What happened
On 23 April 2023, a Saab 340A, registered VH-KDK, was performing a non-revenue freight flight from Wagga Wagga to Charleville. While cruising at 22,000 feet near Cobar, New South Wales, the flight crew received a cargo smoke warning. The crew donned oxygen masks and goggles, but shortly thereafter, thick black smoke filled the flight deck, severely limiting visibility of the instruments and external references.
As the crew diverted to Cobar, they encountered additional complications, including a right engine fire detection failure and a cabin depressurization. During the emergency, the crew attempted to follow the cargo smoke checklist but were unable to locate the cross-valve handle. The aircraft eventually landed at Cobar, where the crew elected to stop on the runway and evacuate. Emergency responders later discovered a heat source near the air cycle machine and identified fire damage around the right recirculating fan. The aircraft sustained substantial damage, though there were no injuries to the crew.
The investigation
The investigation established that the fire originated from a failure within the electronic sub-assembly of the right recirculating fan. This fire spread under the cabin floor, and smoke entered the flight deck because a smoke barrier curtain had not been installed.
Investigators also found that the crew's ability to manage the emergency was hindered by a malfunctioning microphone in the first officer's oxygen mask, which delayed communication. Furthermore, the investigation revealed that the crew lacked specific training and familiarity with the differences in the cargo-configured version of the aircraft. Specifically, the crew could not find the cross-valve handle because they were not adequately prepared for this specific configuration, and the operator's manuals did not sufficiently highlight the necessary pre-flight checks for the cargo setup.
Findings
- A failure in the right recirculating fan's electronic sub-assembly caused the in-flight fire.
- Smoke entered the flight deck because the smoke barrier curtain was not in place and the flight deck door was open.
- The crew's familiarity with the cargo-configured aircraft was insufficient, preventing the successful execution of certain emergency checklist items.
- The lack of a manufacturer-provided pre-fly check for the smoke barrier curtain contributed to the smoke's spread.
Safety action
Following the incident, Regional Express Airlines updated its training syllabus to include the specific differences of the cargo-configured Saab 340 and amended its internal inspection checklists to include verification of the cross-valve handle. The airline also committed to fleet-wide inspections of the recirculating fan assemblies. Additionally, Saab revised its pre-flight walk-around checklists to ensure the smoke barrier curtain is properly fitted when carrying cargo.