UK regional operator Flybe amended operating procedures for performance calculations after a serious Embraer 175 take-off incident at Dublin involving an incorrect flap setting.
The crew of the twinjet, bound for Cardiff on 11 August last year, had been intending to depart runway 28, for which the performance calculation specified a 'flap 1' setting.
While this was entered into the flight-management system, the aircraft (G-FBJK) was subsequently directed to runway 10.
The first officer recalculated for a take-off from intersection E7 but, while the crew noticed a change in speeds, neither noticed a change in configuration to 'flap 4'.
Nor did the captain crosscheck the speeds and flap setting against the quick-reference handbook, says the UK Air Accidents Investigation Branch.
As the aircraft – which was conducting a full-length take-off – accelerated along runway 10 it started to rotate at 133kt. But this was 12kt slower than the speed required for the 'flap 1' configuration of the jet.
The inquiry says the rotation appeared normal but stopped at 10° nose-up with the main landing-gear still on the runway.
Only after the airspeed increased to 145kt, in line with the flap setting, some 5s later did the aircraft lift off.
"At the time of this event the operator did not require its pilots to calculate take-off performance data independently," says the inquiry. It adds that the crew did not carry out a gross error check, as required by the company.
But it states that Flybe has since changed its "ineffective" standard operating procedures to align them with European Union Aviation Safety Agency recommendations for both pilots to carry out independent and crosschecked calculations.
Flybe has also introduced a take-off and landing data card on the E175 fleet, which will be used for data transfer from the electronic flightbag, and potentially serve as an extra safety barrier.