[John90290]

My CFI found a nice vertical crack about four inches long on a drive belt on the R22 I was about to fly in...close call. I missed it on my preflight...

Belts had only 50 hours on them.

Thank God for good CFIs.

[JDHelicopterPilot]

Good catch. If the belts are going to fail it is when they are fairly new. Normaly though its in the 10 hour range. When I was a CFI we had an R-22 just back from overhaul and it's belt snapped at the end of the approach. No damage to the aircraft except for the engine overspeed of course.

Fixed it, new engine and belt. No other CFI would fly it so I decided I would put the time on it before putting it in service. Put the hover hours on it as required then went up in the pattern. Just before I was going to put it back on the flight line a mechanic asked me if we could take it to pick up some parts at another airport. We took off and sure enough the clutch light came on several times. I was right by an airport so got priority and landed. Inspected the belt and sure enough it was about to fail again. It had 12 hours on it.

JD

[Goldy]

JDHelicopterPilot, on Nov 11 2009, 19:46 , said:

Good catch. If the belts are going to fail it is when they are fairly new. Normaly though its in the 10 hour range.

Yepp, there are several instances of low time belts failing. A vertical crack or tear isnt as bad as a horizontal one! Often times the belt will start to separate or split where they are fused together.

Is it just me, or does this seem to be more prevalant on the 22 than the 44? Never seem to have that problem in the 44, maybe its just luck.

Goldy

[HelliBoy]

Wasnt there an SB about 'sheave alignment' that was supposed to clear up belt failure on the 22?

What a glaringly huge weak link in safety design....'congratulations, here's your new helicopter, tried and true design...except the drive system might fail. Happy flying!'

[500E]

Watch for the incoming HB

[Goldy]

HelliBoy, on Nov 12 2009, 05:41 , said:

Wasnt there an SB about 'sheave alignment' that was supposed to clear up belt failure on the 22?

What a glaringly huge weak link in safety design....'congratulations, here's your new helicopter, tried and true design...except the drive system might fail. Happy flying!'

Yes, there was some sheave alignment protocols to follow. Also, I think they offered an upgraded sheave if you wanted.

Not sure, never bought a new from the factory ship before, and I'm not a mechanic. But I never take off in any Robbie without a spin of the belts...getting under the ship helps as well...and always check the alternator belt. Many times, this is the worse one...and if it fails it could fly into the clutch belt and cause it to fail. You can see it in the 22, but you have to get on your back to see the one in the 44.

Goldy

[delorean]

I know three people who have had belt issues on the way back from the factory (all local, and all within a few months of each other.)

1- Alternator belt got thrown into the drive belts--dislodged two and snapped the other two. Raven II.

2- Drive belt came apart on a Beta II Instrument trainer. Factory mechanic flew to Texas and replaced the belt that day, but did not torque the fan bolt. About 50 hrs later the fan came off the helicopter, and luckily did not take the tailcone with it.

3- Can't remember the details, but another Beta II. Something happened with the drive belts, but ultimately they someone at the factory forgot to grease the lower clutch bearing.

In all of these situations, the clutch light was the first indication something was going wrong.

[Hovergirl]

500E, on Nov 12 2009, 06:02 , said:

Watch for the incoming HB

What's that? Let me know and I'll watch for it...

[Goldy]

Capulet, on Nov 21 2009, 12:27 , said:

There have been times when I have found small cracks in between the teeth....does anyone know if its ok to fly like that or should the belt be replaced?

Are you talking about the alternator belt? If so, as they age and with the heat they are exposed to, they will have small surface cracks. My PERSONAL opinion is that does not make the ship unairworthy and I would fly it. I would also tell the mechanic to be sure and change it out at the next 100 hour. Any deeper cracks than surface and you will start to lose teeth, even one lost tooth on a belt and I wouldnt fly it.

Remember they used to keep a spare alternator belt hanging back there...but often times it would be just as cracked from exposure as the belt you were using.

Anyway, remember the real risk of losing an alternator belt is not losing alternator power....its having the belt fly into the drive belt and causing the drive belt to shred or come off its pulleys. Which is a good reason Robinson should make a simple shroud over the alternator belt so it can't do that !!

Fly safe, always defer any mechanical questions to your mechanic!

Goldy

This post has been edited by Goldy: 21 November 2009 - 15:48

[delorean]

Goldy, on Nov 21 2009, 14:48 , said:

Anyway, remember the real risk of losing an alternator belt is not losing alternator power....its having the belt fly into the drive belt and causing the drive belt to shred or come off its pulleys. Which is a good reason Robinson should make a simple shroud over the alternator belt so it can't do that !!

And that's exactly what happened to my buddies with a brand new R44RII. In the middle New Mexico with no flat spot to land on. Chopped the tail off on impact, but they were fine. Luckily some farmer found them 3-4 hrs later.

Frank told them they must have been pulling over MCP and Robinson would not be held liable. After some angry phone calls and lawsuit threats, RHC agreed to fix the helicopter. But my buddy said since it had an accident history, it lost value and he didn't want it. He ended up getting a new one about 9 months later and the dealer ate the annual price increase and lost value on the other ship.

I would treat an alternator light on a Robinson like a low oil pressure light. Get it on the ground ASAP.

[kodoz]

delorean, on Nov 21 2009, 17:25 , said:

I would treat an alternator light on a Robinson like a low oil pressure light. Get it on the ground ASAP.

The rationale being that an alternator light ~ failing alternator, which could be due to a failing belt, right? So would you go thru the resetting the alternator step, or land and figure it out?

[Goldy]

kodoz, on Nov 21 2009, 17:51 , said:

The rationale being that an alternator light ~ failing alternator, which could be due to a failing belt, right? So would you go thru the resetting the alternator step, or land and figure it out?

Or an alternator light could mean a bearing is going out in the alternator itself....and the belt might soon follow by failing.

Either way, I would want to be on the ground as well.

Why would Robinson think that pulling over max power would cause the alt belt to fail?

[Inferno]

Goldy, on Nov 22 2009, 11:53 , said:

Why would Robinson think that pulling over max power would cause the alt belt to fail?

I was wondering the same thing....

[delorean]

Inferno, on Nov 23 2009, 12:37 , said:

I was wondering the same thing....

So they could blame the PIC since none of their products EVER fail. It was just a blame game.


Also, yes, I wouldn't try to diagnosis it in the air. It could be a bad diode or brush, but the threat of the belt shredding makes it an emergency for me.

Land as soon as possible, but maybe "as soon as practical". If the belt does look bad, the bearing has failed, or the light won't go out after several resets, you are grounded. The alternator is a required piece of equipment per the limitations section and you cannot take off with it inop.

Even if you have a MEL, you cannot defer an alternator on a Robinson (at least you didn't used to be able to......just the light provided the ammeter worked.) So a ferry permit or on-site maintenance was the only way to legally takeoff after that PL.

[kodoz]

So how common is it for the alternator light to come on, but go off after cycling the switch?

[500E]

Never understood why recycling cures light, have driven literally millions of miles and if an alt failed it failed, stopping and starting had no miraculous repair fairy.

[Goldy]

kodoz, on Nov 23 2009, 12:34 , said:

So how common is it for the alternator light to come on, but go off after cycling the switch?

Never had an alt light come on, or an alt fail in flight. One of the guys found the alt belt pretty well shredded on a pre-flight though, so the flight before was a lucky one!

[Pohi]

500E, on Nov 23 2009, 14:52 , said:

Never understood why recycling cures light, have driven literally millions of miles and if an alt failed it failed, stopping and starting had no miraculous repair fairy.

Turning the alternator off, waiting, and then turning it back on resets the relay. A spike in the electrical system might have tripped it off, and that is the way to reset it.

It would be nice if there was a low fuel fairy though, that would make things pretty sweet.

I did have an alternator light that would come on if the helicopter was flying in the rain and the landing light was turned on. The belt was a little too loose so that was an easy fix.