Aviation safety issues and actions
Recommendation issued to: CASA
|Date issued:||23 December 2005|
|Safety action status:|
|Background:||Why this Recommendation was developed|
The Australian Transport Safety Bureau recommends that the Civil Aviation Safety Authority alert operators and review the continuing airworthiness of all Australian registered Fairchild Industries SA227 model aircraft, or other aircraft model types using fuel immersed capacitance-type fuel sensors (probes), with specific regard to possible high impedance wire chafing within the fuel tank.
|Date issued:||23 February 2006|
Following an investigation into the occurrence, and a review of the ATSB recommendation, CASA supplied the results of that investigation and review to the ATSB. A summary of those findings is included below:
Following the preliminary review of data available the decision was made not to ground the Australian fleet on the following basis:
Considering the age of the aircraft and the uncertain maintenance regime that existed for the majority of its operational life causal factors that may have contributed to this defect are numerous, as an example:
There is no indication as to whether this is an old defect, recent failure or a continuing issue. No evidence exists that would indicate a fleet trend. From the data available, I agree with the finding of the TC [type certificate] holder in that this is an isolated incident. Whilst the potential for fire is always present when an ignition source and a volatile fuel are brought together, there is minimal risk that the arcing that occurred could cause a fire in the aircraft considering the low power and the high flash point of the Jet A1 fuel in use.
An Airworthiness Bulletin is to be issued recommending greater scrutiny of the FQIS, particularly the fuel quantity probes, during scheduled and unscheduled maintenance. Operators will be encouraged to report any anomalies found in an attempt to identify possible trends. This would include verification of the FQIS reading against physical quantity of fuel present.
|Date issued:||05 July 2006|
|Response status:||Closed - Partially Accepted|
As a result of further communications with the Civil Aviation Safety Authority (CASA) on the issue following notification of another fuel probe from a different aircraft displaying the same anomaly, CASA conducted a review to further examine the issue. It provided the Bureau with an extensive report detailing the review. The conclusion of the report stated:
'Following the review CASA maintains that:
The review also included proposed actions to revise Airworthiness Bulletin 28-1 to better represent fuel related hazards and to develop and publish additional educational material on the matter.
Although the Civil Aviation Safety Authority considers the risk of fuel tank explosions due to electrical shorting as negligible, the Bureau considers the possible introduction of an ignition source into a fuel tank by way of electrical discharge or shorting, even though of low energy, as undesirable.