What happened
On 22 April 2013, an Airbus A330, registration 9V-STO, was operating a scheduled flight from Singapore to Dhaka, Bangladesh. While cruising at 36,000 feet over the Gulf of Thailand, the flight crew received a smoke warning indicating a potential issue in the rear cargo compartment. This was accompanied by a burning smell reported by a cabin attendant near the forward door area. In response, the crew discharged the cargo fire extinguishing agent and diverted the aircraft to Suvarnabhumi Airport in Bangkok.
The aircraft landed without incident, and the crew requested an external inspection by the Airport Rescue and Firefighting Service (ARFS). After an initial inspection showed no visible smoke, the aircraft taxied to a parking bay and passengers disembarked safely. However, once the aft cargo door was opened, white smoke began billowing from the compartment. During the subsequent unloading process, the contents of cargo container 42L burst into flames, leading to a significant fire that required water to extinguish.
The investigation
The investigation examined the sequence of events from the initial smoke detection to the fire re-ignition. Investigators analyzed the aircraft's damage, which included soot deposits and heat damage to the aft cargo compartment's ceiling and sidewall panels. The investigation also reviewed the communication between the flight crew, air traffic controllers, and the ARFS, as well as the handling of dangerous goods documentation (NOTOC).
Findings
- The investigation could not pinpoint the exact ignition source, though the presence of undeclared ethanol within the cargo was noted.
- The fire rekindled because fresh air entered the compartment when the cargo door was opened, igniting embers remaining within container 42L.
- There was a lack of proactive communication regarding the specific details and locations of dangerous goods from the flight crew to air traffic control.
- The flight crew prematurely considered the emergency terminated based on information from the controller, rather than waiting for confirmation from the firefighting service.
- Communication between the ARFS and the flight crew was indirect, relying on the air traffic controller as a middleman, which hindered efficient decision-making.
Safety action
- It is recommended that operators require flight crews to volunteer specific details regarding the location of dangerous goods immediately upon declaring an emergency.
- Flight crews should be reminded not to consider a fire risk mitigated until confirmed by the firefighting authority.
- Air traffic control authorities should consider arrangements for direct communication between the ARFS and the flight crew during emergencies.