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Preliminary

Summary

On 23 September 2005, a Fairchild Metro III, registered VH-SEF, with 2 crew and 16 passengers on board, was being operated on a scheduled passenger service from Thangool, Qld, to Brisbane. At about 1942 Eastern Standard Time, when the aircraft was just north of the Gayndah non-directional beacon, the L XFER PUMP (left fuel transfer pump) warning illuminated. In accordance with company procedures, the crew selected the alternative fuel boost pump. However, the warning remained illuminated. The crew diverted the flight to Bundaberg. When the aircraft was about 10 NM from Bundaberg, the left engine failed. The crew conducted a single-engine visual approach and landing to Bundaberg aerodrome.

A maintenance engineer subsequently drained the aircraft fuel tanks, obtaining 2 L of fuel from the left tank, and 28 L from the right tank.

The Metro III fuel system consisted of two integral fuel tanks, located in the left and right wings. Each wing tank contained a hopper tank and two fuel boost pumps to provide fuel to the aircrafts engines. According to the Metro III Airplane Flight Manual, when a fuel boost pump was operating, activation of the fuel transfer pump warning indicated that there was 65 to 75 pounds (36 to 43 L) of fuel remaining in the respective tank.

The aircrafts fuel quantity indicating system consisted of five capacitance sensors and a temperature compensator in each wing tank. The capacitance values, adjusted for temperature, were transmitted to a dial-type fuel quantity gauge located in the cockpit, which displayed the quantity of fuel, in pounds, in each fuel tank. After the aircraft landed at Bundaberg, the fuel gauge indicated that there was approximately 400 pounds (227 L) of fuel in the left tank, and 300 pounds (170 L) in the right tank.

Prior to the occurrence flight, the aircraft had completed a scheduled passenger service from Brisbane to Thangool. Before departure from Brisbane, the pilot in command had been told that there was 850 pounds (483 L) of fuel on board the aircraft. He subsequently arranged for the aircraft to be refuelled with 642 L. The aircraft was not refuelled in Thangool.

The aircraft was fitted with a mechanical fuel totaliser, which recorded the quantity of fuel that had been consumed by the aircrafts engines. It was the operators practice for pilots to reset the totaliser to zero before each flight. The recorded totaliser values indicated that the total fuel consumed during the Brisbane to Thangool and Thangool to Bundaberg flights was 1,283 pounds (729 L).

Immediately before the flight from Brisbane to Thangool, the aircraft had been at an independent maintenance facility undergoing various maintenance actions, including the replacement of the aircrafts fuel gauge1. The maintenance organisation reported that the replacement fuel gauge was calibrated according to the aircraft manufacturers instructions before the aircraft was released for service.

Each fuel tank was also fitted with an optional direct-reading mechanical fuel level indicator called a magna-stick. A magna-stick was located on the underside of each wing, inboard of the engine nacelle, and consisted of a doughnut-shaped float inside the fuel tank, which was attached to a calibrated indicator stick. The magna-stick could be used to provide an indication of fuel quantity if the quantity in the tank was between approximately 30 and 160 US gallons (115 and 585 L).

Following the occurrence, the Civil Aviation Safety Authority (CASA) required the aircraft to be refuelled to full tanks before it was flown by day and without passengers to Brisbane for maintenance examination.

Safety Action

1. On 27 September 2005, CASA prescribed a temporary direction on the operator regarding the total fuel to be carried on all Metro aircraft flights. On 28 September 2005, CASA rescinded that direction and further directed the operator to amend the company Metro III operations manual with respect to the pre-flight procedure for the check of fuel on board. A copy of that procedure is at attachment A.

2. On 28 September 2005, CASA issued the following directions to the operator with regard to aircraft maintenance:

  • A formal fuel indication system inspection and calibration check was to be conducted on the operator's fleet of three Metro aircraft in the presence of a CASA airworthiness inspector. Plans for those activities were to be completed within five working days
  • Maintenance control manual procedures were to be developed for recording fuel related maintenance activities. Those procedures were to include provision for engineers to enter the maintenance fuel burn after engine runs and fuel system maintenance in the flight log or the maintenance log. Those procedures were to be communicated as a notice to pilots and to all relevant maintenance organisations. The procedures were to be included as a revision to the company's maintenance control manual.
  • Within the next 10 working days, the company's Metro system of maintenance relating to ATA2 Section 28 fuel indicating systems was to be reviewed in conjunction with CASA airworthiness inspectors.
  • Within the next 10 working days, the company's Metro minimum equipment list relating to ATA Section 28 fuel indication system defects was to be reviewed in conjunction with CASA airworthiness inspectors.

3. On 24 September 2005, the operator advised all Metro III flight crew of the contents of Standing Order #155 via emailed memo and individual telephone calls. On 28 September 2005, the operator issued company Standing Order #155, effective immediately, which amended its Metro III operations manual as follows:

The following fuel checks must be carried out before every departure and or after every refuelling:

  1. A Magna-Stick Check must be carried out, and its reading noted (take at least 3 readings and use the lowest reading).
  2. This reading must then be compared to the gauge reading.
  3. If there is any discrepancy between the two, the Lower reading must be used for all fuel calculations and the Higher reading must be used for all weight and balance calculations.

Remember Magna-Sticks are only useful when fuel tanks are less than half full (2171 lbs) but have at least 201 lbs in them. Whenever possible, limited fuel loads to no more than 2170 lbs to allow an accurate Magna- Stick reading.

Accurate readings are obtainable only when the airplane is on a reasonably level ramp because the Magna-Stick indications depend upon the level of the fuel in the tank. Avoid inaccurate readings caused by binding of the indicator stick in its bushing by tapping the bottom surface of the wing around the Magna-stick as and before taking readings. Due to the slope of some of our parking bays (i.e. Armidale) accurate reading will not be obtained. Therefore, so long as there is no unexplained discrepancy between planned fuel remaining upon arrival and the actual fuel remaining upon arrival, the aircraft may depart without completing a Magna-Stick Check, provided a Magna-Stick Check is completed before departure from the next port that contains a level parking bay.

On Wednesday 28 September, the operator issued company Standing Order #156 as follows:

Effective immediately, before every departure the Pilot in Command MUST complete the attached form [see Attachment A]. The completed form MUST be returned with the FDL [flight deck log] at the completion of the days flying.

I would also like to remind all pilots of the obligation to carry out a 3% check before each flight as per CAO [Civil Aviation Order] 20.2.6.1.

If the difference is calculated exceed 3%, maintenance control must be notified before further flight.

With regard to the Metro, the procedures stated in Standing Order 155 must also be completed.

With regard to the CASA directions of 28 September on Metro aircraft maintenance, the operator reported that the following action had been taken:

  1. A notice to pilots and engineers was issued to direct engineering organisations that maintain the company's Metro aircraft to record fuel burns and uplifts in the captain's report area of the current FDL, in advance of a new style FDL being released.

  2. An internal task force was convened on 6 October 2005 to review, in conjunction with CASA, the company's system of maintenance and minimum equipment list for the Metro aircraft with regard to ATA Section 28 items.

  3. A notice was issued to pilots and engineers stating that the preferred method of calibration (complete system calibration) and not the alternative method (abbreviated method) was to be used whenever maintenance action that required fuel system calibration was conducted.

  4. A complete fuel indication system check and fuel system calibration was scheduled for completion on two of the company's Metro aircraft by 11 October 2005. Fuel system calibration of the occurrence aircraft would be undertaken once repairs had been completed. All calibration checks would be conducted in the presence of a CASA airworthiness inspector.

Attachment A: Procedure for pre-flight checks for fuel on board
Attachment A


1 The fuel gauge was a single display incorporating an indicator for each of the two fuel tanks.
2 A specification issued by the Air Transport Association of America that establishes a standard for the presentation of certain data produced by aircraft, engine, and component manufacturers, required for the support of their respective products.


 
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