Nepal for fliers

Today's fatal crash of a Dornier 228-200 in Nepal was the second in that mountainous country this year. There have been nine fatal crashes of twin turboprop commuter airliners in the last ten years, and many more before that.

The crashes in the last decade included three recent fatal accidents involving Dornier 228-series aircraft, four de Havilland Canada Twin Otters and one Beechcraft 1900D.

Today's accident is different from the others, and the reason for it is not clear. Although the weather was good, the aircraft crashed only 2km from the airport where it took off, the pilots trying to return with some kind of problem. Clearly unable to stay flying, they attempted a forced landing close to a river, probably the least cluttered space they reckoned they could reach. Local speculation talks about a birdstrike. Well, Nepal is home to some very big birds, and a strike to propellers, especially both, would be dire. We'll see.

Twin-turboprops are the only category of commercial transport aircraft capable of ferrying the thousands of mountaineers and trekkers that visit Nepal each year to the remote airstrips in the Himalayan foothills - some high among the mountains - from which they can start their adventures.

As a flying environment, Nepal is demanding. Kathmandu is in a deep valley where the visibility is frequently reduced by air pollution. Nepal's mountains, the highest in the world, are a terrain threat to aviation unlike any other. The fickleness of the local weather in the high valleys and in the vicinity of remote airfields is yet another considerable challenge to pilots.

Finally the airstrips themselves are notoriously challenging, with short runways that are uneven, sloping, or both, and with approach and departure paths obstructed by high ground. When the weather changes rapidly, pilots are faced with difficult decisions about whether it is safe to continue an approach, and if the weather closes in too fast, abandoning the approach may be equally risky.

All this is not to say that Nepal couldn't do better in the next ten years. Probably the most effective advice would be from the airlines to their pilots: don't press on when you don't like the look of the  weather. Pilots who try too hard to do their job - getting their passengers to the destination they have paid for - can be dangerous. It's called press-on-itis.