Full down Autos, What next?

[Vfrpilotpb]

Whilst being taught in (wait for it) the R22, I had the benefit of being shown then doing for myself(CFI alongside) a couple of FDA's, after which we made a point of entering an auto(to recoveryat 500ft) with nearly every lesson, needles to say this action now holds no worries for me, if I had to react to the quietness of a failed engine.
BUT with the small nature and strength of components in the R22, what stresses are involved and invoked on the machinery, Ok the skids can be seen if they are not right, but what about the head or inner chassis type frame work, when or where do any stresse's show up on these components, for no matter what you do with your initial walk round before start up, it is impossible to see the area's of potential serious problems, Ie the head the shaft, the alignment of the entire drive system, and yet when eager young and old things are being taught we walk around , examine and very rarely will anyone say what has gone before, is it all down to the knowledge of the CFi's or should some sort of log be kept of what is done in training type Heli's, or is the 50 and 100hr service intervals enough even on the R22 and other trainers! :hmm:

[Helinut]

Such things will be type specific, and I am just thinking about the R22. The R22 is pretty resilient to such abuse, but you can damage any helicpter if you take it far enough.

My experience is now a bit old, but I guess that there have not been too many changes. The actual landing on an EOL (as distinct from the accumulated effects of lots of autos during training) tends to affect odd bits of the aircraft, but not the MR system, in my experience.

The most frequent damage seemed to be to the fairing around the MR mast. It comes into contact with the cabin roof and in particular the bolt heads that are left proud of the roof, ahead of the fairing. The contact "chews" the bottom edge of the fairing, usually at its front. The engineers who used to maintain the aircraft I knew suggested that this damage was more cosmetic than serious. This damage seems to be caused during landings where one or more of the following exist:

MRRPM is lowish,
on uneven grass/dirt,
if the aircraft is landed one skid first

If the landing is "heavy"ish, then the movement of the tail boom can cause damage. Usually, this seems to occur as a wrinkle towards the front of the tailboom on its underside. The tail boom is a monocoque construction, so damage like that means that repair work is required.

In my experience, the skids and landing gear of the R22 were really impact resistant (much more so than for example a JetRanger). There is a substantial degree of movement in the landing gear response to dynamic loads. This seems to absorb the loading progressively and elastically. You are supposd to be able to tell whether the landing gear has been dammaged by checking the height of the tail fin stinger above the ground. However, you need level ground, so it never seemed a really practical proposition for a pilot check.

The really useful precautions for pilots lie with prevention and reporting of any possible damaging landings. A current R22 instructor should be able to turn an engine off to the ground to a power recovery even at a very late stage of the process- if there was any doubt. Any doubt about the landing, and it should be reported without fail.

[Hilico]

Concur with Helinut. The oldster on one school's training fleet had just such marks in the pylon fairing, and it flew no worse (or better) than any of the others.

It would be an excellent idea, though, to have a couple of life-size models of rotor heads that had been subject to out-of-limits forces, simply so everyone knew exactly what to look for.

[Buitenzorg]

The R22 Maintenance Manual shows that if a visual inspection shows no damage, internat components (gearboxes, driveline, rotor hubs) will not need further inspections. Only when external damage is found, may you need to more thoroughly inspect and/or replace components. My experience with flight school operations in R22's, including full-downs, hover autos, running landings etc. have shown this to be completely correct.

Overspeeds are a different story altogether, of course.

[bugdevheli]

If you come across a Robinson with damage around the mast fairing, I would take a good look around the pushrods and jackshaft that operate the cyclic and collective. I have been lucky enough to get hold of one or two Robinsons (knackered ones), to cut up and evaluate. The main frame tube movement appears to be around the main rotor gearbox mountings , but is quite difficult to measure whilst the mast is in situ. A good clue is if there is any visual distortion of the horizontal firewall . I would not be too concerned about the main rotor geabox, the bearing setup in there is a real confidence booster. I would however question if its a wise thing to leave your pride and joy out in the rain too much, because unless the rubber gaiter on the swahplate is watertight it seems possible that water might get into the bearings.

[The Nr Fairy]

When I was learning to fly R22s in Australia, the three items pointed out as potential damage indicators were 1) dinks in the fairing below the pylon, 2) wrinkling on the underside of the tailboom at the forward end, and 3) the "smiliness" of the rear lower crosstube.

Anything different / odd about those three mean I need to talk to someone.

And the swashplate gaiter is an item which should be checked every day as part of the Check A / daily / whatever.

[Helinut]

I agree with budgevheli about keeping R22s in hangars in wet climates. I had a bad experience with an upper sheave bearing failure on a R22 that had been kept outside in the wet. The bearing failure was at least partly put down to water ingress into the bearing - not to mention the general extra corrosion work every annual.