Tailrotor failure - is it always unrecoverable ?
TC - I'm not saying it was the right thing to do but I'm not rubbishing someone else's story just because I haven't done one myself.
Some thoughts - in an emergency situation, why would you worry about brake speed limits or running landing limits? If you have a pilot who is not confident of surviving an EOL without the TR (and I suspect there are more than a few of those out in the big wide world) then adapting something you already know (and may well have practiced in the sim) might seem a more attractive option.
The modern twin-driver will likely have very few EOLs under his belt and may have only ever done one in the Sim.
What if your RFM doesn't even give you the option of a EOL - only a high speed running landing?
He may have made the approach at 140kts but that doesn't mean he touched down at 140 or anything like it.
If 140kt is what you need straight and level to keep straight then in a descent of say 500'/min that speed will be a lot less as you have less Tq to oppose.
As you get to the ground you can flare a little more speed off as well - if you can get the touch down speed below 100kts, that is reasonably manageable as long as you have lots of runway and are gentle with the lever/throttles. personally I would consider shutting down one engine on the approach so I only had one throttle to worry about on the ground.
I regularly do 80-100Kt landings in the sim and 50-60Kt running landings in the aircraft as part of TR failure drills.
You and I would conduct a low speed handling check (exactly what I teach at the moment) but a lower-time pilot may not have been shown that or not understand it has to be done VERY gradually at a safe height.
So, no crystal meth, just not prepared to decry a story which might just turn out to be true
Some thoughts - in an emergency situation, why would you worry about brake speed limits or running landing limits? If you have a pilot who is not confident of surviving an EOL without the TR (and I suspect there are more than a few of those out in the big wide world) then adapting something you already know (and may well have practiced in the sim) might seem a more attractive option.
The modern twin-driver will likely have very few EOLs under his belt and may have only ever done one in the Sim.
What if your RFM doesn't even give you the option of a EOL - only a high speed running landing?
He may have made the approach at 140kts but that doesn't mean he touched down at 140 or anything like it.
If 140kt is what you need straight and level to keep straight then in a descent of say 500'/min that speed will be a lot less as you have less Tq to oppose.
As you get to the ground you can flare a little more speed off as well - if you can get the touch down speed below 100kts, that is reasonably manageable as long as you have lots of runway and are gentle with the lever/throttles. personally I would consider shutting down one engine on the approach so I only had one throttle to worry about on the ground.
I regularly do 80-100Kt landings in the sim and 50-60Kt running landings in the aircraft as part of TR failure drills.
You and I would conduct a low speed handling check (exactly what I teach at the moment) but a lower-time pilot may not have been shown that or not understand it has to be done VERY gradually at a safe height.
So, no crystal meth, just not prepared to decry a story which might just turn out to be true
Ok here is my 2 cents worth.
If you have a full blown TR drive failure you are going to be in "Immmediate Actions" mode and will most likely have to enter full Autorotation ( engines off ). This will severely impact your options. Best or luck!
If you are dealing with loss of tail rotor control or stuck pedals ...things are looking up.
If the aircraft is controlable ....
Slow to 80 knots in level flight. Look at the Ball...is it off to the left or right? Go to the opposite side then ..Lucky Left- Rotten Right . ( basically ball to the LEFT = rotten right, Ball to the Right = Lucky Left.) NB. The further the Ball is out..the worse your problem is.
If Lucky Left you will be able to land with higher torque perhaps even bring it to the hover. Rotten Right landing will be at a lower torque and run on will be required.
(Oh this is for North American machines, EU folks use "Lousy Left ...Righteous Right)
Truck on back to your "suitable forced landing area".
Set up an normal approach starting at 80 knots initialy with a 2-300fpm descent rate ( use cross wind to your best advantage. Left xwind for Rotten Right..Right xwind for lucky left.)
Slow down but keep it at a speed/ torque setting that keeps the nose aligned with the runway.
At the slowest possible speed land be prepared to shut down engines if Rotten Right.
Some smart person wrote a very nice blurb on this with diagrams and it used to be in our OPS Manual.
Worked well. Actually I believe he posts here from time to time. Great training guy and a darn fine pilot.
If you have a full blown TR drive failure you are going to be in "Immmediate Actions" mode and will most likely have to enter full Autorotation ( engines off ). This will severely impact your options. Best or luck!
If you are dealing with loss of tail rotor control or stuck pedals ...things are looking up.
If the aircraft is controlable ....
Slow to 80 knots in level flight. Look at the Ball...is it off to the left or right? Go to the opposite side then ..Lucky Left- Rotten Right . ( basically ball to the LEFT = rotten right, Ball to the Right = Lucky Left.) NB. The further the Ball is out..the worse your problem is.
If Lucky Left you will be able to land with higher torque perhaps even bring it to the hover. Rotten Right landing will be at a lower torque and run on will be required.
(Oh this is for North American machines, EU folks use "Lousy Left ...Righteous Right)
Truck on back to your "suitable forced landing area".
Set up an normal approach starting at 80 knots initialy with a 2-300fpm descent rate ( use cross wind to your best advantage. Left xwind for Rotten Right..Right xwind for lucky left.)
Slow down but keep it at a speed/ torque setting that keeps the nose aligned with the runway.
At the slowest possible speed land be prepared to shut down engines if Rotten Right.
Some smart person wrote a very nice blurb on this with diagrams and it used to be in our OPS Manual.
Worked well. Actually I believe he posts here from time to time. Great training guy and a darn fine pilot.
Last edited by albatross; 24th Sep 2017 at 16:02.
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Mighty Gem, I remember the night that "Lucky" told me the story of that landing, as we approached Speke, at 500 feet in the dark. I asked which crew it was, and he laughed and said "Us" so that made me feel better, or something.
Looking at the video later that evening. I decide to check the door latches myself before getting back in.
What an awesome bit of flying, by an awesome pilot.
Looking at the video later that evening. I decide to check the door latches myself before getting back in.
What an awesome bit of flying, by an awesome pilot.
Avoid imitations
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Albatross,
Yes, "Lucky left/rotten right" is only so for counter-clockwise rotor rotation, e.g. Sikorsky, Agusta. For French helicopters, it's the other way round.
As someone who has had to fly helicopters of different main rotor blade directions, the thing I taught myself and my students to remember is that the "lucky" side is the retreating blade side. Hopefully most pilots remember that from when they started up the "aircraft of the day"!
I don't blame TC's scepticism about the very high speed running landing. I just wish he could be slightly less rude about it. Just to reiterate, I never taught him that, no-one taught him that and by all accounts he was very lucky to survive.
Yes, "Lucky left/rotten right" is only so for counter-clockwise rotor rotation, e.g. Sikorsky, Agusta. For French helicopters, it's the other way round.
As someone who has had to fly helicopters of different main rotor blade directions, the thing I taught myself and my students to remember is that the "lucky" side is the retreating blade side. Hopefully most pilots remember that from when they started up the "aircraft of the day"!
I don't blame TC's scepticism about the very high speed running landing. I just wish he could be slightly less rude about it. Just to reiterate, I never taught him that, no-one taught him that and by all accounts he was very lucky to survive.
...
Set up an normal approach starting at 80 knots initialy with a 2-300fpm descent rate ( use cross wind to your best advantage. Left xwind for Rotten Right..Right xwind for lucky left.)
Slow down but keep it at a speed/ torque setting that keeps the nose aligned with the runway...
Set up an normal approach starting at 80 knots initialy with a 2-300fpm descent rate ( use cross wind to your best advantage. Left xwind for Rotten Right..Right xwind for lucky left.)
Slow down but keep it at a speed/ torque setting that keeps the nose aligned with the runway...
Once the nose is pointing straight you can't be applying any more power.
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Reference T/R Failures, not always a total loss
Had a cargo door come loose on a UH-1H. Took out the T/R and 90 deg gear box. Did a running landing in a rice paddy. No further damage.
I don’t care where the nose is pointing except no where on the non-power pedal side.....for a situation where I have an excess of tail rotor thrust that affords a left of center to aligned orientation.
Maneuver the aircraft to arrive at the minimum forward speed with the nose aligned with the direction of travel.
Excess thrust can be minimized by reducing MR rpm to the bottom of the power on green arc.
Making a long shallow approach to a foot or so off the surface and decelerating very slowly till the nose is aligned or the aircraft is in a stablehover....the landing and then carefully reducing rpm to idle/flat pitch....makes a Bobby yer Mum’s brother!
Maneuver the aircraft to arrive at the minimum forward speed with the nose aligned with the direction of travel.
Excess thrust can be minimized by reducing MR rpm to the bottom of the power on green arc.
Making a long shallow approach to a foot or so off the surface and decelerating very slowly till the nose is aligned or the aircraft is in a stablehover....the landing and then carefully reducing rpm to idle/flat pitch....makes a Bobby yer Mum’s brother!
Gullibell - agreed, in fact it is the anticipation of that swing into alignment that is the difficult thing to teach, if you wait until it swings before you land it is already too late. The control inputs are very subtle and each knot of speed and each degree of collective are very important.
Also, unless you have done a low speed (breakaway) handling check, 80Kts might still be too slow for the initial stages of the approach.
A crosswind from the 'lucky' side will help enormously.
At the start of the approach, I teach my students to look at how far out of alignment the nose is from the runway - the further away it is the slower the speed for the run on will be.
If at the start you are already aligned with the runway then you are already at your absolute minimum speed for the approach and need to be very careful not to let 'ground-rush' make you wash speed off in the descent.
Also, unless you have done a low speed (breakaway) handling check, 80Kts might still be too slow for the initial stages of the approach.
A crosswind from the 'lucky' side will help enormously.
At the start of the approach, I teach my students to look at how far out of alignment the nose is from the runway - the further away it is the slower the speed for the run on will be.
If at the start you are already aligned with the runway then you are already at your absolute minimum speed for the approach and need to be very careful not to let 'ground-rush' make you wash speed off in the descent.
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I agree with what you are saying crab - speed control is the key. The students who get it wrong are the ones who are not scanning the airspeed constantly.
A slight variation on the technique, which seems to work well in my experience:
Start as already discussed, ideally nose slightly left, and as you approach the landing area, adjust the speed carefully until it is stabilised with the nose straight and with the aircraft flying maybe 10 or 20 feet above the runway. At this point, be prepared to change your brain to think about steering with the collective. If you pull up- nose goes right ( in normal helos!) if you push down, nose goes left.
To initiate the descent for the last 10 or 20 feet, just raise the nose a tad, and as the speed washes off, the helo will descend. You just need to keep steering with the collective as you touch the runway with the main wheels. If you hold the nose up off the ground, you will brake aerodynamically until the nose falls naturally, and you can slowly lower the collective.
A slight variation on the technique, which seems to work well in my experience:
Start as already discussed, ideally nose slightly left, and as you approach the landing area, adjust the speed carefully until it is stabilised with the nose straight and with the aircraft flying maybe 10 or 20 feet above the runway. At this point, be prepared to change your brain to think about steering with the collective. If you pull up- nose goes right ( in normal helos!) if you push down, nose goes left.
To initiate the descent for the last 10 or 20 feet, just raise the nose a tad, and as the speed washes off, the helo will descend. You just need to keep steering with the collective as you touch the runway with the main wheels. If you hold the nose up off the ground, you will brake aerodynamically until the nose falls naturally, and you can slowly lower the collective.
I think it depends on some degree whether you are flying wheeled or skidded helicopters.
We get down to 5 or 6' above the runway before reducing speed, you have almost maximum ground effect to reduce your power required and it enables you to land far more promptly as the nose starts to swing. The additional benefit is that you usually need to lower the lever slightly to land which, if you haven't anticipated the nose swinging round early enough, gives you a little help in controlling the Tq reaction.
Another option is to just fly with between 3 - 500'/min RoD all the way to the ground, with just a gentle flare at the very end - this is definitely more suited to wheeled helos with nice big oleos to soften the impact, but it does reduce your power required and therefore the amount of Tq reaction you are opposing with speed.
With a wheeled aircraft it helps to 'plant' the nosewheel (if it is a lockable one) as that also helps with directional control - just don't dump the lever as soon as you are on the ground.
We get down to 5 or 6' above the runway before reducing speed, you have almost maximum ground effect to reduce your power required and it enables you to land far more promptly as the nose starts to swing. The additional benefit is that you usually need to lower the lever slightly to land which, if you haven't anticipated the nose swinging round early enough, gives you a little help in controlling the Tq reaction.
Another option is to just fly with between 3 - 500'/min RoD all the way to the ground, with just a gentle flare at the very end - this is definitely more suited to wheeled helos with nice big oleos to soften the impact, but it does reduce your power required and therefore the amount of Tq reaction you are opposing with speed.
With a wheeled aircraft it helps to 'plant' the nosewheel (if it is a lockable one) as that also helps with directional control - just don't dump the lever as soon as you are on the ground.
No, you don't want to be aligned with the runway. You want a power/speed configuration where the nose is pointing left of the runway direction (for anti-clockwise main rotor). Reason being, when you are in the process of terminating the approach with application of power, the nose will then come into alignment with the landing direction. If the nose is already straight when you start to apply power you're going to mess up that which would have otherwise been a scratch and dent free landing.
Once the nose is pointing straight you can't be applying any more power.
Once the nose is pointing straight you can't be applying any more power.
Thanks for the correction.
Cheers
Albatross
I must say I find the Puma story a little tall too. In my previous company we had three Super Puma tail rotor failures and one (that I am familiar with - could have been more before that) on a 330J. One of the 332 ones was at low power and the pilot (it was effectively SP as using a foreign co-pilot and a translator) was able to successfully autorotate to a ditching without too much initial drama. A second one happened at a moderate cruise speed/power following a lightning strike, with the crew poised to react. When the TR 'let go' the subsequent motion was described by the handling pilot as like a Lomcovák and only stopped with the throttles off. The third was at the bottom of an ILS (in VMC), so less than cruise power at slightly less than cruise speed, at around 200 ft and was an uncontrolled impact with serious injuries. The 330J event was in the cruise, and the aircraft tumbled so violently that at least one of the pilots lost his headset and it was not a controlled ditching that resulted in fatalities.
So, none of the above lends itself to the idea that you can have a TR failure at 140 kts and then take the aircraft to land on a runway - unless we are talking about TRCF not loss of thrust.
So, none of the above lends itself to the idea that you can have a TR failure at 140 kts and then take the aircraft to land on a runway - unless we are talking about TRCF not loss of thrust.
Would you notice a loss of TR thrust at 140 kts in the cruise? The TR can't be at that high a pitch with all the tail boom and vertical fin working for you.
I know the Brit Mil Puma was not brilliant in terms of directional stability but I thought that had been addressed with extra area on the tail on the civil versions.
Is it so bad that you can't achieve any power/speed/sideslip configuration to make a powered approach?
I know the Brit Mil Puma was not brilliant in terms of directional stability but I thought that had been addressed with extra area on the tail on the civil versions.
Is it so bad that you can't achieve any power/speed/sideslip configuration to make a powered approach?
If you had a TR control malfunction and a double DECU at the same time....well, the likelihood of that happening is zero.
Last edited by gulliBell; 26th Sep 2017 at 14:29.
Gullibell - I think chopjock is talking about light singles with a twistgrip throttle.
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Originally Posted by [email protected]
Would you notice a loss of TR thrust at 140 kts in the cruise? The TR can't be at that high a pitch with all the tail boom and vertical fin working for you.
On the subject of controllability if the TR gearbox comes off, I was talking with Pat Cox at Robinson a year or two ago about the fact that I seemed to remember the R22 manual originally calling for a running landing for TR failure, and that I think it changed to calling for an auto in the 90's sometime. He said that they believe the R22 is uncontrollable (due to CG shift) if the gearbox departs, but that the R44 and R66 are probably controllable. My only point is that it's probably highly aircraft specific which ones are controllable if you lose the gearbox. I guess it also helps if you're not at the forward CG limit when it happens
