Investigators from the Australian Transport Safety Bureau (ATSB) have determined that a manoeuvre that caused a collision between two jets flying in formation had not been included in the mission briefing.
Marchetti S.211s VH-DQJ (Viper 1) and VH-DZJ (Viper 2) were flying in formation over Port Phillip Bay in November last year on a filming mission when they collided, with Viper 2 aircraft crashing into the bay. Neither the pilot nor the back-seat cameraman survived the impact. Viper 1 was able to return to Essendon with the damage it incurred.
Investigators, aided by on-board video cameras, found that the two jets collided whilst Viper 1 was leading the formation inverted and Viper 2 moved from echelon right to echelon left, moving beneath Viper 1 as it went. When Viper 2 executed a break-away, the wingtips of the two jets colliding as it climbed and banked away.
The damage to Viper 2 resulted in a loss of control that led to it crashing into the water.
It was the second attempt at the manoeuvre, and although the pilots discussed it on the radio, the move had not been part of the original mission briefing on the ground.
“This in-flight discussion did not allow the pilots to fully consider the risks associated with the manoeuvre before it was attempted for a second time,” Chief Commissioner Angus Mitchell said.
“Pre-briefing of in-flight manoeuvres is critical to safe formation flying to mitigate the risks of increased pilot workload and distraction.
“Minimising the risk of these flights requires pilots to prioritise operational safety, in particular through in-depth briefings, pre-flight planning of manoeuvres, and strict adherence to procedures and the agreed plan.
“This ensures everyone has a similar understanding of the intended manoeuvres, and can fully consider the associated risks.
“In-flight briefings can also reduce the lead’s ability to assess that there is mutual understanding before approving a manoeuvre."
ATSB investigators also found that the aircraft operator didn't have the approvals to perform the filming mission, and that the pilot of Viper 1 had a medical restriction that allowed them to fly jets only with a safety pilot and in aircraft with side-by-side crew seating only. The S.211 has a tandem cockpit, and as a warbird is not permitted to be used for the type of operation conducted at the time of the crash.
“While these factors did not directly contribute to the aircraft handling or decision-making that led to the collision, regulatory limitations exist to mitigate known risks associated with this type of operation,” Mitchell explained.
The ATSB has produced a video showing the moments that led to the collision, and the full investigation report is on the ATSB website.