hot prop

[Amelia]

The 1980 Mooney 231 is in the throes of its annual inspection, and the IA insists the owner get the hot prop repaired before he can, in good conscience, sign it off. Is he right? The only operator of this aircraft knows it doesn't work, has had it repaired over the years, and the repair never lasts long, That person doesn't fly in ice, and doubts if s/he'd trust that hot prop to shed much ice, anyway....  The mechanic was asked if he could stick a little sticker saying 'in-op' on the rocker switch, and he said no. As original equipment, it needs to work. Bless his heart, one appreciates his attention to dotting 'i's and crossing 't's, but is this probably expensive exercise in futility really necessary?

 

Thanks!

 

[ArtVandelay]

Well, the statement about it needs to work because it's original equipment is wrong, and it's not required equipment for flight (tomato flames, etc), so I would push back on that. Almost every mooney has at least 1 original equipment inop, usually an old EGT gauge.

I'm assuming it's not on the Minimum Equipment List, the plane is Not FIKI rated, and is not used in commercial operations.

[carusoam]

The POH should have a list of required equipment specific for your plane.

The list has things required for flight, for day, night, and for IFR. Look for a chart with columns of check marks.

I can't imagine that a hot prop is on those lists... But check your POH...

As far as an opinion on hot props...

I briefly considered getting the heated version of my prop while updating the FWF. Mechanic said heating just the prop was of little value...

As far as maintenance on the rotating contacts goes... Is there a simple way to clean and lube (maintain) the system to make it work properly?

Best regards,

-a-

[Nathan Peterson]

Amelia,

That is incorrect. Part of the sign off in the logbook should reference the hot prop as inoperative and flight into known icing is prohibitive.

Nate 

[Amelia]

Thanks, Nate! I have informed the A&P, IA, and he seems content. He probably was just trying to avoid any future conversations with lawyers.

[Guest]

Thanks, Nate! I have informed the A&P, IA, and he seems content. He probably was just trying to avoid any future conversations with lawyers.

If its within regulation to label the prop deice as "in operative" which I would think it is. Ask the owner to sign a letter to the IA acknowledging that it is in operative and that he is fine with the log reflecting it. The IA can keep a copy in his records for future reference.

Clarence

[AndyFromCB]

The POH should have a list of required equipment specific for your plane.

The list has things required for flight, for day, night, and for IFR. Look for a chart with columns of check marks.

I can't imagine that a hot prop is on those lists... But check your POH...

As far as an opinion on hot props...

I briefly considered getting the heated version of my prop while updating the FWF. Mechanic said heating just the prop was of little value...

As far as maintenance on the rotating contacts goes... Is there a simple way to clean and lube (maintain) the system to make it work properly?

Best regards,

-a-

 

Anthony,

 

I beg to differ here just a little bit. A functioning hot prop is of a lot more value without any deice otherwise, than a set of boots without a prop deice. Ice often forms on the propeller even in conditions where it would not form on the wings. Ice on the prop is not a pleasant thing to deal with, especially when attempting to escape it when all the rate of climb is needed. Not being able to generate thrust is often much more of a problem than some smooth ice on the leading edge. A Mooney will deal just fine with an inch on the leading edge as long as the prop can pull it.

 

Now, to throw in my two cents, my Bravo was a TKS retrofit, so while I'm TKSed, I fly with a big sticker stating PROPELLER DE-ICE INOP simply because my original electric de-ice is no longer installed (but the big button is still there), instead being replaced by a fluid slinger ring. So I'd have to say the A&P is in the wrong here.

[kortopates]

Technically, I believe your IA was right originally; since the aircraft was certified with the prop heat (unless I am wrong it was optional equipment - I am not certain).

With respect to the regs - seems like many of us just refer to the ones we want to make use of. Most owners understand 91.213 which allows us to operate with an inoperative instrument or equipment. But fail to understand that this is not a permanent authorization to operate with the discrepancy. 91.405© Maintenance Required spells it out "Shall have any inoperative instrument or item of equipment, permitted to be inoperative by 91.213(d)(2) of this part, repaired, replaced, removed or inspected at the next required inspection. (91.405 d goes on to say the inop instrument/equipment needs to be placarded as as such, but it is referring till it's fixed at the next inspection). So I am sure your IA was reacting to 91.405 as he was taught to do which requires all previously allowed inop equip to be fixed or removed if they are optional equipment. I really wouldn't want to see it removed if it was mine, as I would expect to see the plane take a substantial hit in resale.  

 

In the case of the Bravo with a TKS retrofit, that is entirely different because the Type certificate has now been modified by the STC for TKS and the STC (whatever it says) governs the prop deice issue. But it sounds like all has been removed except for a button on the panel so still very different.

 

So what has been the problem with getting it back to working? Brushes are cheap, boots aren't that bad, the ammeter was $800 last time I saw but the timer I imagine would be the most expensive to deal with. Hopefully its not the timer.

[Amelia]

This is an old-ish stock 231, Paul, There never was any known icing certification. Nothing has been removed or modified, it's just boots on a propeller, and for some reason the thing needs to have some electrical magic done every few years. I already have a little sign, original equipment, yet, that says, "not certified for flight into known icing."  And the repair, usually is not more than a few hundred bucks, plus the time and expense of going and finding a prop shop, and sitting all day. I put it off out of sheer orneriness, I guess. There's nothing really very close or convenient. But the day will come, and I WILL pay to get it fixed. Again. Like for about the fifth time, even though I don't have FIKI, and don't ever fly in known icing.So, I need the annual signed off this month. I'm not flying anywhere, prop heater or no, until all this NC 'known icing' goes away for the year, which shouldn't be long, and then I'll pick up all my good intentions right where I dropped them.

[kortopates]

Amelia. I hear you.What I wasn't sure of was if the 231's had prop heat as optional added equipment. And now I recall a few clients that did not have prop heat so I also just looked at a early 231 POH and sure enough, Prop heat was optional. It did become standard equipment later but that's irrelevant, point is the certification didn't require it.  Anyway this reasoning is just to say that you and your IA could opt to remove the prop heat and be done with it. But as mentioned previously that would be silly since removing it would likely be more expensive than fixing it and would certainly cause a hit in resale value. But it really has nothing to do with being FIKI or not. Consider your other anti-ice device on the pitot tube - pitot heat. You could placard and in-op pitot heat for the same argument you make on the prop heat under 91.213 but come the next required inspection, your annual since you don't fly for hire, 91.405 requires that it must now be fixed.Or hypothetically speaking, one could probably get approval to replace it with unheated pitot tube i.e. remove the heated probe. But of course it would be preferable to fix it and that's the intent of 91.405. Your IA was just trying to do the right thing.

Anyway, I am betting it must be the brushes that are worn since you mention it happens every few hundred hours. If so, the brushes run ~$70 (i recall from the last time I replaced mine using the RAPCO PMA part) and your regular home based A&P/IA should be able to change them for you. 

Its also been shocking seeing the cold spells out east this winter, hope you see spring real soon!

[DonMuncy]

I don't know whether he knew what he was talking about, but my A&P/IA insisted on removing the brush block, but left the ring behind the prop and the elements on the prop itself. This was after I labeled the switch "in-op".

[carusoam]

Paul,

Thanks for the detailed explanation of what the mechanic's responsibility is.

That is enlightening.

Best regards,

-a-

[aviatoreb]

I had a funny situation for deice when I got my plane.  It had a functioning TKS system except for the prop.  When the rocket upgrade was done sometime after the tks upgrade, they had not bothered putting a tks slinger on the prop.  The hosing in the cowl leading fluid to the prop was all in place though.  It had been through several annuals in that state.  So when I got the plane I had the slinger ring and boots installed on the prop to complete the tks system. 

[kortopates]

Paul,

Thanks for the detailed explanation of what the mechanic's responsibility is.

That is enlightening.

Best regards,

-a-

Thanks Anthony,

Of course its always the owner/operator that is ultimately responsible for the maintenance and airworthiness of a part 91 aircraft. And certainly an IA shares in that when (s)he signs off on an inspection or annual and doesn't want to risk their livelihood or certificate by ignoring discrepancy's - but I am sure we've all seen some of these rules stretched one time or another. You scratch your head though when you read some stories such as Eric's above. 

[jetdriven]

This is easy to fix. Repairs and annual inspection are two distinctly different operations. He doesn't want to sign off the prop. Fine. I disagree. But he did inspect the airplane, and that's makntenance, which must be documented. So the FAR's say the IA can log the inspection as completed, and a list of discrepancies given to the owner. Not in the log book, not noted as "unairworthy" , just give you the list with "prop heat inop". Now that must be placarded and deactivated, and signed off as complied with by any old A&P. You're done.

[kortopates]

Yep, you could do that all right. But that is pretty much reserved for when the IA and owner are in disagreement and want to end the inspection and complete repairs elsewhere; perhaps a disagreement of method of repair or cost. But it is not a return to service signature like an airworthy plane would get: 

- 43.11(a)(4) "I certify that this aircraft (or engine or prop) has been inspected in accordance with a annual inspection and was determined to be in airworthy condition"

instead 

- 4311(a)(5) ...If the aircraft is not approved for return to service because of needed maintenance, noncompliance with applicable specifications, airworthiness directives, or other approved data, the following or a similarly worded statement  --   "I certify that this aircraft (or engine or prop) has been inspected in accordance with a annual inspection and a list of discrepancies and unairworthy items date, (date), has been provided for the aircraft owner and operator." As noted the actual list of discrepancies does not get included in the logs, its a separate piece of paper. 

So as a result, the return to service signature comes from any A&P that signs off on each of the items on the list.

In this particular case, since its an item that is permitted to be inoperative under 91.213(d)(2), then the IA must also ensure its placarded "Inoperative" and as stated any A&P could then sign it off with a maintenance log book entry that either fixed it or removed it.

 

Although it never got to this point in this, if it had, generally speaking though, as long the relationship isn't soured its going to be better to just defer his/her airworthy sign off till after you complete the repair or removal so that you can avoid having the unapproved annual sign off all together - at least I wouldn't want the inspection signed off with a list of discrepancies noted in my log book as long as there were reasonable alternatives since its going to raise eyebrows down the road about the owners maintenance habits.  But that's my opinion, YMMV.

[jlunseth]

The list in the POH is not a "Required Equipment List," it is an Installed Equipment List, there for weight and balance purposes.  If you remove something that is on the list or make a substitute, you need a new w&b from the mechanic, but the list tells you nothing about what must be working.

 

The one thing I have not seen mentioned is the Type Certificate, because that is where the true Required Equipment List is for all Mooneys.  It is obtuse to figure it out, because it is not a list, it is a set of footnotes you need to trace through based on model and serial number to figure out what your aircraft contained, as certified. 

[kortopates]

Agreed, the POH shows installed equipment, but it is also easy to ascertain OPTIONAL equipment, which is what I referred too. Optional equipment is not X'd in the original master list (before its modified for your serial #); hence its optional. Now its also true being standard or non-optional does not make it Required, but optional equipment can not also be required. If it wasn't optional, then yes we would have to dig deeper beyond the POH find it was required. You're quite right about how its is an obtuse process to look up and the TCDS is where to start. Mooney wasn't nearly as friendly as some manufacturers that added columns to their equipment list for what was required for Day VFR, Night VFR and IFR like for example Cessna does on their AFM's. 

[carusoam]

In the POH for the R...

Section II - limitations...

The chart lists items, and has checks for VFR, night VFR , IFR and night IFR...

The heated pitot is required for both IFRs.

I was hoping Amelia would find some light in her POH.

Best regards,

-a-

[Amelia]

Pitot heat works fine. POH isn't here, but I'll look next time I'm at the airport... haven't found the prop heating element even mentioned in the POH I have for a similar 231. The mechanic traced the electricity for the hot prop as far as the prop itself, so brushes, etc. are apparently OK. Probably yet another broken wire, which will be seen to, shortly....thanks, all y'all!