History of the flight

The pilot of a Cessna 402C aircraft, VH-NMQ, was conducting a scheduled passenger service from Tindal to Darwin, with 4 passengers.

During the climb to the planned cruise altitude of 8,000 ft, the fuel quantity gauges indicated that fuel was being consumed from the left tank only. At the top of climb, the fuel gauges indicated 100 lb in the left tank and 200 lb in the right tank. Once established in the cruise the pilot tried to balance the fuel load by positioning the left fuel selector to allow the left engine to be supplied with fuel from the right tank.

Approaching the midway point between Tindal and Darwin, the fuel gauges confirmed that the imbalance remained. The pilot assessed that sufficient fuel was available to continue to Darwin. As the flight approached the last suitable alternate aerodrome, the pilot calculated that 13 lb of fuel was needed to reach Darwin from that point, based on the current consumption rate. The left fuel tank gauge showed 40-lb remaining.

The pilot requested and was given a direct approach to runway 29. During the landing roll the left engine stopped, and the right engine stopped soon after the aircraft cleared the runway. The fuel quantity gauges showed 20 lb for the left tank and 200 lb for the right tank.

The operator's ground support staff then towed the aircraft to the terminal area where the passengers disembarked normally.

The aircraft had flown from Darwin for Tindal the previous day with 650 lb of fuel on board. The pilot's navigation log showed that 365 lb was required for the flight from Tindal to Darwin. This comprised 230 lb flight fuel (59 minutes), 100 lb fixed reserve (30 minutes), 25 lb variable reserve fuel, and 10 lb taxi fuel. The navigation log also showed the total fuel on-board at Tindal before departure for Darwin was 385 lb. The pilot reported that before departure from Tindal, the aircraft fuel quantity gauges showed 185 lb in the left tank and 200 lb in the right. The pre-flight check of the fuel cross-feed was normal.

A landing at an alternate aerodrome was not considered necessary, as the pilot had calculated sufficient fuel was available to continue to Darwin, and was conscious of the operating schedule for the aircraft. However, company management stated that there was no instruction or pressure on pilots in this regard.

The pilot held a current commercial pilot licence, a command multi-engine instrument rating a valid medical certificate, and had logged 2,454 hours aeronautical experience. This included 150 hours on Cessna 402C aircraft. The pilot's last proficiency check was on 8 March 2000.

On the day of the occurrence, 5 May 2000, the pilot did submit an incident report to the operator. However, due to a breakdown in the operator's reporting procedures following staff changes, the ATSB was not notified of the occurrence until 15 May. As a result, it was unable to conduct an examination of the fuel selector system fitted to NMQ before the aircraft was returned to service.

Background

The then Civil Aviation Authority of Australia issued Civil Aviation Advisory Publication No: 234-1 (0) in March 1991. It provided advice about the quantity of fixed reserve fuel to be carried, and noted the use of fixed reserve fuel was limited to unplanned manoeuvring in the vicinity of the destination aerodrome. It further noted that fixed reserve fuel would normally be retained in the aircraft until the final landing.

The operator's fuel policy stated that in all foreseeable circumstances an aircraft should complete a flight with at least the fixed reserve fuel intact. The standard fixed reserve for the operator's Cessna 402C fleet was 100 lb of fuel for 30 minutes of flight.

Cessna 402C Fuel Selector System

The two fuel selector controls are attached to the cabin floor between the pilot and co-pilot seats. The selectors enable the fuel selector valves, located behind the engine firewalls, to be positioned to the corresponding tank, crossfeed, or off. The arrow-shaped ends of the selector control handle points to the position on the selector placard that corresponds to the control valve position. Each handle connects directly to a gearbox located under the floor. Cables connect each gearbox to their respective fuel selector valve.

An inspection by the maintenance provider in Darwin confirmed that the pilot had positioned the right fuel selector handle to the right tank. However, the cable connecting the gearbox to the fuel selector valve did not position the valve to the right tank.

The right fuel selector gearbox was removed, the selector gearing adjusted and the selector cable re-rigged. The aircraft was returned to service after the fuel selector system was ground tested.

The Pilot's Operating Handbook for the aircraft contained a description of the fuel system and it's operation. In the Normal Procedures section of the handbook, pilots were cautioned that they should "Feel for (the) detent" when placing the fuel selector at the desired position.

Maintenance action

The operator's maintenance controller was located at Alice Springs. A sub-contract maintenance provider conducted maintenance at Darwin. The operator's maintenance controller was not advised of the occurrence until 23 May, and was therefore unable to specify extra inspection procedures for the operator's Cessna 402C fleet until that time. The maintenance controller issued maintenance alert MA/C400/2 on 25 May. It was applicable to all Cessna 402C aircraft used by the operator and its associate company, and required a detailed inspection of the fuel selector system. These checks were to be conducted at each scheduled inspection until the requirements were included in the operator's System of Maintenance.

During one such check of the fuel selector system on another of the company aircraft, VH-TZH, the screws securing the selector cable lever arm/travel stop to the sector gear were found to be loose. This allowed the travel stop to slide under the base-plate and the sector gear to move beyond the end of its travel, resulting in loss of synchronisation between the selector handle and the selector valve.

The operator immediately issued an amendment to maintenance alert MA/C400/2 that included photographs of the defective fuel selector on TZH. The alert specified that the selector gearbox was to be checked if the fuel selector valve was found not synchronised with the selector indicator. During the investigation the fuel selectors of two other of the operator's Cessna 402C aircraft were found to lack an effective detent.

At the time of the occurrence, the maintenance release for NMQ contained an annotation arising from a previous report of uneven fuel consumption from the left tank. Examination of the fuel system related maintenance documentation for the aircraft revealed 17 events since December 1999. Seven involved reports of the aircraft using more fuel from the left tank than the right when the fuel selectors were correctly positioned. There was one report of greater fuel usage from the right tank. The rectification section for four of the entries stated that the fuel selector system was re-rigged. The reported defect for three of the entries was annotated "not major defect" and transferred to the deferred defects list. The fuel related defect entry for the 18 April 2000 stated "fuel not feeding correctly. Fuel noted to be crossfeeding some fuel in level flight - report further".

The last reference to fuel transfer problems, prior to the incident, was on 20 April. The endorsement on the trip record stated "both engines draw fuel from the left tank only". The rectification section of the record noted the fuel selector valve was removed, lubricated, refitted and pressure tested. The selector cable was re-rigged, and the system operated satisfactorily during ground testing.

Fuel system pre-flight checks

The fuel system pre-flight checks specified in the operator's Cessna 402C Operations Manual differed from the procedures specified in the manufacturer's Pilot's Operating Handbook.

The operator's standard operating procedures required pilots to operate the fuel supply cross feed for 60 seconds to verify normal operation. Also, pilots were to ensure normal operation of the fuel valves by positioning the fuel selectors to the off position to observe a decrease in fuel flow. Following these checks, pilots were to position the fuel selectors to the main tanks.

The manufacturer's Pilot's Operating Handbook did not specify checks for crossfeed operation or positioning the fuel selectors to the off position to observe a decrease in fuel flow.

The pilot did not move the fuel selectors to the off position as part of the pre-flight checks. This was because the Fleet Manager had advised his intention to amend the pre-flight check to delete the requirement. The pilot reported awareness of the need to feel for the detent when moving the fuel selectors, and was confident the detent was achieved during the pre-flight check.

On 16 May the operator issued a memo on the occurrence to its Cessna 402 pilots, and included new instructions for pre-flight operation of the fuel selector. The memo cancelled the previous requirement for pilots to position the fuel selectors to the off position to confirm a decrease in fuel flow.

The crew of the Fairchild Metroliner was conducting endorsement training in the Cowra area when they advised air traffic services (ATS) that their aircraft had a hydraulic failure and they were returning to Bankstown. An uncertainty phase was declared by ATS and the aircraft returned to Bankstown where a flapless landing was carried out.

The subsequent maintenance inspection found a cracked hydraulic pipe in the left landing gear wheel-well that had allowed the loss of the hydraulic oil contents from the power pack. The crack was in the bend radius of the pipe and was not visible to the naked eye. The crack only became apparent with the application of more than 800 psi of hydraulic pressure to the system during the maintenance inspection. The pipe was changed and the aircraft returned to service.

The pilot in command reported that he had experienced two similar hydraulic pipe failures in this aircraft type and the company fleet had five or six similar failures in the preceding twelve months. He also reported that he had a concern that the escaping oil in this situation could have started a wheel-well fire.

The design of the hydraulic system is such that, when a failure occurs in one of these hydraulic pipes, there is no redundancy. As a result, the leak drains the contents from the hydraulic reservoir, which is the common source of hydraulic fluid for both the left and right engine-driven hydraulic pumps. Without hydraulic services, nosewheel steering, anti-skid braking, flap operation and normal landing gear retraction and extension would not be available to the pilot.

The Piper PA34 Seneca III, took off from Canberra for Bankstown under the Visual Flight Rules (VFR). The pilot in command had planned to embark five passengers at Bankstown then to conduct a scenic flight around Sydney Harbour, proceed to Cessnock for lunch and return to Bankstown where he intended to disembark the passengers before returning to Canberra.

The flight to Bankstown was uneventful. On departure from Bankstown, the pilot proceeded southeast to the coast and then north, at low level, along the VFR coastal route to Manly. A delay was experienced at Manly, prior to turning south and entering Sydney Harbour. The Sydney Harbour scenic flight was then conducted, completing a circuit of the Harbour Bridge to Rushcutter's Bay loop. The pilot then returned to South Head and proceeded north via Aeropelican for a landing at Cessnock.

During the return flight, the pilot deviated west of the planned track in order to avoid severe weather that had been indicated on the aircraft's weather radar. Shortly after passing Brooklyn Bridge, which was the start point for the northern inbound VFR track to Bankstown, at an altitude of 2,500 ft, the pilot reported that the left engine suddenly stopped. The pilot reported that he then carried out the engine failure checks from memory, feathering the propeller. Approximately one minute later, the right engine began to gradually lose power, before stopping after approximately a further 20 seconds. The pilot reported that he then pushed all of the engine and propeller controls forward and attempted to restart the engines. That action resulted in the inadvertent unfeathering of the left propeller due to operation of the unfeathering accumulator.

The pilot conducted a forced landing into a treed area beside a main road. The aircraft struck the trees, rotated to the right and impacted the ground left wing forward. Four of the six occupants sustained serious injuries and the aircraft was destroyed.

Pilot information

The pilot was appropriately licensed for the flight and had accumulated a total of 270 hours flying experience with 14 hours on the aircraft type.

Flight and fuel planning

The aircraft arrived on the operator's flight line five days before the accident, after delivery from Tamworth. The technical log indicated that the last recorded refuel had been conducted at Tamworth on 13 March 2000. Between that time and the delivery flight to Canberra the aircraft had undergone a 15-minute dual engine run following a propeller change. The engine run included a period of one to one and a half minutes with both engines at full power. Prior to departure from Tamworth, the delivery pilot reported that he visually assessed the fuel tanks as full. Upon arrival at Canberra, the fuel tank content was assessed as 280 L, using flight time and fuel usage calculations.

The pilot planned the accident flight utilising a computer-based flight planning application. He did not plan for any aerial work at Sydney Harbour, despite having an intention to conduct a scenic flight in that location. Air Traffic Services (ATS) radar data indicated that the scenic flight duration was approximately 12 minutes. In addition, he planned the flight using figures for full fuel tanks, however he used the total fuel tank content figure of 465 L instead of the useable fuel tank content figure of 454 L. Further, he was aware that the aircraft had only an assessed 280 L of fuel on board and considered that that amount was sufficient for the flight from Canberra to Cessnock and for the return flight to Bankstown. He had decided not to add fuel prior to departure from Canberra due to a perception that the aircraft would be over Maximum Take-off Weight at Bankstown or Maximum Landing Weight at Cessnock, after the addition of the five passengers.

Fuel management

The pilot reported that he visually checked the fuel tank contents at Canberra before departure, with fuel just visible through the fuel cap opening. That quantity was then cross-checked with the aircraft fuel gauges and it appeared to agree with the previously calculated total. An attempt was also made to check the fuel tank contents using the aircraft's fuel dipstick, however, that was unsuccessful as the fuel level was well below the lowest graduated scale on the stick. The pilot reported that he again checked the fuel level on arrival at Bankstown. At that time the level was out of sight of the fuel caps, however, the total fuel remaining on the fuel gauges appeared to agree with his assessment. Prior to landing at Cessnock the fuel gauges were again checked, with the pilot considering that the indicated fuel level was what he expected from his mental calculations to allow for the return flight to Bankstown.

ATS radar data indicated a total flight time of 159 minutes from take-off at Canberra to the accident site. That figure did not include any allowance for ground taxi at Canberra, Bankstown and Cessnock. Using the operator's recommended fuel usage planning figure of 100 L per hour, 159 minutes flight time would have consumed 265 L of fuel.

The aircraft manufacturer's recommended engine fuel leaning procedure for cruise flight was detailed in Section 4 (Normal Procedures) of the Pilot's Operating Handbook, which stated:

"For 45, 55 and 65% power the mixture should be leaned to 25 [degrees] F rich of peak E.G.T. [Exhaust Gas Temperature] but not to exceed 1,650 [degrees] F E.G.T.", and "For maximum engine service life, cylinder head temperatures should be maintained below 420 [degrees] F..."

The pilot reported that he had been taught to lean the fuel mixture to the top of the green arc on the exhaust gas temperature gauge. The green arc on the gauge extended from 1,200 to 1,525 degrees F. He reported that during the accident flight he leaned the mixture according to that method, however he had subsequently enriched the mixture one or two graduations below the top of the green arc. Advice from the aircraft manufacturer and other Seneca III operators, indicated that that action may have increased the fuel flow by up to approximately 10 L per hour.

Approximately one litre of fuel was recovered from the aircraft wing tanks, however the fuel tanks had been substantially damaged during the impact sequence. There was no evidence of fuel leakage on the ground. Inspection of the fuel system components revealed no evidence of fuel contamination. The left engine fuel selector control was positioned at the OFF position and the right engine selector was positioned at ON.

Engine and fuel system information

Both engines had recently been overhauled and had flown 57.3 hours since fitment to the aircraft.

During the flight, a short time after passing Aeropelican, the pilot reported that the left engine had required increased throttle to maintain the selected manifold pressure. While taxying after landing at Cessnock the left engine appeared to idle slower than before and the alternator light flickered on and off. The light had extinguished when the pilot increased engine RPM. After vacating the aircraft, the pilot noticed evidence of an oil leak along the outboard side of the left engine cowling, on the underside of the left wing and on the left flap. A check of the left engine oil quantity revealed that the engine had used about half a quart during the flight. Confirmation with the operator by telephone indicated that the oil level was within tolerances. The source of the oil leak was not able to be located. The pilot reported that operation of both engines from departure at Cessnock to the point of engine failure appeared normal.

Technical investigation at the accident site revealed that the left engine number 4 cylinder exhaust rocker pivot was loose and that the rocker had contacted and holed the inside surface of the rocker cover. The forward rocker pivot-retaining stud had sheared flush with the surface of the head with evidence of a fatigue failure on the stud fracture surface. The number 4 cylinder inlet valve push rod had also failed close to the outboard tip of the rod. Detailed technical examination of both engines at an engine overhaul facility noted that the exhaust valve on the number 4 cylinder of the left engine remained closed during rotation of the crankshaft and the inlet valve on the same cylinder only opened a small amount. Both engines were then test run in an engine test cell. The test run of the right engine revealed no condition that would have contributed to the in-flight loss of power. The test run of the left engine indicated that it was capable of operation, however it's performance was affected by the damage evident on the number 4 cylinder's valve mechanism.

The pilot of a Cessna 172M was conducting a private visual flight rules (VFR) flight, with two passengers, from Narromine to Shepparton. The passenger seated next to the pilot was also a qualified private pilot and the owner of the aircraft.

On arrival at Shepparton, the aircraft overflew the aerodrome. After noting from the aerodrome windsock that the wind was a moderate westerly, the pilot decided to use runway 18 for landing. The owner of the aircraft observed that the aircraft was high on the base leg and on final approach. He remarked that the pilot was having difficulty with the crosswind conditions, since the aircraft was drifting left during the landing attempt.

Witnesses noticed from several locations around the aerodrome that the aircraft was flying erratically 3 or 4 metres above the level of the runway, with a pronounced nose-up attitude. It was flying slowly and making apparently repeated attempts to touch down on the runway. Its height was varying slightly and its wings were rocking from side to side. This was confirmed by the pilot of a following aircraft who noticed that the Cessna 172 was only a few metres above ground level, three-quarters of the way down the runway and drifting out across the grass to the eastern side of the runway. A second witness, who was a private pilot endorsed on Cessna aircraft, reported seeing some flap but could not remember how much.

A go-around from the attempted landing was commenced as the aircraft neared the end of runway 18. The aircraft continued south beyond the runway, drifting east with the wind and out over the boundary fence at the southern end of the aerodrome. The witnesses feared that the aircraft would not clear a line of trees, approximately 20 metres tall, running approximately east-west beyond the aerodrome boundary. The aircraft then turned to the left while banking sharply and tracked eastwards at very low altitude with its wings rocking and a pronounced nose-high attitude. Its nose then suddenly dropped and it adopted a steep nose-down attitude before impacting the ground. Witnesses attended to the seriously injured occupants while waiting for the local emergency services to arrive. The pilot died in hospital from his injuries.

The owner, who had flown regularly with the pilot, said he was very meticulous with his procedures and that his late decision to go around was out of character. The owner only vaguely remembered the go-around procedure but said he believed that the pilot's actions were standard.

The aircraft came to rest in an open field about 600 metres south of the departure end of runway 18. Ground scars and propeller slash marks showed that the aircraft had impacted in a steep, nose-down, almost wings-level attitude with little forward velocity. It had then bounced about 9 metres to the south-east, where it came to rest. Impact forces severely disrupted the forward section of the fuselage. Post-accident inspection of the airframe indicated that it was intact when it struck the ground.

Approximately 25 litres of clean avgas was drained from each fuel tank 2 days after the accident. Tests revealed no indication of fuel contamination. The weight and balance of the aircraft was calculated to be within limits for landing at Shepparton.

No defects or deficiencies were identified with the aircraft engine or the aircraft's systems that may have compromised its performance or contributed to the accident. The flaps were in the fully retracted position when the aircraft struck the ground and this was verified by the position of the flap position actuator. Damage to the propeller and the ground slash marks made by the propeller at the impact point indicated that the engine was under power at the time of impact. Several witnesses described the engine sound as being normal for an engine at high power.

The Bureau of Meteorology had installed an Automatic Weather Station (AWS) at Shepparton aerodrome. The AWS provided 1-minute averaged data for wind direction and speed and automatically recorded the data for future reference. At the time of the accident the surface wind, as measured by the AWS, was 310 degrees at 9 knots, with a maximum gust within the previous 10 minutes of 20 knots. An experienced private pilot who was flying his aircraft in the Shepparton circuit area at the time of the accident described the wind as a moderate westerly of approximately 15 knots. He noted that he experienced a combination of both mechanical and thermal turbulence, particularly at low level.

With the wind from the west and a turn to the east from a runway heading of 180 degrees, the aircraft will drift downwind while turning. This can create visual illusions that may result in mishandling of the flight controls which, combined with turbulence and wind gusts, may result in height loss, particularly if the aircraft is operating at a high angle of attack.

During descent into Cairns, the pilot of the Embraer EMB-110 observed the right engine fire warning annunciator illuminate. The pilot then conducted the quick reference handbook `fire during flight phase' checks, which included shutting down the right engine. During these checks the fire warning annunciator extinguished, and as there was no visual indication of fire or smoke, the pilot elected not to discharge the engine fire bottle. The quick reference handbook allows for an 8-second wait after the engine is shut down. If the fire warning persists then the fire extinguisher should be discharged. The pilot advised Air Traffic Control and the aircraft passengers of the engine shutdown. An uneventful single engine approach and landing was successfully completed.

The engine fire detection system consists of two independent circuits for each engine. The sensors are located in the hot section, accessories section and the generator cooling air discharge, and are connected to a control box. When a fire or overheat condition is detected a fire warning light will illuminate in the T handle for the affected engine, the master caution light will illuminate, and the fire horn will sound.

Investigation by the operator's maintenance organisation found that three fire detector sensors had failed, resulting in a false fire warning. The failed sensors were found to contain moisture. The operator indicated that the aircraft had operated in rain shortly before the incident flight.