The US Federal Aviation Administration has grounded all MD-11 and MD-11F aircraft for inspections following the crash of an MD-11F operated by UPS Airlines (5X, Louisville International) on November 4.

The regulator said in an emergency airworthiness directive on November 8 that it "has determined the unsafe condition is likely to exist or develop in other products of the same type design". This justified the immediate grounding of the aircraft family pending inspections and corrective actions approved by the FAA. The directive does not specify what corrective actions could be necessary.

The McDonnell Douglas trijet is no longer active in passenger service. ch-aviation data shows the three remaining operators of the MD-11Fs are FedEx Express (58 units), UPS Airlines (26), and Western Global Airlines (14).

UPS Airlines and FedEx said they proactively grounded their MD-11F fleets on the advice of Boeing (which took over McDonnell Douglas in 1997), before the FAA directive came out.

Western Global Airlines did not respond to ch-aviation's request for comment. Despite having the fewest MD-11Fs in absolute terms, the airline is proportionately the most affected, as its fleet only includes four other aircraft (all B747-400 freighters in various variants). For FedEx and UPS, the MD-11Fs account for less than 10% of their recently active fleets in terms of aircraft numbers.

The directive was prompted by the crash of N259UP (msn 48417) during take-off from Louisville International, after the left engine detached from the wing. The crash is under investigation by the US National Transportation Safety Board (NTSB).