Letter: Come in, please

Sir: Professor Hughes points out that misunderstandings over aircraft radio frequencies might be avoided by these being changed automatically from the ground (letter, 11 September). Whilst this is technically practical, it should be remembered that VHF radio voice communication has remained virtually unchanged since its inception during the Second World War. This means that all aircraft throughout the world can communicate with each other and with the ground. A change as fundamental as that which Professor Hughes suggests would require the replacement of the radio equipment in all aircraft, from the largest 747 to the oldest Cessna 150, as well as that in all control towers, from Heathrow to the smallest landing strip.

Unless this happened overnight, a true "millennium bug" of misunderstanding could infect the skies.

MICHAEL FADIL

Horsham, West Sussex