A Virgin Australia Boeing 737-800 suffered a tailstrike on takeoff from Auckland Airport after a reduction in headwind resulted in a drop in airspeed, an Australian Transport Safety Bureau (ATSB) investigation has found.
The incident occurred on January 17 2018, when 737-800 VH-YIR was operating flight VA91 to Rarotonga in the Cook Islands.
The ATSB final report published on Thursday said the takeoff had occurred in gusty conditions – including a slight crosswind – with the aircraft speed reducing during rotation.
“A decrease in the headwind component reduced the airspeed during rotation and extended the time required for VH-YIR to leave the runway, resulting in a reduced tail clearance and subsequent tailstrike,” the ATSB report said.
The ATSB report said an analysis of the flight data showed airspeed reduced by up to 11kt during rotation, with the pitch attitude of the aircraft at lift-off at 10.55 degrees.
Further, the data showed the aircraft “was slow to lift off the runway” at six seconds from the point of initial rotation.
“During rotation, as the aircraft continued to accelerate, a reduction in headwind resulted in an initial drop and then stagnation in airspeed until just after lift-off,” the report said.
“The airspeed variations were reportedly not identified and called out by the PM (pilot monitoring), as required in the flightcrew training manual.
“Stagnation in airspeed at rotation had a similar effect to that of rotating too early: reduced lift and an extended takeoff roll, as confirmed by the flight data.
“The continued rotation with the main landing gear remaining on the runway then resulted in a reduced tail clearance.”
The ATSB said the flightcrew felt a bump from the rear of the aircraft and concluded it was most likely the result of a tailstrike. Cabin crew reported there had been a very loud noise from the rear of the aircraft during takeoff.
The captain then contacted air traffic control to request a runway inspection, which identified no debris or damage to the runway.
After levelling off at 12,000ft, the captain then conducted an overweight landing back at Auckland Airport.
There were no injuries to the two pilots, four cabin crew and 135 passengers on board.
“The flightcrew were proactive in gathering information from all available sources, which enabled them to make a complete assessment of the situation,” the ATSB report said.
“They were decisive in their actions and kept cabin crew, passengers, ATC and ground staff up to date with clear communications.”
An engineering inspection then confirmed the aircraft had sustained a tailstrike during takeoff.
“The damage was limited to a scratch on the tailskid shoe that was found to be within the allowable limits. An overweight landing check was completed and the aircraft was determined to be serviceable,” the ATSB said.
The ATSB report said the captain noted that due to the crosswind conditions significant yoke input was required to keep the wings level.
“Even so, the aircraft became airborne with the right wing slightly lower than the left,” the ATSB report said.
“The captain noted that in strong crosswind conditions, flightcrews are required to make a quick decision on the compromise between keeping wings level and avoiding raising a spoiler, which has a corresponding loss of performance.”
Although it was discovered during the off-loading of bags and freight there were 10 fewer bags in the forward compartment of the cargo hold than detailed on the load sheet, the ATSB said this minor discrepancy was not significant and did not contribute to the tailstrike.