What happened
On 10 March 2006, a Boeing 757-236, registration G-CPET, was prepared for departure at London Heathrow Airport. Following the start of both engines, the co-pilot noted the presence of fumes within the cockpit. While the cabin crew appeared to be unaffected by the odor, the flight crew began to experience physical symptoms. After the aircraft had been pushed back from the stand, the co-pilot reported feeling unwell, euphoric, and light-headed. As the aircraft was positioned on the taxiway, the commander also began to feel light-headed.
The investigation
Investigators established that the aircraft had not yet begun taxiing under its own power at the time the symptoms were first reported, as it was still in the pushback phase of the operation. Due to the deteriorating physical condition of the flight crew, both engines were shut down. The crew determined they were no longer fit to continue the taxiing process, and the aircraft was subsequently towed back to its parking stand.