Having read your cover story on sky marshals (Flight International, 13-19 January) with great interest, I must say that I am fully persuaded that the British Air Line Pilots Association's position on sky marshals protocol is not clear enough.

Therefore, I remain adamantly opposed to the potential use of guns on board aircraft. I am convinced that ground-based security systems should ensure that passengers and baggage are fully screened at domestic and international airports, thus preventing any potential terrorist to board the aircraft.

We have to be aware that a terrorist act starts on the ground; it is planned and plotted well before the flight. Terrorist acts performed on board aircraft are only the implementation of the plans conceived on the ground. On board, having an armed terrorist, who is prepared to kill passengers and crew to gain control of the aircraft, is a lost battle.

It is also wrong to presume that terrorists will only use low velocity guns or other non-damaging weapons. They have to obey certain orders on how to perform a terrorist attack. Therefore, air security starts and ends on the ground. With sky marshals on board I will not feel safer. It seems that 11 September 2001 has not yet finished haunting and terrorising Europe.

Aleksander Cicerov Trzin, Slovenia

Source: Flight International