What happened
On 20 October 2013, a Boeing 757-224, registration N41140, was operating a scheduled passenger flight from Newark to Dublin. During the descent, the aircraft encountered increasing turbulence. As the weather stabilized, the co-pilot observed that the airspeed indicated on his instruments was dropping. Fearing an impending stall, the co-pit applied forward pressure on the control column and increased engine thrust to regain speed. After the aircraft's speed appeared to recover briefly before dropping again, the co-pilot repeated the nose-down maneuver.
Upon realizing the discrepancy, the commander took control of the aircraft and stabilized the flight. During the recovery, the crew received an alert regarding a loss of pressure in the centre hydraulic system. The turbulence and subsequent maneuvers caused minor injuries to 4 crew members and 13 passengers. The aircraft sustained significant damage to the cabin ceiling panels and the centre hydraulic system service bay. The flight landed in Dublin with emergency services on standby.
The investigation
The AAIU examined the flight data, cockpit voice recordings, and aircraft systems to determine why the airspeed indications were inconsistent. The investigation focused on the discrepancy between the pilot flying's instruments and the commander's instruments, as well as the subsequent hydraulic failure and the physical damage sustained by the aircraft's interior and systems.