My personal soapbox. Why do we insist on calling completely unrelated malfunctions virtually the same name? Tail Rotor Drive Failure versus Tail Rotor Control Failure.
In the heat of the moment, it's easy to jump down the wrong rabbit hole. I've seen multiple crews open up the cards to the wrong section and start the wrong drills because of this.

My suggestion; Tail Rotor Failure = Loss of drive/TGB detached

Yaw Control Malfunction = Stuck/Sloppy pedals.

Simples

Often because they are not as familiar with the cards as they should be.........I have seen the same for the same reason

This makes interesting viewing

https://www.youtube.com/watch?v=fNkwk2d_DJ8

Agreed Crab. But a simple change in nomenclature from the outset would effectively stop any confusion before it has time to start.

I can't remember what the latest flight safety just culture management buzzword this kind of thing fits into, but there's got to be some systemic failing. We have for years, collectively, set up a man trap that we repeatedly see crews fall into, but don't do anything about it. Stating that people should be more familiar with the cards/drills doesn't fix anything.

Well, looking at the title of your post, if all tailrotor failures were "Unrecoverable" there would be no Emergency Procedures called for. Just as there are no "Wing Falls Off" checklists in fixed wing nor "Loss of Main Rotor" in helicopters.
There are procedures that must be carried out...initial actions are "Memory Items" Reaching for a checklist as you spin like a Kid's top will not lead to a optimal outcome.
You must be fully aware of the initial actions and carry them out.
FYI I had a friend who had the tailrotor and gearbox of a Hughes 500 depart the airframe in cruise flight ..he got it down OK ..his underwear and seat cushion were unrecoverable!

A Twin Squirrel landing after a TR drive failure. Not good quality video, but the stationary TR can be seen.

I recall a Met Police Bell 222 had a TR failure around 1980 and made a run-on landing at Hatfield. I think it rolled over but all walked away.

Jellycopter - I just think it is down to training - and that includes knowing the cards through self-study and practice in the simulator.

I think the difference between a TR drive failure and a TR control failure is quite clear, perhaps because I have taught it quite a lot.

TR drive and TR control failures were mandatory parts of the 6-monthly sim on the Sea King as I am sure they are on many other types.

I don't know what you would call the two conditions that would be any clearer.

Crab, if I had a Euro for every misguided helicopter pilot that glibly stated that they'd autorotate in the event of a TRCF I'd be quite a bit better off than I am now.

If you turn the problem through 90 degrees, no one ever gets the drills for stuck collective mixed up with MGB/input drive failure. But we're talking, effectively, the same thing. Why do less well trained crews continue to make the same mistake?

The fact that someone on this thread decided to bring stuck pedals/TRCF into it shows the depth and universal nature of the problem.

I wish, for the good of Rotary aviation, people would stop using the term 'Tail Rotor' when referring to a control malfunction. Call it what it is, a Yaw Control Malfunction.

Because that is what they are. It is not possible to be confused which of the 2 you have, whatever you care to call them. They are so obviously different malfunctions.

TR drive failure don't even bother getting out the emergency checklist, the immediate actions are all memory items. If it's an impending failure e.g. vibration in pedals or airframe, TGB/IGB chip light on, grinding noise etc, but you still have pedal authority then sure, turn towards a suitable landing area and get out the ECL and review the procedure. Maintain height, slow down to best rate of climb speed. Do not descend until you arrive at a point in space where you can execute an autorotation to the landing area.

TR control malfunction there are no memory ECL items, this is a far more sedate problem to deal with. You have time to get out the ECL. The next thing is put your test pilot hat on and diagnose the problem as per the checklist. But as I said before, it doesn't matter whether stuck pedal, broken control cable etc, the landing technique is the same for all of the causes of TR control problem.

Whether TR drive failure or TR control malfunction, if you have a suitable landing area to aim for you should be able to execute a safe landing without putting a scratch on the aircraft.

One could always ask the TOLL Chief Pilot on the NSWA AW139s if a tail rotor strike is unrecoverable. By all accounts, they did recover, but by truck to Bankstown!

As the OP on this, I really was only referring to tail rotor failure in the sense that it has failed completely for reasons of a broken driveshaft or blade failure or hub/bearing failure etc etc.

This video would best illustrate the failure type I was thinking of - with the best video quality I can find showing the TR condition. I also chose this as the pilots survived the forced landing.

I find it hard to believe that it is possible to confuse the two malfunctions too. It shouldn't be possible.
However, after decades as an instructor and examiner I have had many pilots that have. I believe that when pilots give either malfunction the 'tail rotor' label all too often they opt for the dump the lever option when it's exactly the wrong thing to do.

Crab has experienced the same. Are there any other instructors/examiners out there that have seen this from time to time?

I remember Dennis Kenyon demonstrating Tail Rotor Failure recovery whilst doing his display at an airshow at Cranfield in the 1980s. He was flying his normal, excellent, display in an Enstrom when something "went a bit wrong"! He then flew a couple of low passes down the active runway and, on the third pass, did a run-on landing. Everything was OK - apart from the broken TR cable!

Palma - that is exactly what Jellycopter is talking about - it wasn't a TR failure, it was a loss of TR control.

It is straightforward, with a TR failure, the TR is producing no thrust in any direction and probably not turning at all. With a TR control failure, the TR is still turning and may be producing thrust one way or the other, depending on the nature of the failure, or none at all if it has gone to flat pitch.

I never understood the obsession with tail rotors.... Just fly a tandem rotor, at least then all the bits that can break aren't in places where you are going to put them into a tree...

Except that hitting/losing one of those rotors is guaranteed to be catastrophic:ok:

Karma. Toll was reluctant to let me do any training in their NSWA AW139. They got to bend one first with their own people before I ever got close to one.

Confusion reigns for many recurrent trainees when diagnosing TR control malfunctions. But for TR drive failure they don't have time to get confused before they need to carry out an immediate action in response to their predicament. What that immediate reaction is can be surprising...I've seen a pilot just take his hands off the controls and leave the outcome of TR drive failure entirely up to the will of Allah. Needless to say it didn't end well.