Pilots of a Norwegian Boeing 787-9 departing London Gatwick inadvertently taxied over 400m beyond the beginning of the runway, shortening the take-off distance and risking an overrun in the event of engine failure.

The aircraft, bound for Buenos Aires, had been given instructions to enter runway 26R along taxiway AN. This taxiway is unusual because it feeds into the runway in a straight line rather than requiring a turn to line up with the runway heading.

Runway 26R also has a displaced threshold and, in the dark, the pilots taxied up to this threshold, some 417m past the beginning of the runway, before commencing the take-off run.

This meant the aircraft had insufficient thrust to meet regulatory take-off performance criteria for the length of runway available. The 787 rotated about 600m from the runway end.

“After departure both pilots commented that there was not much runway remaining at lift-off,” says the Air Accidents Investigation Branch.

“Given the limiting length of the runway, the load had been reduced to allow take-off, and therefore the crew were not surprised by the length of the runway used during the take-off run and were unaware of any problem.”

But had the aircraft suffered an engine failure at the critical V1 speed, an attempt to abort the take-off could have resulted in an overrun, says the inquiry. Analysis by the carrier indicated that the aircraft was 12t too heavy for the available distance.

Four other similar incidents involving aircraft not starting their take-off run at the beginning of 26R were recorded in the period between September 2017 and the Norwegian event on 28 March this year.

Neither pilot of the 787 (G-CKWC) could recall seeing anything which indicated they were in the wrong place, although a take-off distance sign, illuminated at night, is positioned to the left of the beginning of the runway.

Runway 26R is not the main runway at Gatwick, but the airport’s operator has proposed bringing it into routine use for departures – at least for single-aisle aircraft – as part of a strategy to increase capacity.

In the aftermath of the Norwegian incident a NOTAM amendment was issued describing the position from where take-off runs should commence on 26R, as well as a safety notice which included a photograph showing visual references and the view from taxiway AN.

Gatwick’s operator has agreed to examine other paint schemes which might increase awareness of the beginning of the runway, especially at night. While it is also prepared to look at whether a more conventional turn-to-line-up junction could be introduced, the inquiry acknowledges that this would present “significant challenges” for the airport in terms of taxiway lighting.

Source: Cirium Dashboard