Tail rotor drive failure video

[Aser]

Just found it :ooh:
http://www.nothingtoxic.com/uploads/32b05a267517dc1e2b7bfe7fa0ba80bd.jpg
http://www.nothingtoxic.com/uploads/db4374cd5e7dc9b22335fa2b146177d5.wmv

looks like a good job!

[crispy69]

Good video. lucky guy he hit ground pretty hard.

[Impress to inflate]

Ouch !!!!!!!

[NorthSeaTiger]

"Grandpa you stay there" gotta love it !! :D

[cptjim]

I watched the video over and over again but couldn't see the plane! :confused:

I guess it must have been behind the smoking helicopter :}

Glad the pilot made it out ok :ok:

[NickLappos]

You can see how cool he was, punching off the load away from the building in the cleared out area, then holding it level and allowing it to turn as he lined up a clear area to land in, lowering altitude while spinning until he was about 50 feet (too high, frankly, but far far easier to judge from here then from in his shoes). He cut the throttle there, stopped rotating and then settled down, running out of rpm and control at about 25 feet, where the forward CG caused the nose to pitch over (while he was probably on the aft cyclic stops.)\Hard landing and he walked away. He gets a solid A on that whole thing!

[SASless]

I talked to the pilot about a week after the incident. What absolutely amazed me was his humility about the whole thing. A couple of times he expressed genuine sadness over not being able to land safely and causing the aircraft to be damaged as it was. He gave a very detailed and graphic description of what happened and how he tried to cope with it. As I recall, he was trying to make it to a flat spot but just could not get there.

The salient point of his whole story was that of "flying the machine and thinking about what he was doing".

As Nick rightly says....Grade A! Gold star...step to the front of the class!:ok:

[Gary Smith]

awesome video for grandma's first attempt, give her a video job with a harness :} :}

[treadigraph]

I saw this vid on TV some time back but the bu@@ers didn't say (or I missed it) what happened to the crew - it's nice to finally hear that it worked out well.

[Aser]

He is "iceman" waiting to be near the ground to cut engines...

anyway I would expect a more violent yaw in the first rotations...

[topendtorque]

at about 25 feet, where the forward CG caused the nose to pitch over

Just run that one by again please Nick. I've downloaded the video and only watched it once, will do again in a day or so when time prevails and come back then
cheers tet

[212man]

I was impressed by how quickly the rotation stopped with the throttle chop. Sadly matched by an equally rapid Nr decay:\

[NickLappos]

topendtorque asked about the phrase, "at about 25 feet, where the forward CG caused the nose to pitch over"

Some more details on the diagnosis, kind of walking through the aerodynamics of the landing:

You can see how cool he was, punching off the load away from the building in the cleared out area.

He obviously knew he was too high to just cut the throttle, and he saw that the rotation rate was not unmanageable, so he decided to ride it out by holding it level and allowing it to turn as he lined up a clear area to land in and reduced altitude. This was a conscious piloting act to just allow the turns, but also fly the aircraft down while spinning. It also means that he had to sweep the cyclic around as the aircraft rotated, so that the aircraft stayed level. Remember that the cyclic needs to be put a bit into the wind, otherwise the aircraft attitude will rise and dip and wallow as the rotor is spun around, as the part of the rotor that is upwind is lifted by the wind. That this wallowing didn't happen indicates that he was sweeping the cyclic around in the cockpit to keep the upwind part of the disk down. If you stood outside the aircraft, you would see that he was simply keeping the cyclic into the wind as the aircraft rotated. I had to do this when I did the "snap turns" in the Fantail and Comanche, it is surprisingly easy to get the hang of it with practice, and hard to do when you have to learn it while hovering over an office building!

He held this approach technique until he was about 50 feet above the ground, when he choce to cut the throttle. This was a bit too high, frankly, but is far far easier to judge from this key board then from in his shoes. He cut the throttle there, which immediately stopped the rotating. Of course it does, the turning is powered by the torque of the main rotor, take that torque away and the spin is immediately countered by the slight drag of the main transmission, which acts to make the fuselage rotate WITH the rotor.

The aircraft then settled down in a hovering autorotation, when it ran out of rpm at maybe 25 feet. The allowable CG envelope is a function of cyclic control power, where the cyclic has the control to overcome the moment from the forward (or aft) CG. In this case, the forward CG (lost tail rotor parts) required more control than the low low rotor speed could deliver at about 25 feet, so this caused the nose to pitch over (while he was probably on the aft cyclic stops.) He had a hard landing and he walked away.

He gets a solid A on that whole thing!

A similar take:
A Sikorsky Test Pilot named Cliff Brown had a tail rotor failure in an S-61N while flying with a foreign pilot, they were stabilized in a 100 foot hover over the water. He did much the same thing, riding the aircraft down to a managable 10 foot altitude before cutting the throttles and landing without further damage. He had to shout at the CP to keep him from moving the engine levers, "Stop! I will tell you when to cut them!!" he said. At ten feet above the water, he looked at the guy and said, "Now you can cut them!"
Cliff is well known in USAF circles because during a hot combat rescue in Korea, he got out of the helo to take a leak in the LZ. The rescuee fighter pilot looked in complete awe at "the bravest person" he ever met, and thus was born the Cliff's nickname, "No-Sweat Brown."

[lynx247]

Excellent thread! First class lesson in how to do it if it ever happens, and great explanations and backup info from some experienced pilots - I have printed this one out for my prune folder and students... well done to the pilot involved.

[Matthew Parsons]

If you look at the frames around 1:33 into the video you see four intact tail rotor blades. I don't think there was a shift in the cg.

My guess is that he chopped throttles to stop the yawing and then used cyclic to try to make it to a more desirable LZ. I wouldn't be surprised to hear the pitch forward was commanded. If you look where he came to rest, it looks like just short of that ledge was a larger drop so it was probably a good thing he pitched forward.

In any case, what matters the most is that he walked away. Well done!

[Darren999]

Hi All,
wonderful thread.. However I do have a question. Please no real abuse replies but.... I saw a clip on here prevoiusly it was a sky crane with LTE and the pilot dumpped the water and continued to fly away. Nick explained what happened which was to me , extremely informative. However, the case in question above, why couldn't the pilot, once the load was released, lower collective, reducing power and fly out of it, any which way possible, or am I totally missing something here... Thanks in advance for your help...:uhoh:

[Darren999]

Ok everyone!!! just looked again, and seen the problem, and also read title!!!:ouch:

[NickLappos]

If you look carefully at the time of original failure, you can see the tail wiggle a few times and the aircraft yaw to the LEFT. Then the TR stops and the fun begins with the classic right yaw. I have a suspicion that the failure was due to loose control cables, which can cause an instability in the tail rotor controls that causes a rapid divergent TR pitch problem that eventually leads to very high left pedal, then failure.

Why not just fly away? There was no antitorque as the right yaw developed, and fly away was simply not possible. This case is far different from the Skycrane, which had merely pulled the rpm low enough to swamp the tail thrust with the main torque.

[BlenderPilot]

Does this helicopter have a collective mounted power control grip? (throttle)
He chops the power while still quite high, I'm GUESSING he must have hurried to take his hand, off the collective, put it up there where the lever is pushed it back, then go back to collective to cushion landing.
He must have seen the ground come up really fast so he decided to do it early or else he wasn't going to have time to cushion landing.
Of course all of the above could only be remotely correct if this particular helicopter hasn't a collective mounted power control, if it does forgive my ramblings.
One more reason to have collective mounted power control in my tired opinion.

[[email protected]]

Nick, I'm not sure why you think that a loose TR cable would lead to a total loss of drive (the TR blades are stationary in the descent). If it were a broken or loose cable the ability to change the pitch of the TR would have been reduced or lost completely but the TR would still be driven. I don't know if this model had the same folding tail pylon as our military Wessex did but if so, the disconnect coupling would be a prime culprit - the profile looks exactly like a friend of mine had a few years ago in a SAR Wessex.

BTW Blender, the only civilian S58 I have seen did have collective mounted throttles.

[IntheTin]

The S58 that used to be at Heliflight had collective mounted throttles.

;)

[NickLappos]

Crab,
I am speculating (and that is all) that the failure is an instability in the tail control system, not a stuck control, that is why the TR drive was possibly damaged enough to separate. The failure mode is a divergent oscillation of the yaw controls that leads to extremely high left pedal, then right then left at perhaps 2 Hz. Note the wiggles and left yaw just before the fun starts. Do not think of this mode as a stuck anything, it is a divergence that ends up failing the TR drive.

Regarding engine controls, all S-58's, recip and turbine, have throttles on the collective.

Regarding Blender pilot's impossibly large type comments, I find that the larger the type, the smaller the thoughts. It is wonderful to see how pilots might redesign helos to solve all the rare and almost impossible problems and not even think about the ones that get us. Should blender pilot ever actually read any accident statistics, I would hope he would use even larger type to ask for CFIT protection, or IFR capability and instruments for all helos, or fixes for all the things that actually get helos. But that would be a stretch, wouldn't it?

Asking for twist grip throttles to solve a TR problem is like donating $1,000,000 to the Cancer society not for a cure, but for fancy caskets. Sort of forgets that we might actually just fix the baseline problem, huh?

[[email protected]]

Nick I have difficulty understanding how a basic cable operated TR control system can suffer a fault such as you suggest. The system only comprises a quadrant to change the yaw pedal input from rod to cable at the front end and a similar arrangement at the end of the tail to convert it back to rod and route it up the pylon to the pitch change lever on the TR gearbox. From there it relies on a magill bearing to transmit the pitch change to the TR spider. The only divergent mode I can imagine is a sort of 'bounce' in the TR cables which would mean the tensioner has failed and in many years of the brit mil operating the Wessex, I have never heard of such a failure mode. It would take some fairly major and very rapid pitch change reversals ( more than an autopilot with limited authority could manage) to trash a fairly beefy TR driveshaft like that on the S58.

I don't know what caused the initial left yaw before the failure (turbulence, control input, power change, autopilot malfunction) but a divergent 2Hz oscillation would surely have produced more than one wiggle before drive train failure occurred.

It matters not anyway as the pilot did a very good job, my friend who had the TR failure over a lake in Wales had the same difficult job assessing a suitable height to chop the throttles and ended up going in backwards with low Nr.

[Aser]

It matters not anyway as the pilot did a very good job, my friend who had the TR failure over a lake in Wales had the same difficult job assessing a suitable height to chop the throttles and ended up going in backwards with low Nr.
Crab, your friend? http://www.helis.com/movies/s58rot.mpg
http://www.helis.com/movies/s58rot.jpg

[SASless]

What amazes me is the ability some have to view a video and not only tell me what the pilot in the cockpit did....but also tell me what the guy was thinking and planning to do.

That is pretty darn amazing!

[NickLappos]

SASless, I accept the jibe, but he still did a great job, even if he was thinking of you when he did it!

Crab,
You must know that the TR servo is not at the TR but on the upper deck, and the force from the TR propellor moment is conveyed along the TR cables to the upper deck. The frequency of the cable tension response is set by cable tension, if the tension is very low, the natural frequency of the cable can tune down until it matches the natural frequency of the TR collective pitch and excite the "umbrella" mode of the rotor, sort of like collective bounce in a H-1. Since the TR stops are on the upper deck, the TR pitch can go to very big numbers, the ride is short, exciting and often leads to a TR failure. Cable tension is a nice thing. All this is speculation, of course, but I cannot explain the yaw twitches and obvious left yaw just prior to the TR failure any other way. I could be very wrong, it has happened before!!

[IntheTin]

Why didn't he enter an auto once he was above his point of landing instead of descending then trying to hover auto? Wouldn't he of had enough rotor RPM to use? :confused:

[SASless]

Nick,Perhaps you can discuss "Tail Rotor Buzz" as used to apply to the 58T. Could that have played a role in this....I would think it is different to the cable tension issue you note already.

[Matthew Parsons]

Perhaps the drive system disengaged and then re-engaged a few times before it ultimately failed. That would explain yaw both left and right, and the endstate of a stopped tail rotor.

Any type experts that can add comment?

[toolguy]

The aircraft suffered a loss of tail rotor drive due to a failed tail driveshaft coupling. The S58 uses two opposing jaws with bonded rubber separating then the teeth letting go, this is way before the Thomas Coupling, simple and effective, but you had to kep an eye on the rubber segments. Pilot did a heck of a job, but barely missed being impaled on a pole from the chain link fence. :}

[[email protected]]

Aser - yes that's him - he and another good friend survived, sadly some cadets who were on air experience did not.

Toolguy, thanks for that - it is as I suspected, the disconnect coupling needs to be well maintained - even using the wrong kind of grease can cause the spring loading to stick and prevent proper location of the drive teeth. The Wessex drive disconnected and the TR started to slow down, when the drive bit again the shock loading twisted the TR driveshaft like a coke-can and the video posted by aser was the end result.

[Tweedles]

Mr. Lappos,

I too am wondering about the option of flying away from the TR failure.

Earlier you stated "...he saw that the rotation rate was not unmanageable."

What made it so? Is the lowering of collective, and therefore torque, the key to keeping the yaw rate manageable? I would have expected a helicopter in a high power required HOGE to start yawing very rapidly and almost immediatley become unmanageable.

In cruise flight I understand that the fuselage will streamline with a degree of sidelsip and roll. A run-on landing and/or autorotation (depending on type) are then your two available options. Somewhere between cruise and hover my little mind is telling me that I might be able to reduce collective and spiral to attain the streamlining effect, altitude permitting.

Would the rule-of-thumb be that one would initiate a descent (with rotation)and a hovering auto once the helicopter has begun swapping ends? Or is there any merit in attempting to sweep the cyclic while trying to attain enough forward airspeed for it to streamline?

My RFM only states to execute a hovering auto if TR thrust is lost while hovering.

Thank you for your time. Your willingness to share your knowledge is much appreciated.

Todd

[[email protected]]

Tweedles you have a lot of height, around 1000' feet or so you might stand a chance of getting into forward flight but if you watch the video of the yellow wessex, he tries this but cannot gain sufficient airspeed and he was doing around 60 kts at the time of the failure.

I do not believe there is a rule of thumb for this manoeuvre but hovering at heights up to about 500' it may be worth lowering the lever sufficiently to get a manageable rate of descent and a manageable rate of rotation but there are no guarantees and it will vary from type to type. Having a slab sided tail boom like the S58 will help as it creates a lot of drag and reduces the rate of rotation a bit. You have so little control in this situation you can only hope you get to a position where you can chop the throttles and carry out a hover EOL.

[Hiro Protagonist]

I am reminded of this (http://www.pprune.org/forums/showthread.php?t=232911) thread.

Perhaps a different failure (pitch rather than power), but still not the reaction outlined in the manual... And he avoided swimming!

[Aser]

I can't remember exactly but I was having fun in a 412 sim in hover maybe 2000' agl when the tail rotor departed (funny instructor)... everything went crazy (helo spining like mad) :} I put 30º nose down, lowered collective and I got airspeed to streamline the helo, then I cut engines and safe landing!.
level-d sim and so... but a good computer game anyway, I wouldn't try that again in real life in a hover below at least 2000' agl.

[rotorrookie]

Remember this one.http://www.pprune.org/forums/showthread.php?t=200217&highlight=puma+crash+video I agree with Blender... overhead throttles should be banned.... it's like having the ignition switch of your car in the trunk..just stupid. :ugh:
But you could be smart and fly Bell:ok:

[IrishSarBoy]

Great video, and some interesting comments. Re the Wessex that went in, the captain of that aircraft was an instructor of mine at shawbury and had some interesting thoughts on tail rotor drive failures at low level. As for me I'd love some more info on the S61 test pilot and how he coped with the failure from the 100ft hvr so I can try it out in the sim. With ref to the sim, they changed the model for this particular failure with the c of g making a much greater impact than before and after looking at the video it would seem that these changes have made the sim more realistic. As for walking away from the tailrotor failure in the S61 sim, the lowest I could be in transit and then have an 'acceptable' ditching was 500', hence the fact that I now fly at a min of 500' unless required to be lower! fly safe :@)

[toolguy]

One benefit of overhead throttles in an emergency is crew coordination. Nothing worse than calling for rollback on no.1 one then getting no. 2 rolled back by the CP. Had that happen in the 430 sim, where you have different collective throttle orientation between pilot and CP sticks.

[Tweedles]

Thanks for the info crab, Aser and ISB.
HP, I had forgotten about that thread. It was worth reading again.
Check out this thread for another TR incident: http://www.pprune.org/forums/showthread.php?t=247997

[as355f1]

http://www.break.com/index/helicopter_crash_at_airshow.html

[thecontroller]

mmm.. it seemed to catch fire before it hit the ground. does anyone know the reason for this?

[Aser]

repost => http://www.pprune.org/forums/showthread.php?t=243966&page=5

[as355f1]

Sorry about the repost but i only did it a few hours after the original and did not notice it :}

[NickLappos]

That horrendous tape is a lesson in many ways.

The tail rotor is probably hit (collision?) off camera. This leads to the loss of the tail section just ahead of the vertical pylon, most likely caused by the imbalance of the loss of a tail blade, and the ensuning structural loads at the "weak point".

This antitorque failure results in spinning about the mast, and then wild cyclic excursions as the pilot is unable to maintian orientation. One can speculate that if the collective had been dumped then, fast, the spinning might have stopped and some kind of controlled low-power (zero power) descent could have been arranged. But that is asking alot.

Note that the bucking of the fuselage as the spinning occurs leads to blade-fuselage contact. The bucking is because the rotation of the fuselage exposes different sections of the rotor to the relative wind, so that the "back flap" affects the rotor sequentially as the fuselage turns. If the crew is not able to know where the wind is coming from, they cannot keep the fuselage level. This pitching and rolling eventually leads to large flapping events and blade to fuselage contact. The broken blades are uneven in length, so there are large cyclic imbalances that help tear the helo apart.

I believe the helos are Mi-2's which are 1st gen machines with relatively weak structures (or very light structures, depending on viewpoint.)

The tearing apart ruptures the fuel cells, which spray avgas everywhere, especially onto the running engine, which ignites same.

Not at all a pretty picture.

[fkelly]

Note the comment from the person posting on the site "...I hope everyone was OK"

Now I know it takes all sorts to make this world but.... should they let people like that vote? :ugh:

[skadi]

NickL wrote
I believe the helos are Mi-2's which are 1st gen machines with relatively weak structures (or very light structures, depending on viewpoint.)



I think, it was bigger than a Mi2, probably a Mi8.

Skadi

[nickg_44]

Actually, I believe that the helicopters flying in formation are mi-2s while the helicopter with the TR failure, is a larger mi-8.

Anyone agree?

[jab]

All machines in the vid are Mi-17's. The "stub wings" for the rocket pods change the usual silhouette somewhat.

[Shawn Coyle]

I think they were all Mi-2, but difficult to tell. Does anybody have any idea where this was filmed? that might give a clue.
Mi-2 had / has a very weak tail rotor attachment fixture- The Poles told they tried to get the Russians to let them (the Poles) re-design it as it was causing problems. In typical Socialist fashion, they were told - if you re-design it, that means that the original designers didn't know what they were doing, and we can't accept that. Leave it as it is....
That's why the Kania (the Allison engined version of the Mi-2) is so different - the Poles did re-design it. Sadly, they seem to lack any management or sales capability, and have faded out of the market.

[nickg_44]

Yes, those mi-2's are horrendous helicopters. The Russians used to turn up to the World Championships in them, didn't stop them totally wiping the floor for all the trophies though!

Here are useful links to allow people to decide for themselves what the helicopters really are:

mi-2: http://www.scramble.nl/mil/2/kop/gfx/mi2-orbat.jpg
mi-8: http://www.pidocchio.net/turboland/leteckce%20museum/26Mil%20Mi%208%2002.jpg

mi-17: http://perso.orange.fr/aeromil-yf/MI%2017%20BULGARE%20Roulage%20CK%200201.jpg

I think JAB may be correct on the TR failure with the mi-17. To me (a rather untrained eye on russian aircraft) it looks like mi-8 and mi-17 are relatively similar. Any thoughts on this?

nick

[jab]

Hi Shawn

Definitely Mi-17's with hard points. I have flown the civil version quite a bit and although the tail looks too long and thin, its quite strong. Did have some problems with skin cracks during logging but thats hard on any machine. I have never heard of a tail breaking off for no reason. Friend had a tail rotor blade delaminate in flight and the entire tail rotor transmission broke off as they touched down, lucky.

[tecpilot]

Definitely all Mi-17! I couldn't understand how some of you guys could confuse it. The Mi-2 is a much smaller helicopter with nothing in common with Mi-8/17.
Have flown and tested both types in civil and military outfit and equipment for more than 500h and we have never found any weak structural designs. Astonishing Shawn, you as a real expert believe it? They have problems in flight performance and some other problems, but this kind of russian helicopters are real "iron pigs".
For the Mi-8/17 as a more than 12to MTOW helicopter exist limits. But's the same as on other big ships.
I don't know the reason for this tail rotor separation. But i would bet, it was a main rotor strike into the tail boom. This and only this is a weak point on Mi-8/17 with several accidents. This big and hinged rotor with very flexible blades don't like aerobatics. The distance between rotor and tail boom isn't large enough. And it is no problem to strike the blades into the tailboom. And if the blades strikes the boom, than they will do it in the vicinity of the intermediate gearbox. And that's exactly the first breaking point in the vid.

[nickg_44]

Test pilot,

I wasnt debating that the mi-2 is a smaller helicopter! i was merely saying that i thought that the helicopters going from right to left were mi-2s because of their stubby look.

Maybe its just the camera angle, and its a fairly poor quality vid anyway.

still dont know the difference between mi-17 and mi-8?

nick

[mylesdw]

Nick Lappos made the interesting comment that if the pilot had removed power quickly things might have ended up better; it does appear from the video that there are quite a few seconds before the situation turns really ugly. What do the experts on the panel think?

[skadi]

tecpilot wrote:
I don't know the reason for this tail rotor separation. But i would bet, it was a main rotor strike into the tail boom. This and only this is a weak point on Mi-8/17 with several accidents. This big and hinged rotor with very flexible blades don't like aerobatics. The distance between rotor and tail boom isn't large enough. And it is no problem to strike the blades into the tailboom. And if the blades strikes the boom, than they will do it in the vicinity of the intermediate gearbox. And that's exactly the first breaking point in the vid.


I remember the video ( somewhere in this forum ) of the ditched Mi, where the mainrotor struck the tail while attempting S/E Water T/O.

skadi

[tecpilot]

Running the vid in slow motion and found my first toughts right. At first the ship lost the complete last tailboom part incl. the intermediate gearbox and not only the T/R. A few seconds later parts of rotor blades disintegrated. For me a sign of a damaged M/R. And a damaged M/R is not the result of a "simple" T/R loss.

On this scenario a power cut will do nothing. The damaged M/R blades will result in heavy vibrations, an unbalance and may be in an uncontrollable helicopter. This unlucky guys were doomed. May be they have done it and tried an AR. But an increasing M/R RPM will rapidly increase the forces on the blades and a disintegration.

still dont know the difference between mi-17 and mi-8?

The best way to decide if seeing an older Mi-8 or the newer models (names are difficult, sometimes Mi-17 variants are decribed as Mi-8 MTV) is to look at the engine cowlings. On the newer variants with the more powerful engines the engines are much shorter than the old TW117 on the Mi-8. Therefore there is more distance between the front of the helicopter and the air inlets. The next, the newer models have the T/R on the left side. At least the first helicopters in the vid seems to have a left sided T/R.

The tearing apart ruptures the fuel cells,
No, this armed Mi-17 variants have selfsealing and azotic pressurized fuel tanks. They couldn't have ruptures on the cells due to a few fast rotations and they have no fuel lines in the tailboom. I believe after the disintegrated M/R blades the unbalance broke out the main gearbox and engine struts, rupturing fuel or hydraulic lines in the vicinity of the engines.

[mylesdw]

tecpilot: if you look very carefully at the video when the stricken machine first comes into view there is some debris falling to earth and the rear tail-boom section is still attached. The falling piece is well below the ship so it could have come off a few seconds earlier. My guess was that it is a tail rotor blade but it is not at all clear. Would the vibration caused by losing a TR blade cause the boom to fail?

[nickg_44]

thanks tecpilot.

nick

[tecpilot]

Would the vibration caused by losing a TR blade cause the boom to fail?
Not impossible of course. Really difficult to see on the vid. But losing a t/r blade without outer influence seem to me unlikely. The t/r on such ships are stronger and heavier than the most m/r on western ships. A few hundred kg heavy made "hand forged" t/r fully hinged with a lot of hydraulics and anti-icing.
Never heard about design problems, only limited on cross wind.
I liked these ships, this is an old Mi-8. Long engines, t/r right side.
http://www.airforce.ru/photogallery/gallery8/mi-8t/ap_mi-8.jpg

This is a Mi-17. Short engines, m/r blades disintegrated, surely after tail boom or ground contact. Not inflight surely.
http://www.rob.com/pic/oops/AIR_Pg1_MI_17.jpg

[212man]

"I remember the video ( somewhere in this forum ) of the ditched Mi, where the mainrotor struck the tail while attempting S/E Water T/O."

Er, not quite: the nose 'submarined' under whilst attempting a running take off (or taxying too fast) in a choppy sea. The MR blades hit the sea in front of the aircraft.

[skadi]

I remember the video ( somewhere in this forum ) of the ditched Mi, where the mainrotor struck the tail while attempting S/E Water T/O."

Er, not quite: the nose 'submarined' under whilst attempting a running take off (or taxying too fast) in a choppy sea. The MR blades hit the sea in front of the aircraft.


Yes, 212man, youre right, but after hitting the sea, the m/r-blades chopped off the tailboom, other cause but same result.

skadi

[nickg_44]

very useful tecpilot. thanks v much

nick

[MightyGem]

tecpilot, looks like that 8 driver was a bit heavy handed on his nose wheel brake!