Pilot Seat May Have Caused 787’s Drop. It Wouldn’t Be the First Time.

• A Latam Airlines Boeing 787 dropped midair Monday, injuring at least 50 people.
• The cause may be due to a flight attendant inadvertently hitting a switch on the pilot’s seat.
• If true, that would be reminiscent of when a military Airbus A330 suddenly nose-dived in 2014.

On Monday, a Latam Airlines Boeing 787 carrying 263 passengers and crew suddenly dropped midair during a flight from Sydney to Auckland, New Zealand, injuring at least 50 people.

While CNN reported one of the Latam pilots told a passenger his cockpit gauges “went blank” in a supposed aircraft malfunction, new information points to a mishap in the flight deck, rather than a technical failure.

The Wall Street Journal, citing unnamed officials briefed on preliminary evidence, reported a flight attendant may have inadvertently hit a switch on the pilot’s seat while they were serving a meal in the cockpit. This would have turned on a system that pushed the chair and the pilot forward into the flight controls.

The switch is designed with a cover and is not supposed to be used when someone is in the seat, the Journal said. Still, it could have been accidentally activated — pointing the plane’s nose down and causing the sudden drop in altitude.

If true, this wouldn’t be the first time a pilot’s seat forced a widebody plane into a nosedive. 

A pilot-seat mishap sent a military Airbus A330 plummeting

Ten years ago, on February 9, 2014, a Royal Air Force Airbus A330 plummeted 4,400 feet in about 30 seconds. The tanker-transport aircraft involved was part of the British military’s Voyager Fleet, which is based on the civilian version of the A330 but can provide midair refueling and military transport.

On the day of the event, Voyager Flight 333 was shuttling nearly 200 passengers and crew from the RAF Brize Norton base in the UK to Camp Bastion in Afghanistan, according to the final report published by the UK’s Military Aviation Authority. It was a military mission but operated mostly like a traditional commercial flight — meaning passengers were served by flight attendants and shown an in-flight movie.

Both pilots were military aviators with thousands of hours of experience. But despite the captain’s more than 5,500 hours of flight time, he made a crucial mistake while he was solo in the cockpit.

According to the report, the captain was killing time at cruising altitude by taking photos using a DSLR camera on the flight deck while the first officer was taking a break in the galley.

While this is OK when there are two pilots in the cockpit, according to RAF policy at the time, it was forbidden for one pilot to perform “non-relevant” flight duties while the other pilot was away — which was where the problems began.

When the captain set down his camera to speak with the purser on the flight, he placed it next to the A330’s side-stick. This controls the Airbus’ fly-by-wire system, which allows the pilot to command the plane’s pitch and roll.

Distracted by the purser, the captain did not remove the camera before he later adjusted his seat forward. When he did this, the seat’s armrest pushed the camera against the side-stick with enough force to disconnect the autopilot — which the plane is designed to do — and send the plane into a nosedive.

The negative G-force of the drop launched passengers and crew, including the first officer, into the air and against the jet’s ceiling — similar to the Latam event.

Fortunately, Airbus’ advanced automation saved the plane by automatically reducing the plane’s thrust and leveling off once the jet reached a certain speed and pitch-down limit, according to the report. In other words, the A330 aircraft has built-in protections that help it recover from a nosedive after a pilot error.

While the Latam incident is still under investigation, it’s possible a similar cause and effect occurred in the recent altitude drop. The Boeing 787 system involved has a fly-by-wire system, but instead of a side-stick, the planemaker has installed the traditional yoke.

In the aftermath of Voyager Flight 333, several recommendations were made to address the event regarding things like loose objects in the cockpit, the pilot-seat design, and how long one pilot can be left alone on the flight deck.

For Boeing, the planemaker sent out a memo to 787 operators on Thursday to check for loose covers over the switches and provided information on how to turn off the motor, the Journal reported. This follows a similar notice sent to airlines seven years ago regarding the seat.

“We have taken the precautionary measure of reminding 787 operators of a service bulletin issued in 2017,” Boeing said. “We are recommending operators perform an inspection at the next maintenance opportunity.”

If it’s proved this was human error and not a technical issue, Boeing is sure to breathe a sigh of relief that the problem isn’t related to another quality fault on one of its passenger jetliners.