R22 Clutch Light EP

[Tenacious T]

EP for a clutch light that stays on or flickers for more than 8 seconds in an R22 is to pull the circuit breaker, land immediately, and be prepared to enter autorotation if necessary. However, it doesn't explain what would happen that would make it be necessary to enter an auto. I am thinking that if the clutch disengages the main rotor from the drive system causing RPM to droop. I am trying to apply real world scenarios to EPs as opposed to simple memorization of the POH so any other examples people post to compare POH to real world situations are welcome.

[RockyMountainPilot]

EP for a clutch light that stays on or flickers for more than 8 seconds in an R22 is to pull the circuit breaker, land immediately, and be prepared to enter autorotation if necessary. However, it doesn't explain what would happen that would make it be necessary to enter an auto. I am thinking that if the clutch disengages the main rotor from the drive system causing RPM to droop. I am trying to apply real world scenarios to EPs as opposed to simple memorization of the POH so any other examples people post to compare POH to real world situations are welcome.

 

You have to scenarios here. One is a broken belt. If this happens, the clutch will try to retension the remaining belt to that of two belts causing the single belt to break. There are actually four belts on an R22, but two are combined into one single belt. If the belt breaks, you have no power going to the main rotor and you need to enter autorotation.

 

The other scenario is a failing sheave bearing. When it begins to fail, it will wobble causing the tension on the belts to flucuate and making the light flicker. If the bearing fails, you can have parts whipping around out of control causing damage to the airframe or controls. So, you want to get on the ground ASAP.

 

Hope this answers your question.

[delorean]

Remember that the clutch light just means the clutch motor is running.....it could be loosening the belts, but it could also be tightening them. That's why the book says to pull the breaker to freeze the motor then make a NORMAL approach. Normal approach because you should always be able to do an easy auto from one (Steep approach, too slow; Shallow approach, too low.) If the the belts are loose the lower pulley could start slipping and burn up the belts as soon as you pull power; if the belts are too tight they could snap.

 

I know three people who have had to pull the clutch breaker coming back from the factory with new helicopters (2 R22s, 1 R44) All three didn't have anything to do with the clutch motor itself, but the clutch light was their first indication something was going wrong. One was an alternator belt that snapped and was thrown into the drive belts; one was an un-lubed lower clutch bearing that seized; the other, a bad set or misaligned belts which shredded. In all three cases they ended up doing an auto within a seconds of seeing the clutch light.

[Tenacious T]

Very helpful, exactly the type of stuff I needed. Anyone feel free to add different EPs with real world causes/solutions.

[swissheli]

Very helpful, exactly the type of stuff I needed. Anyone feel free to add different EPs with real world causes/solutions.

 

Well, I don't know exactly what mean EPs but as I can ready I have a pretty bad experience with the clutch.

 

Clutch light comes on, pull the breaker and land on a golf cours just north of Boston. The problem, the lower bearing on the engin shaft between engine and fan stocks because of bad maintenance. It's recommanded to grease every 300h it was not done and I didn't know. Result, all the fan comes out and the back side of the engin compartment was broken.

[Tenacious T]

EPs=Emergency Procedures

 

Major emergencies have been dissected in the forum before, I'm looking for less dramatic situations, chip lights, strange vibrations, electrical failures, instrument issues at night, etc. and peoples initial reaction to these situations. So far you guys are on the ball, maybe we can expand the topic beyond clutch issues (but not excluding them). Instead of a hypothetical "what would you do if?" more of a "what i did when...".

[RockyMountainPilot]

EPs=Emergency Procedures

 

Major emergencies have been dissected in the forum before, I'm looking for less dramatic situations, chip lights, strange vibrations, electrical failures, instrument issues at night, etc. and peoples initial reaction to these situations. So far you guys are on the ball, maybe we can expand the topic beyond clutch issues (but not excluding them). Instead of a hypothetical "what would you do if?" more of a "what i did when...".

 

The chip light reminds me of a pilot write up I once saw. It said "Chip light illuminated and engaged fuzz burner. Chip light reilluminated twice and engaged fuzz burner twice. Chip light reilluminated fourth time prior to set-down." LOL

 

For anyone that doesn't know, you engage the fuzz burner once. It the light reilluminates, get on the ground ASAP!

[fulldownauto]

Remember that the clutch light just means the clutch motor is running.....it could be loosening the belts, but it could also be tightening them.

 

I was under the impression that when the clutch switch is in the engage position, it can only tighten the belts, it cannot reduce tension. So when the light comes on in flight, it is always because tension is being added.

[RockyMountainPilot]

I was under the impression that when the clutch switch is in the engage position, it can only tighten the belts, it cannot reduce tension. So when the light comes on in flight, it is always because tension is being added.

 

You are correct sir!

[K-38]

I was under the impression that when the clutch switch is in the engage position, it can only tighten the belts, it cannot reduce tension. So when the light comes on in flight, it is always because tension is being added.

That is not correct. The clutch light illuminates both when the belts are tensioning, and when they are untensioning. The entire purpose of the clutch is to disengage the load of the main rotor from the engine during startup. Then you engage the clutch and the belts tighten (clutch light illuminates). During shut down you disengage the clutch and the belts loosen (and the clutch light illuminates).

[K-38]

.

[K-38]

That is not correct. The clutch light illuminates both when the belts are tensioning, and when they are untensioning. The entire purpose of the clutch is to disengage the load of the main rotor from the engine during startup. Then you engage the clutch and the belts tighten (clutch light illuminates). During shut down you disengage the clutch and the belts loosen (and the clutch light illuminates).

Sorry for the electronic lecture you were correct and I screwed up. I missed that you said in the engage position in your post. Whoops! I will pay more attention before posting next time. Carry on.

[shb47]

So here we are 2 years later....I also am under the impression that with the clutch switch ENGAGED, the clutch can only increase tension. Does anybody have a reference for this? It came up on a written test. The POH is ambiguous.

[delorean]

No, it will increase or decrease tension to the maintain the factory set tension (1300 psi, I believe) when the clutch is engaged. The clutch switch forward (engage) tells the motor via the leaf spring switches to maintain that pressure--whether it is increasing or decreasing. Of course, when you're starting the helicopter, it will be increasing pressure.

 

You may see the light in flight after the belts have warmed up or during a large power change. It may be increasing or decreasing pressure.

 

Clutch switch back (disengage) overrides those switches and loosens the belts until the disengage limit switch is closed. This is adjusted via a set screw on the right side behind the fan scroll. If the blades are turning during cranking, or they take more than 5-10 seconds to start turning after engaging the clutch, this needs adjustment.

[shb47]

No, it will increase or decrease tension to the maintain the factory set tension (1300 psi, I believe) when the clutch is engaged. The clutch switch forward (engage) tells the motor via the leaf spring switches to maintain that pressure--whether it is increasing or decreasing. Of course, when you're starting the helicopter, it will be increasing pressure.

 

You may see the light in flight after the belts have warmed up or during a large power change. It may be increasing or decreasing pressure.

 

Clutch switch back (disengage) overrides those switches and loosens the belts until the disengage limit switch is closed. This is adjusted via a set screw on the right side behind the fan scroll. If the blades are turning during cranking, or they take more than 5-10 seconds to start turning after engaging the clutch, this needs adjustment.

 

OK, you sound like you know what you're talking about. After reading this and other forums, I see there is a lot of confusion on this question. Can you cite a reference for your answer? Thanks.

[delorean]

RHC Safety School

RHC Maintenance School

and the R22 & R44 Maintenance Manuals.

 

Take a look the MM and see if it's explained at the very beginning of the drivetrain section, otherwise look at the wiring diagram.

 

But that's how it works.......

[shb47]

RHC Safety School

RHC Maintenance School

and the R22 & R44 Maintenance Manuals.

 

Take a look the MM and see if it's explained at the very beginning of the drivetrain section, otherwise look at the wiring diagram.

 

But that's how it works.......

 

Thanks. I've not seen the mx manual, but I figured that's where the answer was. They only give us pilots the minimum knowledge required.

[amphibpilot]

From RHC Tech Support (customerservice@robinsonheli.com):

 

"When the Clutch switch is in the Engaged position, the belt tension actuator ("clutch") can only extend and increase belt tension due to applied electrical polarity at the gearmotor. Conversely, when the Clutch switch is in the Disengage position the belt tension actuator can only retract and decrease belt tension, again due to the [reversed] applied polarity at the gearmotor. For specific circuit details please refer to R22 Maintenance Manual Figures 14-4 & 14-4A dated JUN 99, and R44 Maintenance Manual Figure 14-1F dated OCT 2006."

[shb47]

From RHC Tech Support (customerservice@robinsonheli.com):

 

"When the Clutch switch is in the Engaged position, the belt tension actuator ("clutch") can only extend and increase belt tension due to applied electrical polarity at the gearmotor. Conversely, when the Clutch switch is in the Disengage position the belt tension actuator can only retract and decrease belt tension, again due to the [reversed] applied polarity at the gearmotor. For specific circuit details please refer to R22 Maintenance Manual Figures 14-4 & 14-4A dated JUN 99, and R44 Maintenance Manual Figure 14-1F dated OCT 2006."

 

 

Ok...now my head is exploding. This is what I believed, but delorean sounds like an experienced mech on the R22. See what I mean about a lot of confusion on this issue?

 

Thanks for the reference.

[delorean]

If that's what RHC said, I would go with it.....

 

I though they told us at factory school it would do both, but it makes the system much simpler the way the email describes it (and it is a simple system). It's been 10 yrs since school and I haven't flown or worked on a R22/44 in 5 yrs, but I swear I heard that.

 

The procedure remains the same though--pull the CB after 8 seconds. You don't know if the system is tightening or loosening. A short, a bad switch, etc *could* cause that motor to reverse polarity. Usually a light for that long would indicate a failing belt, and the motor is tightening up the ones left. Lock the motor and land.

 

Light ON, means motor running. You don't know which way, but it *should* be in the direction selected.

[Goldy]

500 AGL at 75 knots in the 44 today and on comes the clutch light. After the usual 7 or 8 seconds passed, I thought hmmmm...this may not be good. Few seconds later I pull the CB and head back to the airport. Not really a big deal, but it's the first time I've ever had to terminate a flight in the air for mechanical reasons.

 

Was going to be a beautiful night in the air too....missed it.

 

Goldy

Edited December 20, 2009 by Goldy

[amphibpilot]

<snip>

Not really a big deal, but it's the first time I've ever had to terminate a flight in the air for mechanical reasons.

<snip>

Goldy

 

Better on ground wishing flight than vice versa.

 

What are the findings?

 

Happy holidays!

[Goldy]

Better on ground wishing flight than vice versa.

 

What are the findings?

 

Happy holidays!

 

I saw that the actuator fuse was blown, hence the light. However, the ship is on a 135, so I just have to wait for the 135 mechanic to check it out.