08 lessons learnt from asc runway excursion occurrence ... lessons learnt from asc... ·...

Lessons Learnt from ASC

Runway Excursion

Occurrence Investigation

Working Group

Lessons Learnt from ASC

Runway Excursion

Occurrence Investigation

Working Group

Michael Guan Ph.D.

Aviation Safety Council, Taiwan

3rd AsiaSASI Workshop 2

� Statistics and Analysis of Aviation Occurrence in Taiwan

� Runway Excursion Occurrence Investigation Working Group

� Application Tips and Checklist

� Conclusions

Contents


Statistics and Analysis of Aviation

Occurrence in Taiwan

The detailed report is available at ASC Web

http://www.asc.gov.tw/asc_en/every_statistics_eng.asp


Hull loss rate with 10-year moving average

4.10

3.38

2.72 2.62 2.61

3.18 2.73

1.71 1.75 1.75

1.17

0.58

4.86

4.10 4.15

3.51

2.83

2.06

1.10

1.17 1.25 1.31

0.00 0.00 0

1

2

3

4

5

1993-2002

1994-2003

1995-2004

1996-2005

1997-2006

1998-2007

1999-2008

2000-2009

2001-2010

2002-2011

2003-2012

2004-2013

渦輪噴射機全毀事故率渦輪噴射機全毀事故率渦輪噴射機全毀事故率渦輪噴射機全毀事故率（（（（次次次次////百萬離場百萬離場百萬離場百萬離場））））

渦輪螺旋槳全毀事故率渦輪螺旋槳全毀事故率渦輪螺旋槳全毀事故率渦輪螺旋槳全毀事故率（（（（次次次次////百萬離場百萬離場百萬離場百萬離場））））

Per

mil

lio

n D

ep

art

ure

s

Turbojet

Turboprop


Aviation Occurrence – by category(1999-2013)

0 2 4 6 8 10 12 14 16 18

OTHR

SEC: Security related

RAMP: Ground Handling

ICE: Icing

WSTRW: Windshear or…

CTOL: Collision with obstacle…

MAC: TCAS alert/ loss of…

GCOL: Ground collision

RI: Runway incursion

SCF-PP: Powerplant…

TURB: Turbulence encounter

ARC: Abnormal runway contact

F-NI: Fire/smoke

SCF-NP: System/component…

RE: Runway excursion


Runway ExcursionDate Time Aircraft Type Precipitation type

1999.09.02 11:48 B747-200 None veer off

2000.04.24 07:30 MD82 Heavy rain veer off

2000.08.24 01:48 MD90 Light rain over run

2000.10.31 21:50 B737-800 Heavy rain veer off

2003.08.21 11:13 MD82 Light rain veer off


2004.10.18 17:59 A320 Light rain over run


2007.08.22 09:20 MD82 Light rain veer off

2008.08.15 21:50 A340 None veer off2010.09.02 21:37 B747-400 Heavy rain veer off

2011.02.26 22:49 A330 None veer off


2012.05.16 10:42 MD82 Light rain over run

2012.08.12 15:26 A330 Heavy rain veer off

2012.08.17 21:27 ERJ-190 None veer off

2012.09.13 12:43 A330 Heavy rain veer off

All Landing Occurrences / no fatality

* 82.4 % Landing RV; 47.1% heavy rain


Runway Excursion Occurrence Investigation Working Group

(REOI WG)

Duration: 2011/08 ~ 2013/12


� Revise ASC’s existing SOP, review on-scene data collection items.

� Collect and share the technical materials from AIBs

� Improving ASC’s analysis capabilities� Progressive development of hydroplaning

investigation skills

The major objectives for the REOI WG

3rd AsiaSASI Workshop

Points of highlight1. Flight crew information and training records

2.Wet/Conta. RWY operational techniques; CMC/FMC data

3. Available flight data, crew interviews, and related OBS flight

1. ATC issued reports/received PIPREPs (poor/nil braking)

2. GND records (Rainfall rate, LLWAS, runway frictions)

3. Water depth measurement, friction & drainage analysis

1. Tire trend identification & damaged tire marks

2.Tire pressure & wear conditions

3.Anti-skid, auto-brake exam./test; related maint. records

1.Site Survey (GND tracks, marks, debris pos.)

2.Data mapping & evaluation (ASDE/SSR/ FDR path)

3. A/C braking performance analysis (FDR data, friction coeff.)

FOPS

ATS & Airport

A/C Sys.

A/C Perf.

9


Intermittent sliding

A/C Braking Performance Vs. Slip Ratio


NASA’s Flight Test for B727

Runway grooving can increase the Aircraft deceleration performance


Results

Currently, ASC’s REOI WG has finished:� Tentative On-scene Checklist

� Task forces among with CAA, Operator and ASC

� Technical guidance for investigators to conduct investigation involved with wet runway (not limited to runway excursion!)

� On-scene tasks, must-analyzed items , outsourcing contact lists, and reference materials

Internal Training

12


1 on-scene checklist

+ 9 reference charts� Aircraft basic dimensions and

wheel configuration

� Relationship of hydroplaning

critical speed and Tire Pressure

� Investigation Procedure for

suspected hydroplaning

� Relationship of rainfall rate and

water depth (TTI)

� Relationship of rainfall rate and

water depth (TC)

� Relationship of ground vehicle

friction and Aircraft Friction

� Runway Condition Assessment

Matrix (FAA)

Runway Condition Assessment

Matrix For Landing (Airbus)

Site Survey Forms


� Progressive development of hydroplaning investigation skills

� On-Job Training at other AIB

� Evaluate aircraft performance degradation and possibility / types of hydroplaning

� Comprehensive study of “new” technical materials� ICAO Runway Condition Reporting (ICAO CIR 329)

� ICAO Runway Safety Team Handbook

� IATA/ICAO/FSF ALAR & RERR toolkits, ICAO regional runway safety meeting materials

� EASA RuFAB- Runway Friction Characteristics Measurement & Aircraft Braking

� FAA Takeoff & Landing Perf. Assessment Aviation Rulemaking Committee

� Winter Operations, Friction Measurements & Conditions for Friction Predictions (AIBN)

� REOI WG has finished a formal safety study report

results(cont’)


Application Tips and

Checklist


FAF1000 ft500ft50ft

Stabilized Landing Stabilized Approach

Go AroundAborted Landing

Stabilized Approach Vs. Stabilized Landing

� FDA/FDM is good tool to monitor stabilized

approach (refer to ALAR/FSF)

� How to define key parameters to monitor stabilized

landing? The term of “stabilized landing concept” , by Jim Burin/FSF)


Stabilized Landing GuidelinesA landing is stabilized when all of the following criteria are met:� Fly a stabilized approach

� Height at threshold crossing is 50 ft

� Airspeed at threshold crossing is not more than Vref+10 kt,

and not less than Vref

� Tailwind is no more than 10 kt for a non-conta. runway, no

more than 0 kt for a conta. runway

� Touchdown on runway centerline at the touchdown aim

point

� After touchdown, promptly transition to desired

deceleration config.- brakes, spoilers, thrust reversers(note: once T/R have been activated, a go-around is no longer an option)

� Speed is less than 80 kt with 2,000 ft of runway remaining.


160 kt

150 kt

140 kt130 kt

120 kt

5 deg

4 deg

3 deg

2 deg

1 deg

25 ft

20 ft

15 ft

10 ft

05 ft

00 ft

Runway Veeroff Vs. Crab & speed

).(

)(

ndeclinatiomagAngleDrift

xSinVY

headingmagneticACheadingtrueRWY

GS

++−=∆

∆=∆

ψψφ

φ

� During flare and De-

rotation operation,

consider crab angle of 5-

deg, touchdown speed btw

120 ~ 160kt, then the A/C

lateral dev. 18 ~ 24 ft.

� If crabbing 3~ 5 deg and

continue to fly 5 sec, then

the A/C lateral dev. 50~ 125 ft.

� FDM/FOQA “Heading Deviation

at TKO/LND > 5 deg”

18


key parameters for stabilized landing

�Attitudes: bank < = 5 deg; pitch (related to A/C conf.)

�Crossing Runway Threshold: RA dev. ±±±± 10 ft ，，，，Vref 0 ~ +10 kt

�Load Factor: 1.3 ~ 1.6 g

�Long Flare: 12 ~ 14 sec (50 ft to M T/D)

�Long Landing: 2,000 ~ 2,500 ft (related to A/C)

�Heading deviation: <= 5 deg (RA 100 ft �� M T/D �� GS 50 kt)

�LOC. deviation <= 0.25 dot

2013/01 CAA/UK RE study�Long Flare: >= 2,100 ft (RA 20 ft ~ M T/D)�Long Landing: >= 2,500 ft (RA 50 ft ~ M T/D)�Insufficient runway remaining:

<= 4,000’ ( LDA – M/TD)19


Runway Veeroff CaseB738 RV: RCTP RWY 05L MHD053 THD049

RA 95’& 30’

Down wind, bank > 5 deg

RA 80’

Crab > 10 deg

Condition RA 42’ (0 s) M T/D (+8s) Drift to RHT(+12s) Max. drift (+16s)

A/C MHD 44 40 38 31

A/C DR 8.4 16.9 16.5 21.5

A/CMHD-53 -9 -13 -15 -2220


veeroff13:50:12 M T/DRA 42’

053053053053

31313131----53=53=53=53=----22222222

S METAR 13:48 010/36 G52 RVR 500 TW25.68kt, LCW26.3kt

(heavy rain) 13:53 010/37 G52 RVR 500

FDR RA 100’ ~ 50’

HW 26.8kt, LCW30kt

Recommend Crosswind Guidelines for B737-800 : 27 kt (wet)

Runway Veeroff CaseB738 RV: RCTP RWY 05L MHD053 THD049

21


Aircraft basic dimensions and wheel configuration


Runway Tire Marks

Black tire marks �� high friction, mostly dry runwayWhite erase marks �� lower friction, wet runwayNo marks �� almost no friction, flooded runway,

(partial) dynamic or viscous hydroplaning.

Dry runway -Main gear tire marks

(heavy braking)

23


Dry Runway

skiddingWet or conta. runway

Reverted rubber

skidding

RIB ROB

LIB- WEAR 95% RIB- WEAR 65%

Damaged Tire Conditions


How to Know the Water Depth?

d = water depth, inches

T = macro texture depth, inches

L = drainage length, feet

I = rainfall intensity, inches/hour

S = cross slope, ft/ft

� Empirical model – TTI model

� Direct measurement – NASA water depth gauge


Relationship of rainfall rate and water depth


Relationship of hydroplaning critical speed and Tire Pressure

27

B744 VP 108-127kt，M T/D airspeed140kt (DR 0.16g, 2 kt)

(1)Tail wind 10 kt, at least 6 sec to encounter dynamic hydroplaning

(2)Head wind 10 kt, at least 1 sec to encounter dynamic hydroplaning

Spin down (rotating tire)Spin up (non-rotating tire)Spin down (rotating tire)Spin up (non-rotating tire)


Yes No hydroplaning

No

Did A/C left blackrubber tire marks on the

Runway?

Evidence of revertedrubber on tire tread

?

Yes

Reverted rubber investigation: Antiskid & brake pedal Auto brake sys. & setting Runway texture & slope Runway friction & drainage Rainfall rate & water depth on

runway & distribution Surface wind Tire tread depth & condition

No

FDR/QARData available ?

Yes

No

A/C TD speedgreater than critical

hydroplaning speed?7.7/9 SQRT(Tp)

Did A/C manufacturerstopping distance analysis

For wet runway(µµµµ)match FDR perf.?

Yes

No

hyd

rop

lan

ing

Typ

ical

wet

run

way p

erf

.

Good runwaytexture and tire

tread?

Yes

Yes

No

hyd

rop

lan

ing

Viscous hydroplaning investigation:Except the tire inflation pressure, same asdynamic hydroplaning

Confirm the ground tracks passed through: Rubber deposit areas; Threshold marking, touchdown zone Runway edge marking.

NoDynamic hydroplaning investigation: Tire inflation pressure Tire tread depth & condition Runway texture & slope Runway friction & drainage Rainfall rate & water depth on

runway & distribution Surface wind

FDR key parameter: Braking devices Deceleration Ground & tire speed A/B mode BSCU status FMC/CMC fault messages

Outsourcing items: Check- runway texture Check- runway friction Airworthy- A/B brake sys. Manufacturer’s perf.

soft: aero., engine, & brake characteristics

No

Investigation Procedure for suspected hydroplaning


ASC Site Survey Formsitem Contents Confirm time

1 After received the aviation occurrence notification,

contact the aircraft operator to turn off CVR power immediately.

2 Supervise the aircraft operator to remove the Flight

Recorders (CVR & FDR), and secure at airside management division.

3 Perform the alcohol test for the occurrence flight crew.

4 Mark and photography the damaged navaids and relevant debris, and FOD.

5 Locate the position of nose gear and main gears, inward photography of the aircraft (8 pieces).

6 Follow the aircraft ground tracks to aircraft stopped place, take relevant photos.

7 For wet runway conditions, perform the pavement observation（□ Damp/□ Wet/□ Water patch/□

Flooded）; If applicable, measured the water depth_______(mm)

8 Settle an appropriate place for the flight crew to wait for interview.

Note: suggested equipment ( waterproof of digital camera, GPS)


Sample of site survey


Runway Overrun CaseMD-80 RO: RCQC RWY 02 LDA 7,382 ft; light rain

�MD-80 AFM, tail wind limitation 10 kt

�ATC wind 16/170, RVR 3,200 m

�A/P disengaged, tailwind 21kt; touchdown tailwind 14kt.

�During the A/C touchdown (T/D), both spoilers fully deployed

�After T/D 3 sec, T/R in REV IDLE about 10sec; then move

to 1.2 ~ 1.6 %RPM

�After T/D 7 sec, brake pedal reached max. and until A/C stopbeyond the end of runway about 330 ft.

31


RA 50’

16 sec

6 sec 2.5 sec

MT/D NT/D veeroff

Runway Overrun CaseB747 RV: RCTP RWY 24 heavy rain

After MT/D, combination of floating and weathervane effect, ASC excluded the possibility of hydroplaning


Conclusions�Stabilized approach and stabilized landing are key effects

to mitigate the risk of runway excursion.

�The study reviewed the accidents involving runway

excursion in the last 50 years, and collected many

technical reports, to develop investigation tools, on-scene

checklists, and hydroplaning investigation procedures.

�In an occurrence involving with suspected hydroplaning,

preserving “easy loss of evidences” is the first priority.

Evaluating runway friction and aircraft braking

performance is a challenging task - wind, rainfall rate, the

combination of hydroplaning and weathervane…etc.

08 lessons learnt from asc runway excursion occurrence ... lessons learnt from asc... ·...

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