Inquest finds inadequate inspection contributed to fatal air tanker crash

A coroner’s inquest found that an inadequate inspection contributed to the crash of an air tanker in New South Wales, Australia.

Dromader M-18 air tanker
File photo of Dromader M-18. Photo by Ted Quackenbush.

David Black, 43, died when his M18 Dromader single engine air tanker crashed while fighting a fire at Wirritin in Budawang National Park, 40 kilometers west of Ulladulla, October 24, 2013 when a wing snapped off the aircraft as it was approaching the fire. The crash started another bushfire which, along with high winds, hampered efforts to reach the pilot.

Below is an excerpt from an article at 9news:

[The aircraft] was tested and inspected just over two months earlier by two companies, Aviation NDT and Beal Aircraft Maintenance, but [Deputy State Coroner Derek] Lee said the work was inadequately done.

He wrote in his findings that testing by Aviation NDT used an unauthorised method and did not comply with the mandatory requirements of the Civil Aviation Safety Authority.

Further, the plane’s wings were not removed during a visual inspection by Beal Aircraft Maintenance, meaning that corrosion and cracking on one of the left wing’s attachment lugs was not detected.

By the time Mr Black crashed in October, the Australian Transport Safety Bureau found that cracking on the inner surface of the lug had reached a critical length of 10.4 millimetres and at least 32 secondary micro cracks were also identified.

The engineer behind the visual inspection, Donald Beal, told the inquest the manufacturer’s service bulletin did not mandate removal of the wings, so he didn’t see any need to remove them.

Mr Beal also said there was ambiguity about what visual inspections actually involved, Mr Lee recalled in his findings.

Thanks and a tip of the hat go out to Chris.
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2 thoughts on “Inquest finds inadequate inspection contributed to fatal air tanker crash”

  1. Points out the difficulty in using a “Safe Life” structural fatigue management program using flight hours as the limiting factor. Without an extensive flight load monitoring program, engineers have to estimate the correlation between flight hours and actual structural fatigue incurred from actual load cycles.

    The more flight hours [in this case an old aircraft with an unknown early history] the greater the problem introduced by misestimating the correlation of flight loads to flight hours.

  2. The other part of the issue is that these wing attachment fittings are 4130 steel equivalent (carbon steel), which is very prone to corrosion. Tiny corrosion pits in this material can lead to “premature” fatigue cracks so even if you have your flight loads correct and proper analysis completed, with corrosion being part of the issue, prediction becomes more difficult. The key (as is with most fatigue critical inspections) is to have a rigorous inspection protocol with verified calibration standards for NDT inspections and the inspectors trained and experienced in their use.

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