All Nippon Airways twinjet had just touched down after Cat III autoland approach in fog.
US investigators have determined that a Boeing 787-9 captain inadvertently activated the take-off/go-around switch during touchdown at Houston, causing the twinjet to pitch up and sustain a tail-strike.
The All Nippon Airways twinjet, arriving from Tokyo Haneda on 27 February this year, had conducted its approach to runway 26L.
National Transportation Safety Board investigators have disclosed that, given the presence of fog, the crew opted for a Category III approach using autoland.
According to the testimony of the captain, who was flying, his main focus was “constantly” on the head-up display owing to the poor visibility.
He told the inquiry that he confirmed the thrust levers were at full idle on touchdown, and that the speedbrakes had deployed.
But just as he moved to raise the thrust-reversers, he said the nose “rose unexpectedly, which surprised me”, and added: “When I shifted by eyes to the [primary flight display], the pitch had already reached 7.5°.”
Recorded flight data showed the autopilot pitch and autothrottle were both in ‘flare’ mode at the time of touchdown.
But about 0.5s after touchdown, the data showed the take-off/go-around switch was pressed.
As a result, the autopilot pitch and autothrottle modes both transitioned to take-off/go-around mode.
While the autothrottle transition was cancelled when the throttle levers were moved to reverse thrust, the autopilot pitch mode commanded a target go-around pitch attitude.
The nose-up pitch increased from 3.5° to 7.4° over the course of 2s.
About 5s after the go-around mode was activated, says the inquiry, the captain made a nose-down input on the control column.
“Thinking ‘this is bad’, I forcefully pushed the column forward with both hands to disengage the autopilot,” the captain stated.
“Since pushing the ‘autopilot disconnect’ switch while pushing the column would cause me to lose pushing force, I disengaged it by the force of the push itself.
“Afterward, I pulled the column significantly to prevent the nose-gear from slamming down.”
The nose-up attitude had peaked at 7.9°, sufficient for a tail-strike.
Flight data showed the tail-strike protection function had activated but, owing to “limited authority”, it could not prevent the pitch attitude increase that resulted in runway contact, says the inquiry.
“There was no evidence of an autopilot system malfunction, therefore it is likely the captain inadvertently pressed the [take-off/go-around] switch when he reached for the thrust-reversers at touchdown,” it states.
According to Boeing, conditions that inhibit take-off/go-around activation were not yet satisfied at the time the switch was pressed.
“I have no conscious awareness or sensation of my fingers touching a switch during that interval,” the captain testified. “I don’t know if I touched it while moving my hand. In all my years of operation across various aircraft types, I have never accidentally hit it.”
While the aircraft (JA873A) received substantial aft fuselage underside damage, none of the 197 passengers and 12 crew members was injured.
The post Captain accidentally pressed go-around switch before 787-9 tail-strike at Houston first appeared on FlightGlobal.