Sharjah

A Turkish Challenger 604 corporate jet impacted a mountain near Shahr-e Kurd in Iran, killing all 11 on board. The aircraft departed Sharjah, UAE at 13:11 UTC on a flight to Istanbul, Turkey. The aircraft entered Tehran FIR fifteen minutes later and the Tehran ACC controller cleared the flight to climb to FL360 according to its flight plan. About 14:32, the pilot requested FL380, which was approved. Before reaching that altitude, the left and right airspeeds began to diverge by more than 10 knots. The left (captain's) airspeed indicator showed an increase while the right hand (copilot's) airspeed indicator showed a decrease. A caution aural alert notified the flight crew of the difference. Remarks by the flight crew suggested that an 'EFIS COMP MON' caution message appeared on the EICAS. As the aircraft was climbing, the crew reduced thrust to idle. Approximately 63 seconds later, while approaching FL380, the overspeed aural warning (clacker) began to sound, indicating that the indicated Mach had exceeded M 0.85. Based on the Quick Reference Handbook (QRH) of the aircraft, the pilot flying should validate the IAS based on the aircraft flight manual and define the reliable Air Data Computer (ADC) and select the reliable Air Data source. The pilot did not follow this procedure and directly reduced engine power to decrease the IAS after hearing the clacker. The actual airspeed thus reached a stall condition. The copilot tried to begin reading of the 'EFIS COMP MON' abnormal procedure for three times but due to pilot interruption, she could not complete it. Due to decreasing speed, the stall aural warning began to sound, in addition to stick shaker and stick pusher activating repeatedly. The crew then should have referred to another emergency procedure to recover from the stall condition. While the stick pusher acted to pitch down the aircraft to prevent a stall condition, the captain was mistakenly assumed an overspeed situation due to the previous erroneous overspeed warning and pulled on the control column. The aircraft entered a series of pitch and roll oscillations. The autopilot was disengaged by the crew before stall warning, which ended the oscillations. Engine power began to decrease on both sides until both engines flamed out in a stall condition. From that point on FDR data was lost because the electric bus did not continue to receive power from the engine generators. The CVR recording continued for a further approximately 1 minute and 20 seconds on emergency battery power. Stall warnings, stick shaker and stick pusher activations continued until the end of the recording. The aircraft then impacted mountainous terrain. Unstable weather conditions were present along the flight route over Iran, which included moderate up to severe turbulence and icing conditions up to 45000ft. These conditions could have caused ice crystals to block the left-hand pitot tube. It was also reported that the aircraft was parked at Sharjah Airport for three days in dusty weather condition. Initially the pitot covers had not been applied. The formation of dust inside the pitot tube was considered another possibility.

The Aircraft was operating a flight from Sharjah International Airport, UAE to Khartoum International Airport, Sudan, with a total of six persons on board: three flight crew members (captain, co-pilot, and flight engineer), a ground engineer, and two load masters. All of the crew members sustained fatal injuries due to the high impact forces. Sometime after of liftoff, the core cowls of No. 4 engine separated and collapsed onto the departure runway, consequently No. 4 Engine Pressure Ratio (“EPR”) manifold flex line ruptured leading to erroneous reading on the EPR indicator. The crew interpreted the EPR reading as a failure of No. 4 engine; accordingly they declared engine loss and requested the tower to return to the Airport. The Aircraft went into a right turn, banked and continuously rolled to the right at a high rate, sunk, and impacted the ground with an approximately 90° right wing down attitude.

During the takeoff roll, the left main gear collapsed. The aircraft sank on the runway, causing the left wing and the engine n°1 to contact the runway surface. All six crew members escaped uninjured while the aircraft was damaged beyond repair.

The aircraft departed Payam Airport on a cargo flight to Sharjah. Shortly after takeoff, while in initial climb, the crew declared an emergency following technical problems with three engines and was cleared for an immediate return. After the captain realized he could not make it, he attempted an emergency landing when the aircraft crash landed in a field located 5 km from the airport. On impact, the aircraft broke into several pieces, bursting into flames. All 12 occupants escaped with minor injuries.

The four engine aircraft was completing a cargo flight from Al Mukalla to Sharjah with eight crew members on board and a load consisting of 7 tons of fish. During the takeoff roll on runway 06, at a speed of 225 km/h, the nose gear collapsed. The captain initiated an emergency braking procedure. To avoid a collision with the radio-technical equipment car, he steered the aircraft to the left. After it veered off runway, the aircraft rolled for about 400 metres and came to rest in a sandy area about 30 metres to the left of the extended centerline. All eight occupants escaped uninjured while the aircraft was damaged beyond repair.