(New York) Oxygen generators on more than 2,600 Boeing 737 family planes operating in the United States must be inspected “immediately” to ensure they are in proper position, the U.S. aviation regulator said in an airworthiness directive (AD) on Monday.
According to the FAA, this inspection must be carried out “within 120 to 150 days” on “certain Boeing 737-8, 9, -8200, -700, -800, and -900 aircraft.”er “, that is, old and new generations.
Some 2,612 U.S.-registered planes are to be inspected, the FAA said, without ordering that the affected planes be grounded in the meantime.
The directive concerns the oxygen mask system provided to passengers in the event of cabin pressure loss during flight. A 737 has an average of 61 oxygen generators, each equipped with two straps.
It stems, according to the regulator, from several reports that passenger service units (PSUs) – equipment located above the seats with lighting, ventilation, and from which oxygen masks drop in an emergency – have moved due to a “failure of the attachment”.
According to the document released by the FAA, Boeing examined this equipment and identified that the problem came from an attachment point for the generator straps. Not all planes in the 737 family were equipped in this way, but, as a precaution, all should be inspected.
The aircraft manufacturer explained that it had provided airlines with instructions in June for checking these straps.
“A new adhesive used on the straps in August 2019 was found, under certain circumstances, to have allowed the blocks to move up to 3/4 inch,” Boeing said. “We have reverted to the original adhesive for all new deliveries to ensure the generators remain firmly in place as designed.”
If this problem is not resolved, the FAA noted, the PSU oxygen generators could “move and become nonfunctional, rendering them unable to provide supplemental oxygen to passengers during a depressurization episode.”
“The FAA is issuing this AD to eliminate the unsafe conditions of these products,” she noted.
Inspections conducted to date on aircraft awaiting delivery and the in-service fleet have not identified any malfunctions in the units. And, when oxygen masks were deployed in flight, the generators functioned properly.