The US National Transportation Safety Board (NTSB) stated on Sunday that a “key missing component” of a Boeing (BA.N) 737 MAX 9 aircraft involved in the emergency landing of an Alaska Airlines (ALK.N) plane was recovered from the backyard of a suburban home, Reuters reported.
A door plug ripped off the left side of an Alaska Airlines plane on Friday following takeoff from Portland, Oregon, en route to Ontario, California, causing the aircraft to depressurise. The pilots were forced to turn back and land safely with all 171 passengers and six crew members on board.
The Federal Aviation Administration (FAA) ordered on Saturday the temporary grounding of the 171 Boeing MAX 9 aircraft, equipped with the same panel that weighs about 60 pounds (27 kg) and covers an extra exit door, mostly used by budget airlines.
The missing door was discovered on Sunday by a Portland schoolteacher in the Cedar Hills neighbourhood who found it in his backyard, NTSB Chairwoman Jennifer Homendy stated, expressing delight at the find. She had earlier told reporters that the aircraft part was a “key missing component” in determining the cause of the crash.
“Our structures team will want to look at everything on the door – all of the components on the door to see to look at witness marks, to look at any paint transfer, what shape the door was in when found. That can tell them a lot about what occurred.”
According to Homendy, the force caused by the loss of the plug was strong enough to open the cockpit door during the flight. She cited pilots interviewed by investigators:
They heard a bang. Communication was a serious issue… It was described as chaos.
Homendy claimed the cockpit voice recorder did not capture any data as it was overwritten, and reiterated his call for regulators to mandate that existing aircraft be retrofitted with recording devices that capture data in 25 hours, instead of the two hours currently required.
The chairwoman also stated that the automatic supercharger malfunction indicator light went off on the same Alaska Airlines plane on Dec. 7, Jan. 3 and Jan. 4.
However, it remains unclear whether there was any connection between those incidents and the crash. Following the warnings, Alaska Airlines decided to prohibit the plane from making long over-water flights to Hawaii so that it could quickly return to the airport if necessary.
The Seattle-based airline previously stated in response to questions about the warning lights that recalls of the aircraft’s supercharger system were typical of commercial aviation flights with large aircraft.
The airline stated that “in every case, the write up was fully evaluated and resolved per approved maintenance procedures and in full compliance with all applicable FAA regulations.”
Alaska Airlines cancelled 170 flights on Sunday and another 60 on Monday and stated that travel disruptions due to the grounding were expected to last until at least midweek. United, which suspended flights on 79 MAX 9 planes, cancelled 230 flights, or 8 percent of scheduled departures, on Sunday.
The accident has put Boeing under renewed scrutiny as the company awaits certification of its smaller MAX 7 as well as the larger MAX 10, which is needed to compete with Airbus’ key model (AIR.PA).
In 2019, global authorities subjected all MAX aircraft to a wider flight ban that lasted 20 months after disasters in Ethiopia and Indonesia linked to poorly designed cockpit software killed a total of 346 people.
