FAA Proposes A New Airworthiness Directive For Boeing 737s

Date: November 9, 2022

By Riley Pickett, Simple Flying

On November 9th, the Federal Aviation Administration (FAA) put out an airworthiness directive (AD) for select models of the Boeing 737. The AD particularly addresses the inspection of skin lap splices across the aircraft. The directive comes following the discovery that select splices on these aircraft may be subject to widespread fatigue damage (WFD). Aircraft operators must comply with this order, or their 737s will no longer be deemed airworthy.

Airworthiness directives

ADs are one of the many regulations that must be complied with for an aircraft to be deemed airworthy. ADs are released after an aircraft has received certification and been put into production. As various operators use an aircraft, design flaws will inevitably arise. For this reason, the FAA will issue an AD. Each AD will require the owner or operator to have a mechanic administer prescribed maintenance.

An easy way to understand what an AD is to think of it like a recall on a car. The difference is the manufacturer won't fix it for you; all costs fall on the aircraft owner. All ADs must be complied with and documented in order for the aircraft to be airworthy. Some ADs are recurring, while others are non-recurring and only need to be complied with once. This specific AD must be adhered to by December 27th. Every Boeing 737 model listed on the AD not in compliance with the directive by this date will be grounded until the appropriate measures are instituted.

The 737 models listed on the AD include the 737-600, -700, -700C, -800, -900, and -900ER. The issue in question regards skin lap splices on the aircraft's exterior. These skin lap splices are points where metal skins are joined together. The FAA issued a summary of the issue in the AD. It reads,

"This proposed AD was prompted by an evaluation by the design approval holder (DAH) indicating that the skin lap splice at certain stringers is subject to widespread fatigue damage (WFD). This proposed AD would require an inspection for any repair at certain skin lap splices and depending on the configuration, repetitive inspections for buckling, wrinkling, bulging at affected skin lap splices and repair, repetitive inspections for cracking at affected locations common to fuselage skin on the left and right sides and repair, and alternative inspections and on-condition actions. The FAA is proposing this AD to address the unsafe condition on these products."

737 MAX AD

One of the most famous ADs in recent years was the AD that helped unground the MAX. The MAX series was grounded after the two tragic Boeing 737 MAX accidents. Several changes were made to the aircraft's design before it would be allowed to return to the skies. The changes that needed to be made were listed in an AD for all MAX airplanes.

Most ADs are standalone maintenance orders that are simple and straightforward. However, this AD was accompanied by a Continued Airworthiness Notification to the International Community and a list of MAX training requirements for pilots. Once all of these were complied with, the airplanes were allowed to return to the skies.