Sequence of events

On 5 March 2005, at about 1240 Western Standard Time, an Avions Pierre Robin R-2160 aircraft, registered VH-OXY, was inbound to Jandakot Airport, WA. The flight was being conducted in the private category and the pilot was the sole occupant of the aircraft.

The pilot recalled that the aircraft was about 2 ½ NM west of the aerodrome and at an altitude of 1,200 ft when the engine suddenly lost power. The pilot was attempting to make an emergency landing on a residential street, when the outboard portion of the right wing collided with a suburban power pole. The aircraft rolled inverted before impacting the ground. The aircraft was substantially damaged. The pilot sustained minor injuries and vacated the aircraft without assistance. There was no spillage of fuel at the accident site and no post-impact fire. The maintenance personnel who attended the accident site inspected the aircraft's fuel tank and found that it did not contain any fuel.

An overhauled engine had just been fitted to the aircraft and the pilot reported that he was carrying out the engine manufacturer's procedure for engine break-in¹. That procedure included that, after reaching cruise altitude, a pilot conducting the recommended 2.5 hours break-in flight should:

• Reduce the engine power setting to 75% maximum rated for the first hour of the flight. Data contained in the engine manufacturer's operator's manual indicated that 75% power was obtained at 2,450 RPM, and that the fuel consumption at that power was about 38 L/hour.
• Alternate the engine power between 65% and 75% during the second hour. The engine manufacturer's operator's manual indicated that 65% power was obtained at 2,350 RPM and resulted in a fuel consumption of about 34 L/hour.
• Operate the engine at 100% power for 30 minutes, provided that the engine and aircraft are performing within the published operating manual specifications. Data extracted from the engine manufacturer's operator's manual indicated that 100% power would be achieved at 2,700 RPM and resulted in a fuel flow of about 53 L/hour.

Based on data contained in the engine manufacturer's operator's manual, it was estimated that the recommended engine break-in flight could have consumed between about 108 and 137 L of fuel.

The pilot reported that, during the engine break-in flight, he operated the aircraft's engine as follows:

• between 2,500 and 2,600 RPM for the first 2 hours of the flight
• at 2,700 RPM for the remainder of the flight before returning to Jandakot. The aircraft engine lost power 2 hours 41 minutes after take-off.

The pilot stated that he used a calibrated dipstick to dip the aircraft's fuel tanks prior to the flight, and that the tanks contained 118 L of fuel. He had expected the aircraft to use 35 L/hr, which was the standard fuel consumption used by the company for flight planning in that aircraft type.

The aircraft was equipped with an annunciator panel that included a warning light to indicate a low fuel quantity. However, black adhesive tape had been stuck over that panel, preventing the pilot's view of the low fuel quantity warning light. Neither the aircraft's owner/operator nor the relevant maintenance organisation could explain why the tape was stuck over the panel.

1. First in-flight run of a newly overhauled engine.

At about 1240 Western Standard Time on 05 March 2005, an Avions Pierre Robin R-2160 aircraft, registered VH-OXY, crashed on a residential street, about 2 ½ NM west of Jandakot Airport, Western Australia.

The pilot reported that he was inbound to Jandakot when the engine suddenly lost power. The outboard portion of the right wing collided with a suburban power pole during the approach for the emergency landing and the aircraft rolled inverted and impacted the ground. The pilot, who was the sole aircraft occupant, sustained minor injuries and vacated without assistance. There was no spillage of fuel at the accident site and no post-impact fire. Personnel at the accident site inspected the aircraft’s fuel tank and observed that it did not contain any fuel.

The aircraft was on its first flight following maintenance, which had included the installation of an overhauled engine. During the flight the pilot completed the procedure for break-in of an overhauled engine. At the time of the accident, the aircraft had been airborne for 2 hours 41 minutes.

The circumstances of the engine failure were consistent with fuel exhaustion. Contributing to the fuel exhaustion were the higher than normal power settings, and therefore fuel consumption, associated with the conduct of the break-in flight.

Although uncertain as to the meaning of 'reverse bay', the flight crew thought the term was used to indicate the method of positioning the aircraft on the bay. Any uncertainty about the reverse manoeuvre should have been resolved by the crew before the aircraft was reversed.

The stop signal used by the marshaller was ambiguous as the arms were repeatedly crossed at chest height and not over the head. The operator's ground handling manuals included information that the use of marshalling bats would minimise the risk of misidentification. The opportunity for any misinterpretation of the stop signal used may have been minimised if marshalling bats had been used in this instance.

The intervention of the off-duty marshaller was timely and appropriate. Had he not taken this action, it is likely that the aircraft would have collided with the terminal building. The crew's uncertainty with parking on a reverse bay, and the marshaller's use of an unfamiliar hand signal combined to create doubt in the minds of the crew as to what the marshaller's intentions were.

On 19 February 2005 at 1310 Eastern Daylight-saving Time, a de Havilland Canada DHC-8-102 aircraft, registered VH-TQR, was being operated on a scheduled regular public transport service from Canberra, ACT, to Sydney, NSW. On arrival at the terminal the crew was given marshalling instructions from ground staff to taxi onto bay 57R and stop. The pilot in command (PIC) then reversed the aircraft until instructed to stop by an off-duty marshaller who had seen that the tail of the aircraft was very near to the Terminal 2 building.

While en route to Sydney, the crew had contacted the operator's movement control officer to request a parking bay and to advise that the weather radar was unserviceable. The crew were advised to expect a 'reverse bay'. The crew discussed the requirement to park on a reverse bay. They were uncertain if the aircraft was to be reversed onto the correct stopping point. There was no discussion about the marshalling signals they would expect to see. The PIC referred to the aircraft's parking bay diagrams (see Appendix A) and was satisfied that the lead in lines painted on the tarmac and the signals of the marshaller would provide sufficient guidance.

After vacating runway 34 left, the crew was advised by the operator to park on bay 57 reverse (57R) so that engineers could repair the weather radar. Bay 57R is located near the southern end of Terminal 2 Pier B (see Figure 1) and required aircraft to park with the nose pointing away from the terminal.

Figure 1: Parking bay 57 (for illustrative purposes only)

The bay is also marked 57A for aircraft parked facing the terminal. Bay 57R was used to park aircraft in conditions of strong westerly winds, or if engineering staff required the nose of the aircraft to be facing away from the terminal building. The bay was commonly referred to by both ground staff and flight crew as 57 reverse or a reverse parking bay.

The PIC taxied the aircraft to Bay 57R, where it was marshalled into position and stopped by the crew when they observed the marshaller cross his arms once at approximately chest height. The position of the aircraft at that stage was correct for Bay 57R. However, the crew were concerned that the aircraft was positioned too close to a vehicle access road marked on the movement area and after briefly discussing between themselves the meaning of the signal used by the marshaller, decided that the instruction was to reverse. The PIC then reversed the aircraft and anticipated that the marshaller would signal them to stop at the correct point. The crew noted that the marshaller was walking toward the aircraft as it reversed, using hand signals which they interpreted as confirmation of the reverse manoeuvre, but which the marshaller intended as a signal to stop.

The marshaller had been told that the aircraft had a problem with the weather radar, which required that the ground power unit (GPU) be positioned away from the aircraft's nose. When the aircraft started to reverse the marshaller thought the crew were also positioning the aircraft away from the GPU.

Three off-duty marshallers were in a lunchroom, adjacent to bay 57R, when the shift supervisor observed the aircraft being marshalled onto the bay. He then saw the aircraft reversing and alerted the other two marshallers in the room to the situation. They observed the aircraft marshaller signal the PIC to stop the aircraft, by crossing his arms repeatedly at chest height. One of the off-duty marshallers ran out onto the tarmac to the aircraft's two o'clock position¹ and signalled the crew to stop by crossing his arms over his head. The tail of the aircraft was estimated by that off-duty marshaller to be within 1 m of the terminal. The shift supervisor also went onto the tarmac and marshalled the aircraft forward to the correct bay 57R stop position.

The on-duty aircraft marshaller had received training on aircraft ground marshalling in accordance with the operator's ramp handling course document. The description for 'stop' in that document was in accordance with the Civil Aviation Safety Authority Civil Aviation Order (CAO) 20.3 Issue 5, Air Service Operations, Marshalling and Parking of Aircraft.

Stop is indicated by the arms to be repeatedly crossed above the head. (the rapidity of the arm movement related to the urgency of the stop, ie. the faster the movement the quicker the stop).

Other documentation used by the operator that included marshalling signals were a Customer Service Ground Handling Manual and a Flight Deck Engineering Manual that both stated:

Arms extended to full length above head in vertical position with bats or wands held steady. Widely accepted signal for use when there is no urgent stop requirement.

Although not in accordance with CAO 20.3, this signal was recognised by ground staff and by flight crew to indicate stop.

All of the manuals reviewed as part of the investigation stated that marshalling bats should be used to minimise the risk of misinterpretation. However, marshalling conducted by the operator during daylight was conducted without the use of marshalling bats.

1. The numbers on a clock are used to describe relative position, where 12 o'clock is directly in front. For example, a person or object observed abeam to the left of an aircraft would be said to be at 9 o'clock.

On 19 February 2005 at 1310 Eastern Daylight-saving Time, a de Havilland Canada DHC-8-102 aircraft, registered VH-TQR, was being operated on a scheduled regular public transport service from Canberra, ACT, to Sydney, NSW. On arrival at the terminal the crew was given marshalling instructions from ground staff to taxi onto bay 57R and stop. The pilot in command (PIC) then reversed the aircraft until instructed to stop by an off-duty marshaller who had seen that the tail of the aircraft was very near to the Terminal 2 building.

On 17 February 2005, a Boeing Company 737-838 aircraft, registered VH-VXN, with seven crew and 150 passengers, was being operated on a scheduled passenger flight from Adelaide, SA to Sydney, NSW. The crew reported that, as the aircraft was climbing through flight level (FL) 180 (18,000 ft), they noticed the stabiliser trim wheel moving opposite to the direction of the control column (elevator) movement.

The pilot in command was the handling pilot for the sector and was manually flying the aircraft when the movement was observed. The crew considered that the trim movement was uncommanded and consequently completed the non-normal procedure for a runaway stabiliser. As the non-normal checklist did not contain the words 'Plan to land at the nearest available airport', the crew levelled the aircraft at FL270 and continued the flight to Sydney.

Following the occurrence, a built in test equipment check was carried out on the flight control system and no faults were found. The two flight control computers were subsequently removed from the aircraft and tested at the operator's avionics workshop with no faults being found in either unit.

Previous flight

A different flight crew operated the aircraft on the preceding flight to Adelaide. That crew reported uncommanded stabiliser trim wheel movement while the aircraft was being taxied to the terminal, after landing at Adelaide. The crew also reported that when the aircraft was shutdown, the autopilot warning horn sounded. They did not notice any autoflight flight director system status annunciations on their respective Electronic Attitude Director Indicator (EADI), nor did they observe the illumination of the autopilot disengage indicator lights on the pilot and copilot instrument panels when the warning horn sounded. The operator's engineering personnel were advised about the apparent uncommanded movement of trim. A built-in test equipment check was subsequently carried out prior to the flight to Sydney but no fault was detected in the flight control system.

Stabiliser trim

The horizontal stabiliser is positioned by the main electric trim motor and is controlled through either of the stabiliser trim switches on each pilot's control column, or by the autopilot trim servo motor. The stabiliser may also be positioned by manually rotating the stabiliser trim wheels located on the control stand between the two pilots.

Pitch control of the aircraft includes a speed trim system. This system is used to improve flight handling characteristics during operations with low gross weight, rearward centre of gravity and high thrust when the autopilot is not engaged. The system provides positive speed stability characteristics to the pilot by adjusting the control column force so that the pilot must provide a significant amount of 'pull' force to reduce airspeed, or a significant amount of 'push' force to increase airspeed. The system trims the stabiliser in the direction calculated to provide the pilot positive speed stability characteristics. Since pilots typically attempt to trim control column force to zero and the speed trim system attempts to trim to positive stick force, the speed trim system operation may be opposite to the direction the pilot is trimming.

Autopilot flight director system

The autopilot flight director system is a dual system consisting of two individual flight control computers and a single mode control panel. The two flight control computers are identified as 'A' and 'B'. For autopilot operation, the computers send control commands to their respective pitch and roll hydraulic servos, which operate the flight controls through two separate hydraulic systems. For flight director operation, each computer positions the flight director command bars on the respective EADI located on the instrument panel for each pilot.

Either autopilot can be engaged in command mode or control wheel steering mode by pushing the appropriate engage switch on the mode control panel, which is located on the glare shield in front of each pilot (Figure 1).

If the autopilot flight director system is engaged in control wheel steering mode, the following system status annunciations will appear above the attitude indications on each pilot's EADI:

Flight data recorder information

Following the occurrence, data from the aircraft's flight data recorder (FDR) was downloaded and analysed by the aircraft manufacturer and the Australian Transport Safety Bureau (ATSB). The data indicated that during the previous flight the autopilot was engaged after landing at Adelaide. The autopilot was engaged by pushing the control wheel steering mode autopilot engage switch for the 'B' autopilot flight director system. The autopilot engagement occurred when the 'B' system flight director switch was selected to the OFF position while the aircraft was taxiing to the terminal. The flight director switches are usually selected to the OFF position by the crew while carrying out the 'taxi in' normal procedures when the aircraft has vacated the runway after landing.

The 'B' system flight director switch and the control wheel steering engage switch are in close proximity to each other on the glare shield mode control panel, above the centre instrument panel (Figure 1).

The data showed that various up and down trim movements were commanded by the autoflight flight director system following engagement of the control wheel steering mode after landing at Adelaide. The data also showed that the 'B' autopilot flight director system remained engaged when the FDR recording ended for that flight. The aircraft manufacturer advised that 'it is expected that it [the autopilot] disengaged later on (with warning horn) when additional power switching or configuration changes occurred.' The aircraft operator advised that the autopilot would have disengaged when the engines were shutdown and the electrical power source to the autoflight flight director system transferred from the engine driven generators to the auxiliary power unit driven generator.

The aircraft manufacturer also advised that, from their review of the FDR data, 'no trim anomalies could be seen on the following climb out [the occurrence flight]'.

On 17 February 2005, a Boeing Company 737-838 aircraft, registered VH-VXN, with seven crew and 150 passengers, was being operated on a scheduled passenger flight from Adelaide, SA to Sydney, NSW. The crew reported that, as the aircraft was climbing through flight level (FL) 180 (18,000 ft), they noticed the stabiliser trim wheel moving opposite to the direction of the control column (elevator) movement.

The pilot in command was the handling pilot for the sector and was manually flying the aircraft when the movement was observed. The crew considered that the trim movement was uncommanded and consequently completed the non-normal procedure for a runaway stabiliser. As the non-normal checklist did not contain the words 'Plan to land at the nearest available airport', the crew levelled the aircraft at FL270 and continued the flight to Sydney.

Following the occurrence, a built-in test equipment check was carried out on the flight control system and no faults were found. The two flight control computers were subsequently removed from the aircraft and tested at the operator's avionics workshop with no faults being found in either unit.

The Australian Transport Safety Bureau (ATSB) was requested by the Civil Aviation Safety Authority (CASA) to conduct an examination and analysis of several damaged thrust bearing elements from the propeller drive shaft of a Teledyne Continental Motors model GTSIO520M aircraft engine (serial number 810712). Information received indicated that the bearings and accompanying propeller shaft were removed from service during maintenance activities; the discovered damage prompting the aircraft operator to submit a defect report / service difficulty report (SDR) to CASA. A second similar instance of bearing failure and shaft damage was also reported, having occurred on a similar engine (serial number 239168R) approximately one month previously.

The assessment of bearing compliance with the manufacturer's specifications or the direct applicability of the particular bearing part to the engine within which they were installed was not within the scope of the investigation.