Following a cargo flight to Jersey, the aircraft was to be flown back to Bournemouth. As part of his line training, the first officer would be the handling pilot. The aircraft taxied for departure from the full length of runway 27 and the takeoff and initial climb progressed normally. Some 17 seconds after lift off, the first officer requested ‘climb power’ and the commander then proceeded to reduce the fuel trimmers towards the climb power setting. At this point the crew heard a loud ‘bang’ and the left engine Fire Warning activated. The FO continued to control the aircraft, keeping it straight against the potential yaw and maintaining a climb profile. The commander shut down the engine, feathered the propeller and activated the fire extinguishers for the engine. He instructed the first officer to climb to 1,500 feet and make a left turn to conduct a visual left hand circuit to land back at Jersey. A mayday call was made to Jersey Tower informing them of the problem and the commander’s intentions. On the downwind leg, the commander took over the handling of the aircraft and conducted a single engine approach and landing on runway 27, which was carried out uneventfully. CAUSAL FACTORS: “The investigation identified the following causal factors: 1. Minimal fatigue strength margin of the engine HPT disc resulted in it being susceptible to rapid cracking if subjected to vibratory excitation, such as resonance. 2. The abutment between the HPT and IPT discs probably resulted in a small gap being present between the seal arms while the engine was operating. This allowed sufficient reduction in the natural frequency of the turbine disc vibratory mode for it to be excited while operating within the normal speed range of the engine. 3. The protracted time taken following the G-OJEM event, due to the nature of the tests required, to understand the cause of the failure, precluded the timely introduction of suitable preventative action aimed at avoiding recurrence prior to the HPT disc failure on G-CEXF. 4. Fuel leakage from a severed low pressure pipe, part of the engine bay fuel system, led to a major fire, external to the nacelle.”