Your report on the Milan Linate collision (Flight International, 24 February-1 March) is indeed alarming. There can be no doubt that plenty of airports are accidents waiting to happen, judging from my observations in other countries. The UK pioneered all-weather operations with the Hawker Siddeley Trident, the first airliner designed for autoland. As a result, it was also at the forefront in developing the criteria for the aerodrome ground lighting and signage needed for use in minimum visibility. Much of the International Civil Aviation Organisation's Annex 14's contents in that respect stems directly from those developments, and the criteria have been implemented at all UK airports. That is not the case in other countries.
One of Annex 14's standards concerns lighting circuit design, one element of which is the requirement that when a stop bar is illuminated, any taxiway centreline lights installed beyond it "shall be extinguished for a distance of at least 90m [295ft]". If green centreline lights were visible after the stop bar at Linate, they might have enticed the Cessna Citation CJ2 crew to proceed. With poor ground markings and lack of signage, a lethal combination was created irrespective of the many other shortcomings that emerged.
The criteria have been in place for years now. Failure to comply with them at a major airport having frequent low visibility is incomprehensible and unforgivable.
Chris Hedge Braunston, Northants, UK
Source: Flight International
