The Federal Aviation Administration is asking Boeing to provide “additional data” before it approves ”an extensive and rigorous” inspection protocol that would allow the Boeing 737 Max 9 to return to service.
The FAA had grounded 171 of the type earlier this week after an in-flight accident on an Alaska Airlines example on 5 January resulted in a rapid decompression of the aircraft. An emergency exit door plug had blown open, leaving a gaping hole into the left side of the fuselage.
The accident has prompted regulators to take a closer look at Boeing and its processes.
“We are working to make sure nothing like this happens again,” FAA Administrator Mike Whitaker said. “Our only concern is the safety of American travellers and the Boeing 737-9 Max will not return to the skies until we are entirely satisfied it is safe.”
The FAA says it has reviewed Boeing’s proposed inspection instructions, and determined that it needed additional information before approving them.
“Accordingly, the FAA is requiring plug-door inspections of 40 aircraft,” the US aviation regulator says.
Furthermore, it is “encouraged by the exhaustive nature of Boeing’s instructions for inspections and maintenance”.
But that said, it is waiting to review data from the initial round of 40 inspections, and following that, the regulator will decide if these “satisfy compliance with the highest standard of safety”. If the FAA approves Boeing’s instructions, operators will be required to perform that regimen on every grounded aircraft before it is returned to service.
Earlier in the day, the FAA launched an audit into Boeing’s production system as part of its investigation into why the Alaska airframe’s emergency exit door plug failed in-flight. The aircraft, operating as flight 1282 from Portland to Ontario, California, had climbed to about 16,000ft when the door plug blew and a rapid depressurisation took place. No passengers or crew were seriously injured and after the pilots declared an emergency, the jet landed safely back in Portland.
Experts have told FlightGlobal that the circumstances suggest a quality problem on the part of Boeing.
The agency said it is also considering appointing an outside entity to oversee Boeing’s quality system and is reviewing the so-called “delegated authority” system over oversight. Under the delegated authority process, the FAA grants Boeing and other aerospace manufacturers a large degree of autonomy in ensuring they comply with federal aviation regulations.
United Airlines - the world’s biggest operator of the Max 9 with 79 examples in its fleet - and Alaska Airlines, with 65 aircraft, have both had to cancel hundreds of flights since the event. United said on 12 January that it’s cancelled Max flights through 16 January, while Alaska has done so through 14 January. Both carriers say are endeavouring to “save” as many flights as possible by switching to other aircraft types and re-booking passengers to other itineraries.