What happened
On September 6, 1971, a Paninternational BAC 1-11, registration D-ALAR, departed Hamburg for Malaga with 121 occupants. During the initial climb, approximately 700 feet above the ground, the crew experienced explosive noises from both engines. The engines suffered a massive loss of thrust, making continued flight or a return to the airport impossible.
Recognizing the emergency, the pilot attempted an immediate forced landing on the Hamburg-Bad Bramstedt Autobahn. During the descent, the aircraft' 121 occupants experienced a hard touchdown, causing the left main landing gear to collapse. The left wing struck the roadway, hitting guardrails and an emergency telephone pole, which caused the aircraft to rotate and strike a bridge pier. The impact severed the forward section of the fuselage and the tail assembly. The wreckage slid 390 meters before coming to a halt. After the survivors evacuated, the wreckage caught fire due to spilled fuel.
Of the 121 people on board, 22 fatalities occurred, including one crew member and 21 passengers. Additionally, 19 individuals sustained serious injuries and 38 sustained minor injuries.
The investigation
The BFU investigation focused on the cause of the simultaneous engine failures and the subsequent impact. Investigators examined the engine components, finding significant overheating damage to the combustion chambers, high-pressure turbines, and low-pressure turbines. Chemical analysis of the water injection system revealed the presence of kerosene in the lines.
Further investigation into the aircraft's water supply revealed that the demineralized water used for the engine's water injection system had been stored in unmarked containers. These containers had previously been used to collect fuel during maintenance work on another aircraft. When the water was transferred to the aircraft's onboard tanks in Hamburg, the containers were contaminated with kerosene.
Findings
- The primary cause of the accident was the introduction of kerosene into the water injection system via the demineralized water supply.
- The use of unmarked, unstandardized containers for transporting demineralized water allowed for the accidental contamination of the supply with fuel.
- The contaminated fluid caused severe overheating in the combustion chambers and turbines of both engines, leading to a critical loss of thrust.
- The heavy landing gear failure and subsequent impact with the bridge pier were exacerbated by the aircraft's high landing weight, which exceeded the maximum allowable limit for landing.