T/R failure practice
Just to add a few notes regarding the R44 failure and as mentioned already, many FIs in the UK offer specific training so pilots have a sporting chance of coping with the condition ... albeit being outside the EASA/CAA approved PPL syllabus. Yes, it is a fact that too many T/R failure cases result in a major accident involving fatalities but I'd like to think that given a reasonably amount of dedicated instruction and subsequent practice, plus a slice of luck at the moment of failure and a fairly flat piece of ground, most pilots should be able to land the helicopter safely.
So to add my pennorth can I continue. When in practice exercises, I have my pilot place both feet on the cabin floor clear of the yaw pedals. I then make a 'best guess' at the yaw angles that would be experienced by observing the power settings in combination with the airspeed being used. I accept that these may not be exact, but the exercise does provide, as near as I am able, the changing yaw angles and attitudes required to maintain control.
For the exercise, the major items to be considered are ... power in use at the moment of failure ... then the next three being airspeed, height and aircraft weight. Helicopters having a large keel surface such as the Big Bells and the Enstroms generally allow a better level of control relative to airspeed selected. Taking a standard current production American aircraft as our example, a partial or total failure of the T/R system does, as we all know, produce an immediate loss of directional control as Newton's third law of motion takes over and engine torque drives the nose rapidly RIGHT (left in most European makes).
To remove any mystery of the condition, I teach my pilots that they don't actually have a problem! Pause to think! What they do have is an engine that they can no longer control. So initially we just carry out an exercise we have practiced many times ... ie to get rid of the source of the problem by lowering the collective lever and closing the throttle to enter autorotation. With a reasonable airspeed (say 70 knots) and lowish power (say under 50%) the RIGHT yaw might extend out to the 'two o clock' position but whatever, the pilot's immediate action of power reduction prevents further yaw, while the lowered lever drops the nose either increasing or at least maintaining speed. Using cyclic the pilot's first task is to level the 'wings' and maintain at least 60 knots. With the RIGHT yaw stopped, transmission friction take over causing the nose to slowly commence a yaw to the LEFT but again highly dependent on the speed being maintained.
With the nose rotating toward the LEFT 'ten o clock' position, the pilot can now use engine to control left rotation and by raising the collective lever increasing power to yaw the nose once again RIGHT ... the plan being to discover the maximum power setting that can be used at a given airspeed to allow a controlled yaw to the original 'two o clock' position. It should be borne in mind that the resultant 30 degree yaw involves large ASI errors. Opposite use of cyclic assists control, ie with right yaw use left cyclic, the plan being to achieve straight & level flight if possible, or at least a reduced rate of descent ... much depending on aircraft weight.
IF control can be achieved with steady height and airspeed at the 'two o clock' position, the world becomes your oyster! Or at least allows more time to select a suitable emergency landing area. If the former, you may even have time to return to your base airfield or at least reach a better landing site, alert the emergency services and carry out safety emergency drills.
Once over the selected landing site, the helicopter should be positioned so that a shallow rate of descent can be made to the landing site. Lowering the collective lever allows the nose to yaw LEFT back to the 'ten o clock' position while maintaining speed and directional control with a combination of lever position (power) and cyclic (speed). Ideally the approach needs to be made at progressively reduced speed bearing in mind the ASI errors.
So far, the procedure hasn't been that difficult but if a non-damaging landing is to be achieved, the handling co-ordination requirement to control the final rate of descent, the airspeed and yaw is now at its highest. At this point the pilot is aiming to bring the helicopter to within a few feet of the landing surface with as much power as can be used to achieve the lowest rate of descent and minimum forward speed.
At around 20 to say 30 feet the helicopter is initially flared with aft cyclic to further reduce speed but then pushed forward to level the skids for the landing attitude. As the helicopter sinks collective lever is raised allowing the nose to yaw RIGHT back toward 'two o clock' but at around the 'one o clock' position the throttle is closed quite rapidly and as the nose yaws back toward the 'twelve o clock' position the cyclic is pushed forward to make rapid skid contact with the surface. With skids on the ground, collective lever and perhaps throttle is used to keep the helicopter straight allowing skid friction to stop forward movement.
It needs to be borne in mind that once the landing site is reached and descent commenced it will not usually be possible to make a 'go-around' and the pilot is committed to a landing.
I appreciate these suggested handling techniques are more applicable to a failure from a fairly benign configuration and may not apply to a worse-case take-off or landing or low height zero speed hovers where more advanced handling would be required.
I also hasten to add, that these notes are for guidance only and perhaps to promote discussion on such an important life-saving exercise, but I'd have to say, I've never been a supporter of the usual PFM recommendation to handle the T/R failure problem by ... "entering autorotation." For sure that technique will stop the rapid right yaw problem but will not allow the helicopter to be landed safely since the initial right yaw will, as outlined above, be followed immediately by a yaw to the left and in my view it matters not a lot whether the helicopter impacts the ground in a right or a left spin. And just to remind pilots that our European friends turn their rotors differently so where I say RIGHT .... use LEFT and vice-versa.
Just to close, much of the above has been learned from my four 'actual' T/R failures I've experienced in 14,000 plus hours over a forty-year career. Luck allowed me to survive the first in 1973 when a T/R shaft sheared on a sales demonstration, the second was a hover failure when a licenced engineer obligingly fitted the T/R blade assembly in a reversed 'trailing edge' first configuration which being an 'ace' pilot, I did't spot on the pre-flight inspection. With some experience under my belt, I completed a high speed run-on landing at Cranfield in 1986 and a later further occasion when I landed on a cricket field at one of Noel Edmonds 'Mr Blobby' events in Somerset. The final episode occurred at the 1999 Biggin Hill Air Fair when, with the hoped for 'slice of luck', I managed to get the Enstrom FX down without further damage. But Guys & Gals out there, I'm still waiting for my first engine failure!
Safe flying to all and I sincerely hope my words will help another pilot one day. DRK