BOEING 767-322UNITED AIRLINES INC
Houston, TX, USA · 2023-07-29·N641UA
What happened
NTSB summary, verbatimAfter a stabilized approach, the main landing gear of United Airlines flight 702 touched down and the nosewheel contacted the runway harder than expected. The airplane then bounced, and the first officer (the pilot flying) reacted by pulling the control yoke aft to keep the nosewheel from impacting the runway a second time. The first officer applied the thrust reversers, the speed brakes deployed, and the nosewheel bounced a second time. Subsequently, the nosewheel impacted the runway a third time and, the airplane began to decelerate normally. The abnormal nosewheel impacts with the runway resulted in substantial damage to the fuselage. Although the first officer stated he held aft pressure on the control column during the initial touchdown, flight data showed that he also made nosedown column inputs during the landing sequence. These nose-down inputs contributed to the nosewheel abnormally impacting the runway. Normal operation of the speedbrakes includes deployment during initial main gear touchdown, if the speedbrakes are in the armed position and the thrust levers are at idle. The only indication that the speedbrakes are armed is a demarcation line located on the control stand. If they do not automatically deploy during main gear touchdown, the pilot monitoring (in this case, the captain) announces the abnormal operation and slowly raises the speedbrake handle to the up position while the pilot flying slowly lowers the airplane’s nose to the runway. In addition, the speedbrakes will automatically deploy if the airplane is on the ground and either thrust lever is moved to the reverse idle detent. However, the speedbrakes were not armed before landing and after the airplane’s first bounce, data showed the speedbrakes automatically deployed with the first officer’s application of the thrust reversers, as designed. The deployment of the speedbrakes with the thrust reversers was while the nosewheel was still in the air. This likely contributed to the second abnormal runway contact of the nosewheel and the subsequent damage to the airplane. It is also likely that neither flight crewmember noticed that the speedbrakes were not armed before landing. Crew Performance De-rotation is the lowering of the aircraft’s nose gear to the runway following touchdown on the main gear during landing. The first officer’s nose-down column inputs were contrary to United Airlines’ procedures and training. The first officer’s training records showed inconsistencies in airplane handling as recent as a few months before the accident. He received an unsatisfactory performance rating and, upon re-evaluation, a satisfactory rating with a condition to recheck after 90 days (instead of 9 months). This was due to, among other things, marginal performance with landings. According to the check airman who completed the first officer’s second evaluation, the purpose of the recheck was to ensure, due to the first officer’s previous “struggles,” that his “proficiency is up to standards”. The first officer had accumulated about 129 flight hours in the accident airplane make and model. Due to the satisfactory performance rating on the first officers second evaluation, the investigation was unable to determine if the first officers training inconsistencies contributed to the accident.
Photographs
1the aircraft, and what the investigators foundProbable cause
the Board's determinationThe first officer’s improper control inputs after the airplane touched down. Contributing to the severity of the damage was the flight crew’s lack of recognition that the speedbrakes were not armed, which led to their delayed deployment.
Occurrence sequence
1 stepsNTSB coding · CICTT taxonomy- 1 · Landing-flare/touchdownHard landingdefining event
Findings
2 causal · 0 contributing- CAUSEPersonnel issues › Action/decision › Action › Incorrect action performance — Copilot
- CAUSEOrganizational issues › Support/oversight/monitoring › Training › Initial training — Operator
Sequence of events
20 timed eventsfrom the FDR factual report · claude-sonnet-5- 07:32:32 CDTDeparturep.6N641UA departed runway 22R at EWR.
- 07:36:17 CDTClimb/Cruisep.6The autopilot was engaged. The takeoff, cruise, and approach were uneventful.
- 10:26:25 CDTApproachp.6The localizer mode was operational.
- 10:28:25 CDTApproachp.6Pressure altitude was 6,045 ft, computed airspeed was 214 kts, and magnetic heading was 265 deg. Localizer and glideslope deviation were -0.04 dots and -0.18 dots, respectively. Flap handle was 5 deg. The speedbrake handle was in the down position.
- 10:31:47 CDTApproachp.6The landing gear was down and locked. The flap handle was 15 deg. The speedbrake handle was in the down position. Localizer and glideslope deviation were 0.00 dots.
- 10:33:49 CDTFinal Approachp.6Radio altitude was 635 ft, computed airspeed was 142 kts, and magnetic heading was 266 deg. Localizer and glideslope deviation were -0.02 dots and 0.00 dots, respectively. The flap handle was 30 deg. The speedbrake handle was in the down position. The autopilot was disengaged.
- 10:34:31 CDTFinal Approachp.6Engines 1 and 2 throttle resolver angle (TRA) were 47.29 deg.
- 10:34:37 CDTFinal Approachp.6Engines 1 and 2 TRA were 33.75 deg and 33.93 deg, respectively.
- 10:34:41 CDTLanding/Touchdownp.6The air-ground switch was ground, and the left and right main gear were not tilted. The maximum vertical acceleration recorded at landing was 1.1465 g. The control column position recorded was approximately 0.35 deg. Speedbrake handle was down.
- 10:34:42 CDTLanding Rolloutp.6The maximum recorded control column position was 5.71 deg. The control wheel position was -14.96 deg and reduced to -6.53 deg. Speedbrake handle was down.
- 10:34:43 CDTLanding Rolloutp.6The maximum recorded control column and control wheel position were -4.39 deg and -24.48 deg, respectively. The right main gear changed from not tilted to tilted and the air-ground switch changed from ground to air. Vertical acceleration reduced from 1.2381 g to 0.6909 g within the second.
- 10:34:44 CDTLanding Rolloutp.7The nose gear squat switched from air to ground and back to air, all within the second. The right main landing gear was not tilted. Vertical acceleration increased from 0.7344 g to 1.4258 g. The control column was 3.87 deg before it decreased to -4.75 deg. Engines 1 and 2 TRA were 34.28 deg. Speedbrake handle position was in the down position.
- 10:34:45 CDTLanding Rolloutp.7Engines 1 and 2 TRA were 31.82 deg and 23.73 deg. Speedbrake handle changed from the down position to the up position within the second. Vertical acceleration reduced from 1.1442 g to 0.3430 g and back to 1.5540 g, all within the second. The nose gear squat changed from air to ground.
- 10:34:46 CDTLanding Rolloutp.7Engines 1 and 2 thrust reversers were in transit. Vertical acceleration changed from 1.5540 g to 0.9863 g, increased to 1.5746 g, and reduced to 0.6314 g, all within the second. The nose gear squat was air for one sample of the second.
- 10:34:47 CDTLanding Rolloutp.7Engine 2 thrust reverser was fully deployed. The nose squat was ground, and the main gears were not tilted. Engines 1 and 2 TRA were 24.79 deg and 6.68 deg, respectively. Vertical acceleration was 0.7802 g and increased to 1.5563 g, and reduced to 0.7505 g, all within the second.
- 10:34:48 CDTLanding Rolloutp.7Engines 1 and 2 TRA were 4.75 deg and 3.87 deg, respectively. Vertical acceleration hovered around 1 g for the remainder of the landing rollout.
- 10:34:49 CDTLanding Rolloutp.7Engine 1 thrust reverser was fully deployed. The remainder of the landing rollout was uneventful.
- 10:34:59 CDTLanding Rolloutp.7The autobrakes disarmed was selected.
- 10:35:04 CDTLanding Rolloutp.7Engines 1 and 2 thrust reversers switched from deployed to not deployed.
- 10:38:16 CDTEnd of Recordingp.7The last recorded sample was recorded.
NTSB analysis
from the final reportAfter a stabilized approach, the main landing gear of United Airlines flight 702 touched down and the nosewheel contacted the runway harder than expected. The airplane then bounced, and the first officer (the pilot flying) reacted by pulling the control yoke aft to keep the nosewheel from impacting the runway a second time. The first officer applied the thrust reversers, the speed brakes deployed, and the nosewheel bounced a second time. Subsequently, the nosewheel impacted the runway a third time and, the airplane began to decelerate normally. The abnormal nosewheel impacts with the runway resulted in substantial damage to the fuselage. Although the first officer stated he held aft pressure on the control column during the initial touchdown, flight data showed that he also made nosedown column inputs during the landing sequence. These nose-down inputs contributed to the nosewheel abnormally impacting the runway. Normal operation of the speedbrakes includes deployment during initial main gear touchdown, if the speedbrakes are in the armed position and the thrust levers are at idle. The only indication that the speedbrakes are armed is a demarcation line located on the control stand. If they do not automatically deploy during main gear touchdown, the pilot monitoring (in this case, the captain) announces the abnormal operation and slowly raises the speedbrake handle to the up position while the pilot flying slowly lowers the airplane’s nose to the runway. In addition, the speedbrakes will automatically deploy if the airplane is on the ground and either thrust lever is moved to the reverse idle detent. However, the speedbrakes were not armed before landing and after the airplane’s first bounce, data showed the speedbrakes automatically deployed with the first officer’s application of the thrust reversers, as designed. The deployment of the speedbrakes with the thrust reversers was while the nosewheel was still in the air. This likely contributed to the second abnormal runway contact of the nosewheel and the subsequent damage to the airplane. It is also likely that neither flight crewmember noticed that the speedbrakes were not armed before landing. Crew Performance De-rotation is the lowering of the aircraft’s nose gear to the runway following touchdown on the main gear during landing. The first officer’s nose-down column inputs were contrary to United Airlines’ procedures and training. The first officer’s training records showed inconsistencies in airplane handling as recent as a few months before the accident. He received an unsatisfactory performance rating and, upon re-evaluation, a satisfactory rating with a condition to recheck after 90 days (instead of 9 months). This was due to, among other things, marginal performance with landings. According to the check airman who completed the first officer’s second evaluation, the purpose of the recheck was to ensure, due to the first officer’s previous “struggles,” that his “proficiency is up to standards”. The first officer had accumulated about 129 flight hours in the accident airplane make and model. Due to the satisfactory performance rating on the first officers second evaluation, the investigation was unable to determine if the first officers training inconsistencies contributed to the accident.