An Etihad Airbus A330-200 departing Brisbane for Singapore was forced to make an emergency landing after wasps nested in a vital system.
Etihad Flight EY437
The incident involving Etihad Flight EY437 on 21 November 2013 was recorded by the Australian Transport Safety Bureau (ATSB) as a serious incident.
The ATSB preliminary report released today shows that mud-dauber wasps had built a nest in the pilot’s air speed indicator tubes.
This is a known issue that was thought to be the cause of an air disaster in 1996 when a Boeing 757-200 (Birgenair Flight 301) crashed shortly after take-off from the Dominican Republic on route to Frankfurt. The aircraft was carrying 176 passengers and 13 crew. There were no survivors.
The ATSB report into the EY437 incident shows the potentially serious consequences of the wasp’s nest building activities. The mud-dauber wasps will either build its own cylindrical nests out of mud or will take advantage of man-made cylindrical structures – such as the tubes used on aircraft that measure airspeed. The 1996 incident occurred after the aircraft had been standing for 25 days without protective covers on the tubes and again one of the three tubes was found to be blocked.
Pushed back to Singapore
The ATSB report states that “at 1152 EST, the aircraft was pushed back for the return flight to Singapore. At 1204 EST, the captain discontinued (rejected) the takeoff after observing an airspeed indication failure on his display. The maximum airspeed recorded by the flight data recorder during the rejected takeoff was 88 kt.” The maintenance team at Brisbane then investigated the problem and disable on of the three probes.
The report then goes on to say that “at 1345 EST, during the second takeoff, the crew became aware of an airspeed discrepancy after V1 and the takeoff was continued. Once airborne, the crew declared a MAYDAY and decided to return to Brisbane where an overweight landing was carried out at 1439 EST.”
The captain’s probe was removed from the aircraft and sent to the probe manufacturer in the USA. Examination showed that it had been almost completely blocked by an insect nest, composed of sand and mud, that was consistent with the nest of a ‘mud-dauber’ wasp.