posted on Aug, 12 2016 @ 01:29 PM
The ATSB is taking steps to address a condition on ATR-72 aircraft that resulted in an aircraft suffering extensive damage to the tail that wasn't
discovered until 13 flights later. It was determined that the aircraft suffered a major overstress, almost 50% beyond the ultimate load.
Under rare conditions the aircraft can suffer from a separation of the pitch control, where the elevators are controlled individually by each pilot.
Instead of both elevators moving under a single input, the right controller will control the right elevator, and the left controller will control the
left elevator. In February 2014, a Virgin Australia ATR suffered a pitch split when the pilots input separate control inputs, resulting in a high
speed pull up. The maintenance crew didn't follow a procedure that required a detailed inspection of the tail and elevator assembly, so the damage
wasn't discovered for five days, after the aircraft was thought to have suffered a bird strike.
During the investigation, the ATSB found 11 more pitch split incidents, none of which occurred as a result of what the system was designed for, a
jammed control link. ATR was unaware of this happening in flight, and thought the problem was limited to ground operations.
ATR and Virgin Australia have taken steps to prevent pilots from accidentally overstressing the ATR 72’s tail and to help maintenance engineers
identify a rare but significant condition when the aircraft’s pitch-control system separates pilot and copilot inputs.
The changes are the result of an Australian Transport Safety Bureau’s (ATSB) investigation into a February 2014 incident with a Virgin Australia
Regional Airlines ATR 72 and a number of similar incidents that came to light as part of the investigation.
The common factor is the ATR pitch-control system design. It features a “pitch disconnect” that, in cases of jammed controls, gives the captain
control of the left-side elevator and the first officer control of the right-side elevator. In normal mode, each pilot controls both