Exactly ten years ago this week, flight TG 311 from Bangkok was making its final approach into Kathmandu airport. The Airbus A310 dipped into the monsoon clouds but, because the jet was too high, the Thai pilots decided to go around for another approach. It was 12.30 PM, 31 July 1992, and it was the last anyone heard from the plane.
Despite an intensive aerial and land search along the approach path, the wreckage was only found four days later, 40 km north of Kathmandu. The plane had slammed into a ridge below Langtang at 500 kmph at an altitude of 3,500 m. An inquiry showed that the pilots, distracted by a flap problem, had made a 360 degree turn instead of a U-turn and headed due north in zero visibility. Ninety-nine passengers and 14 crew were killed, no piece of the aircraft larger than one metre was found.
Two months later, on 28 September, flight PK 268 from Karachi was making the same approach in identical weather conditions. This was also an Airbus A310, and contact was lost soon after the Pakistani pilots reported ten miles from touchdown. The wreckage was found a few hours later just below the ridge line at Bhatte Danda. Of the 155 passengers and 12 crew, none survived.
The two crashes, beamed worldwide on television, made Kathmandu infamous as "the most dangerous airport in the world"-a reputation that the airport has found difficult to erase even after a decade. It was stupendous bad luck that, after 25 years of safely handling jet aircraft, two major disasters happened in such quick succession.
An approach radar at the airport would have prevented both crashes: controllers could have warned the Thai pilots that they were dangerously off course, and the Pakistani jet that it was in a no-no zone below the descent profile. The Japanese government helped install a radar tracking system, and in the past five years air traffic controllers say that at least two potential crashes have been averted because pilots were warned in time.
"We have much better equipment than we did ten years ago," says Binod Gautam, chief of the Aviation Safety Department at the Civil Aviation Authority of Nepal (CAAN). "But there is a need for more navaids in Kathmandu and other airports."
While Kathmandu airport now has state of the art radar and guidance systems, most other airports in Nepal have minimal or no navigational aids. And this in one of the most difficult flying terrains in the world. Nearly all crashes in Nepal in the past ten years have been what aviation experts describe as "controlled flight into terrain" (CFIT)-an airworthy aircraft under control of crew flies into a mountain in poor visibility.
"You better know exactly where you are while flying in Nepal in the monsoon," says one veteran Royal Nepal Airlines captain. "This terrain doesn't forgive mistakes." There were painful reminders of this in two crashes in the past two months: a Skyline Twin Otter in Surkhet on 17 July and the Asian Airlines Mi-17 helicopter which was lost on a flight from Makalu Base Camp to Lukla on 31 May and has still not been found.
That chopper, ferrying 12 mountaineering staff and Russian pilot, did not have the standard Emergency Locator Transmitter (ELT), and this is one reason it can't be found. CAAN allows Russian helicopters to fly without the transmitters because installation would require major design changes.
A Royal Nepal Twin Otter that crashed into mountains in cloud while approaching Dhangadi in July 2000 did not have a Global Positioning System (GPS) which may have helped avoid the crash. "
You can have the best equipment in the world, but carelessness and over-confidence can still cause crashes," says one instructor pilot, who, like many of the people interviewed for this investigation, wanted anonymity. The Skyline aircraft in Surkhet had a GPS, but still flew into high ground on approach. It also had a cockpit voice recorder, but crash investigators have not been able to go to the site after the initial rescue because of security concerns.
Aviation safety experts say that the best safeguard against CFITs are the sophisticated "enhanced ground proximity warning system" (EGPWS) which is an onboard computer that stores global terrain data and, in conjunction with a GPS, warns pilots with a coloured 3-D map of approaching mountains in time to take evasive action.
CAAN made standard GPS mandatory early this year, but officials told us they cannot force airlines to install the $35,000 enhanced version because of cost considerations. "Finding the right balance between safety and cost is tricky, and every airline has to weigh it carefully," says one senior pilot with a private Nepali airline. But given Nepal's terrain, weather and lack of other ground navigational aids, and the fact that almost all crashes involve planes flying into mountains, it is clear that onboard EGPWS could improve safety.
Although mechanical defects on aircraft have not been the cause of any major disaster in recent years, the International Civil Aviation Organisation (ICAO) has audited CAAN's airworthiness certification procedures and has said that its checks are not rigorous enough. "I have been flying for over six years and I have come across only one surprise check," one pilot told us.
As Nepal's domestic airlines suffer from the tourism slump and decreased revenue, there is belt-tightening all around. Pilots tell us that this leads to maintenance lapses. "It is so embarassing to have all these MEL (minimum equipment list) stickers on your cockpit instruments," one pilot told us at Kathmandu airport. Budget shortfalls are forcing most airlines to cannibalise cockpit instruments and spares just to allow the plane to get through an MEL category validity check. Some are cutting down pilot training time on simulators abroad because it is so expensive. One pilot told us that things in his carrier are so bad, it has no spare tyres or wheel brake units in stock.
CAAN became an independent authority five years ago, but the government still calls the shots, and often breaks its own rules. CAAN officials have their own list of woes: low budget, lack of manpower and insufficient training.
. Crowded airways, especially on mountain flights and the Kathmandu-Pokhara corridor
. Corrupt ground handlers in remote airports overloading cargo (an investigation showed that the Twin Otter that crashed in Dhangadi was seriously
. Inadequate crew training, route familiarisation and STOL field clearance
. Deterioration in visibility at Kathmandu airport due to increasing pollution from brick kilns on the approach path.
. Bird strikes and runway intrusion
. Questions about aviation fuel quality (one of the factors leading to Singapore Airlines suspending operations to Kathmandu)