What happened
On 7 December 2005, a BAe 146-200, registration G-JEAW, was preparing for departure from Southampton Airport. The aircraft was performing its fifth sector of the day, having undergone de-icing earlier that morning. During the pushback and taxi phase, cabin crew and several passengers noticed an acrid smell throughout the cabin.
Several individuals experienced physiological symptoms due to the fumes. One cabin crew member suffered from nausea and vomiting, while another reported a racing heartbeat and light-headedness. Five passengers also reported symptoms, including one person who experienced a burning sensation in their eyes. After holding at point B1 for approximately five minutes, the commander decided to abort the flight. Although the crew attempted to purge the cabin by switching from APU bleed air to engine bleed air, the fumes persisted. The aircraft returned to the stand, and all passengers disembarked.
The investigation
Investigators examined the engines and the APU for potential oil leaks that could have contaminated the bleed air system, but no leaks were identified. The hydraulic system was also inspected and found to be functional. Ground runs were conducted using bleed air to attempt to replicate the event, but the fumes could not be reproduced.
Subsequent inspections of the environmental control systems revealed a significant amount of de-icing fluid. The investigation established that the APU air inlet, which is permanently exposed on the upper left side of the rear fuselage, had collected de-icing fluid running down the aircraft's skin. This fluid was then ingested into the APU compressor.
Findings
- The presence of de-icing fluid in the APU air intake caused the contamination of the cabin air supply.
- The APU inlet design makes it vulnerable to fluid accumulation from the fuselage during de-icing operations.
- De-icing fluid running down the fuselage entered the APU inlet.