Spanish investigators have disclosed that the Spanair Boeing MD-82 which crashed on departure from Madrid Barajas last week descended and struck the ground tail-first while struggling to climb away.

The aircraft travelled for 1.2km, hitting terrain three times before coming to rest.

Spain's Comision de Investigacion de Accidentes e Incidentes de Aviacion Civil (CIAIAC) revealed the information in the first update on the inquiry's progress since the 20 August accident which killed 154 of the 172 on board the jet.

MD-82 Aircraft Trajectory 
 © Tim Bicheno-Brown/Flight International

It says that no marks or debris from the aircraft were found on the runway. Initial impact marks have been discovered to the right of the runway, indicating that the aircraft struck tail-first and that a section of the tail - possibly the tail-cone, which can detach to aid evacuation - came away.

The investigation agency has not confirmed the angle of attack of the aircraft at the point of impact.

CIAIAC's Francisco Javier Soto states: "[The MD-82's] movement along the ground lasted approximately 1,200m."

There is no firm indication of the height the aircraft achieved before it descended.

The CIAIAC sent a team with the flight data recorder and cockpit voice recorder to the UK Air Accident Investigation Branch for downloading. The AAIB says the downloading has been completed and the CIAIAC team has taken the data back to Spain.

The aircraft's Pratt & Whitney JT8D-217 engines, thrust-reversers and auxiliary power unit have been recovered and stored for examination, along with some of the MD-82's avionics.

No conclusions have yet been reached over the status of the aircraft's engines or other systems at the time of the accident. The investigators are still collating data from several sources, including video surveillance, airport radar, air traffic control and maintenance personnel.

CIAIAC says that it is required to produce an initial factual report on the accident within a month.

See Operations & Safety Editor David learmount's latest blog on the Spanair Md-82 crash
PICTURES: See more images of the crash on AirSpace
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Source: Air Transport Intelligence news