Russian Il-76 crashed near Ivanovo
Mistrust in Management
I thought the high lift devices were linked mechanically
The inboard trailing edge flaps are powered by No 1 hydraulic system, and the outboard trailing edge flaps are powered by the No 4 hydraulic system. If either of these hyd systems are lost then the corresponding inboard or outboard traling edge flaps on both sides of the aircraft will not operate unless the electrical alternate system is used. When the alternate electrical backup is used all flaps, inner and outer on both sides, operate electrically with bypass valves isolating the hydraulic systems from the flaps.
As for leading edge flaps and slats, they are also completely independent from each other and operated pneumatically - again with electrical back up.
Kind regards
Exeng
Last edited by exeng; 13th Mar 2024 at 22:36. Reason: error in typing
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Apologies, a slight thread slip there which I have rectified.
It was a pre-delivery test flight - knowing that it was probably going to be pretty bad, those not involved in actually flying the aircraft went to the very back - they all survived the crash. Those on the flightdeck all perished.
Not so at all on the 747, or any other Boeing airliners as far as I know.
The inboard trailing edge flaps are powered by No 1 hydraulic system, and the outboard trailing edge flaps are powered by the No 4 hydraulic system. If either of these hyd systems are lost then the corresponding inboard or outboard traling edge flaps on both sides of the aircraft will not operate unless the electrical alternate system is used. When the alternate electrical backup is used all flaps, inner and outer on both sides, operate electrically with bypass valves isolating the hydraulic systems from the flaps.
As for leading edge flaps and slats, they are also completely independent from each other and operated pneumatically - again with electrical back up.
Kind regards
Exeng
The inboard trailing edge flaps are powered by No 1 hydraulic system, and the outboard trailing edge flaps are powered by the No 4 hydraulic system. If either of these hyd systems are lost then the corresponding inboard or outboard traling edge flaps on both sides of the aircraft will not operate unless the electrical alternate system is used. When the alternate electrical backup is used all flaps, inner and outer on both sides, operate electrically with bypass valves isolating the hydraulic systems from the flaps.
As for leading edge flaps and slats, they are also completely independent from each other and operated pneumatically - again with electrical back up.
Kind regards
Exeng
Thank you for pointing out these details. My goal was to emphasise the end result of the damages created by the two engines detachments... loss of control due to asymmetric lift available. Actually, the right L.E. flaps were mechanically destroyed by the collision of one or both engines flown away. Anyway, with pneumatic, electric and hydraulic system failures (on the right side) the consequences were poor control by "flight control devices" (ailerons and spoilers) plus the Outer T.E. flaps.
That wanted to be just a quick answer to the "sabotage case".
Assuming this was caused by a drone entering the engine and as there was no large bang, so the drone didn't have a warhead, presumably the drone would cause that engine to start shedding bits. So it's likely there was a lot more damaged, controls, wires, hydraulics etc that would have contributed to the crash. We also don't know the experience or competence of the crew. There is a war on and they are loosing crews at a rate of nots. So possibly an inexperienced crew facing a major complex failure in a large, complex and seriously damaged aircraft. There's also the fog of war aspect. They may have assumed they were hit by a missile and more damaged than they actually were. Everything coming together in a perfect storm to bring the aircraft down.
T/E flaps are driven by torque shafts to port and starboard sides through gear boxes etc; same with outer T/E flaps in a separate drive torque shaft layout.
Similar with L/E devices.
In my type rating cover, only the BAC1-11 had a back up drive train, a secondary drive shaft system which rotated with the main, but had a lost motion coupling, if and only if a main shaft was sheared/ disconnected, say anywhere along its length, this second drive would catch up driving from the outer wing inwards.
Lot of maintenance items, lubrication needed.
Last edited by aeromech3; 14th Mar 2024 at 05:27.
Mistrust in Management
Aeromech3,
Thanks for politely pointing out the error in my post. The inboard TE flaps are mechanically linked via the torque drives from the power unit, as indeed so are the outboard TE flaps.
Apologies to TURIN if my post was misleading.
Kind regards
Exeng
Thanks for politely pointing out the error in my post. The inboard TE flaps are mechanically linked via the torque drives from the power unit, as indeed so are the outboard TE flaps.
Apologies to TURIN if my post was misleading.
Kind regards
Exeng
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Drone ??
Assuming this was caused by a drone entering the engine and as there was no large bang, so the drone didn't have a warhead, presumably the drone would cause that engine to start shedding bits. So it's likely there was a lot more damaged, controls, wires, hydraulics etc that would have contributed to the crash. We also don't know the experience or competence of the crew. There is a war on and they are loosing crews at a rate of nots. So possibly an inexperienced crew facing a major complex failure in a large, complex and seriously damaged aircraft. There's also the fog of war aspect. They may have assumed they were hit by a missile and more damaged than they actually were. Everything coming together in a perfect storm to bring the aircraft down.
From the videos, the fire was eventually extinguished, engine 4 subsequently departed the airframe, engine 3 appeared to be compromised as well.
Finally, the aircraft rolls towards the failed / missing / compromised power-plants.
Possible explanations ? a straightforward Vmca departure, structural failure of the SBD wing, or perhaps some flap / slat asymmetry on deployment or as an aggravating factor
Where does this assumption come from ?
From the videos, the fire was eventually extinguished, engine 4 subsequently departed the airframe, engine 3 appeared to be compromised as well.
Finally, the aircraft rolls towards the failed / missing / compromised power-plants.
Possible explanations ? a straightforward Vmca departure, structural failure of the SBD wing, or perhaps some flap / slat asymmetry on deployment or as an aggravating factor
From the videos, the fire was eventually extinguished, engine 4 subsequently departed the airframe, engine 3 appeared to be compromised as well.
Finally, the aircraft rolls towards the failed / missing / compromised power-plants.
Possible explanations ? a straightforward Vmca departure, structural failure of the SBD wing, or perhaps some flap / slat asymmetry on deployment or as an aggravating factor
DTR2, et al
The assumption is that the design and certification standard of the Russian aircraft matched those of comparable western types; this may not be so.
A very enlightening 2 weeks flying with a Russian test pilot, to approve a western 4 engined aircraft for their use, identified significant differences in standards.
The test pilot had been involved with the IL-76 and a comprehensive range of large Russian aircraft, but had not flown other western types (the test engineer had). Questioning the western type revealed surprising features of the IL-76; how fast can engine power be changed, how to alleviate foot forces with bank, can flaps be moved during a turn, can altitude be maintained on 3 engines after takeoff.
On top of which, consider the training required and crew experience in this particular situation.
The assumption is that the design and certification standard of the Russian aircraft matched those of comparable western types; this may not be so.
A very enlightening 2 weeks flying with a Russian test pilot, to approve a western 4 engined aircraft for their use, identified significant differences in standards.
The test pilot had been involved with the IL-76 and a comprehensive range of large Russian aircraft, but had not flown other western types (the test engineer had). Questioning the western type revealed surprising features of the IL-76; how fast can engine power be changed, how to alleviate foot forces with bank, can flaps be moved during a turn, can altitude be maintained on 3 engines after takeoff.
On top of which, consider the training required and crew experience in this particular situation.
Just a quick question, but in the video clip that we all watched, has if been established that that object we saw was an engine falling from the right wing?
