I asked myself, looking at a long list that included multiple main fuel-control (MFC) changes, variable exhaust gripes, fuel-inlet tubes (FITs) rubbing on bell cranks
, and an engine that shifted in flight.
The "emergency airworthiness directive" calls for safety inspections of the bell cranks
, a part of the critical elevator control system, located on the tail of an aircraft.
Another possibility: the cables, each made up of more than 100 stainless steel threads, could have been frayed by heat, resulting in loose strands getting tangled in the network of pulleys and bell cranks
that guide cables to the wings and tail.