An Airbus A319-131, G-EUOE, was damaged in an accident at London-Heathrow Airport (LHR), U.K. None of the 75 passengers and five crew members were injured. British Airways flight BA762 departed runway 27L on a scheduled service to Oslo, Norway. At that moment, the fan cowl doors from both engines detached, puncturing a fuel pipe on the right engine and damaging the airframe. The symptoms seen by the flight crew included: engine thrust control degradation, the loss of the yellow hydraulic system, and a significant fuel leak. After the loss of the yellow hydraulic system the crew declared a PAN, with the intention of returning to Heathrow once they had fully assessed the situation. ATC provided radar vectors for the ILS to runway 27R. During the approach to land, an external fire developed on the right engine. An engine fire warning on the flight deck prompted the crew to declare a MAYDAY. Although both engine fire extinguisher bottles were discharged and the right engine was shut down, the fire was not completely extinguished. The left engine continued to perform normally throughout the flight. The aircraft landed safely and was brought to a stop on runway 27R at Heathrow. The airport fire service attended and quickly extinguished a small fire on the right engine. The passengers and crew evacuated via the escape slides on the left side of the aircraft, without injury. Causal factors The investigation identified the following causal factors: 1. The technicians responsible for servicing the aircraft’s IDGs did not comply with the applicable AMM procedures, with the result that the fan cowl doors were left in an unlatched and unsafe condition following overnight maintenance. 2. The pre-departure walk-around inspections by both the pushback tug driver and the co-pilot did not identify that the fan cowl doors on both engines were unlatched. Contributory factors The investigation identified the following contributory factors: 1. The design of the fan cowl door latching system, in which the latches are positioned at the bottom of the engine nacelle in close proximity to the ground, increased the probability that unfastened latches would not be seen during the pre-departure inspections. 2. The lack of the majority of the high-visibility paint finish on the latch handles reduced the conspicuity of the unfastened latches. 3. The decision by the technicians to engage the latch handle hooks prevented the latch handles from hanging down beneath the fan cowl doors as intended, further reducing the conspicuity of the unfastened latches.