The ATSB has found that the Moorabbin fatal accident was mainly the result of a lack of pilot situational awareness related to different aircraft night training circuit sizes.
At about 6.40pm on 29 July 2002, two Cessna 172R aircraft collided while on approach to runway 17 left at Moorabbin airport. The two aircraft became entangled, with aircraft VH-CNW on top of VH-EUH and impacted the runway and came to rest after sliding a short distance along the runway surface. The pilot of VH-CNW was fatally injured.
The Moorabbin Air Traffic Control Tower was not in operation at the time of the accident and mandatory broadcast zone (MBZ) procedures were in use that required pilots to see-and-avoid other aircraft and to make various mandatory radio broadcasts.
Six aircraft were operating in the MBZ at the time of the accident and the investigation identified the following significant factors:
- the different circuit dimensions negated the natural spacing provided by the difference in take-off times, even though both EUH and CNW were the same aircraft type and were operating in the circuit at similar speeds. Radar data indicated that the pilots of EUH conducted a wider circuit than the pilot of CNW. While the EUH circuit took about 7 minutes the CNW circuit took about 4.5 minutes. Both were considered within the normal range and not contrary to procedures.
- the pilots involved in the accident did not see the other accident aircraft in sufficient time to enable either of them to avoid the collision.
- the required broadcasts and a discretionary broadcast made by the pilots did not sufficiently assist their situational awareness.
Subsequent to the accident, the flying school operator instituted changed procedures that require company instructors to append their perceived position in the landing sequence to the broadcast they make at the start of the base leg of the aerodrome circuit.
The investigation found deficiencies in the risk management process associated with the reduction in the Moorabbin airport air traffic control tower hours of operation. Identified deficiencies have since been addressed by Airservices Australia.
The investigation could not determine whether the reduction in tower hours after 21 December 1998 contributed to the accident. In September 2002, Airservices Australia approved a plan for an ongoing airport movement review outside tower hours for air traffic control towers that were not open 24 hours per day, which included Moorabbin tower, to monitor the need for an air traffic control service. To date the review has not indicated a need for an increase in control tower hours at Moorabbin.