XL Airways Germany Flight 888T

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XL Airways Germany Flight 888T was an Airbus A320 which crashed into the Mediterranean Sea, 7 km off Canet-en-Roussillon on the French coast, close to the Spanish border, in November 2008. The technical flight originated from Perpignan - Rivesaltes Airport, made an overflight of Gaillac and was flying back to Perpignan Airport, doing an approach over the sea. This flight took place immediately following light maintenance and repainting to Air New Zealand livery on the aircraft done at EAS Industries in preparation for a transfer of the plane from XL Airways Germany, which leased the aircraft, to Air New Zealand, the owner.

Seven people were aboard, two Germans (pilot Norbert Kaeppel and co-pilot Theodore Ketzer from XL Airways) and five New Zealanders (one pilot, three aircraft engineers and one member of the Civil Aviation Authority of New Zealand). Two bodies were recovered within hours of the crash; the others were found during later weeks.

The extent of shattering of the wreckage indicated that the crash occurred at high speed.

The crash area was declared a crime scene and the French justice system opened a manslaughter investigation.

The aircraft had been overhauled by a local French company located at the Perpignan–Rivesaltes Airport prior to its return off lease.


Investigation

On 30 November 2008, divers recovered the second "black box" flight recorder and a third body, unidentified at the time. Although the cockpit voice recorder was damaged, experts said that there was a good probability of recovering data from it.

In late December, French investigators attempted to retrieve data from both black boxes, but the data could not be read. Usable data from the flight recorders was later recovered at the manufacturer's facility.

The investigators' interest focused on the Air Data Inertial Reference Unit following recent similar Qantas incidents on A330s, exhibiting sudden uncommanded maneuvering (see: Qantas Flight 72). The investigation was led by the Bureau d'Enquêtes et d'Analyses pour la sécurité de l'Aviation Civile (BEA), with the participation of its counterparts from the German Federal Bureau of Aircraft Accidents Investigation (BFU), the New Zealand Transport Accident Investigation Commission (TAIC), and the United States National Transportation Safety Board (NTSB). Specialists from Airbus and from International Aero Engines (IAE), from XL Airways Germany, operator of the airplane and from Air New Zealand, the owner of the airplane, were associated with the work of the technical investigation.

Analysis of the data led to an interim finding that the crew lost control of the aircraft. While conducting a planned test of low-speed flight at low altitude, the aircraft was descending through 3000 feet on full autopilot for a go-around. Landing gear was just extended when at 15:44:30 UTC the speed dropped from 136 to 99 knots in 35 seconds. The stall warning sounded four times during violent maneuvering to regain control. By 15:46:00 the warning had silenced as the aircraft regained speed in a rapid descent, but six seconds later, at 263 knots, the aircraft had only 340 feet elevation and was 14 degrees nose down. A second later it was in the water. In September 2010, the Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile published their final report into the accident. The primary cause was incorrect maintenance procedures which allowed water to enter the angle of attack (AOA) sensors. The water then froze in flight, rendering the sensors inoperative and thus removing the protection they provided from the aircraft's flight management system. When the crew attempted an improvised test of the AOA warning system (which was not functioning due to the blocked sensors) they lost control of the plane. The aircraft's computers received conflicting information, and completely disconnected. This led to all automation built into the plane's systems to deactivate. Since the pilots were likely relying on the computer to optimize the aircraft to climb, and it didn't, the crew was unable to recover from the dive. The crew was unaware that the AOA sensors were blocked, but they also disregarded the proper speed limits for the tests they were performing, resulting in a stall. Five safety recommendations were made.




Source:
http://en.wikipedia.org/wiki/XL_Airways_Germany_Flight_888T
https://drive.google.com/file/d/0B8aiechh7K6iak9lektMdXVKbTQ/view?usp=sharing

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