Contaminated and Slippery Runway

8/13/2019 Contaminated and Slippery Runway

1/72

Contaminated and Slippery RunwaysContaminated and Slippery Runways

Performance Engineer OperationsFlight Operations Engineering

Paul Giesman

Performance Engineer OperationsFlight Operations Engineering

Paul Giesman

November 2001November 2001


2/72

CONTAMINATED AND SLIPPERY RUNWAYS

Cont Rwy.2

Contaminated and

Slippery Runways


3/72


Cont Rwy.3

Agenda:

Basic Regulations and Definitions

Physics of Contaminated Runways

Operational Practice

Operational Data/Applications

Other Considerations


4/72


Cont Rwy.4

Contaminated runway

More than 25% of the runway is covered by

slush, standing water, snow covered, Ice

covered or compacted snow


5/72


Cont Rwy.5

Regulatory Requirements FAA Operators

Historically

No definitive regulatory requirements for

contaminated or slippery runway performance

adjustments in Part 25 or 121

Current (737-6/7/8/900) -

Wet runway is part of AFM certification basis

No definitive regulatory requirements for

contaminated or slippery (non-wet)


6/72


Cont Rwy.6

Regulatory Requirements

FAA Guidelines:

Current approved guidelines published inAdvisory Circular 91-6A, May 24, 1978

Provides guidelines for operation with standingwater, slush, snow or ice on runway

Does not provide for wet runways

Proposed Advisory Circular 91-6B (draft)


7/72


Cont Rwy.7

Regulatory Requirements

JAA Operators - New certifications

Specific requirements covered in the AFM

Includes performance based on various runway

conditions (wet, compact snow, wet ice, slush,dry snow)

JAROPS 1

Requires operational contaminated/slipperyrunway data based on possibility of an enginefailure


8/72


Cont Rwy.8

Proposed Advisory Circular 91-6B: Guidelines for takeoff and landing with water,

slush, snow or ice on runway

Defines contaminated runway

Defines braking coefficient used foraccelerate-stop distance calculation

Includes wet runway

Reverse thrust credit for accelerate-stop

Did not specifically address, but were adoptedin the advisory data of the time

15-foot screen height for accelerate-go


9/72


Cont Rwy.9

JAR-OPS 1 / AMJ15X1591: Guidelines for takeoff and landing with water,

slush, snow or ice on runway

Defines contaminated runway

Defines braking coefficient and contaminant

drag to be used in calculations

Includes wet runway

15-foot screen height for accelerate-go

Reverse thrust credit for accelerate-stop


10/72


Cont Rwy.10

Dry, Damp, and Wet Runways areNOT Contaminated

Dry: Neither wet or contaminated (JAR-OPS 1.480)

FAA - No definitive definition

Damp: Surface is not dry, but moisture on thesurface does not give a shiny appearance

(JAR-OPS 1.480)

Wet: - FAA - neither dry nor contaminated (DraftAC 91-6B)

- Shiny in appearance, depth less than 3 mm

of water (JAR-OPS 1.480)


11/72


Cont Rwy.11

Runways are CONTAMINATED When:*

More than 25% of the surface to be used iscovered by standing water or slush morethan 1/8 inch (3 mm) deep

OROR

*As defined by FAA Advisory Circular 91-6B

Has an accumulation of snow or ice


12/72


Cont Rwy.12

Additional considerations:

If the contaminants are lying on that portion of

the runway where the high speed part of thetakeoff roll will occur, it may be appropriate toconsider the runway contaminated.(Draft AC 91-6B)

Do NOT takeoff when the depth of standingwater or slush is more than:

1/2 inch (13 mm) deep


13/72


Cont Rwy.13

Boeing Contaminated RunwayTakeoff Performance

Slush / Standing Water Data

Acceleration/deceleration capability

Slippery runway

Deceleration capability

Ice covered, compacted snow, or wet


14/72


Cont Rwy.14

Agenda:







15/72


Cont Rwy.15

Takeoff Distance Is Proportional to

Large Acceleration (a) Short Takeoff Distance

Small Acceleration (a) Long Takeoff Distance

1a


16/72


Cont Rwy.16

Dry Runway Acceleration

Friction Drag Thrust

gW

a = Thrust - Drag - Friction[ ]


17/72


Cont Rwy.17

Acceleration withSlush/Standing Water

g

W

a = Thrust - Drag - Friction - Slush DragSlush Drag

Slush DragSlush Drag

[ ]

Friction Drag Thrust


18/72


Cont Rwy.18

FSlush = 1/2 Vg CD Slush ATire

= Slush Density, 1.65 slugs/ft3Equal to Specific Gravity of 0.85Vg = Ground Speed - Feet per Second

CD Slush = Slush Drag Coefficient for airplane'sspecific gear arrangement

ATire = Reference Area for Slush Force Calculation

Data Sources: FAA/NACA Convair 880 Tests 1962NASA Langley Load Track Tests - 1960,1962

2


19/72


Cont Rwy.19

CD Slush Accounts for Displacementand Impingement

Displacement

Drag

FWD

ImpingementDragFWD


20/72


Cont Rwy.20

Tire Reference Area for SlushCalculation

ATire = ( bmain + bnose) x Slush Depth

b

Average tire width

Slush depth


21/72


Cont Rwy.21

Ground speed

Slush

force

Slush Force

VHP

HydroplaningHydroplaning


22/72


Cont Rwy.22

Hydroplaning

Tire Pressure in psievaluated for Main Gear

VHP = 8.63Tire Pressure

Specific Gravity

= 8.63 Tire Pressure

80s, 90s method

Current method


23/72


Cont Rwy.23

Slush Force Including Hydroplaning

fHP

=1.6V

HP-V

g

.6VHP

[ ]

2.5Vg

VHP

- 1.5(This factor is applied at speeds

above the hydroplaning speed.

)

VHPGround speed

Slush force

Fs = (1/2 CDSlushVg2

ATire) x fHP


24/72


Cont Rwy.24

ASlush Force From Rotation to Liftoff

Fs = (1/2 CDSlushVg

2

Tire) x fHP x fR x fLOF

VHP

Ground speed

Slush force

VR

VLOF


25/72


Cont Rwy.25

Force Variation With Speed

VHP

Ground speed

Airplane

acceleration

forces

VR VLOF

All engine thrust

Engine out thrust

Total Acceleration Force = Thrust - (Slush force + Aero drag + Friction)

Rolling Friction

Aero Drag

Slush Drag


26/72


Cont Rwy.26

All Engine Acceleration Capability130 Knots

4.03.0

2.0

1.0

0.0

All engine

acceleration

Kt/sec

Dry6 mm

13 mm

747 767 757 737

Dry

6 mm13 mm

Dry

6 mm

13 mm

Dry

6 mm

13 mm

6 mm of slush - 10-20 % reduction in all engine acceleration

13 mm of slush - 20-40 % reduction in all engine acceleration


27/72


Cont Rwy.27

Engine Out Acceleration Capability130 Knots

747

0.0

1.0

2.0

3.0

4.0

6 mm of slush - 15-50 % reduction in engine out acceleration13 mm of slush - 30-110 % reduction in engine out acceleration

6 mm

1/4"1/4"

1/2"

13 mm

1/2"

Dry all

engine

-0.5

Engine out

Dry

767 757 737

6 mm

13 mm

Engine out

Dry

6 mm

13 mm

Engine out

Dry

6 mm

13 mm

Engine out

Dry

Dry all

engine

Dry all

engine Dry all

engine

Acceleration

Kt/sec


28/72


Cont Rwy.28

Effect of Slush On Airplane Stopping Tire to ground friction reduced due to slush

Retarding slush drag acts to slow the airplane

Dry runway

Average brake force

0.9Vhp

Ground speed, knots

Retarding

force

Vhp

Slush drag

Total Slush stopping force = Slush Drag + Wheel braking

Slush wheel braking


29/72


Cont Rwy.29

One Engine InoperativeDeceleration Capability

130 Knots

Deceleration

Kt/sec

Dry

6 mm

1/2"

13 mm

Dry

6 mm

13 mm

Dry

6 mm

13 mm

Dry

6 mm13 mm

8.0

6.0

4.02.0

0.0

747 767 757 737

Dry - AFM performance - includes maximum braking, spoilers, idle thrust

Slush - includes wheel braking, spoilers, reverse thrust, and slush dragreverse thrust, and slush drag


30/72


Cont Rwy.30

Effect of Slush - All Engine767-300 - 182,800 kg, V1 = 163 IAS

Accelerate

Go35 Feet

V=0

Runway available

V1=163 IAS

Stop

Effect of using dry runway performance on slush covered runwayEffect of using dry runway performance on slush covered runway

Baseline - AFM balance field length - 9520 Feet

All engine performance- 6 mm slush

Margin 15%

All engine performance- 13 mm slush

Margin 5%


31/72


Cont Rwy.31

Effect of Slush - Engine Out767-300 - 182,800 kg, V1 = 163 IAS

V= 138 knotsV= 138 knots

Go

Stop

Accelerate

V=0

Runway available - 9520 feet

V1= 163 IAS14 Feet14 Feet

Effect of using dry runway performance on slush covered runwayEffect of using dry runway performance on slush covered runway

Engine out performance - 6 mm slush

Engine out performance - 13 mm slush

Accelerate

V=0

V= 142 knotsV= 142 knots

LiftoffLiftoff Go

Stop

V1= 163 IAS


32/72


Cont Rwy.32

Agenda:







33/72


Cont Rwy.33

Boeing Contaminated RunwayData Adjustments - Choices

All engines operating

Weight reduction

NoNo V1 adjustment provided

Preserves 15% margin

Data presented in airplane Operations Manual, FPPM, and PEM

Engine failure is considered - JAROPS 1

Weight reduction and V1 adjustment providedCredit for reverse thrust

15 foot screen height


34/72


Cont Rwy.34

FAR Dry Field LengthTypical Twin Engine Airplane

Accelerate - Stop

Accelerate - Go

1.15 All Eng Distance

Minimum Runway Required - FAR Dry

1

Distance

Weight

Altitude

Temperature

Flap

V V1 balanced


35/72


Cont Rwy.35

Contaminated Runway Case

All Engine Data

Accelerate - Stop

Accelerate - Go



1

Weight

Altitude

Temperature

Flap

V 1 balancedV

Distance

1.15 All Eng Distance(Slush)

All Engine Slush Runway RequiredAll Engine Slush Runway Required

{IncreaseDistance


36/72


Cont Rwy.36

Constant Field Length Weight Reduction

All Engine Data

Note: Stop has not been considered nor has continued takeoff following

engine failure

Altitude

Temperature

Flap

Fieldlength

FAR Dry Field

Length

Brake release gross weight

Slush All Engine

Field Length

Increase

Distance

{


37/72


Cont Rwy.37

Constant Field Length Weight Reduction

All Engine Data

Note: Stop has not been considered nor has continued takeoff following

engine failure

Altitude

Temperature

Flap

Fieldlength

FAR Dry Field

Length


Slush All Engine

Field Length

Constant Field Length

Slush All EngineWeight Reduction

Wt (slush)


38/72


Cont Rwy.38

Sample Ops Manual Slush/Standing Water Page

All Engine Data - 737-500 / 20K Rating

35

40

45

50

55

60

65

70

WEIGHT REDUCTIONS - 1000 kg

Dry Field/Obstacle

Limit

Weight

1000 kg

0.25 in (6 mm) Slush/StandingWater Depth

Airport Pressure Altitude

S. L. 4000 ft 8000 ft

0.0 0.0 0.0

0.0 0.0 0.1

0.1 0.2 0.6

0.3 0.5 1.1

0.5 0.8 1.7

0.6 1.1 2.1

0.7 1.3 2.3

0.8 1.4 2.2

0.50 in (13 mm) Slush/StandingWater Depth

Airport Pressure Altitude

S. L. 4000 ft 8000 ft

0.3 0.5 1.0

0.8 1.2 2.1

1.4 1.9 3.1

2.0 2.7 4.2

2.5 3.4 5.1

3.2 4.3 6.2

4.1 5.2 7.2

4.9 6.1 8.3


39/72


Cont Rwy.39

All Engine Slush Takeoff Distance767-300 - 182,800 kg, V1 = 163 IAS

All engine performanceAll engine performance -- 1/2 inch slush1/2 inch slush

Slush limit weight = AFM weight - weight slushweight slush= 182,800- 38003800 = 179,000 kg

Accelerate

Go35 Feet

V=0

Runway available

V1=163 IAS

Stop


35 Feet Margin 15%


40/72


Cont Rwy.40

Contaminated Runway Case

Engine Failure Considered

Accelerate - Stop

Accelerate - Go



1V 1 balancedV


(Slush)

Distance

Weight

Altitude

Temperature

Flap

Accelerate - Stop(Slush)

Accelerate - Go

(Slush)

Slush Runway Required

Increase

Distance

V1 adjustment


41/72


Cont Rwy.41

Constant Field Length Weight Reduction and V1 Adj.



Altitude

Temperature

FlapField

length

FAR Dry Field Length


V1

FAR V1

{

Slush Field Length

{Slush V

1


42/72


Cont Rwy.42




Altitude

Temperature

FlapField

length



V1

FAR V1

Slush Field Length

Slush V1

Constant Field Length Wt (slush)

V1 (slush)


43/72


Sample Ops Manual Slush/Standing Water Data

Engine Failure Considered - 737-500 / 20K Rating

WEIGHT

(1000 KG)

68

64

60

56

52

48

44

40

36

4000 FT 8000 FTS.L.

-3

-5

-7

-10

-13

-16

-18

-19

-19

-4

-5

-6

-8

-11

-13

-16

-17

-18

-4

-4

-5

-6

-7

-8

-11

-13

-15

6 MM (0.25 INCHES)

V1 Adjustment (1000 kg)

FIELD/OBSTACLE

LIMIT WEIGHT

(1000 KG)

68

64

60

56

52

48

44

40

36

4000 FT 8000 FTS.L.

-9.4

-8.8

-7.9

-7.1

-6.2

-5.5

-4.8

-4.5

-4.3

-10.1

-9.6

-8.8

-8.0

-7.0

-6.1

-5.3

-4.9

-4.8

-10.8

-10.4

-9.8

-9.0

-8.1

-7.2

-6.1

-5.3

-4.6

6 MM (0.25 INCHES)

Weight Adjustment (1000 kg)

CONTAMINATED AND S IPPERY RUNWAYS


44/72


Cont Rwy.44

Engine Out Slush Takeoff Distance767-300 - 182,800 kg, V1 = 163 IAS

Engine out performanceEngine out performance -- 1/2 inch slush1/2 inch slushSlush limit weight = AFM weight - weight slushweight slush

= 182,800- 28,90028,900 = 153,900 kg

Accelerate

Go35 Feet

V=0

Runway available

V1=163 IAS

Stop


Accelerate

15 Feet

V=0

V1

= 147 - 1010 = 137 IAS

Stop

V1

= QRH V1

at Actual Weight -V1 SlushV1 Slush

Go



45/72


Cont Rwy.45

Slippery Runway(Wet or Icy)

No effect on acceleration

Engine out accelerate - go

Go to 15-ft screen height

Accelerate - stop

Reduce tire to ground friction

Credit for reverse thrust

All engine - No effect on calculation of

all engine takeoff distance



46/72


Cont Rwy.46

Airplane Braking Coefficient -

= Average airplane braking coefficientduring the stop(Note: this is not tire to ground friction)

B

B

L

W

Stopping

Force due to

wheel brakes

B

( W - L )=



47/72


Cont Rwy.47

Boeing slippery runway data (PEM/JAROPS 1)

RTO - = 0.05, 0.1, 0.15, 0.2

Landing - = 0.05, 0.1, 0.15, 0.2

Airplane Braking Coefficient - B

B

Typical dry values from Boeing certification testing

= 0.35 to 0.41

Maximum manual braking, anti-skid limited region

B

B

AC 91-6B and AMJ25X1591

Wet can be approximated by 1/2 dry max - fair

JAR certifications, Compact snow - = 0.20

Wet ice - = 0.05 - nil

B

B

B



48/72


Cont Rwy.48

Slippery Runway Case


Accelerate - Stop

(Slippery)

Accelerate - Stop



1 balancedV

Distance

Weight

AltitudeTemperature

Flap

Accelerate - Go

Slippery - 15 foot screen height

Slippery Runway Required

{IncreaseDistance

V1 adjustment



49/72


Cont Rwy.49




Altitude

Temperature

FlapField

length



V1

FAR V1

{

Slippery Field Length

{Slippery V1



50/72


Cont Rwy.50




Altitude

Temperature

FlapField

length



V1

FAR V1

Slippery Field Length

Slippery V1

Constant Field Length Wt (slippery)

V1 (slippery)



51/72


Cont Rwy.51

Slippery Runway Boeing does not correlate friction vehicle

reported runway friction to airplane braking

coefficient. Pilot reported runway braking condition advisory

information only

Assumed

Airplane

Brakingcoefficient

0.20 0.10 0.05

Good Medium Poor



52/72


Sample Ops Manual Slippery Runway Data

Engine Failure Considered - 737-500 / 20K Rating

FIELD/OBSTACLE

LIMIT WEIGHT

(1000 KG)

68

64

60

56

52

48

44

40

36

4000 FT 8000 FTS.L.

-4.1

-4.2

-4.2

-4.1

-3.8

-3.6

-3.6

-3.7

-4.1

MEDIUM


WEIGHT

(1000 KG)

68

64

60

56

52

48

44

40

36

4000 FT 8000 FTS.L.

-10

-13

-15

-17

-19

-21

-22

-23

-25

-8

-11

-13

-15

-17

-19

-20

-21

-23

-6

-9

-11

-13

-15

-17

-18

-19

-21

MEDIUM


-4.1

-4.2

-4.2

-4.1

-3.8

-3.6

-3.6

-3.7

-4.1

-4.1

-4.2

-4.2

-4.1

-3.8

-3.6

-3.6

-3.7

-4.1



53/72


Cont Rwy.53

V1MCG Considerations

V1 reductions associated with slippery andcontaminated runways increases the possibilityof being limited by V1MCG considerations.



54/72


Cont Rwy.54

V1mcg Case

Accelerate - Go

Slippery - 15 foot screen height

Slippery Runway Required

V1 slippery V1mcg

Accelerate - Stop



1 balancedV

Distance

Weight

AltitudeTemperature

Flap

Accelerate - Stop

(Slippery)



55/72


Sample OM Slush/Standing Minimum Field Length Page

737-500 / 20K Rating

AVAILABLE

FIELDLENGTH

FT

4200

46005000

5400

5800

6200

6600

7000

7400

S.L.

30.737.6

44.5

51.8

59.1

66.5

73.8

4000 FT 8000 FT

V1 = V1(MCG) LIMIT WEIGHT 1000 KG

PRESSURE ALTITUDE

6 MM (0.25 INCHES)

28.1

33.7

39.3

44.9

51.0

57.1

63.2

28.1

33.1

38.1

43.1

48.3

53.5



56/72


Cont Rwy.56

V1MCG Limitation based on Accelerate - Stop Distance

Distance Required to accelerate to a given velocity and stop

is less for deeper slush.

737-500/20k rating, V1mcg = 109 kias, GW = 52,000 kg

Slush Depth Accel-stop distance to V1mcg

3 mm 6050 feet

6 mm 5800 feet 13 mm 5600 feet

This is because the slush drag penalty on the all engine

acceleration segment is less than the benefit that theslush drag provides on the stop.

Result - Deeper slush more takeoff weight

when limited by V1mcg



57/72


Cont Rwy.57

V1MCG Speed and Slush

3 mm

6 mm13 mm

Field

length

required




58/72


Cont Rwy.58

V1MCG Speed, Slush and Derate

Thrust

V1mcg

TO

126

TO-1

123

TO-2

117



59/72


Cont Rwy.59

V1MCG Speed, Slush and Derate

TO

TO-1TO-2

Field

lengthrequired


Given Slush Depth



60/72


Cont Rwy.60

Agenda: Basic Regulations and Definitions







61/72


Cont Rwy.61

Operational DataCondition: 737- 500

CFM56-3 series @ 20K engines

Runway length available = 6,000 ftField/obstacle limit weight = 60,000 kgs

Sea level, 0 C, flaps 5

6 mm (0.25) of slush6 mm (0.25) of slush

Step 1 - Determine gross weight reduction

Step 2 - Determine V1mcg limit weight

Step 3 - Lowest of step 1 and 2 is limiting weight

Step 4 - Determine V1 at actual takeoff weight



62/72


Cont Rwy.62

Ops Manual Slush/Standing Water Page0.25 in (6mm) Slush/Standing Water Depth

FIELD/OBSTACLELIMIT WEIGHT

(1000 KG)

68

64

60

56

52

48

44

40

36

4000 FT 8000 FTS.L.

-9.4

-8.8

-7.9

-7.1

-6.2

-5.5

-4.8

-4.5

-4.3

-10.1

-9.6

-8.8

-8.0

-7.0

-6.1

-5.3

-4.9

-4.8

-10.8

-10.4

-9.8

-9.0

-8.1

-7.2

-6.1

-5.3

-4.6

6 MM (0.25 INCHES)




63/72

CO S U S

Cont Rwy.63







Step 2 - Determine V1mcg limit weightStep 3 - Lowest of step 1 and 2 is limiting weight


60,000 - 7900 = 52,100 kgs



64/72

Cont Rwy.64


AVAILABLE

FIELD

LENGTH

FT

4200

4600

5000

5400

5800

6200

6600

7000

7400

S.L.

30.7

37.6

44.5

51.8

59.1

66.5

73.8

4000 FT 8000 FT

V1 = V1(MCG) LIMIT WEIGHT 1000 KG

PRESSURE ALTITUDE6 MM (0.25 INCHES)

28.1

33.7

39.3

44.951.0

57.1

63.2

28.1

33.1

38.1

43.1

48.3

53.5



65/72

Cont Rwy.65







Step 2 - Determine V1mcg limit weight

Step 3 - Lowest of step 1 and 2 is limiting weight


55,450 kgs

60,000 - 7900 = 52,100 kgs

52,100 kgs, lowest of step 1 and 2



66/72

Cont Rwy.66


QRH/FMC Dry

Runway TakeoffSpeeds at 52,100 kgs

132 / 134 / 142

WEIGHT(1000 KG)

68

64

60

56

52

48

44

40

36

4000 FT 8000 FTS.L.

-3

-5

-7

-10

-13

-16

-18

-19

-19

-4

-5

-6

-8

-11

-13

-16

-17

-18

-4

-4

-5

-6

-7

-8

-11

-13

-15

6 MM (0.25 INCHES)


-13

119 / 134 / 142

V1mcg for thiscondition is 109 kias.

Not limiting.



67/72

Cont Rwy.67


1 Go

B + S/B + T/R

52,100 kg

Stop

V = 119

6000 feet

1 Go

B + S/B

60,000 kg

Stop

V = 144Dry runwayDry runway

--

normalnormal

15 feet

35 feet



68/72

Cont Rwy.68

Agenda: Basic Regulations and Definitions







69/72

Cont Rwy.69

Landing on Slippery Runways Touchdown 1,000 ft(1200 for 747) from approach end of runway Maximum manual braking

Reverse thrust

Data provided for normal or non-normal landing configurations

LANDING WEIGHT 1000 LB

LANDINGDISTANCE

1000FT

200 240 280 320 360 400 440

10

8

6

4

2

BB

0.05FAR WET

(REFERENCE)

0.10

0.15

0.20

0.05FAR WET

(REFERENCE)

0.10

0.15

0.20

12



70/72

Cont Rwy.70

Snow EquivalenciesAs Taken From Draft AC 91-6B

STANDING WATER (INCHES)

SNOW

DEPTH

(INCHES)

0

4

3

2

1

01/4 1/2

TAKEOFFSHOULDNOTBEAT

TEMPED

LOOS

EDRYSN

OW

HEAVYWETSNOW

ORSLUSH

Note: On JAR certified airplanes dry snow takeoff performance is

provided as advisory data in the JAR AFM and the operational

takeoff program BTM (777, 737 NG)



71/72

Cont Rwy.71

Crosswind GuidelinesBoeing publishes takeoff and landingcrosswind guidelines in the Flight CrewTraining Manuals

Derived from analysis and piloted simulations

Based on steady winds Function of runway condition - dry, wet, standing

water/slush, snow - no melting, ice - no melting

Accounts for asymmetric reverse thrust Provides guidance on technique (side slip, crab)



72/72

The End

Documents

Contaminated and Slippery Runway