.1_ ..

'.. ~ ~ .. : ; !' ,, . c: .. -:... -11:>-.

I. f,';-v1h ..

.,. . l,.

c '' ... -. ' ..

\.J'- I'

C . ."i'!.J ' ... ri~::~ ~-1:.-~~'-.. :-~~.: (:(::~!. (>~

CHl FA 0~1240 n? F~ 1-r rz SAT

- ~ ' I ... J, _,

y 1 N ~,1 1 A. 1 ~ :_) If 1 s t LL /, 1 ,~ '1 1 :-,n ;rn CID ~" :r --;'j r U>

,,_-. "

.zk(! -r''_.f ~ .o 0 Ri ~o !

,)~19Z, FRl-01? S~T (2a .-lf-_~" t ~ w, Wt S Ill V.tCH " ~~Ts. ~SL UNLESS NCTEO. SYNS. NE-SW QSTRRY .FNT OVR OH I 0 Vt..Y W 1 TH LO PRES WAVES ''01.JG ~EWO .A. LONG THE F~T. ' ! s1Gur t. ovR s w1s s LK ~'tCl-' s LWR ~1cH IND ILL KY PO 1A ocNL ''OGR I

Tt~BC BLO 200. CONT BYD 01 z. StGt 1ET 2. OVR KY S PLF IND S QTR ILL WDLY SCTO E''800 Tsrus. TOPS CBS TO ~so. CNCL AT 01Z. SIG8'ET ). OVR WIS ''ICY IJPR GTLKS INfJ ILL KY uo E IA ''OT A.NO OCNL SVR H'D ICGICIP. C'ONT BYD 01Z. At~ET 1. OVR E 1-ILF LK s PR E i F UPR PICH s A:vo E WIS LK Ht(";H 1 WR-v ICH 1 ND I L KY 0 0 E 1-'LF I A WOSPRn ('I GS Arm VS'WS RI 0 1 TJ..ISD FT ANn 2 u1. r.O T BYD 07Z.

CLOS ANn w~.

"JNN w Ut_F 1A. c30-5om'Jffi80-1ooe w1n..1 sen' c2s@:-6s--. rors YRS 130. scG ovR "I '~N ooz-03z 250-

lr.:_1 "'1'""1' r "": ,;;: ... ~,,.m11 ,,; .. '.~!~@ .. :~::,~

... ,. ;;r~~'~. . .. ,.~ZC ~18 1_-F AFT 20Z~. fi:JF 0&1705 5'DC10'~3R-F PV BRF ::,'.i.q,~-F Y 1_-:=-. n~ ~ C0:B2ZL-F

C2X1/'.( ~~--F OR l-!:". Evy 011711- rc::ttl?ti r- r- ~L .-.2,...,_'/: I F ..... J~ T.)' y JU v) ... v,,,1 .. .t..o.1,-r llv v \f') :.+ __ - IJ:l\..1 ., 1 t.-Au of17cc:; 1'').:;.!lr,Q_ :; 0 i:- r~1)V').~_ v .., v.e...~ ....... ..) .. .J ~- 1'...'., v AUW 0~1705 C25'i5S- 8F:F" c11

I f ti I .~-i n 1. )~ ~ ' ! r' ,_, -

Ci{! .iJ::.- ,; J 1 .. ::-.:, C l:> -2. r:..) If ~.DV '( "'''{ J

T ('" s I ., rn J..J 1~ I\ J.l l ..._, ~ -J L.. ~:. 1.:.

("> r ' \,J;\ .. )

i' :1

11 .~

I r . .' \ .... ! . . .. . ~ .

t ; \ ~ I

t:; :~ .~ .. l. ~

L".,1:: ,!Jc;;! 8C; 1ll ~:1'. ::; ;;_:;:::-:) ;n 1:il. .;c, :-,;1 ....

--- --.- ~ .. ____ -

.

.i~ it. .

... ~.. ~ .. '.; -

.

~

C'Ht'. WS-0 081455 -081455-081900 . $1SMET CH.ARLIE 1. OVA ILL !Ml SWISS LI< MICH S LWR \UCH OCNL ,.ix .ll)T OR ORTA TURBC BLO 150. SIKXX~XIS&a a:>NT ADVY BYD~ 19z. SEE FA I $SUEil f. T 19Z FOR FRTHA ~D VYS

G1-l 1 ws-o 0.01 840 cm1900-08?1 oo

SIG9ET CJ..!AP' IE 2. OVR SWISS I K ~'IC~ S LWR ~~1c1-1 INr' JI l KY ":'~YY~)' P ''0 IA OCf~'. PQGR TUR BC 81.0 200. CO!'iT BYD ?1 Z. SEE C'H I rA VI D 1 9Z.

CHI ws-c on1840 08.1 900-0821 00

\.; SI G-'ET A! FA 3. OVR KY S Ll! F I ND S" QTA I l_f_ WD' Y SCTD E"BDD TSTHS. '\ TOPS rss T 0 ~')O. CO:\JT BYD ?1 z. SEE Cl-I I FA VLD 1 qz FOR F~THR I 1\JFO.

-~~y c 1 WS-8 081 840 081 900-0821 00

/SIGHET' DELTA 4. OVR WIS ' 1 1CH UPR GTLKS IND I' L KY ~o E IA ~~or A~D OCNL SVR 0 ;.0 ICGICIP. CONT P.YD 21Z. SEE C''I r;A VLO 19Z.

W~Jf Y Cq\ WA-A 081 40 081 Q00-18~1 00 AtP.,ET FJ\'TROT lt OVR E 1-ft.F 1 K SUPP E F lH'P ''!CHS ANO E WIS LK 0 1r1..1 '.WP ~1c1-1 ,, .... o IL' l

NATIONAL TRANSPO~ATION SAFETY BOARD Bureau of Aviation Safety Washington, D. C. 2059l

UPPER AIR DATA

Docket No. SA-435 Exhibit No. 5N

i

l ~

t. I

i~>t,-1 , f !) : ": ,, ; .. 7 . -~

;: ~ i r

.. : _.;,; ~

"f:>i

...

:. '!'--...... . :

' . . . -

,- . r--.

.~ -: :.:-:..: .1 ~~ .., . ':" -

' ;.~ .'. . ~-

. .... ....

r'::

c .: ' : ' ,,,Uiij . MIND s12oe. ;,: '. >~MT t.,.,_A '8121 12637 99997 l'.572~ l 1".!06 0'1213 11111 11111 8'48t

! .i

.....

~

. :. : 1 ,80 2~5ll 70005 07100 2504 9 5~58 I 9509 25583 4172 l 29127 / p 13 30920 44911 25624 25039 549// 25112 20178 651// 26651 \.:)

. '5~3 : 651// 26125 ..... 6Sf// 2M5l

'"'fftt.S 26'~"2 463'6 77257 25641 4162UJ ~ - DA'( TTA1' 58121 72429 99988 11J0~f0 12008 00201 Ill// 11111 8'511 -~, ...,, 23"28 10074 0~04 2612152 50'571 145.34 2456e 40736 25742

~- ,.._.'"311-938 4t3u 2-t6'e9 2500-J9 52111 2s611 2e~00 64911 26621 . ! t'""'-6!111 21ua;:.,..

'8fff 69J// 27129 m 45 2n 40 41521

'

aRa TT~ 58125 72645 99999 13320 ~40~5 00199 Ill// //Ill R5~53 123ee 18517 70936 10700 25041 5~545 25563 25074 40703 35~6e .11'84 30989 459/I 24643 25018 551/I 24631 20158 631/I Ill//

. :-, .. 1~36 591// l.0589 5931/ . .11ue1 63511 11111 ~,. , -11269 2 4649 41 nta>

. :;~ ~

" -~

~

. TfA . ,,8f~1 72747 99983 ,,23344 24105 00230 11111 11111 85412 e; 28'L'"'. n'&4a 21J1Gl"'230t,.~,0526 35512 2~150 "406111 45911 e3Q19i$:4 56!// 2-.&00 .. ,. 259s.r 53511 251 t0 2et24 54911 a5'94 =:~i- -~'"85 10566 ,,3/1 255611 172~ 4:!1Jl SS'f Tf A ,s121 72734 99100 It l 0t ~8005 e022t t 1I01 ~8~r"5 !!5.\~'2 J'7H .. ~'~06 70925 17100 231~ . .3 50542 2596Z 25582 4~E99 37758 2,,981 3"4 47111 215139 f'f12 545// 2565g 2l'153 597/I 26142 l~~J2 ,9111 ~6A 10588 573/I 26100 ~11219 5 9'/I 2,6,, 11as 25"8 4t221~

't~P TTAA 5St2t 72662 99908 29l__.5 28006 00264 I/Ill 11111 8'4H a'f.9ff 325""'' 70867 17756 28026 50.!532 .32 54J 24066 40685 457 /I 23-,19 31814,, 5?.9// 24601. 25~91 51911 24~87 201.3Ei 53111 22079 t,319 5'6.W: 24017 1"'77 '1311 26086 esse& ,~,,,,, ~46t1

7~12 ~l 41212(1) src TTO., 5~121 72f,5 99988 l 8957 020~4 el0224 11111 11I11 85431 &8963 t.}~83 1es&s ' 12115 25033 505.38 28956 2406.:S 4e694 41311 24'62 3'1JS85 50511 24134 25002 56711 24626 2014.3 54511 256ee } ~3a.~ 54.9// 25585 10583 58111 11I11 .,,. 5!7'5/ / 2 45,2~

11Ji~ ~4f!5 4~J06t LR, Tl'~ 58121 n562 999~2 :~ 22945 3.3008 0~236 11111 11111 @544f:, 4 2313~ 32,tl 10994 lk'950 26029 50542 26359 24567 4~701 ~5761 .. ~ 2J~ 30896 4791/ 2~123 250,J4 5571/ 2.3622 20155 577// 24129 t!l36 6~~11 246{0 10,9~ 5~'// 26068 ssa1s '~'11 2412s. 7719~ 246~9 40414 , P-IA TTM 5~121 7253'2 99997 04519 1400'3 00175 I/Ill 11111 85450 05300 25Q12 70995 03754 26551 50559 17532 23595 40723 28156

241121~ ~0~3 4'11/'/ 24114 25042 54111 2d624 201R2 6431/ 26148 153,~ 643// 25~~~ 1~505 669// 25606 B8J94 55111 ~6144

1720~ 2615~ 42324~

... .__. .. - 1 KIMn; '4"8'120i ~m TTBB 5812/ 72637 00997 05728 11860 e830il 22850 87100 3~814

. '. ... ~4?'8tl 87lff ,,647 18700 56,00 19509 77467 21514 884, . .. i:T::,~3~. 393a:? 11251 54 9/ I 22212 6~ 111 332! I 651 / / '4~ 1 51 .~

.. . 'll S,[.l ~911 ,-1-515 1'H98 ll602lD \J :~"ti< '. . :t,( . ' - .

~.~ ~121: 12~7 91012 1100.6 12015 15543 98345 17515 18511 .,. . i4 99678 2"'27 24042 24042 909// 24046 91246 26554 26067

.. ~ 917// 250~-4 92145 25600 25619 25618 93045 25621 25641 .ff- 93?tt a91:'.49 2~6t7 94135 21096 26591 26129 94679 21625

;c;.:::. :fa~ f,9.~ 9'-!l/ 266" 2S06lal -~ ;.:J~'Xf.1 "'.'. ~ . . .

ll(y T!BB 5812/ 72429 00988 00910 t L932 03202 22sse e~ses 33792 ... 06 44774 02207 55700 00004 66616 04918 77500 14534 8848!

.~ 'tt 9~3tl 38947 112~ 521// 22200 649// 33178 69~// 44