Responding to “several reports of the rear passenger door departing the airplane in flight” the FAA Wednesday published proposed rules for owners of certain Diamond aircraft models. “Several reports” appears to translate to 31, according to the FAA, and affected models are DA40 and DA40F airplanes. The FAA is proposing to change the models’ “emergency open doors procedure” via temporary revision to the aircrafts’ flight manuals and apply an “improved design” to an open door retention mechanism on some aircraft. The physical change required for door retaining brackets would affect 428 airplanes in the U.S. registry at an estimated cost of $245 per aircraft. But that change does not affect the door locking mechanism, itself, which Diamond says appears to be fine … so long as pilots actually close the door.
The FAA says Diamond has already tested the locking mechanism and has concluded that it provides adequate strength to react to flight loads. Diamond’s own Mandatory Service Bulletin is available, here (PDF). Diamond has determined that the real problem of losing doors in flight is related to a safety-latch design feature currently on the aircraft. The latch is meant to hold the doors in a “near closed” position while the aircraft is on the ground. According to the FAA, it “might not” hold the door in that “near closed” position in flight. Diamond’s understanding is that pilots who have lost doors in flight failed to properly secure the rear passenger door prior to flight. The FAA’s Notice of Proposed Rulemaking (NPRM) is accepting comments prior to Oct. 12, 2010, and is available online.
