Aircraft accident investigation on an accident which happened on 23 Sep, 1999 in Bangkok Airport , Thiland. Operator of plane was Qantas and plane was Boeing 747-400 registered as VH-OJH.

2. Boeing 747-438 VH-OJH
23 Sep, 1999.
Aircraft Accident Investigation

3. Scope
 Executive Summery
 History of Flight
 Ops Investigation
 Technical Investigation
 Findings
 Cause of accident
 Recommendations
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4. Executive Summary
 On 23 September 1999, at about 2247 local time, a Qantas
aircraft overran runway while landing at Bangkok International
Airport
 Runway was affected by water following very heavy rain
 The aircraft sustained substantial damage
 None on board reported serious injuries
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5. History of Flight
 The first officer was the handling pilot for the flight.
 Flight crew was informed that runway was wet. They elected
to use flaps 25 and idle reverse as the configuration
 When the aircraft was approximately 10 feet above the
runway, the Captain instructed the first officer to go around
 The captain immediately cancelled the go-around by retarding
the thrust levers, without announcing his actions. Both of flight
crew did not notice the absence of reverse thrust.
 Aircraft speed did not decrease below the touchdown speed
(154 kts) until the aircraft was 1,625 m or halfway down the
runway. Aircraft stopped 200 m after the runway
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6. Ops Investigation
 The investigation established that, during the landing roll, the aircraft
tires aquaplaned on the water-affected runway.
 This limited the effectiveness of the wheel brakes to about one third
of that for a dry runway.
 In such conditions and without reverse thrust, the aircraft overran
the 100 m stop way at a speed of 88 kts, before stopping 220 m
later with the nose resting on an airport perimeter road.
 The depth of water on the runway could not be determined but it
was sufficient to allow dynamic aquaplaning to occur (i.e. at least 3
mm)
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7. Ops Investigation
 The performance of the aircraft on the runway revealed that
the flaps 25 & idle reverse thrust landing procedure used by
the crew was not appropriate for operations on to water-
affected runways.
 The appropriate approach/landing procedure was flaps 30/full
reverse thrust.
 As with other company B747-400 pilots, the crew had not
been provided with appropriate procedures and training to
properly evaluate the potential effect of the Bangkok Airport
weather conditions 7
Final Position of
aircraft

8. Technical Analysis
 Inspection of the aircraft soon after the accident confirmed
that the spoilers had deployed, the wing flaps were in the
flaps 25 position, and all of the engine thrust reversers were in
the stowed position
 A comprehensive examination of the aircraft and its systems,
FDR and ATC data did not reveal any fault that might have
affected the landing
 The main areas of damage to the aircraft were the lower
forward fuselage, the nose and right wing landing gear and
landing gear bays, and the engines. All damage was caused
by impact forces
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9. Findings
 The flight crew did not use an adequate risk management
strategy for the approach and landing.
 The first officer did not fly the aircraft accurately during the
final approach
 The captain cancelled the go-around decision by retarding the
thrust levers
 The flight crew did not select (or notice the absence of) idle /
full reverse thrust
 The runway surface was affected by water
 The cabin interphone and passenger address systems
became inoperable (due to impact damage)
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10. Cause of Accident
 Human Error- Flight Crew- Avoidable
 The first officer did not fly the aircraft accurately during final approach
 The captain cancelled the go-around decision by retarding the thrust
levers
 The flight crew did not select (or notice the absence of) idle or full
reverse thrust
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11. Cause of Accident
 Contributory causes were
 The runway surface was affected by water
 QANTAS published information, procedures, and flight crew training for
landing on water-affected runways were deficient
 The surveillance of airline flight operations by CASA was deficient
 Components for cabin intercom and public address systems in Boeing
747-400 were co-located in the same, relatively damage-prone, position in
the lower fuselage aft of the nose wheel
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12. Recommendations
 CASA should ensure that all Australian operators of high
capacity jet aircraft have in place procedures and training to
ensure flight crews are adequately equipped for operations on
wet / contaminated runways
 FAA and JAA should review the design requirements for high
capacity aircraft to ensure the integrity of the cabin interphone
and public address systems
 CASA should widen its existing skill-base to ensure that CASA
audit teams have expertise in all relevant areas
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13. QUESTIONS

14. THANK YOU