The FAA has expanded its Emergency AD on MD-11 aircraft to include the entire roster of DC-10 models and their derivatives. The agency issued an AD on Nov. 8 covering MD-11 and MD-11F models but then determined that the engine nacelle and pylon structure that was the focus of the original AD is pretty much the same in all the aircraft. The first AD was issued two days after the crash of a UPS MD-11 in Louisville that was preceded by the left engine and pylon falling off the plane as it neared V1. The crew continued the takeoff and the aircraft crashed just off the end of the runway. Three crew members and 11 people on the ground were killed.
The original AD covered the majority of the fleet, since most of the trijets still in the air are MD-11s operated by UPS (26) and FedEx (28), for a total of 54 aircraft of the 65 MD-11s still flying. The others are also freighters operated by Western Global Airlines (4) and some other international carriers. There are also about 10 DC-10s still flying. Four of them are used as aerial firefighting platforms, two by Omega Aerial Refueling Services, and another serves as a flying surgical hospital for Orbis International. At least three others fly freight for international carriers.
This accident seems very similar to an early DC-10 disaster at KORD. This happened in 1979, relatively early in the fleet’s history. Investigation revealed that mechanics for the operator (American Airlines) had developed a shortcut technique for removing and re-installing the wing-mounted engines, using a forklift to lift the engine in place. Investigators determined the forklift would sometimes mash (bend) the fitting that secured the engine, and that this ultimately led to a fatigue type failure. Unfortunately, when the engine fell off, it cut the hydraulic lines and the crew lost control resulting in loss of all on board. The FAA required strict enforcement of manufacturer’s installation / maintenance instructions on the make and model, but no modification of the fitting. I think the same factors may be in play.
I can’t remember if there are KC-10 tankers still flying. I assume the pylon would be the same for those, although the cycles would probably be lower.