The Australian Transport Safety Bureau (ATSB) has released its investigation report into the fatal crash of a Cessna 172 into the sea off Tasmania in 2014.
VH-PFT was being used in a low-level photography mission over the Sydney-Hobart Yacht Race on 29 December 2014, when it dropped a wing in a steep turn and crashed into the sea near Cape Raoul. Both the pilot and the photographer died in the crash.
According to the ATSB, the aircraft was flying at around 50 feet past the yacht Mistraal when the pilot climbed suddenly and attempted a steep turn that led to a stall and spin.
"As a result of the steep climbing turn, the aircraft's upper wing aerodynamically stalled, resulting in a rapid rotation out of the turn," the investigation report states.
"The steep pitch attitude indicated that, because of the stalled upper wing, the aircraft entered a spin. There was insufficient height for the pilot to recover the aircraft."
Yachts in the vicinity were unable to reach the downed aircraft before it sank.
The ATSB concluded that the pilot had a valid low-level rating and although the last pass was done well below the 150 feet limit set by the CASA dispensation, it was not considered to have been significant as the pilot couldn't have recovered from that altitude either.
In a safety message issued in conjunction with the report, the ATSB said:
"Turning manoeuvres at or close to the aircraft’s critical angle of attack, or stall speed, if poorly handled, can result in a stall that will probably result in the aircraft entering a spin. This is particularly true for aircraft under 5700 kg.
"The normally benign stalling characteristics of these aircraft types are exacerbated by the spin entry, which results in a steep pitch down and rotation towards the stalled wing. Recovery from this condition will take a considerable amount of altitude, dependant on the speed of response by the pilot and the use of appropriate control inputs."
The full investigation report is available on the ATSB website.