A propeller strap that became embedded in a Saab 340 regional airliner's cabin on take‑off from Canberra in November 2022 had been left in place, unnoticed, during preflight preparations, an ATSB investigation report details.
The Link Airways-operated Saab 340 was taking off from Canberra for a passenger service to Sydney when the propeller strap - designed to stop the propeller windmilling - was thrown free of the blade and embedded in the cabin wall. In addition, cowling pins broke free of the strap, and one struck a passenger, resulting in a minor injury (bruising).
The aircraft then returned to Canberra, landing safely, with emergency services assessing the injured passenger.
The ATSB's investigation found that several factors contributed to the propeller strap not being noticed or removed by the first officer, captain, or dispatcher, prior to departure.
Notably, an extension line to the strap, used to guide passengers onto the aircraft, was not fitted.
"The strap extension does not allow the door to be closed while in place - and as such would almost certainly have prevented the flight from proceeding with the propeller strap in place," ATSB Chief Commissioner Angus Mitchell said.
Additionally, the strap did not have a high-visibility streamer fitted in accordance with the manufacturer's design. The operator conducted a post-incident survey that found the condition of propeller straps varied significantly across its Saab 340 fleet.
Further, guidance provided by Link Airways for training of dispatchers from the ground handling contractor, Swissport, did not explain the appearance, function and importance of the propeller straps.
And while it did not contribute to this occurrence, the ATSB also found that Swissport did not ensure that the implemented dispatcher training and audits for operations involving the Link Saab 340 dispatches incorporated all of the elements required for pre-departure walk-arounds in its own ground handling manual.
"For those directly involved in aircraft operations, this occurrence should highlight the importance of vigilance," Mr Mitchell said.
"When there are multiple risk controls in place and multiple responsible parties, it is easy to become complacent from an expectation that earlier checks have been done correctly and that future checks elsewhere in the system will likely catch anything missed."
At an organisational level, Mr Mitchell noted the occurrence illustrates the importance of strong communication and harmonised procedures.
"The use of external ground handling services has become increasingly common in aviation, and the relationship between a carrier and a ground handler can add complexity to ground handling operations," he said.
"It is critical that all involved parties have a complete understanding of their roles and responsibilities, and how they fit together to create a safe and functional operating environment."
Since the occurrence, Link has rectified discrepancies in its propeller straps, and updated its flight crew and cabin crew operating manuals to include additional preflight checks for the presence of the propeller strap and extension.
Link also amended training guidance to Swissport, including more details on the use of propeller straps and extensions, as well as the dispatcher's role in checking for the strap.
And Swissport has informed all ramp staff, including dispatchers and trainers, that walk‑arounds are required on Saab aircraft, and is examining the potential to include more guidance for its auditors to assess specific task elements. It also consulted with Link to better define dispatcher responsibilities and expectations.
You can find here the final report: Aircraft preparation and foreign object damage event involving Saab 340B, VH-VEQ, at Canberra Airport, Australian Capital Territory, on 10 November 2022
