1. British Overseas Airways Corporation Flight 712 took off from London Heathrow Airport at 09:51 on 8 April 1968.2. A fire broke out in the No.2 engine shortly after takeoff, and the crew decided to return to Heathrow immediately.3. The fire intensified rapidly and caused structural damage to the aircraft, with thick smoke filling the cabin.4. The crew made an emergency landing at Heathrow Airport at 10:05, and the aircraft was engulfed in flames after touchdown.5. Evacuation was carried out urgently, but 5 passengers lost their lives and 38 people were injured in the incident.6. The subsequent investigation concluded that the fire was caused by a fatigue crack in an engine fuel pipe, leading to fuel leakage and ignition.