Danish investigators have concluded that a Chinese Boeing 777 freighter struck its tail twice after a bounced landing and that its crew opted to go around even though reverse thrust had already been activated.
The aircraft, operated by China Cargo Airlines, bounced three times as it touched down at Copenhagen after a flight from Shanghai on 17 April 2011.
It had landed with a descent rate of 160ft/min at an airspeed of 143kt, some 5kt below the reference speed for its 252t landing weight.
After the 777F bounced for the third time the speedbrake handle was activated, deploying the ground spoilers and the thrust reversers on the General Electric GE90 engines.
The reversers deployed over the space of 11s but as the aircraft decelerated its pitch gradually increased to 10.5°, enough to cause its tail to strike the runway.
Danish investigation authority HCL says this initial impact resulted from the pilot's failing to keep the pitch under control by applying light forward pressure on the control column.
As the pitch-up attitude increased the pilot opted to abort the landing, despite the thrust-reversers having already been deployed.
Boeing's flight-crew training manual for the 777F states that a full-stop landing "must be made" once reverse thrust is initiated after touchdown.
But the HCL says the combination of the bounced landing, and the limited forward view caused by the pitch-up, "probably caused an uncertainty" regarding the runway available to stop the jet.
HCL analysis, however, shows there was some 1,700m (5,600ft) of runway remaining at the point the go-around was initiated.
"It is the opinion of the [investigators] that the remaining runway was sufficient and safe to make a full stop," it adds.
During the go-around, with reversers and spoilers stowed, the aircraft was rotated to a pitch of 10.2° which resulted in a second tail-strike, prolonged as the pitch continued to increase to 11.9°. The aircraft became airborne with 760m of runway remaining.
HCL says the tail-strikes inflicted substantial damage to the lower fuselage. Several sections of fuselage skin were split through to the interior, while the rear pressure bulkhead's frame was worn. The aircraft returned to make a safe landing on the same runway.