Fuel starvation

On 22 September 2011, at about 1317 hours Western Standard Time (WST), a Cessna Aircraft model U206G (C206), registered VH-SHZ, departed Kalumburru Aerodrome, Western Australia (WA) with the pilot and six passengers on the return leg of a charter flight returning to Wyndham, WA. Following climb-out and in level flight at 5,500 ft above mean sea level (AMSL), the engine shutdown without warning. At the time of the engine shutdown, the right-wing fuel tank was selected and the right fuel quantity gauge indicated less that ¼ tank.

The pilot actioned emergency procedures including switching fuel tanks, and, at about 2,000 ft above mean sea level, the engine restarted. The flight continued on uneventfully and the aircraft landed at Wyndham. Post-flight inspection revealed that the pilot had not properly secured the right-wing fuel tank filler cap following refuelling that morning, resulting in fuel venting from the right tank.

On 18 August 2011, at 0755 Western Standard Time, a Cessna Aircraft Company 210N aircraft registered VH-OCM, departed Mitchell Plateau, Western Australia, on a charter flight to Kununurra. On board were the pilot and five passengers.

Prior to departure the fuel quantity was physically checked and recorded. The pilot completed a normal take-off and climbed to a cruise altitude of 5,500ft above mean seal level (AMSL).  At about 28 NM from Kununurra aerodrome, the pilot commenced descent for a straight-in approach to runway 12.  At 3 NM from the runway threshold, the pilot reduced engine power and lowered the flaps, then commenced the pre-landing checks. The aircraft started to sink below the approach profile during strong wind gusts. The pilot increased engine power to regain the approach profile, and did not complete the pre-landing checks, including selecting the fullest fuel tank for the landing.

At about 0.6 NM from the runway threshold, and approximately 250ft above ground level (AGL) the engine began to splutter then stopped. The pilot lowered the nose of the aircraft to maintain airspeed and checked the fuel mixture, fuel pumps on and both magnetos on. When the engine failed to start, the pilot broadcast a Mayday call. At about 0928 he conducted a forced landing short of the runway threshold. During the landing, the aircraft impacted an earth bank and was seriously damaged and one passenger sustained a minor injury. The pilot secured the aircraft and disembarked the passengers.

In response to the accident, the operator implemented the following actions to reduce the risk of another occurrence.

• An operations manual amendment was raised to require all pilots to use a standardised fuel log on all flights.
• For new engines being run-in, increased block fuel flow figures for flight planning will be used.

The pilot was practising circuits. The engine lost power at about 90 feet in the climb after the fourth take-off. Thinking his foot may have slipped off the throttle, the pilot lifted his foot and pressed down on the throttle again. The engine responded with full power. With the sudden increase in thrust the Trike adopted a steep nose high attitude. Two or three seconds later the engine stopped. The Trike stalled, rolled to the right and began to sideslip. The pilot tried unsuccessfully to recover from the stall. The engine failed because of fuel starvation. A plastic fuel funnel extension was later discovered in the fuel tank. The funnel extension had blocked off the fuel outlet from the tank. The funnel extension was completely unfamiliar to pilot. It is probable that the funnel extension entered the tank during refuelling by a previous owner of the Trike. It is likely that the funnel extension had been present in the fuel tank for a considerable time. This accident was not the subject of a formal on-site investigation.

Circumstances:

The pilot reported that, soon after completing the pre-landing checks during the descent to land, the engine lost power. After checking that the mixture was full rich, he called Hamilton Tower to advise of his situation and was cleared for a straight-in approach. The pilot then changed the fuel selector from the left to the right tank for a short time, but did not actuate the electric fuel boost pump. When the engine did not respond, he re-selected the left tank and again attempted unsuccessfully to restart the engine. Moments later the aircraft made a forced landing into the sea approximately 2 km short of the runway. No fault was found with the aircraft which might have contributed to the accident. Only minute quantities of fuel were found in the fuel system and both tanks contained only sea water. The pilot stated that the aircraft departed Maroochydore with full tanks (337 L) with the left tank selected, and that he changed tanks every 30 min during the flight. He said he had not personally refuelled the aircraft but had noted the fuel level in both tanks prior to DEPARTURE to be at the bottom of the filler tubes. These tubes extend downward into each fuel tank from the filler caps a distance of approximately 10-12 cm. The pilot advised that much of the flight was conducted below 2000 ft with the mixture full rich or only slightly lean. Investigation determined that the actual fuel quantity on board at DEPARTURE was 270-280 L (135-140 L per tank). This meant that 55-65 L remained on board at the time of the accident. Judging from the duration of the flight and the tank selection procedure used by the pilot, the left tank should have been selected for 120 min (4x30 min periods) and the right tank for 90 min. Total usage from the left tank should therefore have been 110-120 L, still leaving 20-30 L in the tank when the power loss occurred. However, had the pilot missed a tank change and had the left tank been selected for 150 min instead of 120, the fuel quantity used from the tank would have been around 150 L, close to the calculated quantity in the tank of 135-140 L. It is likely, therefore, that the pilot missed a tank change, thereby draining the left tank, and that the engine lost power as a result of fuel starvation. Because the electric boost pump was not actuated when the pilot selected the right tank after the power loss, it would have taken more time for the fuel to flow from the right tank to the engine. The left tank was probably reselected before this had time to take place.

Significant Factors:

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

1. The pilot did not have adequate knowledge of the aircraft fuel system.

2. The aircraft fuel tanks were not filled to capacity prior to DEPARTURE.

3. The pilot probably missed a tank change, thereby draining the left fuel tank.

4. The pilot did not actuate the electric fuel boost pump when attempting to restart the engine.

After conducting a thorough pre-flight inspection, the pilot prepared to ferry the aircraft to a maintenance organisation which was to perform a scheduled inspection. The aircraft performed normally until it reached a height of about 200 feet after take-off. At this point the engine lost a substantial amount of power and the pilot was committed to a forced landing. During the landing roll the aircraft collided with a fence and came to rest in the adjacent paddock. Initial inspection revealed that there was a serious leakage of fuel past the fuel filter bowl seal, and it was likely that air had entered the fuel system. The stirrup/clamp which held the filter bowl in place had been subjected to an unauthorised repair, which had probably reduced its overall strength. Fuel had been observed leaking from the filter bowl area several days previously, and it was possible that during the attempts to stop the leak, the stirrup had been incorrectly positioned. The fuel leak had not been drawn to the attention of a licenced engineer.

On 31 October 2010, a Cessna Aircraft Company TU206C, registered VH-EAL (EAL), was being operated on a parachute flight overhead the South Grafton aeroplane landing area (ALA), New South Wales.

Just prior to the parachute drop, the pilot heard broadcasts from an aircraft on the ground at South Grafton and an inbound aircraft. The pilot of EAL requested that both aircraft remain clear of the drop zone. After the parachute drop was completed, the pilot descended the aircraft and continued to converse with the pilots of the other aircraft until the parachutists were on the ground.

The aircraft joined the circuit on crosswind for runway 08.  Due to a preceding aircraft, the pilot of slowed the aircraft down and conducted a wider circuit. The aircraft was turned onto final and shortly after, the engine went quiet. The pilot changed the fuel tank selection and applied full throttle, but the engine did not respond. The aircraft landed about 300 m from the runway and sustained serious damage.

The pilot reported that he had been distracted by the other aircraft operating in the area at the time and did not change the fuel tank selection during the descent or on downwind, as per his normal procedure.

Pilot distractions occur frequently; some can be minimised or removed, while others cannot be avoided. This accident is a prime example of how distractions impact aircraft operations and a reminder that distractions are not unique to any one type of operation and that no pilot is immune.

At about 1545 Eastern Standard Time on 7 August 2010, while returning to Moorabbin Airport, Victoria after conducting aerial photography work, the pilot of a Cessna 152 aircraft, registered VH-KKW, experienced a total loss of power that resulted in an emergency landing approximately 200 m short of the airport. The aircraft was significantly damaged. The pilot and single passenger sustained minor injuries.

The investigation found that the pilot, when preparing for the flight, had misread the aircraft's initial fuel state and had subsequently uplifted a lesser quantity of fuel than required for the flight. Although the fuel remaining was greater than the manufacturer's stated unusable quantity, the investigation determined that the accident was the result of fuel starvation. The aircraft was prone to asymmetric fuel delivery allowing one tank to deplete quicker than the other. That action may have led to the aircraft unporting fuel from the low quantity tank during manoeuvring, which allowed air to be drawn into the engine. The investigation identified inconsistencies in the application of the operator's procedures for recording aircraft fuel states.

As a result of the accident, the operator re-designed the flight time and serviceability log to provide clearer application and recording of aircraft pre- and post-refuel fuel state. It also advised that it had: introduced a requirement that a formal 'Fuel Required' calculation be made for all flights leaving the circuit or training area, with a copy to be attached to the passenger list/weight and balance data; inspected the seat-locking mechanisms on all club aircraft and reminded all staff/students/members of the importance of ensuring all seats are locked; and reviewed training requirements for engine failure

Pilots are reminded that there is the potential for asymmetric fuel delivery on Cessna 152 aircraft and as well as monitoring fuel use, they need to be alert to such situations, particularly in minimal fuel states.

On 14 February 2010, the pilot of a Cessna Aircraft Company TU206C (C206), registered ZK-JAO, was being operated on a private ferry flight under the
visual flight rules (VFR) from Lord Howe Island, New South Wales (NSW) to Coolangatta, Queensland (Qld) via Port Macquarie, NSW. Those sectors comprised the final stage of the ferry flight, which had originated from New Zealand. The pilot was the only person on board the aircraft.

The pilot reported that he had experienced intermittent ferry tank fuel flow problems during the flight from Lord Howe Island, NSW to mainland Australia. The pilot consequently selected the aircraft's main fuel tanks to ensure a reliable supply of fuel to the engine. At approximately 19 km east of South West Rocks, NSW, when the fuel was exhausted from the aircraft's main fuel tanks, the pilot selected fuel from the ferry tank, but was unable to restart the engine. The fuel flow from the ferry tank had been disrupted and the remaining 300 L in that tank was unable to be accessed. The pilot conducted a successful forced landing at an airstrip in the vicinity of South West Rocks, NSW. There was no reported damage to the aircraft or injuries to the occupant.

The reason why the ferry tank's fuel flow was disrupted could not be established; however, the pilot stated it was likely that an air pocket somewhere in the fuel system between the ferry tank and the aircraft's main fuel lines starved the engine of fuel.

The pilot had installed the ferry tank in New Zealand without the appropriate regulatory authorisations and qualifications to do so.

Although there was no evidence as to whether the installation of the ferry tank played a role in the incident; it is a reminder that approved modifications, carried out by appropriately qualified and licensed people are likely to reduce risk.

Interim Factual report released 20 March 2009

While passing through 400 ft above ground level on final approach, the aircraft drifted left of the runway centreline. The crew decided to go around and on applying power, the aircraft rolled and yawed left, resulting in significant control difficulties for the crew. After the crew regained control of the aircraft, they realised that the left engine had stopped. The crew completed the emergency checks, transmitted a PAN call and diverted to Wiluna. It was later determined that the left fuel tank was empty and that the left engine had sustained a total power loss from fuel starvation.

On 4 February 2007, the crew of a Boeing Company 747-338, registered VH-EBY, shut down the number 3 engine in flight, due to a fuel related problem.

Approaching the top of descent the crew noticed that the number 3 main fuel tank quantity indicator (FQI) was reading zero and that both fuel boost pump low pressure lights for that tank had illuminated. The crew then shut down the number 3 engine, broadcast a PAN broadcast and continued the flight for an uneventful landing at Melbourne.

An examination of the number 3 main fuel tank after landing, found that it was empty. An 'over-read' malfunction in the number 3 FQI had resulted in the crew believing there was a greater quantity of fuel remaining in the tank than was actually present. The planned quantity of fuel for arrival at Melbourne for the number 3 tank was 2,500 kg. An investigation of the incident conducted by the operator determined that the FQI malfunction was caused by either an electrical malfunction, water contamination or a combination of both.

The FQI fault was rectified and the aircraft returned to service.

The investigation also found that the operator's refuelling procedures were not able to accurately verify the base line quantity of fuel on board, or to alert the flight crew or line engineers to the consequences of an erroneous fuel quantity indicator system indication. The investigation reviewed the refuelling procedures for the operator's other fleet types to ensure serviceability of those installations. As a result of this occurrence, the operator is implementing a series of safety actions, including amending its refuelling procedures and conducting a risk assessment of its fuel management policies and procedures.