What happened
During a formation flight intended for in-flight filming, two S-2im1 aircraft, identified as Viper 1 and Viper 2, were performing maneuvers. The initial plan involved Viper 2 moving to a line abreast position relative to an inverted Viper 1. However, the pilot of Viper 2 executed an unbriefed maneuver to pass directly underneath Viper 1 to capture better footage.
Following this initial pass, the pilots discussed the maneuver over the radio and agreed to attempt the maneuver a second time. During this second attempt, Viper 2 passed beneath the inverted Viper 1 and began to climb toward it. As the aircraft crossed, the right wings of the two aircraft collided. The impact caused severe structural failure to the outboard wing of Viper 2, leading to a loss of control. Shortly after the collision, Viper 2 struck the water, resulting in two fatalities, including the pilot and the camera operator.
While Viper 1 sustained some impact, the damage was not significant, and the aircraft was able to land safely at Essendon.
The investigation
The investigation examined the sequence of the maneuvers and the structural integrity of both aircraft. Video evidence confirmed that Viper 1 maintained stable, level, inverted flight during the maneuver. The investigation noted that the pilot of Viper 2 may have inadvertently applied control inputs that moved the aircraft closer to Viper 1 while looking at the other aircraft.
Furthermore, the investigation looked into the regulatory and medical compliance of the flight. It was discovered that the pilot of Viper 1 was operating under a medical restriction that prohibited the operation of tandem-cockpit aircraft. The pilot had failed to fully read the requirements of their medical certificate. Additionally, the operator did not possess the necessary operating certificate required for filming flights, meaning the aircraft were not authorized for this specific purpose.
Findings
- The unbriefed maneuver of passing underneath the other aircraft significantly increased the risk of a collision.
- In-flight radio discussions regarding the second attempt were insufficient to allow for a proper risk assessment or to ensure both pilots shared a consistent mental model.
- The pilot of Viper 1 was not adhering to medical restrictions regarding cockpit configuration, which reduced the safety pilot's ability to manage potential pilot incapacitation.
- The operator lacked the appropriate certification to conduct filming operations, leading to a lack of necessary safety assurance.