A Tui aircraft’s performance on take off from Bristol airport was “significantly compromised” due to a cockpit fault, air accident investigators have found.
The Boeing 737-800 with 163 passengers and six crew on board crossed the end of the runway at a height of just 10ft and an adjoining road by 100ft.
“Both pilots had noted how close to the end of the runway they were,” the Air Accident Investigations Branch (AAIB) “serious incident” report said.
The aircraft took off with insufficient thrust when the autothrottle disconnected on a service to Las Palmas on March 4.
“The autothrottle remained in an inactive mode despite attempts to re-engage it,” the AAIB said.
“The flight to Las Palmas was uneventful apart from several attempts to re-engage the autothrottle and subsequent disengagements.”
The AAIB issued a preliminary report into the incident in May.
Its full report said: “The operator has taken a number of safety actions to address both the actions to be taken in the event of an uncommanded disconnection of the autothrottle at takeoff, and their monitoring of events through flight data monitoring.”
The report noted that the “uncommanded disconnect was likely the result of the voltage being supplied to the autothrottle servo motor (ASM) being too low which was a known problem with the B737 autothrottle and the older revision of the ASM part fitted”.
The AAIB concluded: “Neither crew realised that the thrust was not set as required for take off but was significantly less than had been calculated during the pre-flight preparation.
“As a result, the aircraft performance was significantly compromised.
“The uncommanded disconnection was likely caused by low voltage being supplied to the ASM which caused it to disconnect from the throttles.”
Tui declined to comment on the report’s findings.