Revealed: pilots' secret danger list: In the wake of the Pakistani Airbus crash in the peaks of Kathmandu, our correspondents investigate the hazards of the world's airports

DOZENS of airports in use all over the world are regarded by airline pilots as potentially dangerous, according to a confidential list obtained by the Independent on Sunday. The International Federation of Airline Pilots Associations (Ifalpa) has a blacklist of 141 airports used by passenger planes. It includes Leeds-Bradford in Britain, and such busy international airports as Rome, Hamburg, Los Angeles and Hong Kong.

The problem of dangerous airports was highlighted last week when a Pakistan International Airlines flight crashed at Kathmandu, killing all 167 people on board. Kathmandu is surrounded by mountains and has no radar.

The pilots' list is the only significant effort made to monitor airport safety internationally. Even then, it is kept confidential to avoid embarrassing civil aviation authorities. Leaders of the pilot associations believe quiet negotiation is their best method of acheiving safety improvements.

They compile a list annually, based on reports from members. Problems which lead to blacklisting range from minor ones, such as failure to replace landing lights promptly at Leeds-Bradford, to serious failings of management or tricky topography. Ifalpa emphasises that the list is not definitive (Kathmandu is not on it, for example). Some problems are corrected as the list is drawn up, and because it is revised only once a year, it quickly becomes dated. But an Ifalpa 'black star' given to a deficient airport can spur civil aviation authorities to move rapidly. Captain Laurie Taylor, a former senior Ifalpa official, said that the Spanish authorities ordered that a new hotel be demolished after Ifalpa complained it was a navigation hazard obstructing runway approaches at a nearby airport, which he declined to name. The pilots have also won improvements at airports in Indonesia and Egypt and at JFK airport in New York. A meeting of Ifalpa's Asia region next month has Kathmandu on the agenda.

Leeds-Bradford was listed after pilots complained of the need for better approach lighting. Similar complaints about Rome's Fiumicino airport and Hamburg in Germany led to their listing. Pilots say faulty navigational aids have also been reported at Hamburg. Noise abatement regulations at Los Angeles international airport have caused it to be listed for many years. These require pilots to fly in low over the sea. Hong Kong's Kai Tak airport is also listed. Its reputation stems from a tight dogleg approach over Hong Kong harbour before a rapid descent over heavily populated Kowloon.

The list features four airports in a special category of their own, because of the difficulties pilots face attempting to fly into them. Gibraltar, Funchal-Madeira, the Seychelles and Ushuaia in Argentina all involve landing and take-off in difficult terrain. At Gibraltar and Funchal, planes land on narrow runways surrounded partly by sea and partly by mountains. Pilots say wind-shear problems posed by such conditions require great care and skill. Pilots landing at Madeira find headwinds at 300m can suddenly become tailwinds at 100m, forcing them to adjust speedto avoid over-running and crashing into the sea.

Authorities and airlines using such airports allow only the most experienced pilots to fly into them. Less practised pilots learn by sitting beside old hands.

That Kathmandu does not carry the Ifalpa black star, despite two serious accidents in the past three months, indicates the list's shortcomings. Ifalpa relies on pilot associations for their reports. Where pilots are not well-organised, reports are not made. Failings at Bangkok's international airport were recorded only after pilots from other countries reported them. Thai pilots do not have an association of their own, Ifalpa says. The weakness of the Ifalpa reporting system is cited as the reason Kathmandu's Tribhuvan airport does not feature on the latest list, despite its hazardous terrain and lack of radar.

Officially, pilots are told to go around a second time if the runway cannot be seen clearly from 3km away. Unofficially, two pilots who landed there regularly both say colleagues frequently fly much closer before turning away for a second run. Airlines landing at Kathmandu have pressed the Nepalese authorities to introduce radar and some form of ground control. The Nepalese are sympathetic but have other priorities, according to diplomatic sources, and none of the airlines has volunteered to help. Nepal has signed the international treaty governing standards of airport safety. The standards are set by the International Civil Aviation Organisation (ICAO) and are agreed by countries all over the world, including Britain. Although Nepal is committed to reaching the ICAO standards, many countries fail to achieve them because of their other spending priorities. The ICAO has no policing powers to enforce improvements.

Kathmandu's hazards are shared by other Asian airports. Pilots are warned to watch for animals on the runway. Stray water-buffalo are a problem: three years ago an Air India flight had a problem with a stray bull.

Other problems frequently confronting pilots flying to Far East destinations include unpredictable, often violent climatic conditions. Such problems are increasing, pilots say, as growing affluence spurs demand for air travel. Increased tourist and business traffic puts greater strain on many of the region's small, up- country airports, that are ill-equipped with navigational aids.

An experienced Hong Kong pilot said: 'Tourists who travel to China care little about the fact that many Chinese military air traffic controllers, who regulate aircraft over the People's Republic, are not proficient enough in English, the language of the international air community, to make their instructions clearly understood - that is, no one cares until the inquest.'

(Photograph omitted)