Prop de-ice boots

[skidoo]

Can some of you enlighten me on how common it is for prop de-ice boots tend to go bad? It turns out that all three of mine need replacement. I think they may have been bad when I purchased the plane (T182T) some years ago, but I'm not sure. Not sure if they were checked at annuals. So, I am wondering what is the most common reason for them burning out such as simply extended normal use or improper use.

Any tips as to who I should trust to do the repairs, and any type of shop to avoid? Or should I consider just leaving them in-op as is...?

 

[DavidWhite]

have you ever used them? If not, I think you have your answer.

 

[Arbiter419]

Semi related note: maybe I am missing something big here, but what's the use of a hot prop when you have nothing for the wings?

 

[dell30rb]

Keeping the propeller ice free and balanced and the air induction open is more important than keeping the wings ice free.

Obviously an airplane with only prop heat is not FIKI but its better than nothing if you happen to run into ice.

 

[Arbiter419]

Keeping the propeller ice free and balanced and the air induction open is more important than keeping the wings ice free.

Obviously an airplane with only prop heat is not FIKI but its better than nothing if you happen to run into ice.

I can't speak for all aircraft obviously, but the intake on a 182 is well below the spinner, and as far as I know is not heated.

And if it came down to it, I'd rather be a glider than a brick.

 

[dell30rb]

I can't speak for all aircraft obviously, but the intake on a 182 is well below the spinner, and as far as I know is not heated.

And if it came down to it, I'd rather be a glider than a brick.

You've got an alternate air intake if its fuel injected and if carbureted, pull the carb heat and the air is pulled through a heated alternate air intake as well.

Understand where you are coming from but a 182 with a clean airframe and no power is a brick! Obviously you don't want to put yourself in icing conditions but an airplane like a 182 can handle a fair amount of airframe ice (dep on load and altitude) if its putting out all of its HP. If you have no HP it does not matter if the airplane has a light dusting of ice or an inch, you're going down.

 

[skidoo]

Thanks for the input so far. But, I really did not intend to make this a debate over the value of FIKI vs non FIKI, etc... I understand that this is a non-FIKI aircraft. But, it is a well instrument equipped and came from the factory with pitot heat and prop heat. I understand that the purpose is to provide some extra time to divert out of inadvertent icing conditions, not to continue through it. It would be nice to know it works, just in case.

I am wondering what others have experienced, maintenance wise regarding prop heat boots.

 

[Tom-D]

De-ice boots for the prop are very much like any other heater blanket, they have ohm and amperage checks that will show open or shorted heater elements.

They have a brush blocks that transfer power from the stationary engine, to the rotating prop, these are a problem area. the brushes get too short and do not function as they should.

 

[flyingcheesehead]

Heck, I'm just wondering how you find out they're bad? The Mooney has prop de-ice, but aside from the fact that it's drawing current, how can you tell it's working? I've flipped it on a few times, mostly the same times I'd use pitot heat as well, but it's hard to tell if it does anything even when you do run into a bit of ice.

 

[Henning]

Can some of you enlighten me on how common it is for prop de-ice boots tend to go bad? It turns out that all three of mine need replacement. I think they may have been bad when I purchased the plane (T182T) some years ago, but I'm not sure. Not sure if they were checked at annuals. So, I am wondering what is the most common reason for them burning out such as simply extended normal use or improper use.

Any tips as to who I should trust to do the repairs, and any type of shop to avoid? Or should I consider just leaving them in-op as is...?

Brushes/commutator, have a look, usually not a cheap system to repair.

 

[skidoo]

Heck, I'm just wondering how you find out they're bad? The Mooney has prop de-ice, but aside from the fact that it's drawing current, how can you tell it's working? I've flipped it on a few times, mostly the same times I'd use pitot heat as well, but it's hard to tell if it does anything even when you do run into a bit of ice.

On my G1000, when the prop heat is switched ON, an annunciator should illuminate green. Mine has been illuminating amber. Checking the POH, amber indicates a failure. So, it was diagnosed down to the individual boots with excessive resistance directly from the boot lead wires, bypassing all other connections. Excessive resistance means little or no current, and therefore, no heat! So, if it is drawing normal current, it is likely working.

While on the ground, by placing a proper value dummy load in place of the boots and therefore drawing normal current, the annunciator illuminates green as if it was working.

So, I believe my boots need replacement. I have a friend who says he has never seen all three go out at the same time, and was initially suspicious of the diagnosis. I saw the measurements on all three myself, so I am confident of that. But, it got me to wondering how common this really occurs.

 

[Henning]

On my G1000, when the prop heat is switched ON, an annunciator should illuminate green. Mine has been illuminating amber. Checking the POH, amber indicates a failure. So, it was diagnosed down to the individual boots with excessive resistance directly from the boot lead wires, bypassing all other connections. Excessive resistance means little or no current, and therefore, no heat! So, if it is drawing normal current, it is likely working.

While on the ground, by placing a proper value dummy load in place of the boots and therefore drawing normal current, the annunciator illuminates green as if it was working.

So, I believe my boots need replacement. I have a friend who says he has never seen all three go out at the same time, and was initially suspicious of the diagnosis. I saw the measurements on all three myself, so I am confident of that. But, it got me to wondering how common this really occurs.

If you lost all three boots all of a sudden, you have another problem to look for. If you lost one at a time over a couple decades of who knows and here you are testing a 35 year old system and all three test junk, well yeah, they're due.

 

[flyingmoose]

In my experience with prop de-ice problems, many of them trace back to the brush block in between the prop and the engine. Many times they just get dirty and removing them and cleaning will fix the problems. They can also wear out and need replaced. If you have all three blades inop then that might be a good place to start. You didn't say how they tested them, but if they tested the resistance of each pad and they all showed bad then you might acualy have 3 bad pads. Depending on the age of them its possible that they are just old and worn out, but if they were working and are now not look at the brush assembly.

 

[TMetzinger]

If you lost all three boots all of a sudden, you have another problem to look for. If you lost one at a time over a couple decades of who knows and here you are testing a 35 year old system and all three test junk, well yeah, they're due.

On a G1000 airplane, the boots should be relatively new (i.e. less than 10 years old), no?

 

[Tom-D]

On my G1000, when the prop heat is switched ON, an annunciator should illuminate green. Mine has been illuminating amber. Checking the POH, amber indicates a failure. So, it was diagnosed down to the individual boots with excessive resistance directly from the boot lead wires, bypassing all other connections. Excessive resistance means little or no current, and therefore, no heat! So, if it is drawing normal current, it is likely working.

While on the ground, by placing a proper value dummy load in place of the boots and therefore drawing normal current, the annunciator illuminates green as if it was working.

So, I believe my boots need replacement. I have a friend who says he has never seen all three go out at the same time, and was initially suspicious of the diagnosis. I saw the measurements on all three myself, so I am confident of that. But, it got me to wondering how common this really occurs.

If some one placed the de-ice switch in the on position while not flying, or the engine running, the the heater boots burn up, with out cooling.

OBTW, I have never seen a prop de-ice system with a commutator, they are simple slip rings, the same theory as an alternator.

 

[Ted]

On the Aztec, I've had to replace all 4 over the 4 years I've had it. So I'd say it's not uncommon.

If you see the proper current going through, you're good. But you'll confirm it by letting it run through a cycle with hands on the blades to make see which ones are warm. And which ones aren't.

 

[Henning]

On a G1000 airplane, the boots should be relatively new (i.e. less than 10 years old), no?

Meh, even 10 years is life on them. If it's just the boots directly testing bad, that isn't all that bad to deal with.

 

[Jaybird180]

Hope someone can clear me up on terminology:
Boots are mechanical devices that pump up/down to remove ice
Heated Prop runs electrical current through to heat the surface thereby removing ice

1- I didn't know there was a such thing as a prop boot
2- Is there such thing as a heated boot?

 

[AcroBoy]

Props use either an alcohol slinger or are electrically heated. The electrically heated ones have a commutator that makes contact with the heating element in the blade. They can be expensive to fix. THere are no inflatable boots on prop blades.

Wings can use inflatable boots, heated elements by bleed air, weeping wing technology that leaks out glycol, or there are some newer electrical discharge technologies out there. None of them is perfect, and they all have limitations.

My plane is certified for flight into known ice with the weeping wing technology. Although more expensive initially than boots, probably is less expensive in the long run, and does not require maintenance of the boots or periodic replacement. Also, my series of plane still required an alcohol spray bar for the windshield as well as an alcohol slinger for the props, which was still a consumable and didn't last that long in icing.

The TKS does it all for me, and was the right choice for my application.

 

[Ted]

The heating elements on props are often referred to as prop boots. They do not inflate like wing boots.

You also have alcohol props, which just put alcohol on the prop blades.

There have been a couple of experimental electric hot wings, but I don't think it's ever made it very far. You see successful hot wings on jets, and also the Piaggio.

 

[flyingmoose]

Hope someone can clear me up on terminology:
Boots are mechanical devices that pump up/down to remove ice
Heated Prop runs electrical current through to heat the surface thereby removing ice

1- I didn't know there was a such thing as a prop boot
2- Is there such thing as a heated boot?

They are called prop boots most of the time.

From Ram Air:
http://www.ramaircraft.com/Aircraft-Parts/De-Ice-Boots/SMR-Di-Ice-Boots-Propellers.htm

From the McCauley manual:
E. Propeller Deice (Refer to Figure 11)
NOTE: Only components sold by McCauley are described. Some OEMs or STC owners may have
different designs.
(1) If propeller deice is installed, the components include:
• electrically heated rubber boots

Hope that helps.

 

[denverpilot]

If some one placed the de-ice switch in the on position while not flying, or the engine running, the the heater boots burn up, with out cooling.

I thought I remembered something about that from the newer C182 POH with the G1000 system. Seems to ring a bell that someone did it to one of our CAP aircraft, too. Just a vague remembrance from a few years ago.

 

[N801BH]

On the Aztec, I've had to replace all 4 over the 4 years I've had it. So I'd say it's not uncommon.

If you see the proper current going through, you're good. But you'll confirm it by letting it run through a cycle with hands on the blades to make see which ones are warm. And which ones aren't.

One thing I might add is......

When testing the prop heat pads I /we always try to keep the prop slowly rotating by hand so the brushes are not stationary on the commutator /slip rings... That prevents hot spots on that surface IMHO.

Ps.. Make DAMN sure the mags are dead too..

 

[Henning]

When I'm testing systems I do them with it running and you can either use a heat gun to see the temp or you can go feel them after shut down.

 

[Tom-D]

One thing I might add is......

When testing the prop heat pads I /we always try to keep the prop slowly rotating by hand so the brushes are not stationary on the commutator /slip rings... That prevents hot spots on that surface IMHO.

Ps.. Make DAMN sure the mags are dead too..

one more thing you can add, when replacing a prop because the one you removed had burned up boots, be certain you turn off the de-ice switch before you connect the circuits to the brush block on the new prop.

 

[Silvaire]

As Tom pointed out, there is no commutator in this circuit. The rings and brushes are simply a method of maintaining an electrical connection between the stationary and rotating parts. A commutator is a mechanical switching mechanism that converts the alternating output of a generator motor into direct current or, conversely, the direct current from the battery into alternating current for the starter motor. Alternators use slip rings because the AC is converted into DC by a solid state diode bridge.

As for testing the boots, if you have an ammeter you should see the draw when they are turned on. You can also switch them on on the ground and feel the boots for warmth. I don't know of any danger of burning them up as they are on a timer and you'd have to leave the master on as well so it's not something you'd be prone to forget. If they aren't working then simple troubleshooting techniques would be applied. The boots are just a heat coil so you can check them with an ohmmeter. You can also check that voltage is reaching the brushes and the brushes themselves would have visual clues if there were something wrong with them.

 

[kmead]

Many times the prop deice boots are replaced because the are deteriorated from old age or from being parked outside. Burned or overheated boots are very noticeable.

I have installed hundreds of prop boots over the years and the job is not that difficult to do. I would make sure that they have installed some before, they've been known to come off after installation too. I have found large differences in the weight of replacement prop boots, I always compare the weights on a scale. I've had some Malibus show up shaking badly because of a new prop boot.

 

[N801BH]

....... I've had some Malibus show up shaking badly because of a new prop boot.

I bet... Altho I thought any A&P would know to rebalance ANY prop blade that had a replacement boot installed... It seems like a no brainer to me.

 

[douglas393]

Back to the op question I have a 2007 t182t and mine have not worked since I bought the plane in may 2011. I live in Florida and the plane has been always based in florida so not sure how much they have been used. I have not had them fixed yet, nor diagnosed because I think my mechanic( two different places) do not want to deal with it. Annual is next month, and it will be diagnosed. Will let you know.

 

[Henning]

Semi related note: maybe I am missing something big here, but what's the use of a hot prop when you have nothing for the wings?

Traction and balance. No need to let the prop get dirty and kill you.

 

[gprellwitz]

We got the yellow prop deice caution light on the T182T we rented, too, and they were, of course, less than 10 years old. Don't know what the cause was, though. Just more anecdotal evidence.

 

[skidoo]

I bet... Altho I thought any A&P would know to rebalance ANY prop blade that had a replacement boot installed... It seems like a no brainer to me.

Is any A&P that says he can do the job qualified to do so. Or, is there specialized training beyond A&P and or special equipment necessary?

My local A&P says he can't do it and should be done at a prop shop. I have another service shop who has an A&P who say he has done several before including on some twins. He says it is no problem, just takes about a day of labor. One great thing about this shop is they allow me to be there for everything. So, I know exactly what is done to the aircraft. Does this sound good, or should I be searching for a specialized prop shop, which could be far, far away?

 

[N801BH]

Is any A&P that says he can do the job qualified to do so. Or, is there specialized training beyond A&P and or special equipment necessary?

My local A&P says he can't do it and should be done at a prop shop. I have another service shop who has an A&P who say he has done several before including on some twins. He says it is no problem, just takes about a day of labor. One great thing about this shop is they allow me to be there for everything. So, I know exactly what is done to the aircraft. Does this sound good, or should I be searching for a specialized prop shop, which could be far, far away?

The local shop here... Jackson Hole Aviation has a nice ACES prop balancer, and the top mechanic, Todd can get a prop within .002 IPS in about 1.5 hours..

 

[Ted]

It probably depends on who you talk to. I agree in principle that, if you change your prop boots, you should have your prop dynamically balanced. But I don't think the manual says that's a requirement. I also think in principle that props should be dynamically balanced after prop or engine overhaul, as well as after some FOD events that may upset the balance.

None of my prop boot replacements were followed up by a rebalance of the props. In fact, in the 1,000 hours I've had the Aztec, I never did a dynamic balance on the props, and I doubt if they were ever dynamically balanced. If they were, they would've been thrown off significantly more by the gravel chunks that were torn out of the props from up in Canada (still legal without need for rebalance, according to Hartzell).

I did once need to replace an engine mount due to a crack, after about 800 hours or so that I'd put on the plane. One could argue it was caused by lack of balance of props. One could also argue it was caused by close to 10,000 hours of flight time with no previously logged repairs on the engines mounts.

That said, one of the first trips I intend to make with the 310 once it gets new engines on it is to get the props dynamically balanced. If nothing else, I like silky smooth engines.

 

[Tom-D]

A&Ps in the field are only authorized to do minor maintenance on props, parts replacement is not minor maintenance.

 

[N801BH]

A&Ps in the field are only authorized to do minor maintenance on props, parts replacement is not minor maintenance.

Suppose he/she was an IA.... From all your posts it appears like an IA can return to service all type of repairs.?..

To make it crystal clear.. I am referring the the local guys doing a prop balancing... NOT a boot replacement..

 

[Tom-D]

Suppose he/she was an IA.... From all your posts it appears like an IA can return to service all type of repairs.?..

To make it crystal clear.. I am referring the the local guys doing a prop balancing... NOT a boot replacement..

A&Ps or A&P-IAs can only do what the ICAs for the prop allows. Your ICAs are in the owner's manual. every other maintenance routine is directed from the overhaul manual.

and the first pages of that manual will direct who can complete the maintenance of the prop.

any other maintenance on a prop, other than what's allowed in the ICAs are major repairs.

65.81 General privileges and limitations.
(a) A certificated mechanic may perform or supervise the maintenance, preventive maintenance or alteration of an aircraft or appliance, or a part thereof, for which he is rated (but excluding major repairs to, and major alterations of, propellers, and any repair to, or alteration of, instruments), and may perform additional duties in accordance with §§ 65.85, 65.87, and 65.95. However, he may not supervise the maintenance, preventive maintenance, or alteration of, or approve and return to service, any aircraft or appliance, or part thereof, for which he is rated unless he has satisfactorily performed the work concerned at an earlier date. If he has not so performed that work at an earlier date, he may show his ability to do it by performing it to the satisfaction of the Administrator or under the direct supervision of a certificated and appropriately rated mechanic, or a certificated repairman, who has had previous experience in the specific operation concerned.

(b) A certificated mechanic may not exercise the privileges of his certificate and rating unless he understands the current instructions of the manufacturer, and the maintenance manuals, for the specific operation concerned.

 

[N801BH]

A&Ps or A&P-IAs can only do what the ICAs for the prop allows. Your ICAs are in the owner's manual. every other maintenance routine is directed from the overhaul manual.

and the first pages of that manual will direct who can complete the maintenance of the prop.

any other maintenance on a prop, other than what's allowed in the ICAs are major repairs.

65.81 General privileges and limitations.
(a) A certificated mechanic may perform or supervise the maintenance, preventive maintenance or alteration of an aircraft or appliance, or a part thereof, for which he is rated (but excluding major repairs to, and major alterations of, propellers, and any repair to, or alteration of, instruments), and may perform additional duties in accordance with §§ 65.85, 65.87, and 65.95. However, he may not supervise the maintenance, preventive maintenance, or alteration of, or approve and return to service, any aircraft or appliance, or part thereof, for which he is rated unless he has satisfactorily performed the work concerned at an earlier date. If he has not so performed that work at an earlier date, he may show his ability to do it by performing it to the satisfaction of the Administrator or under the direct supervision of a certificated and appropriately rated mechanic, or a certificated repairman, who has had previous experience in the specific operation concerned.

(b) A certificated mechanic may not exercise the privileges of his certificate and rating unless he understands the current instructions of the manufacturer, and the maintenance manuals, for the specific operation concerned.

Tom.
Thanks for posting that for all the "CERTIFIED" aircraft owners.... I have an experimental, and I hold the repairmens certificate, so I make the rules in my application......

Thanks anyway sir...

 

[Tom-D]

I have an experimental, and I hold the repairmens certificate, so I make the rules in my application......

Thanks anyway sir...

And you feel qualified to do what to it?

 

[N801BH]

And you feel qualified to do what to it?

Well................

Seing how I built it from scratch, engineered the entire powerplant /forewall forward systems, wired the entire plane, built my panel, engineered and installed one of a kind flight control systems, completed the ENTIRE project to make it airworthy during a 3000 hour build process. Test flew it for the first time instead of hiring a test pilot. Tested , confirmed and generated the POH for this plane... And I currently have over 400 hours and 60,000 miles on it, I think I can comfortably say .................................

I am QUALIFIED to do anything I want to it...........

And more questions sir...