Classic British Flight Sim

The five failures mentioned here were among the dozen or more engines which were prematurely changed that year, and for some time there was no explanation for this. Eventually, however, the cause was found to be connected with the application of reverse thrust to slow down after landing. As Cedric Flood explained so well in his book A Pilot's Perspective: “The early 200 and 300 series 1-11s had spoilers, but our 400 series (like the 500 series) also had lift dumpers, which were positioned on the top surface of the wing more or less in front of the engines. These were activated by the spoiler lever, but, while the spoilers operated at all times, the dumpers only operated on the ground on landing. American Airlines had the same 400 series 1-11, and they had discovered that when using normal reverse on the short fuselage aircraft fitted with lift dumpers, the airflow to the engine was disturbed, causing temporary overheating, and eventual damage”. It appears that while American Airlines had reported this to BAC, details had not been passed on to other 400 series operators. The problem was not experienced with the longer fuselage 500 series, due to the greater distance between the wing lift dumpers and the engine intakes, and the solution for the shorter fuselage 400 was to use reverse idle instead of normal reverse on landing. Normal reverse was still available, but was to be used only in an emergency or on the rare occasions that a short runway was in use. Subsequently, with this procedure in place, the aircraft were mainly trouble free.