Landing Overruns- Landing Overruns- Human Factors Human Factors Captain David Oliver Captain David Oliver General Manager Flight Technical General Manager Flight Technical Qantas Airways Limited Qantas Airways Limited W037c.1
Landing Overruns - Human Factors Landing Overruns - Human Factors A review of the events leading to, and lessons A review of the events leading to, and lessons learnt from the over-run of flight QF1 at Bangkok learnt from the over-run of flight QF1 at Bangkok Thailand, September 23, 1999. Thailand, September 23, 1999. W037c.2 Qantas Airways Limited
Landing Configuration Landing Configuration • Operating Boeing 747-400 since 1989 • Operating Boeing 747-400 since 1989 • Standard landing configuration up until 1996 • Standard landing configuration up until 1996 was “Flap 30, Full Reverse Thrust” was “Flap 30, Full Reverse Thrust” W037c.3 Qantas Airways Limited
Landing Configuration Landing Configuration (continued) (continued) • Review of landing configuration was • Review of landing configuration was undertaken due to: undertaken due to: – Noise levy at Sydney – Noise levy at Sydney � Flap 25 chosen for lower noise, � Flap 25 chosen for lower noise, better fuel economy better fuel economy – Carbon Brake Wear – Carbon Brake Wear � Idle reverse thrust chosen for � Idle reverse thrust chosen for less noise and longer, harder less noise and longer, harder brake application brake application W037c.4 Qantas Airways Limited
Landing Configuration Landing Configuration (continued) (continued) • Landing configuration Policy from late 1996 was: • Landing configuration Policy from late 1996 was: – Flap 25, idle reverse thrust provided the – Flap 25, idle reverse thrust provided the runway length was not limiting runway length was not limiting W037c.5 Qantas Airways Limited
The Landing The Landing • F/O was pilot flying • F/O was pilot flying • The runway was wet • The runway was wet – The last landing airplane had reported – The last landing airplane had reported “good” braking action “good” braking action – The airplane preceding QF1 executed a – The airplane preceding QF1 executed a Missed Approach due to poor visibility in Missed Approach due to poor visibility in heavy rain heavy rain – This was not relayed to the crew of QF1 – This was not relayed to the crew of QF1 W037c.6 Qantas Airways Limited
The Landing The Landing (continued) (continued) • Airplane crossed the threshold high and fast • Airplane crossed the threshold high and fast (but within Company limits) and “floated” 10ft (but within Company limits) and “floated” 10ft above the runway in heavy rain above the runway in heavy rain • Within a period of just a few seconds: • Within a period of just a few seconds: – The Captain called for “Go- Around” – The Captain called for “Go- Around” – The main gear touched down – The main gear touched down – The rain eased and visibility improved – The rain eased and visibility improved – Captain reached over and took control of – Captain reached over and took control of the thrust levers the thrust levers W037c.7 Qantas Airways Limited
The Landing The Landing (continued) (continued) • The Captain initially only retarded # 2, 3 and • The Captain initially only retarded # 2, 3 and 4 Thrust Levers 4 Thrust Levers • The F/O immediately realized this and retarded • The F/O immediately realized this and retarded #1 to idle, however: #1 to idle, however: – With main gear on the ground and # 1 or – With main gear on the ground and # 1 or 4 T/L advanced, the autobrakes disarmed 4 T/L advanced, the autobrakes disarmed – Speedbrakes deployed automatically after – Speedbrakes deployed automatically after #1 T/L was retarded by the F/O #1 T/L was retarded by the F/O W037c.8 Qantas Airways Limited
The Landing The Landing (continued) (continued) • The EICAS message “AUTOBRAKES” was not • The EICAS message “AUTOBRAKES” was not initially noticed by the Flight Crew initially noticed by the Flight Crew • Manual braking was not applied until 8 seconds • Manual braking was not applied until 8 seconds after touchdown, approx 5000 feet down after touchdown, approx 5000 feet down the runway the runway • No reverse thrust was applied for the whole • No reverse thrust was applied for the whole of the landing roll of the landing roll W037c.9 Qantas Airways Limited
The Landing The Landing (continued) (continued) • When manual braking was applied • When manual braking was applied NO deceleration was felt NO deceleration was felt • Both pilots exerted maximum force on the • Both pilots exerted maximum force on the brake pedals, still with no deceleration brake pedals, still with no deceleration – The airplane was aquaplaning – The airplane was aquaplaning • The airplane only began to decelerate as it • The airplane only began to decelerate as it entered the last 1000 feet of the runway and entered the last 1000 feet of the runway and the groundspeed reduced below 110kts the groundspeed reduced below 110kts W037c.10 Qantas Airways Limited
Acft drifting left Nose gear squat Nose gear SPLR deployed of rw y C/L sw itch air mode departs sw y CAS 160 kts CAS 158kts Acft returning CAS 143kts CAS 88kts GS 158 kts Touchdow n GS 156kts to rw y C/L GS 141kts GS 87kts Air-gnd logic CAS 107kts Manual Nose gear Nose gear squat Acft on rw y C/L to gnd mode SPLR start deploy GS 106kts braking touchdow n sw itch gnd mode at threshold CAS 156 kts CAS 160 kts indications CAS 146kts CAS 139kts CAS 96kts GS 158 kts GS 158 kts V S CAS 154kts GS 145kts GS 138kts W GS 92kts GS 1 2k DECELERATION ft/sec2 -7.00 Acft accelerating Aerodynamic Aerodynamic due to braking and -6.00 residual thrust only w heel braking -5.00 -4.00 -3.00 -2.00 -1 .00 3287ft 4000f 5000ft 6000ft 7000ft 8000ft 9000ft 1 0000ft 1 002m t 1 524m 1 829m 21 34m 2438m 2743m 3048m Deceleration at main gear position Distance from Rwy 21L displaced threshold W037c.11 Qantas Airways Limited
Comparison of rollout deceleration on various runway surfaces and VH-OJH 23 September 1999 -14 Dry runway * Mu 0.35 - 0.41 -12 -10 Wet runway * Mu 0.20 -8 * Good braking action Deceleration (ft/sec2) -6 Flooded runway * Mu 0.05 * Poor braking action -4 Manual braking Aircraft on Aircraft indications 5002ft to rw y centreline at nosegear Aircraft passing Aircraft Aircraft passing over 2015ft to -2 end start of sw y departs end over rw y mkgs and returning to rw y rw y mkgs and abeam rw y end of sw y approaching tw y S centreline 770ft Aircraft drifting left of tw y W 2536ft to rw y 1100ft to rw y end to rw y end centreline 5522ft to rw y end 0 Autobrakes end disarmed 2 Spoilers deploy 4 160 150 140 130 120 110 100 90 80 A cft config for various runw ay surfaces: Ambient conditions: Groundspeed (knots) * 252,000 kg Vref25 + 5 kts OAT 25 deg C * Maximum manual braking QNH 1013.2 23 Sep BKK Dry Rwy Contam Rwy (Good brkg) Contam Rwy (Poor brkg) * Spoilers deployed, Idle forw ard thrust WIND 3.6 kt HWC W037c.12 Qantas Airways Limited
Human Factors Human Factors • Why did this happen ? • Why did this happen ? • Accident analysis showed: • Accident analysis showed: – A number of significant active failures and – A number of significant active failures and – Significant inadequate defences – Significant inadequate defences W037c.13 Qantas Airways Limited
Active Failures Active Failures • The runway was affected by water • The runway was affected by water • Flight Crew failed to use an appropriate risk • Flight Crew failed to use an appropriate risk management strategy for the approach management strategy for the approach and landing and landing • The F/O did not fly the aircraft accurately • The F/O did not fly the aircraft accurately during final approach during final approach • The Flight Crew were confused over who had • The Flight Crew were confused over who had control and did not select appropriate level of control and did not select appropriate level of reverse thrust reverse thrust W037c.14 Qantas Airways Limited
Inadequate Defences Inadequate Defences • Company published information, procedures and • Company published information, procedures and training for landing on water affected runways training for landing on water affected runways was inadequate was inadequate • Flight Crew training in evaluating the procedural • Flight Crew training in evaluating the procedural and configuration options for approach and and configuration options for approach and landing was deficient landing was deficient – The crew may have been “pre-conditioned” to – The crew may have been “pre-conditioned” to the use of Flap 25 and idle reverse thrust the use of Flap 25 and idle reverse thrust W037c.15 Qantas Airways Limited
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