The Federal Aviation Administration (FAA) has highlighted new issues with some parts for Boeing’s 737 MAX jets and an older model, the 737NG.
A notice from the FAA said that leading edge slat tracks may have been improperly manufactured and may not meet all applicable regulatory requirements for strength and durability. Slat tracks are used to guide the slats located on the leading edge of an aeroplane’s wings.
Up to 148 parts manufactured by a Boeing sub-tier supplier are affected. Boeing has identified groups of both 737NG and 737MAX aeroplane serial numbers on which these suspect parts may have been installed.
The issue is understood to affect 179 MAX aircraft and 133 NG models worldwide.
The FAA said: “The affected parts may be susceptible to premature failure or cracks resulting from the improper manufacturing process. Although a complete failure of a leading edge slat track would not result in the loss of the aircraft, a risk remains that a failed part could lead to aircraft damage in flight.”
Boeing says it is working with the FAA and has contacted 737 operators advising them to inspect the slat track assemblies on certain aeroplanes. If operators find the parts in question, they are to replace them with new ones before returning the aeroplane to service.
Boeing is now staging replacement parts at customer bases to help minimise aircraft downtime while the work is completed. Once the new parts are in hand, the replacement work should take one to two days, Boeing says. Boeing will also issue a safety service bulletin outlining the steps to take during the inspections.
“We are committed to supporting our customers in every way possible as they identify and replace these potentially non-conforming tracks,” said Kevin McAllister, President & CEO of Boeing Commercial Airplanes.
The FAA will issue an Airworthiness Directive making Boeing’s recommendations mandatory.
The 737 Max jet has been grounded since March following two fatal crashes that have been linked to a separate concern about Maneuvering Characteristics Augmentation System (MCAS) software on the plane.