The FAA has issued a press release about 737 leading edge slat tracks may have been improperly manufactured and may not meet all applicable regulatory requirements for strength and durability. According to the FAA, the issue affects both 737NG and 737MAX aircraft.
It is unknown whether any of these articles are in distributors’ inventories, or if all of them are still on-wing (although it is likely that they remain on-wing due to the age of the fleets). Boeing claims that it has contacted all of the affected operators.
This issue appears to affect a significant number of aircraft. Boeing claims that 21 of the 737NGs are likely affected but has nonetheless recommended inspecting a total of 133 of them. The FAA press release indicates that the total number of 737MAX aircraft to be inspected is 179 (and Boeing claims that 20 of the aircraft are most likely to have the problematic slat tracks).
The FAA has pledged to issue an Airworthiness Directive (AD) to mandate Boeing’s service actions to identify and remove the discrepant parts from service. We expect to see the AD, soon. After the AD has been published, distributors are advised to examine the AD and ensure that they do not receive slat tracks from among the AD list. The AD was still forthcoming as of this afternoon – ASA plans to publish follow-up information after the AD has been published.