08 Lessons Learnt from ASC Runway Excursion Occurrence ... Lessons Learnt from ASC... ·...
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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
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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
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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
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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
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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
2004.08.24 09:20 MD82 Heavy rain veer off
2004.10.18 17:59 A320 Light rain over run
2006.07.14 19:15 MD83 Heavy rain veer off
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
2011.05.12 20:35 MD90 Heavy rain 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
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Runway Excursion Occurrence Investigation Working Group
(REOI WG)
Duration: 2011/08 ~ 2013/12
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� 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
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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.
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Intermittent sliding
A/C Braking Performance Vs. Slip Ratio
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NASA’s Flight Test for B727
Runway grooving can increase the Aircraft deceleration performance
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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
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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
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� 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’)
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Application Tips and
Checklist
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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)
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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.
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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”
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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
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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
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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
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Aircraft basic dimensions and wheel configuration
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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)
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Dry Runway
skiddingWet or conta. runway
Reverted rubber
skidding
RIB ROB
LIB- WEAR 95% RIB- WEAR 65%
Damaged Tire Conditions
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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
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Relationship of rainfall rate and water depth
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Relationship of hydroplaning critical speed and Tire Pressure
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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)
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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
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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)
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Sample of site survey
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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.
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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
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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.