Loss of control involving a Piper PA-32R-300, VH-MNO, Moormbool, Victoria

On 5 June 1992, the pilot received a one hour checkout in the aircraft from an instructor. On 12 June the pilot flew the aircraft from Coldstream to Lilydale, where his passengers were waiting. While the pilot was checking the weather forecasts an instructor commented that they indicated that the weather conditions were unfavourable. However, the pilot decided to commence the flight and assess the actual enroute weather conditions.

Melbourne Air Traffic Control Radar recorded the track and groundspeed of the aircraft from Lilydale to the area of the accident. The aircraft had passed close to Mangalore Aerodrome, where the cloud base was about 1,500 ft above ground level (agl). It then deviated from the planned track and subsequently penetrated an active military restricted area. Soldiers on the range heard the aircraft approaching and ceased all firing. The aircraft was observed to be flying at about 300 ft agl and clear of cloud. There was no rain in the immediate vicinity and the visibility was reported to be good.

After flying through this and an adjacent restricted area, the track of the aircraft became erratic. During the final minutes of the flight, the recorded groundspeeds varied from 148 kts to 75 kts. The last speed recorded was 138 kts. No radio transmissions were recorded from the aircraft.

Witnesses near the accident site observed the aircraft flying at about 300 ft and reported that the engine noise was particularly loud. Weather conditions were overcast, with the cloud base at about 500 ft and patches of rain and drizzle in the area but not near the accident site. The aircraft was then seen to bank progressively to the left and descend. Impact marks indicated that as the aircraft passed about 140 degrees of bank angle, it clipped the tops of gum trees and then struck the ground. The impact marks and degree of disintegration indicated that the aircraft impacted the ground at high speed.

A detailed examination of the wreckage did not reveal any fault or malfunction with the structure, engine and associated systems of the aircraft which might have led to the accident. The landing gear and flaps were retracted and there was ample fuel on board the aircraft. The weight and centre of gravity were estimated to have been within the prescribed limits.

The area in which the accident occurred was open and relatively flat, with several sites suitable for precautionary or forced landings. Tests conducted in the area indicated that radar coverage existed down to about 250 ft above ground level, with radio communications possible almost to ground level.

The postmortem examination revealed that the pilot had coronary artery disease, but it was not possible to determine whether this had led to an in-flight incapacitation. In addition, the pilot had a history of hypertension, which was controlled by medication. He was also on a weight loss program, which involved taking fenfluramine as an appetite suppressant. Common adverse reactions from fenfluramine include mild sedation, lethargy and giddiness.

The investigation was unable to determine the precise circumstances leading to the apparent navigation difficulties experienced by the pilot, although the weather conditions may have contributed. The behaviour of the aircraft and pilot in the vicinity of the accident site, erratic airspeed, excessive bank angle and failure to take advantage of suitable landing areas, may have been related to the physical problems suffered by the pilot. The onset of any such problems may have been too sudden to permit the pilot to conduct an emergency landing.

Significant Factors

1. Weather conditions were marginal for visual flight.

2. The pilot was probably uncertain of his geographical position.

3. It is possible that the pilot became incapacitated in flight

4. Loss of control occurred at a low height above the ground.