French investigators have deter-mined that an Egyptian Boeing 737-800 crew failed to account for a shortened runway during take-off at Paris, colliding with obstacles on rotation and flying low over a blast fence.

Despite damage to the twinjet, the AMC Airlines crew did not report the collision to air traffic control and continued the flight to Luxor. The incident was only discovered when a taxiing aircraft reported debris on the runway three hours later, and several days passed before the 737 involved was formally identified.

French investigation agency Bureau d'Enquêtes et d'Analyses (BEA) said the 737 was cleared to take off on Runway 27L from taxiway Y11. Construction work meant the last 1,240m (4,070ft) of 27L was closed, and the intersection take-off cut a further 280m from the available distance.

Communication difficulties with Egyptian authorities meant the flight-data recorder had been overwritten before analysis of the 16 August 2008 incident.

Paris air traffic control told the crew that 2,360m of runway remained. But radar data indicated the 737 became airborne after 2,520m - some 160m beyond the provisional runway end - and investigators found damaged marker blocks and crushed lights where the work zone began.

AMC staff found the 737 had sustained minor engine cowl, stabiliser and landing-gear damage.

The carrier's pilots used Boeing OPT software, on laptops, to determine characteristic take-off speeds. BEA found that "failure to take into account the runway restriction" while using OPT explained the event.

It has recommended the European Aviation Safety Agency to study standards for certification of such onboard calculation systems to ensure ergonomics and procedures are "compatible with the requirements of safety".

Source: Flight International