What happened
On July 20, 2013, during a pre-flight inspection at Warsaw Chopin Airport (EPWR), the crew of a Boeing 737-400 discovered damage to the aircraft's left angle of attack (AOA) sensor. The damage was caused by contact with a passenger boarding bridge (jet bridge) during ground operations.
Following the discovery, the crew contacted the operator's Maintenance Control Center (MCC) and Operations Department. A one-time authorization was granted to allow a licensed mechanic to perform the necessary repairs. This authorization permitted the aircraft to operate under specific limitations defined by the Minimum Equipment List (MEL), specifically affecting the autothrottle system (MEL 22.4), the auto slat systems (MEL 27.12), and the stall warning system (MEL 27.13.1).
The investigation
The investigation focused on the circumstances surrounding the contact between the boarding bridge and the aircraft. The inquiry established that the damage occurred due to a ground handling error. The investigation concluded on February 24, 2016.
On July 22, 2013, the damaged AOA sensor was replaced in accordance with the Aircraft Maintenance Manual (AMM 27-32-11), after which the aircraft was returned to service without operational restrictions.