View Full Version : Airshow Crash Russia
Thomas coupling
2nd Aug 2015, 20:41
Tail rotor failure - obviously. But why didn't he chop the throttles and try to stop the descent at the bottom? I don't think the rate of rotation was too disorientating? The 'G' not too great to prevent him reaching the ECU switches?
RiP.
Thomas coupling
2nd Aug 2015, 21:51
Tail rotor failure. Watch again.
He performs a turn in one direction and it is immediately cancelled out by a reverse turn at the same time the TR slows down. :ugh:
That 'X' section TR most definitely has stopped functioning correctly - it is simply free-wheeling.
Tail rotor shaft / bearing failure.
The flicker effect with the helo in the foreground is constant, the failed TR in the doomed chopper is all over the place.
heli kiwi
3rd Aug 2015, 04:12
Damn - I was waiting for them to blow the blades and eject
krypton_john
3rd Aug 2015, 04:26
Based on the spin he seemed to be pulling collective despite tr failure?
Was there not enough time, height and speed to execute an autorotation entry from that attitude?
As TC said, RIP :-(
Damn - I was waiting for them to blow the blades and eject AFAIK only the Kamov 50/52 has ejection seats, this was a MI 28
skadi
jolihokistix
3rd Aug 2015, 06:51
Looks like only one made it out?
whoknows idont
3rd Aug 2015, 06:56
According to the press release, SIC got out, PIC didn't. RIP
Ascend Charlie
3rd Aug 2015, 07:05
Poke the nose over, get some airspeed, the fin might help reduce the spin to something flyable?
BOBAKAT
3rd Aug 2015, 07:36
That is the "normal" procédures On the Alouette and Squirrel series when you lose the T/R control OR Power....( i don't know for other one)
Not easy to do if the T/R power loss
Much more easy if T/R control loss
Rotor Work
3rd Aug 2015, 10:20
From ABC
The defence ministry said the accident was apparently caused by a hydraulic system failure, which was reported by the surviving pilot who ejected from the chopper.
(So there you go heli kiwi, ejected from the chopper)
Russian air force helicopter crashes at Dubrovichi air field, killing pilot - ABC News (Australian Broadcasting Corporation) (http://www.abc.net.au/news/2015-08-03/russian-air-force-helicopter-crashes-killing-one/6666972)
A Russian air force helicopter has crashed in front of thousands of spectators at an air show east of Moscow, killing one of the pilots, in the latest in a string of military crashes involving military aircraft.
The Mi-28N attack helicopter was participating in the show at Dubrovichi air field near the town of Ryazan, 200 kilometres east of Moscow.
The show was part of a competition organised by the Russian defence ministry.
"One pilot has died, the condition of the other is satisfactory," the ministry said in a statement.
The Russian air force proceeded to ground all Mi-28 flights after it was revealed the crash could have been caused by equipment failure.
The air show Aviadarts, where air force plane and helicopter crews compete to carry out timed tasks, was suspended for the day.
Television footage showed rescue workers attending to the smouldering helicopter lying on its side in the airfield after it crashed and burst into flames.
The defence ministry said the accident was apparently caused by a hydraulic system failure, which was reported by the surviving pilot who ejected from the chopper.
"According to the second pilot, the catastrophe happened due to aviation equipment failure," said commander of Russian air force Viktor Bondarev.
"I have stopped all flights on Mi-28 until an investigation is complete."
The Soviet-designed Mi-28 has been used by the Russian air force since the mid-2000s and is also exported to a number of countries including Iraq.
There have been at least six incidents over the past few weeks involving Russian military planes and helicopters.
Would the pilot that 'ejected' be the same one who is seen stumbling out of the wreckage intact and walking around in the OP's posted RT video (at 56 secs in) ?
Rotor Work
3rd Aug 2015, 11:06
That would be the guy
Obviously the ABC didn't get that information.
drakkar
3rd Aug 2015, 12:38
Looks like a VRS. Aircraft seems to be at zero speed on top of the climb with a high nose up attitude and probably low collective pitch. Then start to turn. I agree with Johni for the T/R , it's the video footage. Is the MI 28 single hydraulic boost system like the MI 24 ?
nonsense
3rd Aug 2015, 15:52
Wondering what that acronym means? (https://en.wikipedia.org/wiki/Vortex_ring_state)
Helilog56
3rd Aug 2015, 15:57
VRS....vortex ring state
rotorspin
3rd Aug 2015, 16:03
He had plenty of height to recover? Experienced display pilot in VRS not recovering? I think there is more to this than meets the eye?
tottigol
3rd Aug 2015, 19:28
The Mi-28 started spinning before it started descending, the initial snap yaw at the top of the climb with a high pitch attitude is caused by a TR failure.
A steady spin in the opposite direction as the main rotor is not related to VRS, but rather to a TR loss of thrust or loss of control.
Sad loss of life.
Non-PC Plod
3rd Aug 2015, 19:50
Am I being thick here? The helicopter comes down yawing in the same direction as the rotor blades are spinning. If it was a TR thrust failure, then surely it would result in rapid yaw to the right? This appeared to happen, with initial right yaw but then something else happened to cause the left yaw in the descent.
The Mi-28 started spinning before it started descending, the initial snap yaw at the top of the climb with a high pitch attitude is caused by a TR failure.
A steady spin in the opposite direction as the main rotor is not related to VRS, but rather to a TR loss of thrust or loss of control.
Sad loss of life.
Thomas coupling
3rd Aug 2015, 19:53
Good spot RC but half way down, it reverses the direction of spin???
Maybe because of pilot input? The authorities are talking about hydraulic problems (input shaft servo)? Look at that TR on the way down.
What is debatable is why he didn't cushion the touchdown sufficiently.
If I recall correctly didn't the same happen to AG +1 in a Gaz piece @ Predannack local area at the top of a wing over?
As previously mentioned dumping the lever and nudging it fwd for speed should have helped enormously with the end result.
Maybe the revolutions were enough to disorientate the HP upsetting his decision point just above touchdown??
God knows how the other guy survived :\
Non-PC Plod
3rd Aug 2015, 20:01
Cant pretend I know anything about that particular machine, But if they are talking about hydraulics, maybe there was some sort of control restriction preventing movement of the collective?
Good spot RC but half way down, it reverses the direction of spin???
Maybe because of pilot input? The authorities are talking about hydraulic problems (input shaft servo)? Look at that TR on the way down.
What is debatable is why he didn't cushion the touchdown sufficiently.
If I recall correctly didn't the same happen to AG +1 in a Gaz piece @ Predannack local area at the top of a wing over?
As previously mentioned dumping the lever and nudging it fwd for speed should have helped enormously with the end result.
Maybe the revolutions were enough to disorientate the HP upsetting his decision point just above touchdown??
God knows how the other guy survived :\
Looks like a TR servo hardover since it is yawing left at a constant rate throughout - it appears the pilot had sufficient lever in to control the RoD and maintain a manageable rate of rotation.
He was probably trying to diagnose the problem all the way down and just misjudged the point he needed to cushion the touchdown - he had spun round enough times to be disorientated.
Thomas coupling
3rd Aug 2015, 20:29
I'll go with that big guy! How's the 109 these days?
army_av8r
3rd Aug 2015, 22:14
Certainly looks like a TR failure, and once you get going vertically, it seems to be difficult to get out of while spinning. If you look at the rotor wash created at impact, it looked as though the pilot had pulled an arm full of collective, but just a bit late. Having flown displays while doing this exact maneuver, I find VRS very unlikely. But the lack of effectiveness of the cushion could likely be attributed to VRS as the pitch was pulled. One thing to remember is, once a TR failure starts to spin, it will continue to spin due to inertia until forward airspeed or drag stops it. Even with collective full down and no torque. You can see that the rotational acceleration ceases very quickly and it descends at a very constant yaw rate once established. Those are just my observations!
whoknows idont
3rd Aug 2015, 22:33
Non-PC Plod: The helicopter comes down yawing in the same direction as the rotor blades are spinning.
Again a visual deception because of the frame rate. Looking at pictures you will find that the Havoc has clockwise rotating blades, like most (all?) Russian helicopters.
ShyTorque
3rd Aug 2015, 22:47
Unless that type has a "puller" tail rotor, it wasn't opposing the main rotor torque once established in the descent.
mixing lever
3rd Aug 2015, 23:54
I too may be a bit thick; but since UK/US aircraft yaw right when tail rotor thrust is lost, shouldn't Russian (& French) aircraft yaw left when they lose tail rotor thrust? Regardless of the frame rate, it appears that the tail rotor is not working as advertised. Also, once the yaw exceeds 90-180 degrees, attempts to lower the nose to gain airspeed and fly out of the spin just lead to unusual attitudes on impact - especially in large, heavy aircraft. This pilot displayed commendable discipline in maintaining a level attitude all the way to impact in order to use the crash attenuating features of the MI-28 to their best - the fact that one pilot actually survived and was able to stagger away is testimony to that.
NickLappos
4th Aug 2015, 19:28
I believe the press report of hydraulic failure. The aircraft does not waver in its descent, and there is no attempt to recover in any way, including no pitch pull at the bottom. That is not a "normal" anti-torque failure, the spin rate is too slow. It has the hallmarks of a helo with locked controls trapped in a descent.
Not VRS, the descent is not fast enough.
The Mi-28 has side eject capability, with a bounce pad outside the door to prevent contact with the wings on bailout.
JohnDixson
4th Aug 2015, 21:05
Nick, re locked controls. As I recall you had a chance some time ago to get a thorough walk-around on a MIL-28. Question: They probably have at least two, if not three hydraulic pumps/reservoirs, so losing all hydraulics seems improbable? Video shows no input to the directional or collective controls, but the pitch and roll axes remain fairly level. Does that machine incorporate a collective/yaw mixer and could a mechanical failure therein explain the flight path?
You'll recall the UH-60 accident where the cause was finally determined to be a non-safetied bolt ( there had been maintenance performed by the unit ) in the control mixing unit that fell out and jammed the longitudinal control. Matching witness marks were found on the jammed parts.
In this case there is a survivor, so by now the detailed cause is most likely known.