What happened
On 19 January 2013, an Airbus A3/330-343, registration G-VKSS, was performing a scheduled passenger flight from Orlando International Airport, USA, to Manchester, UK. During the initial climb phase at approximately 530 ft, the aircraft encountered multiple bird strikes. The impact involved the aircraft's radome and the fan blades of both engines.
Following the strikes, an ECAM message indicated a malfunction in the left engine. The crew noted significant vibration through the airframe and observed that the engine oil pressure for the left engine had dropped to zero. In response to the emergency, the commander declared a 'mayday' and later downgraded the alert to a 'pan' as the crew managed the situation. Following established procedures, the crew reduced thrust on the left engine and performed the engine shutdown procedure. The aircraft subsequently returned to Orlando and performed an uneventful single-engine landing on Runway 36R.
The investigation
The AAIB investigation examined the aircraft's flight recorders and the physical damage sustained. Inspection of the aircraft in Orlando revealed damage to the radome, the left engine nose cowl, and several fan blades on both the left and right engines. Analysis of biological remains recovered from the engines identified the birds as likely Ring-necked Ducks, weighing between 1.5 and 2 lbs.
Investigators also examined the engine oil system. While the left engine had been shut down due to the zero oil pressure indication, no defects were found within the engine oil system itself. Subsequent inspection of the engine during overhaul confirmed that the oil pressure transducer supply lines were correctly routed and secured.
Findings
- The primary cause of the incident was multiple bird strikes involving the aircraft's nose and both engines during the climb.
- The left engine was shut down because the Electronic Engine Controller (EEC) oil pump failure logic was triggered, resulting in a zero oil pressure indication.
- The engine manufacturer has previously noted that high vibration, such as that caused by an Integrated Drive Generator (IDG) failure, can trigger this specific oil pressure failure logic.
Safety action
Safety Recommendation 2013-015: It is recommended that Rolls-Royce plc modify the oil pressure indication and failure detection systems of the Trent 700 engine to reduce the likelihood of the EEC oil pump failure logic being activated by high vibration or IDG failure.