The pilot had planned a flight from Cairns to Mt Mulligan, a distance of about 75 km, and return. Based on his flying experience on the helicopter, he assumed a fuel usage rate of 65 litres per hour. The helicopter was refuelled to full tanks (210 litres) before departure. The planned time interval to Mt Mulligan was 38 minutes, based on a true airspeed of 70 kts and a groundspeed of 80 kts. The expected groundspeed for the return flight was 60 kts.
The helicopter departed Cairns at about 1420 and arrived at Mt Mulligan 44 minutes later. The pilot then operated in the area for about 20 minutes before landing. He visually assessed the fuel contents as 136 litres before departing Mt Mulligan for Cairns at about 1620 EST. He advised air traffic services flightwatch of a SARTIME of 1730. The cruising altitude was 3,000 ft. During the latter stages of the flight, when about 10 km west of Cairns, the pilot amended the SARTIME to 1740. He also had to divert south track because of cloud. At this time, the fuel contents gauge was indicating about one quarter full. A few minutes later, when the helicopter was about 3 km southwest of Cairns Airport, the engine lost power. The pilot successfully completed an emergency landing onto a suburban street.
Examination of the helicopter revealed that the fuel tanks contained 4.8 litres of fuel. (The manufacturer's data indicated that the unusable fuel quantity for the helicopter was about 8 litres.) After fuel was added to the tanks, the engine operated normally. No fault was found with any other system that might have caused the engine failure. Calculations indicated that the actual fuel usage rate was about 77 litres per hour. This was in line with data from the engine manufacturer that indicated a usage rate of 75-80 litres per hour for similar operations.
The pilot had not previously operated the helicopter on flights longer than 30 minutes or at altitudes above 2,000 ft and did not properly understand the relationship between operating altitude, power settings, and fuel consumption. This lack of understanding, combined with the fuel usage rate the pilot used in planning the flight, resulted in the fuel supply to the engine being exhausted before the flight reached its destination.
- The pilot used incorrect fuel planning data.
- The pilot did not fully understand the effects on fuel consumption of altitude and engine power settings.
- The engine failed because of fuel exhaustion.
The Bureau of Air Safety Investigation is monitoring the progress of a number of previously issued recommendations to the Civil Aviation Safety Authority. These recommendations relate to organisational checks conducted prior to the issue of an Air Operator's Certificate, on-going surveillance of AOC holders, and the training and checking procedures used to evaluate the proficiency of pilots engaged in fare-paying passenger flights.
The Bureau will also be conducting a review of aviation occurrences involving fuel starvation and exhaustion. A report of this review is due to be completed by July 1999.
Any safety output issued as a result of these deficiency analyses and review will be published in the Bureau's Quarterly Safety Deficiency Report.
|Date:||02 September 1997||Investigation status:||Completed|
|Time:||1820 hours EST|
|Location:||3 km SW Cairns, Airport|
|State:||Queensland||Occurrence type:||Fuel exhaustion|
|Release date:||01 March 1999||Occurrence category:||Incident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Kawasaki Heavy Industries|
|Type of operation||Private|
|Damage to aircraft||Nil|
|Departure point||Mount Mulligan, QLD|
|Departure time||1420 hours EST|
|Role||Class of licence||Hours on type||Hours total|