MIAMI – Via an Airworthiness Directive (AD) the US Federal Aviation Agency (FAA) has warned all Boeing 737 NG and MAX operators of a possible rapid decompression risk.

The warning stems from the discovery of cracked or completely severed lugs – a sort of bolt- fitted on the forward entry door of the aircraft, which could lead to rapid decompression of the aircraft.

To correct the problem, the AD requires inspection, measurement, and replacement if a particular Part Number (P/N) is found to be installed on the door.

Boeing 737 MAX – Photo Luca Flores/Airways

Lug Prone to Fatigue Cracking

As described in the AD, the fault consists in an “undersized thickness of the lug which makes it prone to fatigue cracking which could result in the reduced structural integrity of the forward door and consequent rapid decompression of the airplane.”

The AD does not concern the previous Boeing 737 series but only the NextGen and MAX types, which have mounted the same type of door that is interchangeable between the two types of aircraft.

The AD also indicated prohibition of installation or rotation of door fitted with the concerned P/N. This prohibition is dictated by the fact that doors are often mounted or rotated with the concerned fitting already in place.

Photo: Nick Sheeder/Airways