Boeing 767-322 N641UA accident near Houston, Texas

Probable cause

The 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.

NTSB analysis

After 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.

Text from the NTSB. Open the NTSB docket for DCA23LA384 for the full record.