BOEING 737UNITED AIRLINES INC
Houston, TX, USA · 2024-01-10·N62883
What happened
NTSB summary, verbatimUnited Airlines flight 2498 experienced a tail strike while landing at George Bush Houston Intercontinental Airport (IAH), Houston, Texas. The flight was a regularly scheduled domestic passenger flight from Phoenix Sky Harbor Airport (PHX), Phoenix, Arizona to IAH. The flight crew statements and flight data showed a stable approach to the landing flare. The first officer was pilot flying and stated he began the flare slightly late. Both crewmembers stated the touchdown was firm with a slight “nose-high” bounce. The flight crew was not aware the airplane’s tail had impacted the runway until the ground crew at the gate notified them. Flight data showed that the airplane touched down on the runway with a 6.5-degree nose-up attitude and vertical acceleration of 1.87g. The speed brakes deployed two seconds after the initial touchdown. At the same time, the aircraft became airborne again and the nose began to lower. Two seconds later, as the speed brakes retracted, the airplane’s pitch began to increase, and the airplane touched down a second time with pitch of 7.2 degrees and a vertical acceleration of about 2.87g. The airplane became airborne for a 3rd time for about a second before it touched down for the final time. The nose was lowered to the ground, and speed brakes were extended again. Post-accident assessment of the aircraft revealed substantial damage to the auxiliary power unit (APU) firewall bulkhead that occurred as a result of the aircraft’s aft fuselage’s contact with the runway.
Photographs
1the aircraft, and what the investigators foundProbable cause
the Board's determinationThe airplane’s aft fuselage impacted the runway as a result of a delayed flare and subsequent nose-high pitch inputs during the aircraft’s multiple touchdowns.
Occurrence sequence
1 stepsNTSB coding · CICTT taxonomy- 1 · Landing-flare/touchdownTailstrikedefining event
Findings
0 causal · 1 contributing- FACTORPersonnel issues › Action/decision › Action › Delayed action — Copilot
Sequence of events
8 timed eventsfrom the FDR factual report · claude-sonnet-5- 1109:52 CSTLanding - initial touchdownp.5The aircraft main gear touched down on the runway with a 6.5-degree nose-up attitude while traveling about 149 knots
- 1109:52 CSTLanding - initial touchdownp.5Vertical acceleration showed the initial touchdown peaking at >1.87g
- 1109:54 CST (approx., 2 seconds after initial touchdown)Landing - bouncep.5The speedbrakes deployed two seconds after the initial touchdown and the aircraft became airborne again at the same time and began to derotate
- approx. 2 seconds after becoming airborne againLanding - bounce/second touchdownp.5As the speedbrakes were retracting, pitch began to increase, and the main gear touched down a second time with a vertical acceleration of about 2.87g
- shortly after second touchdownLanding - second bouncep.5Pitch reached a peak of 7.2 degrees
- approx. 1 second after second touchdownLanding - final touchdownp.5The aircraft became airborne again for another second before the main gear touched down for the final time
- after final main gear touchdownLanding rolloutp.5The nose lowered to the ground and the speedbrakes were extended again
- following nose gear touchdownLanding rollout/decelerationp.5Following nose gear touchdown, wheel brakes and thrust reversers were also employed as the aircraft slowed
NTSB analysis
from the final reportUnited Airlines flight 2498 experienced a tail strike while landing at George Bush Houston Intercontinental Airport (IAH), Houston, Texas. The flight was a regularly scheduled domestic passenger flight from Phoenix Sky Harbor Airport (PHX), Phoenix, Arizona to IAH. The flight crew statements and flight data showed a stable approach to the landing flare. The first officer was pilot flying and stated he began the flare slightly late. Both crewmembers stated the touchdown was firm with a slight “nose-high” bounce. The flight crew was not aware the airplane’s tail had impacted the runway until the ground crew at the gate notified them. Flight data showed that the airplane touched down on the runway with a 6.5-degree nose-up attitude and vertical acceleration of 1.87g. The speed brakes deployed two seconds after the initial touchdown. At the same time, the aircraft became airborne again and the nose began to lower. Two seconds later, as the speed brakes retracted, the airplane’s pitch began to increase, and the airplane touched down a second time with pitch of 7.2 degrees and a vertical acceleration of about 2.87g. The airplane became airborne for a 3rd time for about a second before it touched down for the final time. The nose was lowered to the ground, and speed brakes were extended again. Post-accident assessment of the aircraft revealed substantial damage to the auxiliary power unit (APU) firewall bulkhead that occurred as a result of the aircraft’s aft fuselage’s contact with the runway.