Tailrotor failure - is it always unrecoverable ?
Was extremely surprised at the training available from even highly respected organisations. In the sim, single pilot -76, drive failure in the hover, climb the rotating aircraft to 1,000 ft, nose over to gain airspeed, and fly to a suitable landing area. Assumed performance permitting. Having only ever seen one drive failure* in my life thought it suss teaching. Perhaps it is possible, I don't know.
* Huey stuck its tail into the ground in the flare at slow speed. That sucker whipped around so fast I found it unbelievable. Trouble was the tail took out permanently some of the troops waiting.
* Huey stuck its tail into the ground in the flare at slow speed. That sucker whipped around so fast I found it unbelievable. Trouble was the tail took out permanently some of the troops waiting.
In the sim, single pilot -76, drive failure in the hover, climb the rotating aircraft to 1,000 ft, nose over to gain airspeed, and fly to a suitable landing area. Assumed performance permitting.
Your brain would ooze out your ears while pulling pitch to get to 1000', and the "roll coupling" effect where the fuselage no longer stays level and the spin goes more vertical than horizontal would disorient even our mate Nick.
When I did the sim on the 76B at West Palm, the only thing taught for a drive failure from any altitude was throttles-idle auto. I was able to show the sim instructor a different technique (from Huey days, and applying to B206 as well) leading to a running landing - had to show it to him twice before he really believed it - but he insisted that the tried-and-true auto be performed to pass the course.
The only problem with relying 100% on techniques 'perfected' in the sim is that the aircraft modelling might not be accurate enough to 'prove' the technique in the real world.
Having said that, I have valued all the sim training I have received over the years but hope I never have to try it out for real!
Having said that, I have valued all the sim training I have received over the years but hope I never have to try it out for real!
Everyone needs to be aware that sim programmes rely on OEM algorithms to simulate TR failures et al.
Currently it has been found that one major global helicopter manufacturer has not got his ducks in a row when it comes to the "data in" on their TR programme.
It has thrown up some serious questions by test pilots on the efficacy of it all.
The ONLY way to 'manage one's expectations' when it comes to handling TRF and TRCF is to talk to seasoned vets and those who have had one.
Currently it has been found that one major global helicopter manufacturer has not got his ducks in a row when it comes to the "data in" on their TR programme.
It has thrown up some serious questions by test pilots on the efficacy of it all.
The ONLY way to 'manage one's expectations' when it comes to handling TRF and TRCF is to talk to seasoned vets and those who have had one.
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,573
Received 413 Likes
on
218 Posts
Having been part of the team that set up one of the RAF's first helicopter sim. training programmes, I was pleased to hear feedback from one of our pilots who stated that he was of the opinion his life was saved by guidance and training given to him regarding T/R malfunctions.
His aircraft suffered a tail rotor control failure over the sea (limited tail rotor power). He managed to spiral down and safely ditch the aircraft, which was later recovered. He said that without the training he would probably have chopped the engines, which would have been a big mistake; things would undoubtably have gone very badly wrong.
I also know of another pilot (of a non RAF Puma, not given our training) who suffered a tail rotor drive failure in the 140 kt cruise. He initially tried to slow down without chopping the engines but it began to go wrong so he accelerated back to 140 kts, flew back to an airfield and carried out a running landing at that speed. He apparently got away with it, too!
His aircraft suffered a tail rotor control failure over the sea (limited tail rotor power). He managed to spiral down and safely ditch the aircraft, which was later recovered. He said that without the training he would probably have chopped the engines, which would have been a big mistake; things would undoubtably have gone very badly wrong.
I also know of another pilot (of a non RAF Puma, not given our training) who suffered a tail rotor drive failure in the 140 kt cruise. He initially tried to slow down without chopping the engines but it began to go wrong so he accelerated back to 140 kts, flew back to an airfield and carried out a running landing at that speed. He apparently got away with it, too!
Having done, and seen demonstrated, many TR drive failure in S76 sim, nothing has ever come close to that technique mentioned there. The only way to carry out a successful recovery from TR drive failure in S76 sim is to follow the procedure as per the RFM. Real life might be different, but I'd be very surprised if any S76 pilot who climbed to a 1000' from a real TR fail in hover would have any sensibilities left to do anything after such a wild ride which it certainly would be. Especially in a B or C variant.
In the course of my varied professional life, I have been fortunate to debrief literally dozens of pilots who have survived various catastrophic experiences. Apart from making my decision making process more comprehensive, it has made others more aware as I cascaded this information at every opportunity.
In this particualr instance (TRF and TRCF) research, revision and calm - were the common factors with all the debriefers.
Shy - I'm struggling with a 140+Knot running landing on a narrow tricycle undercarriage I am afraid - it's just not going to happen.
And I concur with gullibell - no sane pilot would ever 'knownigly' transition out of a hover after a real TR failure because he would be completely disorientated within seconds as the G foces and dizziness and blurred vision overcame him - again this leaves a lot to be believed.
A TRF in the hover is dead easy - lower the lever. The end.
It requires little or no thinking. You simply take your chance with the impact.
[Chopping throttles and cushioning the landing is a very very nice luxury and tends to be the option available only to the lightning quick and very calm driver).
In this particualr instance (TRF and TRCF) research, revision and calm - were the common factors with all the debriefers.
Shy - I'm struggling with a 140+Knot running landing on a narrow tricycle undercarriage I am afraid - it's just not going to happen.
And I concur with gullibell - no sane pilot would ever 'knownigly' transition out of a hover after a real TR failure because he would be completely disorientated within seconds as the G foces and dizziness and blurred vision overcame him - again this leaves a lot to be believed.
A TRF in the hover is dead easy - lower the lever. The end.
It requires little or no thinking. You simply take your chance with the impact.
[Chopping throttles and cushioning the landing is a very very nice luxury and tends to be the option available only to the lightning quick and very calm driver).
Avoid imitations
Join Date: Nov 2000
Location: Wandering the FIR and cyberspace often at highly unsociable times
Posts: 14,573
Received 413 Likes
on
218 Posts
Shy - I'm struggling with a 140+Knot running landing on a narrow tricycle undercarriage I am afraid - it's just not going to happen.
However, I would definitely NOT recommend the technique, for the same reasons you quoted!
Shy - so you want other peers to believe that a Puma touched down at 162mph with a major malfunction in the knowledge that the very instant he lowered the lever (to stay on the runway) his aircraft would have commenced a side slip due to the yaw differential?
C'mon Shy - perleeeeeeze smell the coffee.
C'mon Shy - perleeeeeeze smell the coffee.
When I did the sim on the 76B at West Palm, the only thing taught for a drive failure from any altitude was throttles-idle auto
A thread I started some time ago.
http://www.pprune.org/rotorheads/579...r-failure.html
Page 46 of the attached, Apache loss of tail drive.
https://www.raf.mod.uk/rafcms/mediaf...6F60697008.pdf
Wessex drive failure.
and
and
I'm struggling with a 140+Knot running landing on a narrow tricycle undercarriage
Shy - so you want other peers to believe that a Puma touched down at 162mph with a major malfunction in the knowledge that the very instant he lowered the lever (to stay on the runway) his aircraft would have commenced a side slip due to the yaw differential?
C'mon Shy - perleeeeeeze smell the coffee.
C'mon Shy - perleeeeeeze smell the coffee.
I cannot attest to the particular event but I know of similar landings post tail rotor problems.
At one Operator I had the misfortune to hire on with.....flying BK's....the procedure taught was exactly that. In training I saw Approach speeds in excess of 100 KTS.....but no touch downs.
When I inquired if the TC was making a very bad joke....he had quite a sense of humor failure and demanded to know what I would do differently.
Up we went...established the same setup....and I did an autoration and accepted some yawning at the bottom with zero ground speed.....which seems far safer an arrival than getting to the bottom at over a hundred knots ground speed and full chat on the rotor system....very limited yaw control....and thoughts that following through with Cyclic might prove to be a bit of a challenge!
But then what do I know?
Last edited by SASless; 22nd Sep 2017 at 23:30.
I once talked with the pilot of the 58T doing the Underslung Load....he said he was trying to get the aircraft to a cleared area and was accepting the yawing and once close enough to the clearing....he cut the Throttles...and entered autorotation and when he tried to move forward a bit....the nose dropped a bit too much and that is when it all went pear shaped.
He was not seriously hurt.....and he did opine he felt very badly about the damage to the aircraft.
He was not seriously hurt.....and he did opine he felt very badly about the damage to the aircraft.
TC - very fast running landings are quite possible in tricycle undercarriage aircraft with TR malfunctions as long as you have enough real-estate to make a very gradual lowering of the lever once the wheels are on.
A lockable nose-wheel helps directional stability and lateral cyclic combined with differential braking help keep you straight-ish.
Not saying you would stay on the runway but I wouldn't dismiss Shy's story out of hand
A lockable nose-wheel helps directional stability and lateral cyclic combined with differential braking help keep you straight-ish.
Not saying you would stay on the runway but I wouldn't dismiss Shy's story out of hand
Gnome de PPRuNe
Join Date: Jan 2002
Location: Too close to Croydon for comfort
Age: 60
Posts: 12,595
Received 275 Likes
on
153 Posts
A Met Police Bell 222 did a run on landing at Hatfield after a tail rotor failure many years ago. I think it rolled on to its side but the crew were ok.
Crab - howdie.
Have you been on the crystal meth too?
Just picture a running landing at 160mph - just for a few seconds will you?
Picture a runway of - on average 2 miles long. You can't use brakes at that speed and as you lower the lever you will need someone standing between the pilots bringing the SSL's back at a very co-ordinated and precise rate according to your instructions.
The helo presently is travelling at 2.7 miles per minute. You have 80 seconds to stop before you run out of runway. Any side slip will result in a catastrophic rollover. Once the cab starts to deviate from anything other than straight ahead at any considerable speed, your corrections will almost certainly cause divergence and pilot oscillations.
You would only survive because of pure unadulterated luck. Choosing to do this voluntarily is crass stupidity and gross ignorance of the limits of your a/c.
Low speed handling checks at height (1000') would offer you the ability to atleast halve this speed whilst still maintaining directional control.
The comment from Shy that it "started to go wrong when he slowed down", suggests mishandling.
Next time you're airborne, shoot an approach to your runway at your Vmax and let me know what it feels like if you had to follow thru and land without brakes and a dodgy steering wheel!!!!!
Have you been on the crystal meth too?
Just picture a running landing at 160mph - just for a few seconds will you?
Picture a runway of - on average 2 miles long. You can't use brakes at that speed and as you lower the lever you will need someone standing between the pilots bringing the SSL's back at a very co-ordinated and precise rate according to your instructions.
The helo presently is travelling at 2.7 miles per minute. You have 80 seconds to stop before you run out of runway. Any side slip will result in a catastrophic rollover. Once the cab starts to deviate from anything other than straight ahead at any considerable speed, your corrections will almost certainly cause divergence and pilot oscillations.
You would only survive because of pure unadulterated luck. Choosing to do this voluntarily is crass stupidity and gross ignorance of the limits of your a/c.
Low speed handling checks at height (1000') would offer you the ability to atleast halve this speed whilst still maintaining directional control.
The comment from Shy that it "started to go wrong when he slowed down", suggests mishandling.
Next time you're airborne, shoot an approach to your runway at your Vmax and let me know what it feels like if you had to follow thru and land without brakes and a dodgy steering wheel!!!!!
Amen! TC gets a Gold Star!
If one is confronted with such an option.....why not do an autorotation as I suggested?
Is not the problem too little “tail rotor thrust”?
If one is confronted with such an option.....why not do an autorotation as I suggested?
Is not the problem too little “tail rotor thrust”?
