David Bentley (Flight International, 29 October-4 November) quite correctly points out that "a four-engined aircraft suffering an engine failure will have to divert exactly as often as a two-engined aircraft." Very true. However, it is the diversion flight after the engine failure, of up to 3h on the one remaining engine which is the concern to anyone travelling long haul in a twin - passengers and crew.

Andrew Hockings Hong Kong

Source: Flight International