An Eastern Australia de Havilland Dash 8-300 on behalf of Qantas, registration VH-SBG performing flight QF-2225 from Sydney,NS to Wagga Wagga,NS (Australia), was enroute about 35nm northnortheast of Canberra,AC (Australia) when the crew reported smoke in the cockpit and diverted to Canberra for a safe landing. The aircraft was evacuated after landing. No injuries occurred, emergency services did not find traces of fire or heat.
Australia's Transportation Safety Board have opened an investigation into the occurrence rated an incident.
On Apr 7th 2017 the ATSB released their final report concluding the probable causes of the incident were:
- The flight management system unit failure and observed smoke were the result of a capacitor, which did not meet current design specifications, overheating.
- Despite a design upgrade in 1998 for new flight management system units, unmodified units remained in service that had the original capacitors.
- At the time of the occurrence, the approved QantasLink training did not provide first officers with sufficient familiarity on the use of the oxygen mask and smoke goggles. This likely contributed to the crew's communication difficulties, including with air traffic control. [Safety issue]
Other factors that increased risk
- Despite removing their oxygen masks to improve communication, by doing so the crew increased the risk of impairment or incapacitation as there was still smoke in the cockpit.
- The stress associated with the smoke in the cockpit resulted in a high workload for the crew and adversely affected their performance, leading to errors in aircraft management and checklist completion.
The ATSB reported that the aircraft was enroute when the crew noticed there was a blank area on the Flight Management System Display. About 10 minutes later the screen went completely blank and thick, light grey smoke emerged from the unit.
The flight crew donned their oxygen masks and smoke goggles, but were having problems communicating and removed the the masks for the remainder of the flight. The aircraft was diverted to Canberra for a safe landing, the flight crew went to a hospital for examinations and was discharged without need for treatment.
The ATSB reported two capacitors had failed resulting in the smoke emerging from and the failure of the unit, that was manufactured in 1997. In 1998 the manufacturer had introduced a modification replacing those capacitors in later manufactured units, however, previously manufactured units were not required to be modified.
The ATSB further found that the training provided to first officers did not transfer sufficient familiarity with the oxygen masks and smoke goggles. The ATSB wrote: "The more-experienced captain’s familiarity with the equipment was enhanced by completion of additional mask and goggles training sessions."
The ATSB analysed:
As would be expected in any emergency situation, the appearance of smoke from the FMS created a level of stress for the flight crew. Their immediate response was to review the Quick Reference Handbook and action the Fuselage Fire or Smoke checklist. The first step was to put oxygen masks on, followed by fitting the smoke goggles before continuing the checklist.
During this time, the crew were interrupted numerous times due to the need to respond to air traffic control (ATC) and calls from QantasLink via radio as the first officer (FO) was reading out the checklist. After each interruption, the checklist was recommenced from the start. However, reports from the crew indicated that communication both between them and with ATC while wearing the oxygen masks was difficult. Consequently, the FO had to repeat the PAN call to ATC multiple times before being understood. This added to the crew’s stress and workload in trying to resolve this difficulty.
The FO’s action to reduce altitude appears based on recognising this requirement from the training in simulated rapid depressurisation procedures. The captain did not recall discussing descending the aircraft with the FO at that time and was not aware that the FO had advised ATC they intended doing so. Consequently, the captain was surprised by the FO’s actions and immediately re-engaged the autopilot.
After the FO attempted to descend the aircraft without a direction to do so from the captain (who was the pilot flying) and, recognising that the FO was anxious, the captain ordered the removal of the oxygen masks. As the smoke goggles and oxygen masks were ‘tangled’ together, both crew members’ masks and goggles remained off for the remainder of the flight.
The captain reported that once the oxygen masks were removed, and better communications established as a result, the FO contacted ATC and determined that Canberra was the closest suitable airport. The crew requested radar vectors for Canberra from ATC as the FMS was no longer working. The captain stated that descent from FL 200 normally required about 60 NM (111 km). In this instance, the aircraft’s proximity to Canberra meant that the crew had to prepare for the descent and landing over a remaining distance of 30 NM (56 km). This resulted in a similar number of tasks being carried out in a reduced period of time.
The inherent stress of the event, together with the associated high workload led to the crew making errors in both aircraft management and checklist completion. This included not completing the ‘transition drill’ when passing 10,000 ft on descent, which includes checking, and changing as required, the fuel system, exterior lights, pressurisation and ice protection. These drills were conducted at 8,000 ft prior to conducting the approach checklist.
As part of the initial conduct of the checklist, the FO retrieved the fire extinguisher and handed it to the captain. However, as the FMS was still an intact, sealed unit, there was no way for the extinguisher to be used on the FMS. The captain’s decision to place the unused fire extinguisher on the floor adjacent to the seat may have been influenced by the impracticality of re-securing the fire extinguisher in the normal stowage location. Consequently, the fire extinguisher presented a potential projectile hazard within the flight deck.
The captain stated that passing about FL 120 the FO was requested to continue with the Fuselage Fire or Smoke checklist. The captain reported a number of interruptions at about this time to the extent that the FO was unable to recommence reading out the checklist actions until passing about 8,000 ft. These interruptions included the previously-mentioned numerous ATC calls and from QantasLink ground personnel, enquiries from cabin crew and the need to make a public address announcement to the passengers.
When the Fuselage Fire or Smoke checklist was recommenced just prior to 8,000 ft, the captain misheard the cessation note as read out by the FO. This note was designed to highlight the need to prepare for and manage an immediate landing if the source of fire or smoke could not be identified and that to do so, the checklist could be terminated. It is likely that when this note was read out, the proximity to Canberra and the need to conduct the approach and landing checklist reinforced the captain’s decision to terminate the checklist at this point, despite it applying to an unknown source of fire.
In both the crew’s initial action to carry out the Fuselage Fire or Smoke checklist, and its review at 8,000 ft, circumstances prevented the completion of the Known Source of Fire or Smoke section. In both cases, the action to open the ‘forward outflow valve’ was missed. However, the associated note for this action specified its completion ‘if necessary to assist in removal of smoke’. Given the crew reported the smoke had dissipated by the time the approach was commenced into Canberra, even if this step was reached, it is unlikely it would have needed to be actioned.