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Hughes/MD 500

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Hughes/MD 500

Old 17th May 2005, 13:50
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There is an AD that needs to be done on the T/R gearbox stud inserts. I hope this is not the cause as it's an old problem.
Not a nice one but a job well done for getting it down.

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Old 17th May 2005, 22:19
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I'm ready to be corrected, but isn't loss of T/R not 'too' much trouble if you can auto straight away since the principle of autorotation removes the need for an anti-torque thrust as the M/R is being 'driven' by upflowing air? Swinging into wind presumably can only be done by cyclic in this case..

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Old 18th May 2005, 00:57
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Thumbs up Damper friction adjustment

The Bendix designed shaft is used on H-500 series as well as the Apache and the Agusta 129. Each of these shafts has a nodal point about which the shaft will whip. At each nodal point the manufacturer installs a stainless ring circling the shaft. This ring rides inside of a damper assembly, which is also installed at the nodal point. If the shaft for any reason starts to whip about itsí rotational axis the stainless ring will contact the inside of the damper causing it to displace. The displacement provides a damping effect canceling out the shaft displacement. The damper is installed between two plates and is restrained in position by springs that are preloaded to a specific setting thus providing friction and restraining damper movement. If the springs are set too loose the shaft will be unrestrained and will whip resulting in fatigue of the shaft and or the Bendix couplings. If the friction is set too tight the shaft will be unable to whip and will be exposed to high stress levels.

At least thatís what I remember from about twenty years ago.

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Old 18th May 2005, 02:04
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As far as I know we have a proper MD hangar bearing instaled.

Blade banger
all current and past AD's are up to date on this machine and it has the 10300 hour tail boom

Mr Selfish
The bill will be a night mare but all bills for helicopters are


Cruising at 1000 feet and between 80-90 knots, when a massive cracking rumbling noise was heard by all in the 500, the pedals froze instantly so we realised it was something in the tail rotor, we maintained our speed and entered autorotation.

we noticed we had only one viable place to go, along a road over the other side of the river. as we got closer we noticed many powerlines crossing right were we wanted to go and some large overhanging gum trees, so we changed heading and went for a large backyard of some house. all the time we kept our speed up around the 70 knot mark, if we slowed down we started to yaw. at the last second we had to pull pitch to slide in between some very large trees. on landing we ran on for as long as we could to stop the tailboom being cut off. it was a fast run on but very soft on the 500 and us.

The whole time as the engine was idling we could here the tailshaft banging around. the tail rotor push pull tube was bent at the moment of shear, that explaines the locked pedals.
Our engineer estimates that ten to twenty more seconds off flight the tail boom would have failed and the t tail and all the rest would have fallen off. not a nice thought.

what intriges us is that is sheared in a stabilized cruise not under load in a hover for example

any more thoughts would be greatly appreciated


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Old 18th May 2005, 05:27
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Hi Rotor 1,
Then I would seriously look at the last TR balancing procedure because when you fit the new bits you could be following the incorrect procedure again and your autorotation proficiency will be tested again.
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Old 18th May 2005, 06:34
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Great Effort!

Rotor 1,

Great effort on your auto!

As a Chinook pilot, it's been a long time since tail rotor malfunctions have been a major concern. (Our major concern is having a mid-air collision with ourselves!) From all reports, the 500 is a great machine to fly and not withstanding the failure, she sounds like she got you out of trouble okay.

Reading your description of the event, I have to say I'm impressed with your aviating. As a CRM facilitator, I'd love a chance to talk to you about it so I can use it as a teaching/learning point for single pilot operations. PM me if you wouldn't mind letting me pick your brains, or email me at [email protected]

Well done and I hope your future flights are less eventful and more enjoyable.

Conway B
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Old 18th May 2005, 17:34
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Rotor 1: when you pulled pitch at the bottom, was your engine still on line or had you throttled it back to GI?

If the latter, did she yaw a little or considerably in the direction of rotation?


Good work by the way!

Take a weeks leave!
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Old 18th May 2005, 19:13
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Congrats Rotor 1 on the safe landing. It never fails to fascinate me to read and learn from these hot off the press tales on pprune - they demonstrate the skill and bravery of professional heli pilots around the world. Let's hope you never get to write another !!

Old 18th May 2005, 19:32
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Tail rotor problems

Well done on walking away from this one.

Flying Foxy

"I'm ready to be corrected, but isn't loss of T/R not 'too' much trouble if you can auto straight away, etc."

Lets hope you never have to find out. You only get one shot at it. The bit at the bottom, if you survive that long, will be the exciting part.

Once again well done.

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Old 18th May 2005, 22:58
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We left the engine at flight power, but once we were asured of landing we shut it back to GI and ran on, due to the speed we maintained there was only a little bit of controlable yaw during the pitch pull sequence

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Old 19th May 2005, 03:32
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how about a photo of the shaft or the landing site.
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Old 19th May 2005, 04:05
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Congratulations on the successful recovery of a bad situation! So glad it was you....and not me. Have you tried to replicate the pedal settings, airspeed and power setting....and played about a bit to see how slow you could get before it all goes blurred?

The question I have....and the answer would be most educational...how was it you arrived at the decision to take the course of action you did? Sounds like it was a pretty exciting time for a while and thus you had to make some pretty darned serious decisions quickly.....an account of what the thought process was would make for interesting reading.

I know from experience when you have caste iron failures in these things....there is not a lot of time to go read a manual. Tail rotor failures are one of those things we spend not enough time talking about or practicing....and those failures require some pretty sharp thinking to get the aircraft down in a re-usable condition.

Well done!
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Old 22nd May 2005, 03:40
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a few pictures of the offending shaft ,

on request from r1,

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Old 22nd May 2005, 05:02
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Thanks imabell for puting the photos up for me.

Is this similar to any other MD500 failures that any one has seen.

Any more information would again be apreciated.

Our thought process was when it happend we did not start yawing so we just kept our speed as is. not very technical, but it worked for us. Slowing down was not a good option to us.

Cheers rotor1
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Old 24th Jul 2005, 09:13
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H500 Ques???

Does any one know if Howard Hughes himself had anything to do with H500 series or had he gone completely mad by that time?
Thanks in advance
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Old 24th Jul 2005, 09:40
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he must have known he was going mad to have had anything to do with helicopters
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Old 24th Jul 2005, 14:57
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Well he owned the Company. He was very aggressive in getting contracts for his Aircraft and electronics. He had a hand in a lot of things. One of the interesting ones is Direct TV. That comes out of Huges Aircraft Sat division. Most of his companies are still around in one form or another. The 500 started out as the Light Scout Helicotper the Army was looking for , Bell came up with what will become the Bell 206, Hiller the FH-1100. The Army ended up with what became the 206 and the 500. Like a lot of things there were a lot of politics going on. LBJ had a huge stake in Bell helicopter at the time. The Army liked the OH-6, they still have them and are buying more of them. Bell improved the 206 and the latest vision is the OH-58D. Howard Huges was a very great man who saw the future better than anyone of his generation. A lot of things we take for granted today is because of some of the far reaching inovations he was able to put to pratical use. You can get 140 channels on Direct TV or around 29 dollars a month, and for a little more you can get 500 channels. Also Internet and phone and a bunch of other things. The casino's in Vegas are gone, along with Huges Air West and TWA. Air West morphed into South West Airlines. Its to bad that the Helicopter division is having troubles, but then again, so is bell and well Hiller is about gone.
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Old 24th Jul 2005, 16:15
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Thirty-six hundred helicopters. 3,600. That's how many LOH helicopters the U.S. Army said it was going to buy. That's an incredible procurement that would make any manufacturer's mouth water. Nowadays, such a high number is just unthinkable.

The story of Howard Hughes' involvement with the little egg that used to bear his name is a fascinating one. Yes, he did have direct involvement with its development, something he probably came to regret. However, one cannot fault his determination.

Because of certain, um, "circumstances," Howard was banned from any involvement at all with the Hughes Aircraft Company. Instead, he turned his attention to the Hughes Tool Company as a way of returning to aviation through the back door. Through the mid-1950s HTC had been doing market research and figured there was a place for a small, two-seat trainer helicopter. In 1955 design work began on what would become the model 269.

Somewhere in our archives we have the actual earliest files relating to the U.S. Army's LOH competition that was announced in 1960. But it's fair to say that knowledge of the competition existed well prior to that- surely back into the late 1950s.

The LOH purchase was going to be big: 3600 aircraft. You can bet that competition for the contract was going to be fierce. Bell figured they could win it with their OH-4. After all, they were already pumping out UH-1's, so gearing up and adding the OH-4 would've been no sweat. Hiller figured they could win it with the OH-5. After all, the U.S. Army had been using Hiller helicopters since forever, and there was a well-established working relationship with the power-that-be.

But Howard Hughes wanted that contract and he wanted it badly. Whether he had any direct involvement in the design of the LOH is doubtful. But it wasn't that "his" OH-6/369 design was any better. (That point is arguable in any event. The Bell and Hiller designs met the contract specs while the OH-6 needed over thirty waivers to be considered.) Howard looked at the contract as vindication. He would finally be considered a successful provider of military aircraft, a long-time goal of his. Perfectly understandable, if you ask me.

What is now also perfectly understandable in retrospect is the lengths to which Howard went to win the contract. Let's not be naive: he pulled out all the stops, using whatever means were necessary. We know fairly reliably that Howard was able to get Hiller's costs (and probably Bell's too) for production. He simply undercut them, whether it meant making a profit or not. He offered the OH-6 airframe to the military (who would supply the engine, remember) at a ridiculous, shockingly low price. The military took the offer and ordered 714 OH-6's (88 in 1965, 168 in 1966 and 458 in 1967). But Howard couldn't produce them fast enough. By January 1967 only 21 OH-6's had been delivered and the poop really hit the fan.

HTC was operating at a loss, and we know that Howard was not happy at all about it. Neither was the Army. The Director of Army Aviation wanted Rea Hopper, Vice President and General manager of the Aviation Division of HTC "removed for incompetence." The beleaguered Hopper had to go a couple of times to Howard for more money, and to get money-losing budgets approved- budgets that his own Board of Directors had rejected. We know that Howard supplied it, begrudgingly, out of his own personal funds. But he wanted that contract. Rumor has it that he spent roughly $90 million of his own money to get it.

It's not that simple, of course. It never is. There is much more to it, and it makes a wonderful story. In the end, the Army got the OH-6 (a terrific LOH by any measure) and the OH-58 (in some people's opinions an LTE accident looking for a place to happen when used in the LOH role). Ironically enough, both Bell and MD Helicopters found themselves competing again for the U.S. Army "Little Bird" competition. Ah, how history repeats!
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Old 24th Jul 2005, 21:54
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Good thread

Interesting read, Project Pilot FH1100. I like learing about heli history...

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Old 10th Nov 2005, 18:10
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Rip Md500/530 ?

I read in one of the FBO rags that MDHI is planning to end production of the MD500E & MD530F, with only the NOTAR-equipped MD520N & MD600N being retained.

End of an era if true. Sorry to see the MD530F go.

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