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In the event of a total failure of the tail rotor, is it possible to maneuver a helicopter to an emergency landing spot that is within, say, 30 minutes flying time?

What are the maneuvers required for a pilot to fly reasonably straight, and how do the aerodynamics work?

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    $\begingroup$ Tail rotor failure procedure is well described on FAA Helicopter Flying Handbook, page 11-16: Antitorque System Failure. It will rely on high forward speed and autorotation to somehow limit the aircraft spin. As the vertical rate will be around 1500 to 2000 fpm, this anyway forbids a 30 mn flight. $\endgroup$ – mins Sep 27 '15 at 18:04
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    $\begingroup$ Not really. The rotor design is to keep the helicopter from not spinning around in circles. The helicopter would most likely spin around and crash. $\endgroup$ – Ethan Sep 27 '15 at 18:26
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    $\begingroup$ @Ethan. It is perfectly possible to recover from a tail rotor failure. There are some flight regimes that might lead to a crash with all but the best pilot and some luck. A tail rotor failure in cruise should be survivable, especially if you can find something hard to land on. The killers are hovering out of ground effect and low altitude, high speed. $\endgroup$ – Simon Sep 27 '15 at 18:34
  • $\begingroup$ I don't think 30 minutes is possible. A better question might be, how far can an auto-rotating helicopter go? This will depend on many things, of course, and you can't just multiply the cruise speed by the time of descent because I'm pretty sure the forward speed during auto-rotation is much less than full cruise speed, so it would be an interesting and non-trivial question. $\endgroup$ – DrZ214 Sep 27 '15 at 19:37
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    $\begingroup$ As it turns out, this has actually been done before for almost thirty minutes. See Earp's answer and his link for the story. I think we all got fixated on auto-rotation, as usually that's what you must do immediately when the tail rotor fails, but main engine can still run despite tail rotor failure and forward flight can be maintained with weathervaning under the right conditions. Hopefully it is still safe to say that actual auto-rotation cannot be maintained for 30 minutes. $\endgroup$ – DrZ214 Sep 29 '15 at 2:43
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Although I used to think this was impossible, I now believe this can be done using weathervaning.

At a fast enough forward speed, the airflow will naturally keep the helicopter facing in that direction. For an example of someone doing this in reality, for an almost identical time period that OP requested, see this link:

http://www.nzherald.co.nz/nz/news/article.cfm?c_id=1&objectid=10493099

According to the link, he needed to maintain 80 knots forward speed to prevent it from rotating out of control. Note whether this is possible may well depend on the weathervaning charactistics of the particular helicopter.

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    $\begingroup$ This is a very nice find, all the more so for someone new to the site. Welcome to aviation.SE! $\endgroup$ – DrZ214 Sep 29 '15 at 2:44
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Yes, but you certainly could not fly for 30 minutes since to do so, you would need power and if you use power, you will spin with no way of stopping it. Apart from a catastrophic failure, this is probably the hardest thing to get right. A tail rotor failure on approach or in a high hover or with speed close to the ground is probably not going to end well.

The correct recovery is to enter auto rotation.

Since this removes the torque from the rotor, the fuselage will not spin apart from that caused by drag in the transmission system which can be countered by keeping speed up and using a little opposite cyclic. The tail boom and vertical stabiliser will tend to keep the aircraft straight whilst there is significant forward speed. Any tendency to spin is opposed by the air flow striking the tail boom and fin on the side opposite to the spin and correcting it.

The problem comes from the landing since you cannot balance torque as you raise collective and increase lift (and therefore drag which increases torque) to arrest the descent.

The solution is to tweak the throttle to control torque. However, a high speed run on landing is inevitable. Hope for a strong wind that you can land into since this will reduce the touch down speed and help to keep the approach and touchdown straight.

In a hover, roll off the throttle and keep it there then perform a hovering autorotation.

In both cases, keeping the throttle rolled off is the key. If you bring significant power from the engine back into the rotor system, you will spin uncontrollably. Small amounts of throttle, rolled rapidly on and off can be used to control torque as can use of collective during the descent of an autorotation.

I hope this one never happens to me. Engine failure doesn't particularly worry me, nor do "stuck pedals" but a tail rotor failure would not put a smile on my face.

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    $\begingroup$ I don't think the exact answer is 'yes but hard to achieve.' The OP was asking for a landing up to 30 minutes flying time away. I don't think any auto-rotation can last that long, but it can certainly save your life. Exactly how far you can go during auto-rotation is probably not the best priority you're concerned with during an emergency, but nevertheless seems to be what the OP is curious about. $\endgroup$ – DrZ214 Sep 27 '15 at 19:23
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    $\begingroup$ Yep, mins has that covered in his comment. No way could you get 30 mins with no tail rotor since the only way to stop the spin (and therefore keep going forward) is to take power off which means you are going to land soon. From typical cruise altitudes < 1 km. $\endgroup$ – Simon Sep 27 '15 at 19:45
  • $\begingroup$ @DrZ214 Wow, see Earp' answer. So someone has done it. Amazing pilotage. I didn't know about this incident and if asked before, would have said impossible. You learn every day... $\endgroup$ – Simon Sep 28 '15 at 6:48
  • $\begingroup$ @Simon in Bristow flight 56C a lightning strike damaged the tail rotor. All people on board survived the autorotation landing on the sea. $\endgroup$ – ratchet freak Sep 28 '15 at 18:30
  • $\begingroup$ @Simon Ah, I was misunderstanding the exact scenario. The article linked to in Earp's answer says only the tail rotor failed, so apparently the pilot flew on for that long because the engine and main rotor were fine and he used the rudder in forward flight to maintain yaw. In this thread I was assuming the main engine had to be shut down, but after re-reading the OP, I see he's only asking about tail rotor failure. $\endgroup$ – DrZ214 Sep 28 '15 at 20:31
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As a helicopter pilot with over 3,000 hours I can assure you that landing with a tail rotor malfunction is possible and that I have given over 100 check rides where I made students land with stuck pedals or simulated total loss of thrust. As with many other questions it all depends on the type of helicopter. If it has an adjustable fuel throttle, you can reduce the fuel flow while making a powered approach to a landing. In other helicopters with FADEC, you can make powered approaches using combinations of crosswinds and air over the tail to make a safe landing. For a total loss of thrust you'll probably land in excess of wheel limitations, but even if pop all the tires you'll still walk away. As far as flying 30 minutes to land-since we aren't in authoritative flight it's possible...but I wouldn't advise it because of the nature of Tail Gear Box issues. If it's eating itself up, will it stay attached and in one piece? How much will that shift weight and balance? Will it catch fire?

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I have no experience flying Blackhawks but I was an aircraft maintenance officer on the good old UH-1 "Huey". If you have tail rotor failure during normal foward flight yes you can continue to fly until you run out of fuel.

You need to maintain at least 60k of foward airspeed and the vertical fin will help keep you from spinning. You can remove the throttle from auto and use the twist grip to use the torque of the main rotor to help turn the nose, this is especially helpful (no make it necessary) during a running landing (landing like a fixed wing aircraft).

Control gets worse if the tailrotor gearbox separates from the tail and even more difficult if you loose part or all of the vertical fin.

If you loose the tail rotor while landing and you are well below 60k airspeed and close to the ground, you then enter autorotation. Once you remove pitch and go to flight idle on the throttle the aircraft slows or even stops spinning.

Tail rotor failure procedures and landings were practiced by all pilots during aircraft check rides under the supervision of an instructor pilot.

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  • $\begingroup$ What is "60k"? Is that 60 km/h or 60 knots? $\endgroup$ – rclocher3 May 23 at 22:28
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Actually lost a tail rotor. On a UH-1 in 1971. Slung a blade, ripped off the gearbox, destroyed the driveshaft. Occurred at about 80 knots. Aircraft has a tendency to nose forward and obviously no yaw control. Control was very tenuous. Since you won't know exactly what's going on back there, suggest you autorotate. That's what I did. It was a normal auto again, with a tendency to want to roll forward so you have to keep control movement slow and smooth. Pulled pitch a little lower than normal and just concentrated on keeping the aircraft as level as possible at that point. Aircraft did about 1 1/2 rotations before it settled in. Slight spread of the skids. Aircraft survived and I had to change my underwear.

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  • $\begingroup$ Welcome to Av.SE, and thanks for an interesting first-person account of how such an emergency landing is possible. $\endgroup$ – Ralph J May 23 at 21:53
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I agree with several responders that in some aircraft unlimited forward flight is possible with some types of tail rotor failure. As a former Crew Chief of a marine corps Sikorsky UH-34d in July of 1967 in Vietnam Nam Our pilot flew to a safe landing about 15 minutes after ground fire severed our tail rotor cable. This particular aircraft ( I understand) was capable of “weathervaning” at speeds above about 55 knots using proper cyclic and throttle control as it had a rather large tail surface. In this case the pilot landed at +-55 knots without autorotation—- hit the brakes and pulled back the cyclic and brought us to a stop otherwise undamaged—— it was a hairy landing, I can assure you. The Squadron was Marine Medium Helicopter-263 flying out of Ky Ha.

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The correct answer is maybe! I learned to fly in a Hiller OH-23 in 1969. We practiced running landings assuming loss of control cables or stuck pedals utilizing throttle for directional control. The Hiller has a very large tail boom surface which allows slipstreaming, hence fairly decent directional stability. BUT we never practiced assuming loss of the blades and/or the gearbox! Remember, the tail rotor is also a rotary wing but in a vertical orientation. Most helicopters do not have the needed surface area in their stabilizers to offset the loss of the wing/lift effect of the tail rotor. My hat goes off to any pilot that can lose the tail rotor and make a landing without rolling the helicopter into a little scrap metal ball. I own a Rotorway 162F.

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Yes, it is possible to make an emergency landing in a helicopter should a tail rotor failure occur. The procedure is that same as that of a engine failure and it's called an autorotative landing. Essentially a powerless helicopter becomes an autogyro (gyrocopter) in flight and can be flown as such. This is a common emergency procedure taught to students working on a pilot certificate for a rotorcraft-helicopter.

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A loss of tail rotor effectiveness in cruise flight is manageable. The vertical fin is cambered in the form of a wing in order to "fly the tail" in some manner. It is imperative to keep a minimum speed of 40 kts to keep the tail effective. For the ASTAR AS350B3E helicopter, the "book" calls for you to continue flying to a landing zone and then to kill the engine at an altitude high enough (more than 1,000') to sustain an autorotation. Once you kill the engine you will reduce the torque thus reducing the need for the tail rotor. Other schools of thought are to keep the engine on and to head to an airport with a decent sized runway and to fly down the runway at 40kts or more and then kill the engine and slow at the same time. You will spin.

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