On the morning of March 09 a cargo flight of True Aviation took off from Cox's Bazar airport R/W 35 for Jessore with shrimps. The set of crew were all from Ukraine. The Captain was a veteran pilot with piles of hours' experience. The co-pilot was a young lad and so was the flight engineer. The navigator was, however, an experienced fellow. The navigator got thrown out of the airplane somehow and survived with multiple injuries while the rest three died on impact.
There have been a lot of speculations about the crash and the equipment. But the aircraft was a real sturdy one and the engines were quite powerful. It just came back from Ukraine in mid-January after a thorough check-up. Decoding the black box will give the correct picture of the crash.
I am analysing the flight from my experience which may not necessarily be the correct picture but will definitely not be way out of line. Soon after takeoff the pilot reported emergency (engine problem) and sought permission to land back. The tower asked them to report right downwind for R/W 35. By then the left engine was stopped in feathered condition. This is a condition where the propeller blades are kept in line with the airflow to reduce drag and ease the live engine load to complete the flight (very technical matter). For reasons unknown, the aircraft came in high and was not aligned with the runway and could not make the landing. So they made a go-around. Which means, full power on the live engine, landing gears up, then with increase of speed raise the flaps to clean the aircraft to reduce drag. Another very technical matter comes up after adding full power. As the power or thrust is not down the lateral axis (centre line), the aircraft will yaw towards the other side of the engine. In this case the right engine was live. For a twin-engine aircraft a very tricky and dangerous situation can be reached if the airspeed washes off to VmCA (velocity minimum controllable speed in air). If an aircraft reaches or goes below this speed and does not have altitude to convert to speed, recovery is impossible.
And in this situation if one tries to give aileron to the live engine, it has a negative effect and the aircraft further rolls over (wing over) or goes into spin. In this case, after the aircraft made the go around, it was in dirty configuration and power on live engine was full, altitude was not sufficient; most likely the airspeed had washed off to VmCA or below. This can be judged from the attitude of the aircraft at that time. It was low, in a left bank and going down. They possibly gave it the aileron which aggravated the situation and helped the aircraft to go down in a left bank and inverted. That is how it was found on the sea bed. The landing gear was found to be extended; the cockpit was crushed into a ball of junk and was inverted and rest of the aircraft was totally tattered.
It is imperative to also mention that the VmCA can go to pilot's disadvantage if the aircraft is in a bank. On the go-around, they possibly wanted to join the left downwind for R/W 35. In the melee they lost track of the speed which was closing in on VmCA - and fast. Then it was too late even for a veteran pilot to recover.
The reasons for this crash could be attributed to three things:
a) Inadequate training to the crew on such rare circumstances and VmCA demonstration with recovery.
b) High density altitude. This was not the case that time of the day with prevailing temperature.
c) The aircraft was grossly overweight. Documents do not say that.
Let us wait for the Flight Data recorder's information after decoding and also listen to the cockpit voice recorder to make positive assessments and not come up with cockamamie stories.
nasimbapa@yahoo.com
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AN-26 crashes in Bay of Bengal
S M Nasimul Haque | Published: March 12, 2016 23:13:18 | Updated: October 23, 2017 05:00:09
AN-26 crashes in Bay of Bengal
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