The pilot was tasked to convey six passengers from Brisbane to Miamba, about 165 NM WNW of Brisbane, and return. The aircraft was parked at Archerfield and the passengers were to be picked up at Brisbane Airport.
The aircraft operator had no formal system of recording the amount of fuel remaining in the aircraft at the end of each flight. Normally, the fuel state was discussed between the pilots of the previous and next flights. In this instance, however, the pilot did not speak to the person who last flew the aircraft. The pilot said that it was his practice to use the fuel gauges and the fuel gauge calibration chart to determine the amount of fuel in the aircraft.
The weather forecast obtained by the pilot indicated the 7,000 ft wind as 110 degrees at 15 kts, and the 5,000 ft wind as 120 degrees at 20 kts. The pilot calculated the following flight times and fuel requirements for the intended flights, assuming a fuel consumption rate of 140 lt per hour:
Archerfield - Brisbane 5 mins, 27 lt
Brisbane - Miamba 59 mins, 174 lt
Miamba - Brisbane 59 mins, 174 lt
Total 123 mins, 375 lt
Before the flight, the pilot obtained information about the destination airstrip and decided to have the aircraft refuelled to full main tanks (415 lt). The fuel gauges for the auxiliary tanks were indicating half full. Using the lesser of the aircraft flight manual and the fuel calibration card figures, the pilot assessed that the auxiliary tanks contained 147 lt. From this information, he calculated that the aircraft contained 562 lt of fuel - sufficient for about 4 hours of flight.
Because of air traffic control requirements and the prevailing weather conditions, the flight from Archerfield to Brisbane took about 30 minutes.
During the flight to Miamba, the pilot selected the auxiliary tanks for a period during cruise at 8,000 ft, but did not record the times when these selections were made. Flight duration was about 66 mins.
At Miamba, the pilot estimated (from the fuel gauges) that there was 280 lt fuel remaining for the return flight to Brisbane. At top of climb (7,000 ft) he again selected the auxiliary tanks. Because the gauge indications reduced faster than he anticipated towards empty, he allowed the auxiliary tanks to empty before re-selecting the main tanks. The pilot said that the fuel quantity gauges indicated about 1/8 when the auxiliary tanks were empty. Because of headwinds, the pilot descended to 5,000 ft to try to achieve a higher ground speed but to little effect. At that altitude, the aircraft was in cloud.
At about 30 nm from Brisbane, with the gauges indicating about 1/8, the pilot became concerned that there might not be sufficient fuel to complete the flight to Brisbane. He descended to 4,000 ft, again seeking a better ground speed. The pilot then elected to divert to Archerfield (which was closer) and told air traffic control that he did not wish to descend further until close to Archerfield. Shortly after being cleared to turn towards Archerfield, the left engine surged and then ceased operating. The pilot feathered the propeller and informed air traffic control that he required an immediate landing at Amberley. He did not declare an emergency.
Soon after the left engine failed, the aircraft flew clear of cloud and the pilot saw Amberley aerodrome. He conducted a straight-in approach to runway 15 at Amberley. He manually extended the landing gear with assistance from the passenger in the right control seat. The aircraft touched down about 5,000 ft along the runway and the pilot deliberately steered the aircraft off the runway edge on to grass late in the landing roll. There was no damage to the aircraft. The flight from Miamba had taken about 84 minutes. After refuelling, the engines operated normally.
Investigation revealed that the aircraft actually contained about 477 lt on start-up at Archerfield - 85 lt less than the pilot believed. That included 220 lt remaining from the previous flight, and 257 lt added during refuel. The aircraft operator said that his company used a rate of 150 lt per hour for flight planning purposes. Based on that figure, there was sufficient fuel on board the aircraft for about 190 minutes flight. From the total flight time of about 180 minutes, the aircraft had achieved an actual fuel usage rate of about153 lt per hour (allowing about 30 minutes ground operating time), close to the planning figure used by the operator. It is logical to conclude, therefore, that the engines performed normally during the flight, and that the fuel supply to the left engine was exhausted, causing it to cease operating. It is likely that the fuel supply to the right engine would also have been exhausted within a few minutes if the pilot had not shut the engine down.
The pilot said that, based on the handling notes for the aircraft, 126 lt fuel per hour would be consumed at 65 per cent engine power (31 inches MAP and 2,200 rpm). He had used a rate of 140 lt per hour in planning for the flight, which he considered more than adequate. Although the pilot's aeronautical experience was significant, over 90 percent of it was as a flying instructor on single engine aircraft. The pilot had little experience in charter operations. His experience on the aircraft type was also low.
|Date:||23 May 2000||Investigation status:||Completed|
|Time:||1549 hours EST|
|Location:||31 km N Amberley, (NDB)|
|State:||Queensland||Occurrence type:||Fuel exhaustion|
|Release date:||01 June 2001||Occurrence category:||Incident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Piper Aircraft Corp|
|Type of operation||Charter|
|Damage to aircraft||Nil|
|Departure point||Miamba, QLD|
|Departure time||1445 EST|
|Role||Class of licence||Hours on type||Hours total|