What happened
On 12 June 2001, an MD 83, registration SE-RBI, was preparing for a passenger flight at Manchester Airport. Upon arrival at the aircraft, the crew was notified by maintenance staff that one of the two onboard batteries had become discharged, preventing the initial start of the Auxiliary Power Unit (APU) due to insufficient voltage. As no ground power unit (GPU) was immediately available, the crew waited until a GPU could be provided to charge the battery.
During the passenger boarding process, the pilots detected an unusual odour within the cockpit. Simultaneously, maintenance personnel on the ramp observed smoke escaping from the Electrical and Electronic (E&E) bay compartment door located under the fuselage. In response, the commander deactivated the battery switch and shut down the APU. As smoke began to accumulate in the flight deck, the crew lost electrical power, rendering communication with air traffic control and emergency services impossible. Because the main cabin door was obstructed by passengers still boarding and the emergency slides were not yet armed, the crew initiated a precautionary evacuation through the rear ventral door using a loud hailer. All 146 passengers and 8 crew members evacuated the aircraft without any injuries.
The investigation
The investigation focused on the source of the smoke and the electrical failure. Investigators examined the state of the aircraft's electrical systems and the circumstances surrounding the battery charging process. It was determined that the smoke originated from the E&E bay and was specifically linked to the condition of the aircraft batteries.
Findings
- The smoke was caused by the boiling of the aircraft batteries.
- The overheating was likely a result of the batteries undergoing a rapid re-charging process.
- The loss of electrical power during the incident prevented the use of standard communication equipment with ground services.