"The captain is alway right", may kill you! - Curt Lewis

Wrong data inputs caused Jet 777 late take-off at London Heathrow

Jet Airways has amended its standard operating procedures for take-off following a late take-off incident that occurred on 30 August 2016, involving one of its Boeing 777-300ERs at London Heathrow airport.

The aircraft, registered VT-JEK, was departing from on a flight to Mumbai at 20:30UTC, when it crossed the airfield boundary at 13ft above ground level and an adjacent road at 30ft above ground level. There were no reports of injuries among the 15 crew and 231 passengers on board.

The UK Air Accidents Investigation Branch classified the case as a serious incident, and delegated the investigation to India's Air Accident Investigation Bureau.

In its final report, the Indian AAIB found that VT-JEK took off from runway intersection S4 on runway 27L, but the used performance figures calculated for intersection N1, which was the full length of the runway. Consequently, regulatory take-off performance requirements were compromised.

The pilot-in-command calculated the aircraft take-off performance from the first four intersections of the runway using the default On-Board Performance Tool (OPT) output corresponding to the full length, whereas the co-pilot had correctly calculated performance for a takeoff from intersection S4W.

The discrepancy was identified during the post-calculation crosscheck of the OPT output. However, the co-pilot changed her OPT entry to match the pilot-in-charge "probably due to the fact that commander was much senior to the co-pilot".

Rotation was initiated with 556m of runway remaining and lift-off occurred with 97m remaining. As the aircraft passed the end of the runway, the three radio altimeters recorded heights above the surface of 16.4ft, 16.6ft and 17ft respectively.

"From a procedural perspective, there appeared to be no assurance that an incorrect or invalid entry into the OPT made at the departure briefing would be corrected before the performance calculation was made," says the AAIB.

The AAIB adds that a contributory factor to the incident include both pilots flying out of the runway for the first time.

Jet now requires its crew to call out and resolve discrepancies between the output of the pilot-in-command and co-pilots OPT before entering data into the control and display unit.