The Australian Transport Safety Bureau did not conduct an on-scene investigation of this occurrence.
During the early afternoon of 30 August 2004, the pilot and six passengers onboard a Cessna Aircraft Company 207 Stationair (Cessna 207) departed Jabiru, NT for a 30 minute scenic charter flight.
The pilot reported that about 10 minutes after departure and while cruising at about 1,500 ft above ground level (AGL), the engine abruptly failed. The pilot reset the mixture and throttle controls, changed the selector position from the left to the right fuel tank, switched the auxiliary fuel pump to ON and established a glide speed of 80 kts. When the engine did not immediately respond, the pilot positioned the aircraft for a forced landing at a nearby outstation airstrip. At about 750 ft AGL the engine restarted. Unsure of why the engine had lost power, the pilot continued with the approach and transmitted a PAN alert. When assured of a landing he shut down the engine as a precaution against fire and landed.
The left fuel tank was found to contain no usable fuel and the right tank about 100L. The aircraft was ferried back to Jabiru with the right fuel tank selected and was operated on subsequent flights without incident.
The day before the occurrence, the aircraft was relocated to Jabiru from a remote base. The procedure at the remote base was to use the left fuel tank for flight fuel, and the right tank for reserve fuel. The fuel selector was positioned to the left tank when the aircraft arrived at Jabiru. However, for scenic flights from Jabiru the procedure was the opposite. The aircraft was refuelled to provide 40L reserve in the left tank and 100L in the right tank. The operator advised that these procedures were intended to reduce the risk of fuel starvation during scenic flights.
Early on the day of the occurrence, the pilot conducted a daily inspection of the aircraft and by dipping the tanks, visually confirmed that the fuel quantity accorded with the operator's procedure. He then conducted a 30 minute scenic flight without incident. As the total fuel on board for the occurrence flight was adequate, the quantity of fuel in each tank was not verified visually. The operator stated that the fuel gauges were serviceable. However, the pilot stated that the fuel gauge indicators constantly flickered between full and empty, which prompted him to disregard them.
The operator's maintenance controller informed the ATSB that the maintenance release had not been annotated with details of a fuel gauge defect. A check following the incident revealed that the indications on the aircraft's fuel gauges matched the dip stick measurements for the left and right fuel tanks. He advised that the aircraft was returned to service and there has been no report of a fuel gauge defect.
The aircraft's fuel selector valve had LEFT, OFF and RIGHT positions. The pilot said that, during the pre-flight cockpit checks for both the preceding flight and the occurrence flight, he had checked that the fuel selector was positioned to a fuel tank, but did not realise that it was positioned to the tank containing only reserve fuel.
The Cessna 207 `engine failure during flight (restart procedures) checklist' in the operations manual was similar to the corresponding procedure produced by the aircraft manufacturer. Importantly, both identified the need to use the auxiliary fuel pump only briefly. However, the pilot said that he had applied a memorised generic engine failure procedure that he had learnt in initial flight training. That procedure did not address specific use of the auxiliary fuel pump. The pilot said that, had there been more time after the engine failure, he would have referred to the copy of the operations manual checklist in the aircraft.
Information provided by the operator indicated that, one week prior to the occurrence, the pilot's induction training had included discussion of engine failure procedures based on a generic procedure similar to that used by the pilot. That training did not include the Cessna 207 `engine failure during flight (restart procedures) checklist' in the operations manual, or in-flight simulated engine failures.
The chief pilot reported that the operator's pilots were required to apply whatever normal and emergency/abnormal procedures they had learnt during early training. The chief pilot stated that: `Once learnt, I believe these checks stand a pilot in good stead for their entire flying career in GA [general aviation] and cannot see any reason to change that approach.' The chief pilot added that: `… all pilots are told when time permits to use the supplied check lists in an emergency.'
The ATSB recently completed an investigation into an engine failure involving a similar aircraft type (Cessna 206, ATSB report 200402049). Although there was fuel on board and no identified aircraft defects, the engine did not restart. The four occupants were seriously injured during the subsequent forced landing. The investigation found that the in-flight engine restart procedures published by the aircraft manufacturer were not followed.
The engine failed after exhaustion of the fuel from the selected tank. Despite the pilot's engine failure recovery actions, 700 to 800 ft of altitude was lost before the engine restarted. If the engine failure had occurred while the aircraft was below 700 ft AGL, it would have resulted in a forced landing.
The different fuel management procedures at the two operational bases led to the inappropriate fuel selector position for operations from Jabiru. The pilot then overlooked the specific fuel tank selection during the pre-flight checks, because he had an expectation that it would already be appropriately positioned. During both the preceding and the occurrence flight, the fuel gauges had the potential to alert the pilot to the developing unsafe condition. This required reliable fuel gauges and regular comparison of their indications with planned fuel usage and fuel tank selection.
The pilot's response to the engine failure was not consistent with the aircraft manufacturer's or the operator's emergency and abnormal checklist instructions. It is likely that sustained operation of the auxiliary fuel pump introduced excessive fuel into the engine preventing an immediate restart. Selection of the fuel pump to the OFF position after priming the engine in accordance with the operator's Cessna 207 emergency and abnormal checklist should have resulted in a quicker restart with minimal altitude loss.
Although the pilot had read the operations manual that contained the relevant checklist, the operator did not require him to be able to recall the specific checklist items following an engine failure. The operator's induction training did not ensure that the pilot was able to follow the type-specific procedure when responding to an engine failure at a relatively low altitude. Standard operating procedures are an accepted means of reducing the risk of aircraft operation. By allowing the use of procedures that were inconsistent with the operations manual, the operator reduced the effectiveness of that risk control.
The chief pilot's belief that emergency procedures learned during early training could be effectively applied to any general aviation aircraft did not allow for significant variations between aircraft systems and in particular fuel systems. For example, the in-flight engine restart procedure for a low-wing aircraft with a carburetted engine that is commonly used for initial flight training is significantly different from the engine restart procedure for the Cessna 207, which is a high-wing aircraft with a fuel injected engine.
Induction training that facilitated memorisation of the Cessna 207 `engine failure during flight (restart procedures)' checklist with the opportunity for in-flight simulated engine failures would have decreased the risk of an inappropriate response to an engine failure.
The operator reported that the fuel management procedure at the remote operating base was changed to be consistent with the procedure for operations from Jabiru.
|Date:||30 August 2004||Investigation status:||Completed|
|Time:||1315 hours CST|
|Location:||19 km NE Jabiru, (ALA)|
|State:||Northern Territory||Occurrence type:||Fuel starvation|
|Release date:||24 December 2004||Occurrence category:||Incident|
|Report status:||Final||Highest injury level:||None|
|Aircraft manufacturer||Cessna Aircraft Company|
|Type of operation||Charter|
|Damage to aircraft||Nil|
|Departure point||Jabiru, NT|
|Departure time||1303 hours CST|
|Role||Class of licence||Hours on type||Hours total|