Aviation safety investigations & reports

Fuel exhaustion and forced landing involving Cessna 441, VH-LBY, 39 km east of Broome Airport, Western Australia, on 2 March 2018

Investigation number:
AO-2018-019
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final

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Safety summary

What happened

On 02 March 2018, at 1549 Western Standard Time, a Skippers Aviation Cessna 441 Conquest, registered VH-LBY, departed on a scheduled passenger service from Fitzroy Crossing to Broome, Western Australia with one pilot and nine passengers on board.

During descent, the FUEL LEVEL LOW annunciators illuminated. The pilot observed that both fuel quantity gauges indicated sufficient fuel remaining and continued flying towards Broome. The right engine began surging, followed by similar surging from the left engine. Subsequently, the right engine lost power and the pilot conducted the engine failure checklist.

The pilot declared a MAYDAY and advised air traffic control that, as the left engine was still operating, the aircraft would be able to reach Broome. However, the left engine also lost power and both engines were unable to be restarted. The pilot landed the aircraft safely on the nearby highway. There were no injuries, and the aircraft was undamaged.

What the ATSB found

Due to water contamination in the fuel tanks, the aircraft’s fuel quantity gauges were significantly over reading on the day of the occurrence and on previous days. The water contamination had existed for some time without being detected by multiple pilots’ fuel quality testing.

Although the pilot routinely compared indicated versus calculated fuel quantities, and indicated versus flight-planned fuel quantities, the pilot did not routinely conduct two other methods stated in the operator’s procedures for cross-checking fuel quantity gauge indications.

In addition, although the operator had specified multiple methods of cross-checking fuel quantity gauge indications for its C441 fleet, there were limitations in the design, definition and/or application of these methods. The primary method used (indicated versus calculated fuel) was self-referencing in nature, and not able to detect gradual changes in the reliability of fuel quantity gauge indications. Pilots also did not record (and were not required to record) sufficient information on flight logs to enable trends or patterns in fuel quantity gauge indications to be effectively identified, and pilots did not routinely cross-check information from fuel quantity gauge indications with information from the independent fuel totaliser.

The FUEL LEVEL LOW annunciators likely illuminated approximately 30 minutes before the fuel was exhausted in each tank, and when the aircraft was still within range of suitable alternative airports. However, the pilot disregarded the annunciations, and relied on the (erroneous) fuel quantity indications and continued to Broome until the engines lost power, at which point a forced landing on a highway was the only remaining option.

What has been done as a result

The operator increased the frequency of a fuel quantity comparison checks to a known quantity to ensure continued quantity measurement accuracy, specified clearer requirements for determining discrepancies when using fuel totaliser figures, implemented additional fuel management record keeping and increased management oversight of its Broome operations. It also increased focus on fuel management procedures during training.

Safety message

Accurate fuel management is a critical aspect of flight operations and it is important to utilise all available means in order to gain the highest assurance that fuel quantity measurement is accurate. It is essential that a reliable quantity cross-check is adopted, utilising at least two independent methods and a conservative approach. Pilots also should understand the functionality of the low fuel warning system on their aircraft and treat any warning annunciations as being accurate unless there is overwhelming evidence otherwise.

Further reading is available in the ATSB research report, Starved and exhausted: Fuel management aviation accidents (AR-2011-112). This report discusses methods that pilots can use to ensure they will have sufficient fuel to land at their destination.

 

Download Final report
[Download  PDF: 2.17MB]
 
 
 

The occurrence

Safety analysis

Findings

Safety issues and actions

Sources and submissions

Appendices

About the ATSB

Safety Issue

Go to AO-2018-019-SI-01 -

Fuel quantity assessment methods

Although the operator had specified multiple methods of cross-checking fuel quantity gauge indications for its C441 fleet, there were limitations in the design, definition and/or application of these methods. These included:

  • The primary method used (indicated versus calculated fuel) was self-referencing in nature, and not able to detect gradual changes in the reliability of fuel quantity gauge indications.
  • Pilots did not record (and were not required to record) sufficient information on flight logs to enable trends or patterns in fuel quantity gauge indications to be effectively identified.
  • Pilots did not routinely cross-check information from fuel quantity gauge indications with information from the independent fuel totaliser.
Safety issue details
Issue number: AO-2018-019-SI-01
Status: Closed – Adequately addressed
General details
Date: 02 March 2018   Investigation status: Completed  
Time: 16:20 WST   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): 39 km east south east of Broome Aerodrome, Western Australia   Investigation phase: Final report: Dissemination  
State: Western Australia   Occurrence type: Fuel exhaustion  
Release date: 27 May 2021   Occurrence category: Serious Incident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Cessna Aircraft Company  
Aircraft model 441  
Aircraft registration VH-LBY  
Serial number 4410023  
Operator Skippers Aviation  
Type of operation Air Transport Low Capacity  
Sector Turboprop  
Damage to aircraft Nil  
Departure point Fitzroy Crossing, Western Australia  
Destination Broome, Western Australia  
Last update 27 May 2021