Capt Prakash Goday (Letters, 21-27 May) draws the conclusion that because of the Air China crash at Busan (Flight International, 23-29 April) and "similar crashes", non-precision approaches are "no longer valid".

Flight 129 crashed because the crew allowed the aircraft to descend below minimum safe altitude before being established on instrument final. Why this was allowed to happen is not clear. Confusion between the crew and air traffic control (ATC) appears to be one factor.

The diagram included in the original article shows that the crew were self-positioning to about a 9km (5nm) final - a tight approach for a large aircraft. Why the crew did not choose to give themselves more room (and therefore time) to prepare for a different approach to a different runway is not explained.

Bad weather and unclear communication between the crew and ATC (there may have been other factors) seem to have led to a breakdown in situational awareness.

The fact that Flight 129 was positioning for a non-precision approach is not the point.

Andreas Jacobs

Riyadh, Saudi Arabia

Source: Flight International