Caspian Airlines Flight 7908

Caspian Airlines Flight 7908 was a scheduled commercial flight from Tehran, Iran, to Yerevan, Armenia, that crashed near the village of Jannatabad, outside the city of Qazvin in north-western Iran, on 15 July 2009. All 153 passengers and 15 crew members on board died.

The crash was the fourth deadliest aviation incident in Iran behind Iran Air Flight 655 (1988), the Iran Ilyushin Il-76 crash (2003), and Ukraine International Airlines Flight 752 (2020). It was also the second-deadliest aviation incident in 2009 behind Air France Flight 447.

The subsequent crash investigation found that the incident had been caused by fatigue failure and consequent disintegration of a rotor disc in the left hand engine (engine #1). In addition to the failure of that engine, fragments of the disc severed two of the three hydraulic control systems, and damaged fuel lines for the centre engine (engine #2). Fuel leaking from these damaged lines ignited, causing a large fire which then destroyed components that controlled the elevators and rudder, resulting in the pilots losing control of the aircraft.

Aircraft and crew
The aircraft was a Tupolev Tu-154M built in 1987 and operated by Iran's Caspian Airlines, according to a spokesman for Iran's aviation agency.

The crashed aircraft had registration EP-CPG, an aircraft which entered service on 20 April 1987 as YA-TAR for Bakhtar Afghan Airlines and was sold to Ariana Afghan Airlines in 1988. YA-TAR served with Ariana Afghan until sold to Caspian Airlines on 15 March 1998, 11 years after it was built. It was re-registered as EP-CPG in 1999.

The aircraft was checked for safety in June 2009 and was given a flight licence until 2010. This was also stated by an Armenian aviation official, saying that the plane had gone through technical controls in Mineralnye Vody Airport in southern Russia in June.

The flight crew consisted of captain Ali Asghar Shir Akbari, first officer Javad Masoumi Hesari, navigator Mahdi Firouse Souheil, and flight engineer Nima Salehie Rezve.

Accident
The aircraft crashed at 11:33 Iran Daylight Time (07:03 UTC), 16 minutes after takeoff from Tehran Imam Khomeini International Airport. According to authorities, the aircraft's tail suddenly caught on fire. The pilot circled, trying to find a safe spot to land, but without success. The aircraft was destroyed after it crashed into a field, carving a crater up to 10 m deep. An eyewitness who claims to have been within 300 m of the crash site described the event as if "the plane just fell out of the sky". Three hours after the crash, fires over a 200 m2 area still remained. A witness told Fars News Agency:

"I saw the plane when it was just ... above the ground. Its wheels were out and there was fire blazing from the lower parts. It seemed the pilot was trying to land, and moments later the plane hit the ground, and broke into pieces that were scattered far and wide."

The aircraft's cockpit voice recorder and flight data recorder were found on 16 July. However, one of the "black boxes" was reported by Chief Investigator Ahmad Majidi to be damaged. Both flight recorders were successfully accessed and contributed data to the accident investigation.

Nationalities
It is reported that 38 (including two crew members) of the 168 passengers were Iranian nationals. 40 passengers were citizens of Armenia. There were also two Georgians on board, two Canadians, and two dual-national Iranian Australians. There were also two dual national Iranian-Americans.

Aftermath
Iranian president Mahmoud Ahmadinejad has expressed his sympathy for the deceased and their families. Armenian President Serzh Sargsyan signed a decree on 15 July 2009 declaring the following day a Day of Mourning in Armenia.

Investigation
Armenian President Serzh Sargsyan announced on 15 July that a governmental commission had been set up to investigate the crash. It would be headed by Vice Prime Minister Armen Gevorgyan.

Iranian officials blamed the crash on technical reasons. It was claimed that the main reason of the accident was an engine failure and destruction due to a bird strike, which resulted in a fire which led to a loss of control and crash of the airplane.

On 23 December 2014 a chronology of events was published: During the climb to the altitude of 9700 m the crew sent a message about a fire in the number one engine. The climb was stopped at 8700 m. The airplane, three minutes before the crash, made a turn of 270 degrees then started to descend rapidly with a high vertical speed of about 70 m per second. 16 minutes after takeoff, the Tu-154M, at high speed, collided with the ground in a field near the village of Jannatabad, approximately 120 km from the Khomeini airport. The aircraft was destroyed upon impact. At the scene of the disaster a crater formed whose depth was approximately 10 m. The Commission found that it was the destruction of the low pressure compressor in the number one engine that scattered debris and damaged the fuselage and fuel lines causing the rapid spread of fire.

A final accident report was likely released by the Iranian authorities in 2011, although it did not come to wider attention until it was partially translated into English in 2019. The report found that the accident had been caused by fatigue failure of the first stage rotor of the low pressure compressor in engine No. 1, that resulted in the rotor disc disintegrating. Fragments from the rotor disc destroyed engine No. 1, severed the No. 1 and No. 3 hydraulic systems, and partially severed the fuel lines to engine No. 2. Hot components and hydraulic fluid ignited fuel spilling from the damaged fuel lines, and rapidly caused a large fire in the tail section of the plane. This fire, in turn, destroyed rods that actuated the rear control surfaces (elevators and rudder) resulting in the pilots losing control of the aircraft.

Prior to the accident the aircraft manufacturer, Tupolev, had released a service bulletin requiring more stringent testing of low pressure compressor components. However, this was only provided in Russian to Russian operators. Six days after the crash of EP-CPG, Tupolev released equivalent service bulletins to all operators.