Abnormal engine indications involving a Boeing 737-476, VH-TJI, Alice Springs, Northern Territory, on 16 December 1993

Just after take-off, the crew felt an impact and noticed a slight airframe vibration. The captain decided to leave the landing gear extended until the serviceability of the aircraft could be verified as he believed that the impact had been near the nosewheel. He advised the aerodrome controller who despatched a vehicle to inspect the runway and found the remains of several birds. This information was passed to the captain who contacted the engineering department of his company for advice. As all engine indications were normal and the vibration had ceased, the captain decided to continue to Adelaide as scheduled.

During the flight the engine vibration indicators showed low readings until top of descent when the right hand engine indicator increased significantly although still within limits. Inspection of the aircraft after landing revealed that a number of right engine fan blades had been damaged. The nature of the damage was consistent with bird ingestion.

A readout of the FDR revealed that vibrations were far greater in the turbine section of the engine than at the compressor. As only compressor section vibration data is displayed on the cockpit engine vibration indicators, there was no way for the crew to be aware of the extent of the engine damage.