ALPA Submission re CMR 3272VIII. WB-120 AIRCRAFT AIRSPEED
GUIDANCE
This section is intended to highlight the fact that, at the time of
the CMR 3272 accident, there was no Minimum Maneuvering Speed
guidance provided to EMB-120 flightcrews.
Also, subsequent to the CMR 3272 accident and based upon a review
of he previous six (6) EMB-120 icing induce upsets, the FAA issued
an NPRM regarding icing operations in the EMB-120 aircraft. This
NPRM was issued in May of 1997. As part of this NPRM, and a
subsequent Airworthiness Directive (AD), a minimum speed in icing
conditions was provided. The FAA did not address the concept of
minimum maneuvering speeds but simply generated a single minimum
airspeed for all aircraft configurations. This FAA defined airspeed
lacks technical justification and may not protect the aircraft in
aII conditions. Comair
5 subsequently generated and provided minimum maneuvering speed
guidance to their Bightcrews.
Tbis section will also identify several conditions where, currently
and in spite of the existing AD, Bightcrews of the EMB-120 aircraft
are provided guidance to operate below the minimum maneuvering
speed identified by the FAA.
Conclusions: .
A.
At the time of the CMR 3272 accident, there was no guidance
available to flightcrews regarding minimum operating speeds in
icing conditions. The FAA issued AD 97-NM-46-AD in December of 1997
(11 months after accident) in which a minimum airspeed in icing
conditions was provided (160 kts). AD 97-NM-46-AD did not mention
or address minhnmn maneuvering speeds for various aircraft
configurations as the NTSB recommended. There is currently guidance
in EMB-120 flightcrew manuals, which direct them to operate at
airspeeds below their minimum maneuvering speeds in daily aircraft
operations under specific conditions or failure modes.
REFERENCE SPEED GUIDANCE
The Comair Flight Standards Manual (FSM), Section 7 is entitled
Maneuvers and Procedures. At the time of the accident, this section
of the FSM did not make any reference to minimum maneuvering speeds
for various aircraft configurations. A minimum maneuvering speed is
normally
5 based on the stall speed for the particular configuration and
weight, and provides a guaranteed protection from stall up to a
specific bank angle. Since the CMR 3272 accident however, Comair
has provided these speeds to their EMB-120 flightcrews.
In spite of the airspeed guidance provided by either the FAA or
Comair, there are several conditions where EMB-120 flightcrews are
provided conflicting guidance that directs them to operate at
airspeeds well below the minimum airspeed provided by the FAA.
Those are summarized below:
40
Take-Off (Reference pp. 4-22 of AFM and pp. 7-32,7-35,36 of FSM):
After take-off and during the initial climb, the aircraft is
accelerated to V2 + 20 kts prior to flap retraction. For an
aircraft weighing 24,000 lb. (the approximate weight of CMR 3272)
V2 is computed, per Comair’s charts, to be 113 knots. At 133 knots,
which is V2+20, the flaps are then retracted and the aircraft is
accelerated to its “final segment airspeed (V,) and climbed to 1500
ft. Vfs for an aircraft weighing 24,000 lb. is 143 knots. There are
no maneuvering restrictions for operation at this airspeed for this
segment of the climb.
.
Flap Control Fault (Reference pp. 3-45 of AFM, pp. 4-54,55 of FSM):
The checklist for a Flap Control Fault calls for adding 35 knots to
the reference speed for flaps 45 (Vrcr 45) when flaps are at 0
degrees. This is the most conservative case. For an aircraft
weighing 24,000 lb., V,f 45 is 112 knots and Vref 45+ 35 knots is
147 knots. Again, there are no maneuvering restrictions for
operation at this airspeed under this failure condition.
Stall Speed (Reference pp. 5-27 of AFM): For an aircraft weighing
24,000 lb., the stall speed is computed to be 114 knots. This speed
is for an aircraft in a clean configuration (i.e. gear and flaps
up).
The above instances demonstrate the inconsistent airspeed guidance
provided to EMB-120 flightcrews. EMB-120 crews operate this
aircraft daily according to established procedures at speeds at or
less than those airspeeds where ice induced roll upsets have
occurred.
ALPA has noted that, in this case and with respect to numerous
other Part 25 turboprop aircraft, minimum-maneuvering speeds for
all configurations are not published. This is in direct contrast to
jet transports, in which a weight-dependent minimum maneuvering
speed is published for each flap conf&uration. ALPA believes
this to be inconsistent with the safe operation of these aircraft
and inconsistent with the concept of One Level of Safety. .
41
. A . . . .
..” . . . . . . -. ..r-LYYnCa \ -‘-‘------
AIRPLANE FLlGHT.MANUAL 2 -??=- TAKEOFF
Power Levers . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . ADVANCE Advance the power
levers until the torque indication match the calculated static
takeoff torque. For rolling takeoff, set power levers to
approximatelly 75% of torque determined bv power setting chart on
runway alignment and advance up to takeoff power, before reaching
50 KIAS during takeoff run.
NOTE: During takeoff run. pedals should be used to steer the
airplane.
Engine Parameters . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . MONITOR During takeoff run, Np
digital indication may oscillate up to 2%. depending on wind speed.
This characteristic should disappear after takeoff.
At VR. rotate the airplane smoothly to 7O. At V2 t 10 KlAS and 35
ft height, with positive rate of climb:
Landing Gear Lever . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . UP
At V2 t 20 KIAS and level off height: F&I Selector Lever . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . UP
ubae
Accelerate to Final Segment Airspeed. t/ fS
NOTE: When at or near critical field length. static takeoff
technique may be accomplished. In this~ case, release brakes after
engine has reached the calculated static takeoff torque. The torque
reading may increase during takeoff, which is normal. During the
climb beyor.. 40011 AGL. if necessary, readjust the torque to the
calculated static torque setting.
- TAKEOFF CHECKLIST COMPLETED -
Maneuvers and Procedures
.‘, :.... . .*
.,
Maneuvers and Procedures
8. At V,, the Pilot Flying will rotate the aircraft to
approximately 7 degrees pitch attitude.
9. When a positive rate of climb is established, the PiIot Not
Flying will call, posifiw me. The Pilot Flying will confhm a
positive rate of climb and call, geur up.
IO. The Piiot Not Flying wig sekt the gear up position and call, in
rrantir, and continue monitoring engine and flight instruments. The
Pilot Not Flying will then call, gear up.
I I. Unless a Standard Instrument Departure procedure directs
otherwise, maintain runway heading until reaching 400 feet AGL or
Obstruction Clearance Attitude.
If departing a Special Use Runway, an immediate turn may be
performed after reaching 50 feet AGL using an airspeed of V2 + 10
with a bank angle not to exceed I5 degrees.
12. AI 400 feet AGL or Obstacle Clearance Altitude, the Pilot Not
Flying will call, 400, V2 + 20. The Pilot Flying will verify V2 +
20 and mpond. jlaps up. climb powr, climb
check.
01 MAY 94 (REV. Reissue)
.1 wr EMB-120 FLIGHT STANDARDS MANUAL
Maneuvers and Procedures
13. The Pilot Not Flying will confirm flaps up; slowly set climb
power, and perform the Climb checklist.
I NOTE I
Np may be Iefl II 100% until level off or reduced Lo 90% a~ 12.OCtl
F&c MSL depending upon lhe climb profile desired. Normally. If
climhmg Lo or &cw FL 180. Ibe Np should be reducecf to 90% at
12,CKM feei.
14. At 1,500 feet AGL, the Pilot Flying will establish a climb
profile of 180 KIAS to 10,000 feet.
120 FSM 7-3s 01 MAY 94 (REV. Reissue)
. . . .
OPERATIONS MANUAL For airplanes Post-Mod SB 120-022-0020 or S/N
120.154.120.162,120.162 and on, when the AP/FD enters the Altitude
Preselect Capture phase the system will maintain the ALT ARM
annunciation.
NOTE: - If during this phase the pilot changes the preselected
altitude value. the AP/FD systems will revert to basic pitch mode
and the ALT annunciator will drop off. To capture a new preselected
altitude the pilot should reset the APlFD modes.
- For airplanes Post-Mod SB 12Og22-0620 or S/N
120.154,120.162,120.182 and on, during altitude preselect capture
phase. a “knob-in-motion” signal or a vertical mode change causes
the system to retumto Altitude Preselect Arm phase. The ALT SEL
mode will still be operative, but the vertical mode will remain
off. The APlFD may or may not capture the new altitude depending on
the attitude of the airplane.
C. ALTITUDE PRESELECT TRACK - There is no indication to the pilots
when the Autopilot/Flight Director systems go from the Altitude
Preselect Capture phase to Altitude Preselect Track phase. However,
this transition normally takes approximately 30 seconds. In this
phase. the pilots can change the preselected altitude value without
affecting the Autopilot/Flight Director operation. When the
altitude is captured. the system automatically engages the altitude
hold mode. For airplanes Post-Mod SB 120-022-0020 or S/N 120.154,
120.162. 120.182 and on, when the AP/FD goes into Altitude
Preselect Track, the annunciation will go from ALT ARM to
ALT.
- DESCENT MODE (DSC)
Prior to selecting DSC mode. the desired altitude should be
selected on the Altitude Preselector. When descent mode is
selected, the autopilot will begin a gradual descent. stabilizing
at an average rate of 2000 feet per minute. The pilot may vary the
rate of descent bv operating the vertical trim switch. The DSC and
ALT ARM annunciators go on when the mode is selected.
- CLIMB MODE (CLIMB1
.Prior to selecting CLIMB mode, the desired altitude should be
selected on the Altitude Preselector. When CLIMB mode is selected.
the autopilot begins a gradual climb, stabilizing at an indicated
airspeed defined by the climb profile. This profile is:
- 155 KIAS up to 20000 ft. then decreasing by approximately 2
kt/lOOO ft to 135 KIAS at 32000 ft. for airplanes equipped with
autopilot computer P/N 6228315302 MOD 67.G.
- 170 KIAS at SL decreasing to 155 KIAS at 20000 ft. maintaining
155 KIAS above 20060 ft. for airplanes equipped with autopilot
computer P/N 6228135402 MOD 71.G.
NOTE: Airplanes S/N 120.287. 120.288. 120.290 and on have the
autopilot computer P/N 6228135402 MOD 71.6 factory
incorporated.
12 AUGUST 199(
ABNORMALPROCEDURES
I NOTE I
Do not exceed the VFE 01 the most extended pair of llaps. VFE for
intemwdiate pOSitions is the nexl higher llaps setting limit.
Landing Reference Speed correction vakms:
Flaps posltlon Correction Indicator
45 VREF + 5 KIAS
Correction values given above have been increased by 5 knots for
flaps positii greater than 14 degrees, IO prevenl Hall warning
system actuation.
The GPWS aural warning may be deactiiated by pulkng the GPWS 1
circuit breaker.
I CAUTION I
The unfactored landing distance will be increased by
73% _....._._................... llaps 0 lo 14 degrees 30%
.,....___._._...__._....., flaps 15 lo 44 degrees 5%
._......._..___._._.................. flaps 45 degrees
These increments should be applied on Ihe landing distance lor Naps
45 degrees.
120 FSM 4 - 55 01 OCT 95 (REV. 7)
~.c.:.:.~: : &yd-ggfiANuaL FLIGHT CONTROLS FAILURE
(Continued)
ABNORMAL PRDCEWRES
(Electronic fault in the control channel(s) not involving
disagreement or asymmetry).
INDICATION: - FLAP & ADVANCED SWS lights on multiple alarm
panel.
- CONTROL FAULT light on Flap Warning Indication panel.
- CONTROL FAULT indication on annunciator panel alphanumeric
display (if applic- able).
- Affected flap pair(s) light bars flashing on flap annunciator
panel.
l Verify Normal Radio Master Switch ON.
l Verity flap position on flap position indicator
NOTE: Flap position indication may not be valid after the RST
button is pressed.
l Press RESET (RSTI button momentarily.
l If successful, flap selector lever may be used as required.
l If unsuccessful, leave the flap selector lever in the last
selected position.
l Land as soon as practical. For VREF correction assume the flap
position indicated before the RST button pressing.
NOTE: l Do not exceed the VFE of the most extended pair of flaps.
VFE for intermediate positions is the next higher flaps setting
limit.
e Landing Reference Speed correction values:
Flaps position indicator Correction
0” to 14O VREF 45 + 35 KIAS 150 to 44O VREF 45 + 15 KIAS 45O VREF
45 + 5 KIAS
Correction values given above have been increased by 5 kt for flaps
position greater than 14O. to prevent stall warning system
actuation.
l The GPWS aural warning may be deactivated bY pulling the GPWS 1
circuit breaker.
CAUTION: THE UNFACTORED LANDING DISTANCE WfLLBE INCREASED BY 73%
(FW’Sg”TO 14”). 30% [FLAPS 15O TO 44O) AN0 5% (FLAPS 459. THESE
INCREMENTS SHOULD BE APPLIED ON THE LANDING DISTANCE FOR FLAPS
45”.
CTA APPROVED
OCTOBER 26.1990
ABNORMAL PROCEDURES
(Electronic fault in the control channel(s) not involving
disagreement or asymmetry).
. FLAP (L ADVANCED SWS lights on Multrple Alarm Panel.
. CONTROL FAULT light on Flap Warning Indication Panel. .
l CONTROL FAULT indication on Annunciator Panel Alphanumeric
Display.
l Attected flap pair(s) light bars flashing on Flap Annunciator
Panel.
Verity Normal Radio Master Switch ON.
Verity tlap position on flap position indicator.
I NOTE I
Flap position indiiatiin may no1 be valrd atter the RST button IS
pressed.
Press RESET (RST) button momentarily.
If successful, flap selector lever may be used as required.
If unsuccesstul. leave the flap selector lever in the last selected
position.
Land as soon as practical.
For VRFF correction, assume the hap position indicated before
pressing the RST button.
CONl$UED ON NEXT PAGE
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