Iran Air Flight 277

Flight 277 had taken off from Mehrabad International Airport, Teheran, at 18:15 local time (15:15 UTC), more than two hours later than scheduled because of poor weather at destination.[2][3]

At around 19:00 local time (16:00 UTC), while on approach to Urmia Airport, the crew initiated a missed approach procedure and announced its intention to return to Teheran. At the time, the weather at Urmia was poor, with low clouds and 800 meters of visibility in snow.[1][4]

Contact with the Boeing was lost shortly after. The aircraft crashed near the village of Tarmani, around 15 km (9.3 mi) south-east of Urmia Airport, breaking into multiple sections.[1][5][6] Of the 93 passengers and 12 crew on board, only 27 survived.[7]

The aircraft involved in the accident was a tri-jet Boeing 727-286Adv with Iranian registration EP-IRP. Built in 1974, The aircraft had spent a long time out of service. It was impounded at Baghdad, Iraq from 1984 to 1990, and then placed in storage from 1991 to 2002. It was then overhauled and returned to service.[8]

Of the 105 people on board, 78 were killed and 27 survived, all but one with injuries.[9][10] In the aftermath of the crash, 36 ambulances and 11 hospitals were utilized in the rescue operations.[6] Rescue efforts were complicated by heavy snow in the area, which was reportedly around 70 cm (28 in) deep at the crash site.[2]

Iran's Civil Aviation Organization (CAO.IRI) opened an inquiry into the crash.[11] The day after the accident, both the flight's cockpit voice recorder and the flight data recorder were recovered and taken to Tehran for analysis.[7][12]

In 2017, CAO.IRI published its final accident report. From its analysis, it emerged that after starting its final approach to Urmia Airport's runway 21 from an altitude of 7,000 ft (2,100 m) – Urmia Airport being at an elevation of 4,300 ft (1,300 m) – a navigational error by the flight crew meant that the aircraft failed to establish itself on the instrument landing system. Descending through 5,900 ft (1,800 m) and having never made visual contact with the runway, the crew elected to go around. The missed approach procedure started normally, with the aircraft climbing to 8,800 ft (2,700 m).[1]

Investigators believe the Boeing encountered severe icing conditions, which caused disruption of the airflow and loss of engine thrust. The aircraft started to descend and entered a turn that momentarily reached 41° bank angle, causing the activation of the stick shaker. Despite application of full thrust, engines No. 1 and 3 began to run down. Descending through 7,000 ft (2,100 m), the flight engineer could be heard announcing that both engines have failed. Subsequent attempts to relight them were unsuccessful. During the last moments of the flight, flaps were retracted and the airspeed progressively decayed; at 4,400 ft (1,300 m), just 100 ft above terrain, the aircraft was flying at 112 knots (207 km/h; 129 mph) with 21° right bank. The last recorded airspeed value was 69 knots (128 km/h; 79 mph).[1]

The report concluded that the main causes of the accident were severe icing conditions and inappropriate actions by the flight crew. Obsolete on-board systems, absence of suitable simulators for adverse weather conditions, failure to follow standard operating procedures, and inadequate crew resource management were cited as contributory factors.[1]

• List of accidents and incidents involving commercial aircraft

External image

Photo of aircraft involved

• CAO.IRI – Final accident report (in Persian) – Archived
• Accident description at the Aviation Safety Network