Tail Rotor Failure... Have you had one?

[Soave_Pilot]

This is an interesting topic that hasn't been brought up yet, me think.
Books and aircraft manuals tell us do this, do that.. bla bla bla. Let's share some lived experiences so we all can learn from it!!:ok:

[puntosaurus]

Philip Amadeus qualifies as a bit of a specialist in this field. He wrote an article (http://www.helicopterlife.com/2008_02/two%20scary.html) in Helicopter Life a couple of years ago that makes good reading.

Enjoy !

[griffothefog]

Had a tail rotor failure crop spraying in Saudi Arabia back in the 80's in a Bell 47...... Just came out of a torque turn facing vertically down when ...Bang :eek:
Farmer witness saw something fly off the back end and spin off across the wheat crop...
Meanwhile back in the bubble, I rolled off the throttle, flared hard and "arrived" in the thick crop. The whole of the rear end from the fuel tanks aft was chopped off in the flair, but the skids were undamaged and thankfully so was I :ok:
Could I have done anything else/better?
No idea, you just react instinctively and hope for the best :{
Not a very nice thing to happen to a young pilot.... completely ruined my ZZ TOP track I was wired into.... ;)

[spinwing]

Mmmm ...

Griffo ..... funny you should mention Saudi .... you'll never guess where I am now ?




Though I'm sure you will !!! :ugh:

[Soave_Pilot]

Hey Punto,

Looks like you have to pay to see that article mate... Do you happen to have it handy?

[griffothefog]

Spinwing,
What did I tell you?
Coconuts et al....
Enjoy......:ok:

[vital actions]

One of a helicopter pilot’s biggest worries is losing a tail rotor. It’s happened to me twice and I wasn’t injured either time. So with a bit of luck and skill, it can be coped with.

Twin Squirrel
The first occasion was back in August 1997. I was sitting in the left hand seat of a Twin Squirrel, while a very good friend of mine, Paul Moran, was flying. I actually asked him that day, “Paul, I sometimes get asked if I’ve ever had an accident and I say no. You’ve had a mid-air collision, what do you say?” He replied “I always say I’m the safest pilot to fly with, as the chances of another mid air are millions to one.”
Hours later, at 2000 feet near Leeds, a Katana light aircraft chopped off our tail, vertical fin and tail rotor complete.
The spin was quite exciting! So sudden that my port sliding door detached, never to be found. The wind took my maps, sunglasses, even my headset. My first instinct was to grab the controls, but I could feel Paul flying so I let go again. He had lowered the lever so I grabbed the throttles, looked at him, then pulled them both back all the way.
We were in a pretty steep nose down attitude, but at least it was all corn fields below. I didn’t know if he had cyclic control. I just locked my seat harness and waited. When Paul started a flare, I knew that unless the blades came into the cabin, or we caught fire, we should have a good chance.
With no fin or rotor we were yawed 60 degrees to the right. Paul flared back and to the side. I knew we would roll, so I grabbed the door handle and covered my head. With collective to cushion we touched down softly, but immediately rolled onto our left, then spun 180 degrees as the blades thrashed themselves to destruction.
I was later told radar tracked us as 30 seconds from impact to ground.
I had mentally determined to exit my door, but now next to me was a wall of flattened corn. Paul was above and I thought, ‘If I don’t move quick, he’s going to fall on me!’ I unclipped, got into the rear, climbed the seat backs and threw his pilot’s door up and open, climbing out onto the side.
Paul unclipped in turn and the only injury between us was bruising to his leg as he fell down. I gave him a hand up, then we both jumped down and ran away laughing and exhilarated.
When all we could hear was the ticking of the cooling metal, I climbed back in and threw out our Nav Bags and kit. I phoned the emergency services whilst kneeling on my map to stop it blowing away. Local farm hands ran up so I asked them the address so we could be pinpointed. A newspaper later reported that ‘the pilot was in shock, down on all fours, unaware of where he was…’
An RAF Sea King took us to hospital for checks, but the Katana pilot declined to fly again that day. He had landed in a field nearby, with broken propeller, smashed canopy and a cut to his hand. I never met him, but he was an ex WWII pilot, so I really have been brought down by the Luftwaffe!

Agusta 109
Forward now nine years to October 2006. I’m off in one of our six Agusta 109’s, on a short five minute flight from Redhill Aerodrome to Biggin Hill Airfield. This was to take two regular clients from their private jet to London heliport.
Just after levelling of at 1400 feet, I heard a bang and despite full left pedal, the aircraft rolled into a right hand turn.
I put out a Mayday call and varied the collective power to see if I could affect the yaw, which would indicate a jammed rotor, but no luck. I knew I had lost any tail rotor effectiveness and would have to make an engine off landing. At least I was flying and maintaining height.
Redhill Aerodrome came round into view, but as it’s a grass field, I decided to continue the right turn and make my landing on one of the hard runways at Biggin. This was to help with an expected fast run-on and to reduce the chance of wheels sinking in and a rollover.
Cross-controlling with the cyclic to the left I managed to fly a mile or so toward Biggin Hill toward my planned descent, but suddenly, with a horrible wrench, the machine pitched up and spun.
I thought the aircraft was coming apart. I instantly lowered the collective, pulled both throttles back to their idle stops and selected gear down, in three quick, instinctive motions. I made another Mayday.
A witness on the ground reported seeing the machine spin ‘as if the blades had stopped and the body had turned’. Biggin Hill is at 600 feet above sea level, so the ground below me was only 900 feet or less away, steeply sloping in places and covered in small irregular woods.
I came out of the spin pointing to a paddock. I knew I was downwind, but this was going to be the place anyway. My eyes went from field to rotor RPM and back to field. I had no time to check ‘Three Greens’; the wheels were either down or they weren’t. I had no time to shut off the engines. I knew speed was important to keep straight, but I didn’t look at the air speed indicator. I just kept the nose down with the ground passing under me, as I flew toward the field.
I didn’t flare much, as I wanted speed to keep straight. I raised the nose enough to get the main gear onto the ground first, using the collective as little as possible. As we rolled across the lumpy grass at about 60 knots I lowered the collective slowly to avoid yawing and a rollover. We slewed to the right and came to a halt.
I shut down the engines, tried unsuccessfully to radio any station, then got out. First I saw a missing tail rotor and gearbox, then a shredded lower fin. After telephoning Police and Air Traffic I noticed the port engine exhaust pipe was missing. I lifted the engine cover and a fractured clamp dropped to the deck. This had allowed the exhaust pipe to detach, which hit a main rotor, before smashing the tail rotor, causing the tail-rotor and gearbox to depart.
The next thing I noticed was the upper vertical fin was leant over at about 30 degrees. I could wave it from side to side. The second event, when the helicopter spun, is thought to have been caused by failure to the stiffness of the upper fin, the structure being much weakened when the gearbox ripped out.
I walked away for a second time without a scratch. I hope I won’t need such luck and skill again.

Conclusion
The exhaust clamp was unlifed with no call for inspection. It is now required to be inspected each year.
A Fenestron or Notar would have helped prevent the second accident, but not the first.
Flying to a clear area for an engine off using the fin is a good idea, so long as the fin holds up.
Getting the lever down quick is paramount, not something all twin helicopter pilots practice much.
Forward G of G with loss of weight at the back seemed within cyclic control range.
Speed is key to keeping straight.
Twin pilots don’t practice engine-off, run on landings. I guess (depending on flight experience) you retain enough skill from flying single engine helicopters in the past.
Philip Amadeus is Chief Pilot and owner of RotorMotion.


This article Copyright Helicopter Life 2008

[Soave_Pilot]

As we rolled across the lumpy grass at about 60 knots I lowered the collective slowly to avoid yawing and a rollover. We slewed to the right and came to a halt.


That was a smart move! didnt make the a/c rollover.

[sycamore]

I had a t/r failure in a Whirlwind 45 yrs ago this month. If you look at p15/16 of `Rotorheads around the world` there are pics of the a/c after landing on top of a `pimple` in Borneo,also the aircraft recovery by Belvedere,plus a couple of other engine failures. The failure was due to a fatigue crack in the blade spindle(tie-bar),one blade coming off,followed by the other plus gearbox etc.
Anyway,when we mention t/r failures,how many different types of failure are there,and what can we do about it if `s*& t happens ?
1.Control lost over the t/r, ie no response to pedal input,but a/c yaws if power changed; it could be, broken pedal(S),cables,rods,disconnection. It may be a hydraulic failure(ie jammed piston possibly),if you have a hyd.pwrd t/r,or if cables,you may consider, again ,depending on the aircraft,is it possible to find the cable/rod control run and use the`loose ends `to effect control. Obviously in this situation one may be flying a larger helo with at least a co-pilot who can assist;in Whirlwinds/Wessex/Sea-king,possibly others, it`s possible to `pull the cables `in the cabin roof/tail-boom.(Good ploy to sharpen up the front end was to `twang the cables if forced to fly in `cattle-class!!). I should mention that a loose /disconnected cable/rod, may well be a separate danger if it should foul/wrap itself around a drive shaft.

2 Drive failure. ie driveshaft breaks,and t/r stops.It may be that some effectiveness can be obtained by using the pedals and hoping that there is some `rudder effect`,but probably unlikely,but it may depend on power/speed combination.
3 T/R blade damage; if it`s suspected that a blade is damaged,ie birdstrike,clipped a branch,get on the ground ASAP; if you can`t,prepare for the worst,but consider if you can fly at a reduced RRPM power on/off,as T/RRPM are about 6-10 times main RRPM,as it will reduce stresses.
4. T/R/Gearbox fail then departs. The C of G will immediately change to somewhere out in front of the nose,plus the yaw,depending on whether it`s taken the fin with it. If it`s possible at all,get any pax as far aft as possible whilst trying to get a measure of control. This one will really spoil your day, and give you sleepless nights if you survive. Even on a light helo ,you can work out the C of G change- ask the engineers for a gearbox+t/r weight,then work out the moment,then the new CoG......
5 Fenestrons. Personally,I would say that they provide the best protection and offer the least problems with any failure mode.

Okay,I`ve simplified it a lot and `it Depends` on the type of helo/large small/fin area/speed at time/Cof G/ etc as a broad-brush run-through of failures,and possible problems.I can`t give any definitive `this is what you should do/should`ve done`, because there are so many variables ie,was it hovering,in the climb /cruise/descent,and armchair advice,especially after a couple of Riojas,is usually fraught with being `shot-down` anyway.
It may be possible to continue flying to reach a safe run-on/eol at the end,but I would say, if you fly a larger helo/multi-crew,use them to assist/advise/pray; if it`s smaller,think about how you load the a/c if carrying pax,ie towards aft Cof G, etc,etc..

Funnily, when Igot back after my `episode` someone on the Sqdn. gave me a USAF Flight Safety magazine( before Air Clues) that he had been reading in the crew-room entitled` How to deal with a Tail-Rotor failure `.......!
I commend you all to think deeply about the possible failures you could have in the a/c you fly,and how you would deal with it,read the article by P Amadeus,the recent H-K one,and anyone elses experience'
Fly safe guys,and always `expect the unexpected`....Sycamore..

ps,,I should add,please shoot this down/discuss/ etc at will,as it`s not meant to be definitive`how-to`...

[SHortshaft]

Had a couple myself!

First was in a Bell 205. The main gearbox started to break up and the drive output to the tail rotor drive shaft failed. Force landed with power on in a dry river valley.

Second was in an AS 350B. I only had 12 hours experience on it when the last meter or so of the back end came off.

The thing that I remember the most during both incidents was the level of vibration which I would describe as ‘significant’.

In the 205 I was able to roll off the throttle as I came into the hover and land without too much trauma.

On the Squirrel it was a lot more frightening. I had to shut the engine down to stop the rotation. I knew I had lost the tail as I could see it falling like a Sycamore leaf every time we rotated past a northerly heading. Also saw my life flash before my eyes and even had a chance to regret not seeing my unborn child.

I was in rugged terrain and ended up parked nose up on about a 60 degree slope. The blades hit the hill side and stopped suddenly. My stumpy tail boom dropped with a thump and dug into the hill side and helped stop me tumbling. A giant crack started at the nose of the cabin and ran slowly back across the roof of the cabin; so much for the strength of fibre glass.

[Gordy]

Had a T/R failure in a B2 Astar on a tour with six passengers on board. I first realized the problem coming out of an out of ground effect hover. To this day I still get confused as to whether you call it stuck left or right---basically I had about an inch and a half of left forward pedal, and was not able to push right pedal. I had the non power pedal forward. Ultimately we found the flexible ball control cable had frayed inside the plastic sheath.

So as I pushed left pedal, the cable would slide freely inside the sheath, when I pushed right --- the frayed cable dug into the sheath and would not slide. Biggest thing to remember—FLY THE AIRCRAFT. I elected to fly back to the nearest airport with crash rescue facilities----not pessimistic, just stacking the odds in my favor, plus it gave me 30 minutes of transit time to figure it out in my head.

Unfortunately for me---I used to switch between a 206 and an Astar frequently---the previous flight less than an hour prior to this was in the Bell---hence I do not like to say stuck left/right but try to think of it as power and non power pedal. Also, the company I worked for did NOT provide factory training, I had never done this procedure in the aircraft---read about it once--- and in fact my annual Astar training consisted of 30 minutes flying with the owner, who flew on average about 30 hours a year. (Welcome to Hawaii !---although to be fair---there are some decent operators out there). I told my passengers everything, (was later chastised by the owner---should have kept my mouth shut---I no longer fly in Hawaii ! !), I felt they were entitled to know what was going on.


For better or worse, I elected to attempt a shallow approach to a run on landing. I had enough fuel for about an hour, so I was in no rush. The wind sock was spinning on the pole, so therefore no wind. I picked the longest runway---as the speed approached about 20 kts, the aircraft started slowly spinning left, and I did a go around without pulling power till I got some more airspeed and chose a different runway. This attempt, same thing, another go around---did not pull power till I got some speed. I was starting to think that if this next attempt did not work---I would cut the engine and do an auto.

This time the aircraft started spinning faster, my gut reaction was to go around, but I started pulling power----WRONG, this increased the spin violently, instinct, gut reaction, luck and the voice in my head said CUT POWER----which I half did.

I got the FFCL out of the flight gate and about half way back to idle, the earth had stop spinning and I was about 10 feet up, drifting slowly forward and descending slowly, with 3 fire trucks about 100 feet in front of me. I let the aircraft settle to the ground, shut it down, and realized that adrenalin is really brown!!!!!!! I personally was not happy the way it turned out---I felt I should have nailed it on the first attempt, I should NOT have let the aircraft spin, but I am somewhat of a perfectionist, and I need to live with that. That being said, No damage to the aircraft, one passenger had passed out and was given medical attention on scene, the rest were all fine, I spilled my coffee on the runway and had to beg a soda from one of the firefighters!!!!
What did I learn?

1. FLY THE AIRCRAFT.
2. As stated above do not refer to this as stuck left/right, it gets too confusing when switching aircraft types.
3. Take your time; make as many approaches as needed.
4. No matter what anyone says—there is no text book way to do it.
5. I did not do the “text book” procedure—but it worked.
6. If you all walk away from it---you did good, learn and move on.

One more side note; The company did not initially refund the passengers their money until a few months later one of them asked for a copy of the NTSB report we filed as it came under NTSB 830.5 (a) (1) ----guess what---company did not file one, make sure one gets filed---you could be liable if not.

[topendtorque]

Tail Rotor Failure... Have you had one?


Yep, a 3B1, and I do believe that it's been the topic of a thread before.
Exciting? yes. cause for panic? no, as long as bits haven't departed the good ol C of G.

Pulling up out of the trees after chasing mooies, felt and heard a bang, everything starts moving rapidly sideways. trees are close, but by now I'm about 15 feet above 40 foot trees.

Can i go or do I stay? I says to myself as the scenary is blurring, I say damnit you'se staying and you'se gotta do it right now, with the feed stick ol' son.

There was a small space not far away below, lever is right down, wait, wait, jerk the lot. just bent the cross tubes a bit.

Rule # 1 Things don't stop spinning when you chop the throttle, only slow down a bit.

Still spinning quite some when we touched down, and steered it successfully around the flat for a while. Jumped out, the blessed forward short shaft had jumped out of its rear spline and was still bobbing around on the grease boot fabric, too short or something.

I was doing a double, the pilot with me was only a very short distance away and watched it all, he remarked later that he had said to himself in very droll terms, he was an extremely funny dry type of bloke,"Boy is he gunna crash!"

Worst part was about midnight that night back at base which was about half an hour away in the F/W the phone starts ringing. Some busy body dude in Canberra has been talking to some dude in FSU who has been talking to some dude in a F27 doing a night freight run.

This was way, way before satellite ELT tracking, and what would we know about a signal going off right about where my helicopter is. Wellll arrrrr, yessir the damm orange little box turnout musta gone off.

It had been flung out and we hadn't seen it when walking around at the time and sure it was doing it's little thing until we went back next morning.

[FH1100 Pilot]

My two were offshore in the GOM, both in a 206. Nuts and bolts come undone under driveshaft covers that don't get removed on preflight. First was just after landing, thank the good Lord. (It was December and the wind was blowing 30 knots.)

Second was just after lifting off to a hover in a 206B. Sitting there, getting ready to go, I hear a BANG! and the world starts spinning sideways. I don't remember consciously thinking, "Tail rotor failure," but you know what it is, believe me. What surprised me was the rate of spin and how quickly it went from nice-stable-hover to spinning uncontrollably. I was thrown toward the center, hanging on for dear life while I collected what few wits I had (half the normal human allotment). With each spin it was translating a little downwind. Mind you, I was on an offshore oil platform with not a lot of room to drift downwind before being out over 100' of nothingness.

I rolled the throttle off, and like TET was dismayed to see the dang thing keep spinning. So instead of holding it off further I put the pitch down a little. The skids touched, we yawed about another 90 degrees, then came to a stop with the toes of the skids over the edge of the deck and me looking down at the water through the chin bubble.

Later, back at HQ for Recurrent, an instructor brought my "event" up during ground school. I did my best, "there I was" and complained about how it did not stop spinning when I rolled it to idle. And he goes, "Idle? Why didn't you go all the way to cut-off?" He did not add the word, "dumbass" but he could have.

And I slapped my forehead and went, "DOH!"

Ah well, sometimes we're Yeager, sometimes we're Homer. Next time, next time.

It sure does spin fast when you lose t/r drive in a hover though! What we simulate in training doesn't come close to the violence of the snap-yaw.

[Soave_Pilot]

2. As stated above do not refer to this as stuck left/right, it gets too confusing when switching aircraft types.


Good way of putting it out... especially when you get out of Robbos and jump on a A-star, etc...

[FH1100 Pilot]

Nice job! Looks like you were one of the reasons they extended that shaft.

Tenneco platform?

[Vertical Freedom]

Looking for some training words for Tail Rotor problems please:
1. Failed TR
2. jammed Left
3. jammed Right

Thank you :ok:

[Gordy]

Posted this before---try doing a search.....here is mine...read and learn....

B2 Astar on a tour with six passengers on board. I first realized the problem coming out of an out of ground effect hover. To this day I still get confused as to whether you call it stuck left or right---basically I had about an inch and a half of left forward pedal, and was not able to push right pedal. I had the non power pedal forward.

Ultimately we found the flexible ball control cable had frayed inside the plastic sheath. So as I pushed left pedal, the cable would slide freely inside the sheath, when I pushed right --- the frayed cable dug into the sheath and would not slide. Biggest thing to remember—FLY THE AIRCRAFT.

I elected to fly back to the nearest airport with crash rescue facilities----not pessimistic, just stacking the odds in my favor, plus it gave me 30 minutes of transit time to figure it out in my head. Unfortunately for me---I used to switch between a 206 and an Astar frequently---the previous flight less than an hour prior to this was in the Bell---hence I do not like to say stuck left/right but try to think of it as power and non power pedal. Also, the company I worked for did NOT provide factory training,

I had never done this procedure in the aircraft---read about it once--- and in fact my annual Astar training consisted of 30 minutes flying with the owner, who flew on average about 30 hours a year. (Welcome to Hawaii !---although to be fair---there are some decent operators out there). I told my passengers everything, (was later chastised by the owner---should have kept my mouth shut---I no longer fly in Hawaii ! !), I felt they were entitled to know what was going on.

For better or worse, I elected to attempt a shallow approach to a run on landing. I had enough fuel for about an hour, so I was in no rush. The wind sock was spinning on the pole, so therefore no wind. I picked the longest runway---as the speed approached about 20 kts, the aircraft started slowly spinning left, and I did a go around without pulling power till I got some more airspeed and chose a different runway.

This attempt, same thing, another go around---did not pull power till I got some speed. I was starting to think that if this next attempt did not work---I would cut the engine and do an auto. This time the aircraft started spinning faster, my gut reaction was to go around, but I started pulling power----WRONG, this increased the spin violently, instinct, gut reaction, luck and the voice in my head said CUT POWER----which I half did. I got the FFCL out of the flight gate and about half way back to idle, the earth had stop spinning and I was about 10 feet up, drifting slowly forward and descending slowly, with 3 fire trucks about 100 feet in front of me. I let the aircraft settle to the ground, shut it down, and realized that adrenalin is really brown!!!!!!!

I personally was not happy the way it turned out---I felt I should have nailed it on the first attempt, I should NOT have let the aircraft spin, but I am somewhat of a perfectionist, and I need to live with that. That being said, No damage to the aircraft, one passenger had passed out and was given medical attention on scene, the rest were all fine, I spilled my coffee on the runway and had to beg a soda from one of the firefighters!!!!

What did I learn?

1. FLY THE AIRCRAFT.
2. As stated above do not refer to this as stuck left/right, it gets too confusing when switching aircraft types.
3. Take your time; make as many approaches as needed.
4. No matter what anyone says—there is no text book way to do it.
5. I did not do the “text book” procedure—but it worked.
6. If you all walk away from it---you did good, learn and move on.

One more side note; The company did not initially refund the passengers their money until a few months later one of them asked for a copy of the NTSB report we filed as it came under NTSB 830.5 (a) (1) ----guess what---company did not file one, make sure one gets filed---you could be liable if not.

[perfrej]

In Swedish proficiency checks, failed tail rotor control is always on the list of things to practice (even for PPL(H)).

Like Gordy says: fly the aircraft - you are not in a hurry. Assuming stuck controls in neutral:

1)
Make a shallow approach at fairly good speed, and don't let the speed go down. Having the wind just a little to the right (in an EC120, or left in a B206) is preferred

2) Bleed off speed at very low altitude without applying too much power. Your nose will be pointing right (again, values for clockwise, like EC120) and you should be skid low rear right

3) Slightly flare to bleed off more speed, use collective only to avoid hitting the ground.

4) As the speed goes to close to zero and you apply just a tad more collective to stay aloft, the spin comes to the left. Cut power immediately and make sure that you do not drift left and that the aircraft is level

5) The spin stops and you do a normal hovering auto (wrong word, I know). Just make sure you catch the drift to the left with cyclic!

About the wind direction... If you, in a clockwise heli, have the wind in just a bit to your right, said wind will actually help arrest the spin as the tail swings into it! The effect of that little detail can be amazing!

My type rating instructor for the 206 showed me what happens when you just come in and hover with stuck neutral. The spin isn't that bad and if you don't have too much wind you can actually stay hovering and spinning for quite some time. The 206 B-II does about 1 revolution per second in this condition, and when you cut power the spin stops perfectly just before the skids touch the ground.

I cannot believe that these procedures are not trained everywhere. Even though it is a rare event (I think), the procedure and the coordination skills to do it well are worth training!

[FH1100 Pilot]

I cannot believe that these procedures are not trained everywhere.

Oh you can't, eh? During 206 recurrent training a couple of years ago, this particular IP spent nearly the entire time doing stuck pedals. It was fatiguing and more than slightly risky to our company aircraft. I've been flying 206's for a long, long time, and it caused me to wonder:

Has anybody EVER heard of an actual case of stuck-pedal in a 206?

[DennisK]

I suppose I must be a magnet for T/R happenings. No 1 ... as a 100 hour pilot in 1973, I experienced a T/R shaft break between hanger bearings number three & four at circa 100 feet on lift-off from Shoreham when the two loose ends hammered into the top tailcone of a 280, non turbo version. Having no idea what to do, I simply dumped the lever in panic and as the heli was about to hit the ground I raised the collective. Accidentally I had at least unknowingly used the basics of a proper response. The aircraft stayed upright.

Number two was again at Shoreham in an air test hover of a 28A when I remarked to the engineer, one Tony Ticehurst that the MAP was at continuous maximum, quickly followed by a loud bang as with the extra power going through ... the transmission seized. A kindly engineer had actually re-fitted the T/R blades trailing edge first! (Yes you can do it and being a clever newby .. I didn't spot it) We touched down safely in a LEFT turn!!! As I later considered the sequence, there was no way the airframe could have rotated left, so I quietly went down to the apron to inspect the skid marks which showed an arc in the tarmac to the left. It took some time before I realised that in my state of arousal, (no puns please) I had slammed the throttle closed the instant the failure occurred effectively producing an engine failure before the blades had slowed.

Number three was at the WHC event at Cranfield in 1986 when pulling a full power torque turn the left hand blade of a 280C intercepted the control cable which allowed the loose end to wrap itself around the transmission whereupon I experienced a second T/R transmission seize. Having significantly thought through the failure now I managed to keep the speed at 75 knots and power below 18 MAP and complete a run-on landing circa 65 knots. The skid marks were around 200 yards.

Number four failure was during a display sequence for Noel Edmonds 'Crinkley Bottom' event when the above failure was repeated. I produced a second speed run-on landing on the local cricket pitch. Now I was worried.

The Enstrom factory got interested as they had experienced a similar failure on a crop spraying task in USA. On the Enstrom system the problem is caused by the rubber bush flapping stops become oiled and soft and this combined with a slack T/R control cable was allowing the blades to flap excessively and slice through the cable at the output position. (The engineer sent my 10 year old son down the tailcone to install a new cable.)

That was in 1991. Now armed with the info and with the factory repositioning the output hole more inb oard and further from the blades, (known now as the Kenyon hole!) Subsequently and before carrying out a display sequence, I ensured that new T/R stops were fitted where required AND the control cable turnbuckles were tightened to the max MM figure.

Now forward to 1999 when the UK distributor asked me to display their latest 280 FX at the Biggin Hill event. A daft case of mis-communication if there ever was one as I shouted across the hangar floor to the duty Saturday morning engineer ... "have you done the tail rotor?" "Yes," came the reply. Sadly for me he only meant he had checked the cables as per the standard MM figures and during my display I promptly lost the tail rotor for a fifth occasion. By now I had a good idea how to cope with the problem and after three dummy passes I again managed to put the helicopter down on the right skid with a right cross wind at high speed luckily remaining upright in the landing roll. God bless the CAA but I did get that year's 'Flying Safety Award' for my effort. Apparently a spectator was later asked what he thought of my display ... "Very good at first" ... "but it got a bit boring at the end as the pilot went round and round the circuit!"

Safe flying to all out there.

Dennis K

I have written up my full recommended sequence of control handling for such an event. For interested parties, just E-mail LOOP (LOOP.aero (http://www.loop.aero)) and they will post you a back copy for a couple of Bob.

u

[perfrej]

FH1100,

I agree totally that it is a fairly high risk procedure, and I also agree that it is very unlikely to happen. I am, however, still in favor of training it as much as possible due to the fact that you learn so much about how to cope with difficult situations and, most importantly, you get a lot of coordination training and learn your aircraft's behavior.

Another good thing to spend a lot of time doing is quickstops. Same there, coordination.

[helispeediii]

had tail rotor failure in 109a in 99 making a slowfinal approach to private site approx 60ftAGL? approx 100 yards to the spot, three greens showing, had landed there hundreds of times in different types, heard?feltbang/shudder i thought a large bird/goose?? had hit us saw nothing untoward up front did i look at the t&ps, dont know< it was inpractical to try to transition away? the aicraft started rotating at a pretty fast pace i try lowering the collective did not seem to slow down so i lower the collectrive as we were spinning round tried to cushion on landing/impact, it did not do the undercarriage much good,but i shut the fuel off shut down the engines whilst checking my pax ok he was i dont remember waiting for the shut downtime on those dear allisonsc20b, put the rotor brake on asap did not wait till it slowed?it smoked a bit did not think at the time thought the air craft was on fire time to get going but without mrb hair cut 109 on its belly front blades pretty low? my door was jammed shut told front pax to depart, eg get the f k out of here! and i followed him out, when i was out i could see it was the rotor brake smoking relielf, the aircraft was a write off, on external inspection i could see tail rotor gear box had departed taking with it most of the lower fin and a fair chunk of the upper fin,! 50/75 ft away we found tailrotor g/box with one blade attached and the root of the other blade ,this was well bedded in the ground eg high powered inpact? the part broken blade was found in a ploughed field,200ft away , aaib,/ informed,/agusta sent over two engineers from italy ,within 24 hrs to inspect,the conclusion discovered later, was metal fatigue ,even though they had a die pentrant test a month earlier,the blades were 75%of 2400to scrap life? agusta told me this had only happened once before and that was the trump machine in the usa which was a fatal ! i think they increased the inspection/xrays on the trb on early 109?, as they say if you walk away its a good one,? i was back flying 109s within aweek, and have done many hundred of hours since, needed a ciropracter to sort out my back !and my brotherinlaw is not keen on flying any more he was the pax! i had a good mate who is an instuctor,who was very helpful at the time . helispeed iii

[chopjock]

Just had one today, bugger. :eek:
I was cruising a 280C at 800ft when I heard a grumbling noise getting louder and louder. I lowered the lever, carried out an auto rotation to the ground and shut down immediately because of the noise. The gears inside the trgb appear to be disintegrated and the casing was jolly hot. No damage to the aircraft and I walked away. The gearbox only had a hundred hours on it!

[Colibri49]

1988 at Aberdeen doing what was then called an "instrument base check" in an S61N and performing an ILS to runway 16. The wind was appr. 40 kts from the west causing violent turbulence particularly below 500' agl, so the training captain told ATC before commencing down the slope that he would assess how bad it was and make a late call either for a go around, or to land and taxi back to base if it was too rough.

I struggled to keep in limits and he elected to call it a day. We taxied back and shut down, followed by me going back to the briefing room while he went to the line office to sign the tech. log.

About 10 minutes later he came running wide-eyed up the stairs and told me to come to the aircraft with him. There were several engineers standing looking at the aircraft's tail which was covered in oil and one engineer was just removing the cover from the intermediate gearbox, which was still smoking.

The normally silver-coloured gearbox was blue around the top bearing area, with brown marks presumably from overheated oil. On removal and inspection 'handfuls' of metal were extracted from the gearbox, having flaked off disintegrating gear teeth. Apparently the gearbox top oil seal hadn't been installed correctly in the factory and it came out, allowing oil pumped to the top bearing to flow through it and escape.

The finding was that the gearbox was a couple of minutes from seizing, which would have happened during the climb if we had gone around from that ILS. Thank goodness that I wasn't able to fly more accurately during the turbulence. For once a poor performance was a good thing !

(In the early 1970s I was a passenger in a helicopter which suffered tail rotor control failure in the hover and crashed on its side due to the pilot's reluctance to lower the collective. But that's a different story.)

[FSXPilot]

How many years did it take to put the 100 hours on the TRGB? Just curious. Also did the chip light come on?

[chopjock]

How many years did it take to put the 100 hours on the TRGB? Just curious. Also did the chip light come on?

About 4 years and the 280C does not have a chip light.

[FSXPilot]

That is damn odd. Never seen a TRGB fail that early on an Enstrom. I would definitely be talking to them about a price reduction for the O/H or if it is totally trashed a price reduction on a new box.
What I have seen is the input seal fail early on a new box but presumably this was not the case in your instance as you would've noticed a loss of oil and the sight glass would've been low before your flight.

[chopjock]

The sight glass was full and blue on the walk around. Still had oil in the glass on shut down too!

[500e]

Saw you lifting off sounded sweet stick with the 500:E.
Good decision though to put it down immediately what with your tail & our MGB not a good year

[FairWeatherFlyer]

Later, back at HQ for Recurrent, an instructor brought my "event" up during ground school. I did my best, "there I was" and complained about how it did not stop spinning when I rolled it to idle. And he goes, "Idle? Why didn't you go all the way to cut-off?" He did not add the word, "dumbass" but he could have.

How many people practise going from idle to zilch (in a 206) with left hand only without diverting attention downwards to idle stop button? You get a chance to do that at shutdown but i doubt many people use the opportunity.

[Soave_Pilot]

True... Idle won´t stop the spinning.

[Hans K.]

In the 80s I dipped the tail of G5 bell 47 in the pacific , back to a hover I noticed I was spinning flat ( no roll from T/R thrust ) . I Figured I would just put it down in the sea than fly it away .On floats with a long swell of 2 ft seas light wind .

I rolled off the throttle and did a hovering auto from 8 -10 feet .My goal was to use all the rpm and slow the rotor before it hit the tail or sea .
The landing was firm and flat ,no blade strike . I pulled pitch and the rotor brake , happy to see I was upright .

Then I saw a tube had cracked and cut the float ,I was going to roll over in a minute . The blade went into the water like a slow butter knife as the ship rolled over . I was doing my log rolling dance with the ship inverted in the deep blue sea .

No big deal the long tubes on the floats were thinner that spec home made gear from metal yard tubing .

10 years before a bearing let go in flight in the transmission . The T/R drive would engaged and disengage every 5 -10 minutes ( bearing cage ).
It seemed like power related failure , so I lost my nerve after the 4th cycle . I made a low power shallow run on to the Glassy sea . lifting it back on deck ( without damage ) They sent out a rebuilt tranny . I changed it in a day but getting my nerve up took two days of test flights .

[FH1100 Pilot]

FairWeatherFlyer:How many people practise going from idle to zilch (in a 206) with left hand only without diverting attention downwards to idle stop button? You get a chance to do that at shutdown but i doubt many people use the opportunity.

Heh. I can do it now!

Soave_Pilot:True... Idle won't stop the spinning.

Sadly, this knowledge came slightly too late for me. Hey, live and learn...