Description

On 3 February 2013, an Airbus A340-600 (A6-EHF) being operated by Etihad Airways on a scheduled international passenger flight from Abu Dhabi to Melbourne with an augmented crew was in the cruise at FL350 in night Instrument Meteorological Conditions (IMC) when a brief period of unreliable airspeed indication on two of the three available displays occurred with loss of the AP. Concurrently, an unintentional excursion above the cleared level took place. On recovery from this and restoration of normal airspeed displays, it was found that the AP could not be re-engaged. Excessive vibration on the left engine then began and a PAN was declared using CPDLC with a diversion to Singapore commenced. The engine remained in use and the vibration ceased during descent with the rest of the diversion uneventful, apart from the need to dump fuel and fly manually.

Investigation

An Investigation was carried out by the UAE GCAA Air Accident Investigation Sector (AAIS). Data from the DFDR and DAR were successfully downloaded and used to support the Investigation but the relevant recording on the 2 hour CVR was overwritten during the diversion.