The US National Transportation Safety Board (NTSB) has recommended the US Federal Aviation Administration to require recurrent inspections of Piper PA-31 Navajo inboard door hinge assemblies until they are replaced by a stronger hinge unit. The NTSB's advisory results from a 1997 regional airline incident in which a Cape Smythe Air Service Navajo landed in Alaska with a partially retracted left main landing gear. Examination revealed that a forward hinge on the gear door had broken, jamming it and preventing the gear from extending fully.
Source: Flight International