Investigation Summary
Flight 6437 was a domestic scheduled flight that had already diverted once to Isfahan due to poor weather at Mashhad. After visibility reportedly improved, the flight departed for its original destination, but conditions deteriorated again while the aircraft was in a holding pattern. The situation escalated when a passenger became seriously ill, prompting the crew to declare a medical emergency and attempt a landing in visibility conditions (200 meters in fog) that were significantly below safe operating minimums. The final report by the Iranian Civil Aviation Authority concluded that the accident was caused by the pilot's decision to land in weather conditions below the aircraft and airport's minimums, leading to a loss of control during the landing roll.
Final Conclusions
The final accident report, released on 28 December 2012, cited pilot error as the sole cause of the accident. The crew's decision to continue the approach and landing despite the extreme low visibility, even with a medical emergency on board, resulted in the airframe being destroyed.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Instrument Landing System (ILS)
A precision radio navigation system that provides short-range guidance to aircraft to allow them to approach a runway at night or in bad weather. The crew utilized this for Runway 31R.
Landing Gear
The nose gear collapsed during the runway excursion, contributing to the right wing strike and subsequent fire.
Interesting Facts
- 01The aircraft was operated by Kolavia on behalf of Taban Air.
- 02Visibility at the time of the accident was reported as 200 meters in fog with a vertical visibility of 200 feet (VV002).
- 03The aircraft was a Tupolev Tu-154M that first flew in 1993 (MSN 93A971).
- 04The accident resulted in the total hull loss of the aircraft due to fire and structural damage.
- 05The flight had 157 passengers and 13 crew members on board.
Safety Actions & Advisories
License Revocation
Source ↗Following the release of the final report, the Iranian Civil Aviation Organization revoked the flying license of the Russian captain for his decision to land in weather conditions below safety minimums.
Operator Suspension
Source ↗Taban Air's Air Operator Certificate (AOC) was reportedly suspended by the Iranian authorities immediately following the accident pending the outcome of the safety investigation.
Known Controversies & Unanswered Questions
Medical Emergency vs. Weather Minimums
Reference ↗There was significant debate regarding whether the reported medical emergency (a passenger with severe illness) justified the captain's decision to bypass strict weather minimums. The final report concluded that the emergency did not override the safety requirement to land only when visibility was within the aircraft's and airport's certified limits.