Flickering Govenour Light

[Low Level Lover]

Was flying the other day and on short final my govenour light started to flicker and by the time I set down it was flickering widely along with the engine / RRPM and would have oversped or drooped if I wasn't over-riding manually. Anybody else had this problem and know what the most probable cause would be i.e. right mag? The preceeding flight was short albeit somewhat turbulent. Any advice would be appreciated before I go sending the control unit back to the factory.

PS. I checked the wiring for loose connections, chafing, etc.

Thanks

[flingwing206]

Call RHC, call a RHC-authorized repair shop, then take the advice you get here as reassurance or counterpoint to what they tell you.

 

Could be in the mag, could be a bad wire or ground, could be a failing control unit or switch, or, or...

 

Get a pro on it, start with the cheapest, most obvious solutions, work your way on from there.

[delorean]

Those governor control units and motors are usually solid.  I've had two do similar things you've described.  The culpret was the pigtail coming off motor/actuator.  The wire had frayed and was grounding out at the base where it enters the motor.  It would only happen when you were moving the collective.  And I don't believe the light came on for that.

 

The "Governor Off" light was an afterthought in the mid-90s.  I can't remember where it is wired through, but I think it is just the switch.  If I remember correctly, if you pull the governor circuit breaker, the light does not come on--it works solely off the switch regardless if the motor is actually operating.  If what I just said is true, you have a switch problem.

 

If not, check the pig tail.  If it was mag problem, you would have an erratic engine tach needle--so it's not the tach points on the right mag.  If you still need to replace the motor or control box, just get it from White Industries or another salvage yard.  Neither of those parts could can be damaged in an accident, so there's tons of them around....1/2 price of new usually.

[Low Level Lover]

Thanks for the input thus far. I should have mentioned that the engine tach needle is erratic as well, and both needles remain married. Someone else had mentioned some reference to some pints in the right mag would probably need cleaning. Can this be done in the field by my local AME or do you have to take the mag to an overhaul shop? Can these points be cleaned with the mag in place so as to not have to re-timed or does it have to be removed to gain access. You input is highly appreciated. Thanks

[delorean]

It's definately the mag points then.....because the governor does not get its signal from the tach, it gets it straight off the right mag.

 

Yes, you can clean the points without removing the mag, but it's tough.  It's a lot easier to just remove it--especially the right side one.  Your mechanic will spend 20 minutes with a 90degree flat bladed screw driver fighting to get the points cap on and off, but a 1/2" socket will have the mag off in 30 seconds.  It will about 2-3 minutes with a "buzz box" to retime it to the left mag and engine (it's really easy--I used to check or adjust them every oil change on a fleet of 4.)

 

The worst thing you can do is blast/spray some sort of cleaning solution on those points--which is why I recommend removing the whole assembly.  When you remove the points cap make a diagram of where all the wires go, if you don't have a Bendix/TCM mag manual.  You can try using some sand paper to clean the points (just let points clamp down on the paper and pull it out), but I usually just replace them.  I think the tach points are around $30 from Kelly/Electrosystems (twice as much from TCM).

 

What is the last time your mags were internally maintained??  The SB says every 500 hrs, because they usually won't make it past 1000 hrs.  I always replaced the main points, starter points, tach points, distributor block, distributor gear, driveshaft main bearing, the condensor, and the coil (coil only every 1000 hrs).  Most people don't replace the condensor, but I had more of those go bad more than anything else in the mags.

 

And no, you don't need to send it to a shop, any well seasoned A&P can do this job in under an hour.  If I was in your area, I'd be over there in a second--I love rebuilding mags.

 

Good luck!

 

-Jonathan

[Low Level Lover]

Thanks Jonathan. Had my mags rebuilt about 350 hrs ago, and I believe everything was replaced. Did a test flight again today after checking connections and such. Warm-up and first few minutes of flight were OK (govenour worked and no flickering light) but then again on final it started ot flicker sporadically and tach fluctuations followed. Will try cleaning the points as first line of attack.

Thanks

Kirt

[delorean]

If everything is new, it's hopefully just some oil on the points.  This is usually a result of putting too much oil on the felt strip.  Another cause could be engine oil leaking into the mag from the oil filter housing (if installed).

 

Just pull a strip of heavy paper or cardstock soaked in solvent through the slightly opened points.

 

Whatever the case, at least we've narrowed down the location of the problem: Tach points in the right mag or the plug/wiring coming out of it.

[Low Level Lover]

Now my AME and myself are at our wits end. It started out with the

govenor light flickering and a wondering rotor and engine RPM (still

married)to the point where now once the machine warms up the govenor

ceases to work at all with an illuminated gov. off light staying on

but will kick in periodically. We've changed out the tach points for

new ones, checked connections,tried by passing the gov. switch and

checked for chafing wires, all with no change to the situation. Every

one seems to be of the same thinking that the gov. motor and

controller unit are bullet proof and either work or don't work so we

haven't concentrated to much on these either other than looking at the

connections.

Any other suggestions of places to look for problems or different

methods of testing or eliminating curtain elements of the gov.

circuitry would be greatly appreciated.

Thanks

Kirt

 

 

 

<font color='#000000'>If everything is new, it's hopefully just some oil on the points.  This is usually a result of putting too much oil on the felt strip.  Another cause could be engine oil leaking into the mag from the oil filter housing (if installed).

 

Just pull a strip of heavy paper or cardstock soaked in solvent through the slightly opened points.

 

Whatever the case, at least we've narrowed down the location of the problem: Tach points in the right mag or the plug/wiring coming out of it.</font>

[delorean]

Check the pigtail from the actuator.......especially where it enters the motor. The two times I had the problem you described, the insulation was worn and the internal waire was ground out on the shielding. The way to check for this:

 

Go hop in your helicopter and turn the mater battery & governor switches on. Pull up and down on the collective about 50 times and see if you can get the GOV OFF light to come on. Better yet, go fly it first and get it flickering and then ENGINE OFF, ROTORS STOPPED, try it again. If you can get it flickering with collective movement, you've found the problem.

[67november]

I agree with delorean, you appear to have a connection problem, check pig tail as mentioned and check all cannon plugs on the circuit for loose, corroded or cracked connections.

[Low Level Lover]

Well we decided to put it all back together temporarlly this morning and also cleaned both the connections at the bottom of the collective stick and the one coming out of the right mag and guess what, it works!!!!!!! Both connections looked a little damp with oil but not so bad to cause a problem, or so we thought. Anyways we hope this is what the problem was because after 8 hrs of chasing our tails we really did nothing else. Now to make matters worse, after an hour or so of flying and a shut down at a friends place I go to start up again as usual but after 15 seconds or so I notice no rotors turning and my clutch light was not illuminated. Cycled the switch a couple of times and nothing so I shut down immediately. Jump out and take a look and all looks normal. Back inside I check the fuse, pulled and re-set it and did another start and all is well. Get home a short while later and shut down and all is normal. Now in the hanger I figured I would try engaging the clutch again and nothing, check the clutch and it all of a sudden starts running. Flip it to disengage till the lights off and try a few more times and it STARTS TO WORK INTERMITTENTLY when it wants to. Man oh man, give me a break, first the gov light and my low rotor horn (just needed adjustment) crap out and now this all within 1.5 hrs. First thing I checked was the actuater fuse (before knocking my head against the wall)and sure enough one end had a build up of crud, cleaned it up and all seems well. Now I think I'll just sit and look at it in the hanger and not fly it for fear of whats to come.........NOT.

Thanks to everyone for their suggestions and ideas, what a great tool this computer can be sometimes (when it works)!!!!!!!!!!!!!!!

Kirt

[delorean]

Don't be too sure that you fixed the governor problem. That wire still might be ground out or have an internal break. Right now it's fine, but give it some time.

 

The clutch.....It sounds like one of the fan spring switches is sticking in, or is broken. If you look on both sides of the fan, you'll see a green microswitch on each side. One is the up limit, the other is the down limit--THESE ARE NOT THE PROBLEM. Their are two more down behind the fan shroud mounted vertically. When the clutch reaches the proper tension the fan springs pop out and hit those two switches. Either one shuts the clutch motor off (if both fail, the up limit switch will kill before the belts snap.)

 

When you disengage the clutch you are using different wiring, so it will always disengage just fine. The disengage system just runs the pulleys back together until that adjustable bolt head hits the down limit switch.

 

Now, if one of the two (or both) fan spring switches sticks, the clutch THINKS its still engaged, and therefore, will not let you start the engine or actually engage the clutch.

 

THIS IS WHY all R22s & R44s built after summer of 2000, have those two white plastic jumper plugs included. You plug them in behind the test switch plate. One plug bypasses the left switch, the other the right switch. It's a "limp-it-home" feature.

 

If you have one of the old ones, you're screwed. There's ABSOLUTELY no way to properly inspect these switches without pulling the fan and shroud. But..........Sometimes when the belts wear, you'll get some rubber belt junk in the switch. If you have a long extension to blast them with some safety solvent and/or shop air, that will free up a sticky switch. It will happen again--buy two switches now.

 

Replace both switches. And ANY time you have that fan off, replace BOTH alternator belts.

 

Have fun, cuz it's a 6-8 hour job.

 

-Jonathan

[Rob B]

Intermittent Clutch problems can also be caused by 'wear' in the plastic fuse holder. Th soldered end of the wire that contacts the fuse with actually wear into the plastic to a point wear the fuse intermittently breaks contact with the wire.

 

Make sure you have had no mice in the area under the seats were they can chew into the wires - I've seen this twice.

[baldguy]

I operated a number of R22s a while ago and experienced the identical symptoms. The cure is surprisingly simple. Once I got to the point of putting an oscilliscope on the electrical sysytem, I found that I was getting large voltage spikes, causing the erratic tach indications and random warning lights. Normally, the battery acts as a condenser and dampens out the spikes, but when you have a loose or intermittent ground connection, this ability is lost. A simple visual check isn't sufficient, because RHC puts shrink tubing over the terminals, thus masking any corrosion or broken terminals. One ground strap terminal was completely cracked through, but was held together just by the heat shrink tubing! The easiest way to detect a defective ground is to just replace the ground strap and see if the problem goes away. That eliminates the problem no matter which end of the strap is causing it.