Piper PA31-350 Chieftain, VH-NDU, Cessna 210-M Centurion, VH-MDU, Over Blacksmith Island, Queensland, on 25 April 1990

Circumstances:

Before the flight and in the presence of the only passenger, the pilot of the Chieftain asked the pilot of the Cessna whether he had been "dumped" yet. The Cessna pilot did not know what was meant by the term and his colleague would not elaborate. The Cessna departed, followed by the Chieftain about one minute later. The flight planned heights for each aircraft for entry into the Mackay Control Zone were 3000 feet (Cessna) and 2500 feet (Chieftain). The pilot of the Chieftain reported that he climbed to 3000 feet outside controlled airspace, maintaining visual contact with the other aircraft and pointing it out to the passenger, who occupied the front right seat of the aircraft. The Chieftain was closing with the Cessna at a rate of about 20 knots when the pilot lost sight of the other aircraft. Impact occurred when the Chieftain struck the Cessna from above, the right wing tip of the Chieftain striking the right aileron of the Cessna. At about the same time, the right tailplane of the Chieftain struck the fin and rudder of the Cessna. As the Chieftain continued its passage over the other aircraft its tail cone contacted the outboard leading edge of the right wing of the Cessna. Both aircraft remained flyable and landed at the nearest aerodrome. Neither pilot declared an emergency. Later, the pilot of the Chieftain said that he meant to overfly the Cessna and descend ahead of it to give the other pilot "a big scare" as part of his initiation into bush flying.

Significant Factors:

The following factors were considered relevant to the development of the accident:

1. The pilot of the Chieftain conducted an unnecessary hazardous operation.

2. The pilot of the Chieftain misjudged the closing speed, distance, and relative height between the two aircraft.