I had a t/r failure in a Whirlwind 45 yrs ago this month. If you look at p15/16 of `Rotorheads around the world` there are pics of the a/c after landing on top of a `pimple` in Borneo,also the aircraft recovery by Belvedere,plus a couple of other engine failures. The failure was due to a fatigue crack in the blade spindle(tie-bar),one blade coming off,followed by the other plus gearbox etc.
Anyway,when we mention t/r failures,how many different types of failure are there,and what can we do about it if `s*& t happens ?
1.Control lost over the t/r, ie no response to pedal input,but a/c yaws if power changed; it could be, broken pedal(S),cables,rods,disconnection. It may be a hydraulic failure(ie jammed piston possibly),if you have a hyd.pwrd t/r,or if cables,you may consider, again ,depending on the aircraft,is it possible to find the cable/rod control run and use the`loose ends `to effect control. Obviously in this situation one may be flying a larger helo with at least a co-pilot who can assist;in Whirlwinds/Wessex/Sea-king,possibly others, it`s possible to `pull the cables `in the cabin roof/tail-boom.(Good ploy to sharpen up the front end was to `twang the cables if forced to fly in `cattle-class!!). I should mention that a loose /disconnected cable/rod, may well be a separate danger if it should foul/wrap itself around a drive shaft.
2 Drive failure. ie driveshaft breaks,and t/r stops.It may be that some effectiveness can be obtained by using the pedals and hoping that there is some `rudder effect`,but probably unlikely,but it may depend on power/speed combination.
3 T/R blade damage; if it`s suspected that a blade is damaged,ie birdstrike,clipped a branch,get on the ground ASAP; if you can`t,prepare for the worst,but consider if you can fly at a reduced RRPM power on/off,as T/RRPM are about 6-10 times main RRPM,as it will reduce stresses.
4. T/R/Gearbox fail then departs. The C of G will immediately change to somewhere out in front of the nose,plus the yaw,depending on whether it`s taken the fin with it. If it`s possible at all,get any pax as far aft as possible whilst trying to get a measure of control. This one will really spoil your day, and give you sleepless nights if you survive. Even on a light helo ,you can work out the C of G change- ask the engineers for a gearbox+t/r weight,then work out the moment,then the new CoG......
5 Fenestrons. Personally,I would say that they provide the best protection and offer the least problems with any failure mode.
Okay,I`ve simplified it a lot and `it Depends` on the type of helo/large small/fin area/speed at time/Cof G/ etc as a broad-brush run-through of failures,and possible problems.I can`t give any definitive `this is what you should do/should`ve done`, because there are so many variables ie,was it hovering,in the climb /cruise/descent,and armchair advice,especially after a couple of Riojas,is usually fraught with being `shot-down` anyway.
It may be possible to continue flying to reach a safe run-on/eol at the end,but I would say, if you fly a larger helo/multi-crew,use them to assist/advise/pray; if it`s smaller,think about how you load the a/c if carrying pax,ie towards aft Cof G, etc,etc..
Funnily, when Igot back after my `episode` someone on the Sqdn. gave me a USAF Flight Safety magazine( before Air Clues) that he had been reading in the crew-room entitled` How to deal with a Tail-Rotor failure `.......!
I commend you all to think deeply about the possible failures you could have in the a/c you fly,and how you would deal with it,read the article by P Amadeus,the recent H-K one,and anyone elses experience'
Fly safe guys,and always `expect the unexpected`....Sycamore..
ps,,I should add,please shoot this down/discuss/ etc at will,as it`s not meant to be definitive`how-to`...