Turkish investigators have attributed the Turkish Airlines BAE Systems Avro RJ100 fatal landing accident at Diyarbakir in January last year to the crew's mistaken identification of the airport's runway lights in poor visibility. All but five of the 80 passengers and crew on board were killed.
The captain opted to descend below the minimum descent height of 2,800ft (855m) as the jet began the non-precision approach to Diyarbakir's runway 34 at the end of a scheduled flight from Istanbul.
The airport did not have an instrument landing system (ILS). Runway 34 has a threshold elevation of 2,160ft and the minimum descent height should, according to the approach procedure, be reached 2.8km (1.5nm) from the runway. Non-precision approaches are made with VOR and NDB beacons, as well as DME navigation aids.
In its report into the 8 January 2003 accident, the Turkish civil aviation administration says visibility was around 1km, owing to fog. But it says the pilots continued the approach, during which they mistakenly identified the military airport's border lamps for the runway lights.
The first officer twice warned the captain about the minimum descent altitude. After the second warning, the crew decided on a go-around, but hit the ground at 131kt and careered for 200m.
TOLGA OZBEK / ISTANBUL & DAVID KAMINSKI-MORROW / LONDON
Source: Flight International