[Rant] STC business

[AndreiC]

I was very excited yesterday because I found an almost new Hartzell scimitar prop for sale. I negotiated a good price with the seller, and was about to start worrying about payment and shipping. But, I called Hartzell to see what it would take to get the STC paperwork. At first it seemed like a pure formality -- pay $500, get the papers that you put in your binder, done. But then they asked for the serial number, and stopped dead in the tracks. Their statement was the following:

-- yes this is the same exact propeller as we would have sold to you for your Mooney;

-- but, because it was sold for an experimental airplane (it was used on a Glasair), we never issued an STC for it, so now we cannot issue an exchange STC to go from the Glasair to your Mooney. 

So basically this prop, despite being exactly the same prop that can be installed on my plane, will never be able to be installed on a certified plane. Ugh! All this trouble for nothing.

[Justin Schmidt]

I am guessing it's because of liability.  Not only due to experimental anyone could have does something to the prop. Additionally,  not issuing stc initially they loose chain of custody.  

[GeeBee]

Yes, experimental means it may not be installed by a licensed mechanic and thus no assurance that the propeller has been treated properly in installation, operation or removal. Sucks but I am sure they have been burned before.

[EricJ]

There is no way of knowing what sorts of non-certified things happen to it on an experimental airplane, so there's good reason to handle it that way.  I don't know wether that status changes if you send it to a proper shop for overhaul, but that probably makes it uneconomical.

[varlajo]

1 minute ago, EricJ said:

send it to a proper shop for overhaul

I'm sure you meant IRAN 

[IvanP]

46 minutes ago, EricJ said:

There is no way of knowing what sorts of non-certified things happen to it on an experimental airplane, 

While that may be true, it is also true for props installed on certificated aircraft. Just becasue something is installed on certifcated aircraft does not mean that bad things did not happen to it. Of course, I understand the CYA approach taken by the manufacturer and the reasons for it. Sucks for the OP, though. 

[Schllc]

I would think if the part numbers are the same.  
some items are identical but the part numbers reflect experimental or certified.  
If it’s experimental it’s a lot cheaper. 
make of that what you will. 

 

 

[icurnmedic]

Wonder why you can’t do an overhaul directly with the manufacturer? I had to do a OH on a wooden prop that developed a groove after rubbing a cotter pin. They sent that back along with the paperwork/logs as if it were new. Maybe too much headache to worry with that though. 

[Aaviationist]

Certified or not, when it gets installed on an experimental it becomes an experimental part. Same for engines. 
 

if a certified engine gets put on an experimental aircraft, that engine immediately becomes an experimental engine. And can no longer be installed on a certified aircraft without a factory overhaul. 

[1980Mooney]

11 minutes ago, icurnmedic said:

Wonder why you can’t do an overhaul directly with the manufacturer? I had to do a OH on a wooden prop that developed a groove after rubbing a cotter pin. They sent that back along with the paperwork/logs as if it were new. Maybe too much headache to worry with that though. 

You can. It’s not the headache, it’s the cost. As he pointed out it is “a good deal on a nearly new Hartzell Scimitar prop”. A 3 blade might cost $5 k to overhaul and another $1.3 k for the prop governor overhaul. It is no longer a good deal. 

[1980Mooney]

35 minutes ago, Aaviationist said:

Certified or not, when it gets installed on an experimental it becomes an experimental part. Same for engines. 
 

if a certified engine gets put on an experimental aircraft, that engine immediately becomes an experimental engine. And can no longer be installed on a certified aircraft without a factory overhaul. 

Bingo. Just like the “cheap” Lycomings sold through Vans. 

[Ibra]

It's mainly "paper" assurance, obviously, there are some corner cases where paper means nothing. In reality, 

New & certified >> old & experimental, everyone will agree on this 

New & certified == new & experimental, it's pure liability and paper trail

So one can conclure,

New & experimental >> old & certified 

Where it becomes tricky is,

Old & certified vs old & experimental? 

An STC tend to rely on certified approved data for parts as well as approved modification of design. A factory overhaul by the part manufacturer, should get you the former.

The paper trail has some value: an aircraft gets priced with large discount the moment one loses it's papers (logbook, history, stc paper...), simply because of the loss of documentation, even if nothing changes in the aircraft.

Edited Thursday at 12:37 PM by Ibra

[Pinecone]

Field Approval?

[AndreiC]

14 hours ago, Pinecone said:

Field Approval?

I asked Cody Stallings, and he said a field approval would be a complicated problem, requiring probably several months of back and forth with a DER from the FAA, then having to put the airplane for a while in the Experimental category while I do test runs, etc. A big mess which I do not want to get into. (Part of the STC paperwork is data on how to adjust the weight and balance, new markings for the tach, etc., all of which I would not have without the official STC from Hartzell. Of course, this information is the same for all installations of this prop, but formally since the STC is specific to each plane, I cannot take that information from my neighbor and use it on my plane. Why? No idea, it's the same prop.) Oh well.

[1980Mooney]

2 minutes ago, AndreiC said:

 Why? No idea, it's the same prop.) Oh well.

Same reason that you can’t unbolt a used “cheaper experimental” Lycoming IO-390 that came with a Van’s kit and put it on using an established Mooney STC. …and calling it “Certified “. 

[AndreiC]

But the point I think is that when this prop was sold it was not cheaper, for experimental use only. I think when Hartzell sells this prop they say "Give me the money. Here is the prop. BTW, what airplane are you hanging this on so we can give you the correct STC for it? Oh, it's experimental, so you don't need an STC? Good luck then."

My understanding is that the issue is that it was used on an experimental plane, so it might have been touched by the unholy hands of a non-A&P. Thus it has been forever desecrated.

[cliffy]

It all comes out to one word---LIABILITY and who assumes it when installed on a certified airplane

Go "Experimental" and the owner/builder now assumes the liability in TOTAL for everything.

All "chain of traceability" for a certified part is lost once "experimental" is used on it.

[AndreiC]

I understand the issue of traceability, but maybe someone with an IA can then answer the following question. Say this prop was not a scimitar model, which is not covered by the original TC, but one of the Hartzell props that were approved in the TC, so I would not need an STC. Could I then install it on my plane? Or is it the case that every part of the plane, down to the smallest bolt, must always have had its life spent on certified planes?

I thought that the only requirement was that all parts of the plane must conform to the TC or to STCs. Can’t my AP (or Hartzell themselves, for that matter) look at my prop and say “yes, this prop is still in working condition as it was designed, so you can install it via the STC or the original TC”?

[takair]

4 minutes ago, AndreiC said:

I understand the issue of traceability, but maybe someone with an IA can then answer the following question. Say this prop was not a scimitar model, which is not covered by the original TC, but one of the Hartzell props that were approved in the TC, so I would not need an STC. Could I then install it on my plane? Or is it the case that every part of the plane, down to the smallest bolt, must always have had its life spent on certified planes?

I thought that the only requirement was that all parts of the plane must conform to the TC or to STCs. Can’t my AP (or Hartzell themselves, for that matter) look at my prop and say “yes, this prop is still in working condition as it was designed, so you can install it via the STC or the original TC”?

Assuming it is on the TC, the. As others suggested, it’s liability. If your IA wants to take that on, then they can declare that prop as airworthy for the application. It happens with avionics and other stuff, but the risk might be less. It’s all risk tolerance. It’s like the question of major/minor.  How much responsibility does an IA or mechanic want to take on. 

[Jackk]

This is why airplane related prices have gone to the moon.

 

 It’s all mostly nonsense IMO

 

 I have not seen a quality difference specific to certified vs exp, old vs new

 It’s really just a matter of the quality of the wrench and the stick 

 

 Plane that I dealt with recently, certified, I go through the logs and the last annual the IA had “checked alternator belt” on the printed annual sticker…problem chief, there ain’t no alternator belt for that type of engine.  

 

Thus logic states the annual was pencil whipped, and all the other work this joker did is now suspect, thus the planes airworthiness is suspect

 

 

 

 In the case of this prop, I don’t exactly think the experimental replaced the oil with super glue or disassembled and reassembled the prop for fun, if it looks and functions as it should this really should be a non event.

Edited Friday at 07:55 PM by Jackk

[cliffy]

It still comes to "Unapproved parts" and the FAAs desire to eliminate them from the supply stream

Here is a cut from AC 21-29D regarding SUPs=

5.3.5 Conduct a visual inspection of the part and supporting documents to the extent necessary to determine if the part is traceable to an FAA-approved source. For detailed guidelines on the identification of replacement parts refer to AC 20-62. The following are examples of positive forms of identification:  FAA Form 8130-3, Airworthiness Approval Tag.  Repair station work order from an FAA-certificated source.  European Aviation Safety Agency (EASA) Form 1 or Transport Canada Civil Aviation (TCCA) Form One, Authorized Release Certificate Maintenance records or release document with approval for return to service. 7/12/16 AC 21-29D 4  FAA Technical Standard Order (TSO) markings.  FAA Parts Manufacturer Approval (PMA) markings.  Shipping ticket/invoice from Production Approval Holder (PAH).

Basically we as A&Ps want to see an 8130 in order to install a prop on a certified airframe. 

You can dig deeper into this by reading the AC itself   AC 21-29D Google Fu works to find it.

[Ibra]

22 hours ago, AndreiC said:

Say this prop was not a scimitar model, which is not covered by the original TC, but one of the Hartzell props that were approved in the TC, so I would not need an STC. Could I then install it on my plane?

TC route will not work neither for major components (engine or propeller) without Form1 or 8140.

The aircraft can be released to service with unapproved data/parts by TC holder but that does not apply to major components even for original design, the same logic apply to STC, as approved data/parts are required for major modifications of design. 

In theory, TC holder could release the whole aircraft with an experimental propeller if they can show that it still meet TCDS (sort of overhaul/recertification, it’s easy if they have all the data from Hertzell, otherwise they have to mimic it).

If you are replacing component like for like, unless it’s TSO or PMA, the used part has to come from certified aircraft or part manufacturer/designer. Sometimes Part145, Inspector, Design office could have the authority to inspect/repair and release but this tend to be limited when it comes to “major components”.

I guess no one would be able to inspect/overhaul a propeller/engine and release it? from experimental engine, it needs to be "zero-timed" before getting bolted as certified, there is more to it once you add any layers of AD that would apply to Part21 aircraft (or SB/SL), these could be missing when engine or propeller were in non-Part21 type.

If the propeller or engine were originally certified by manufacturers (or originally installed in certified aircraft), one could still show that they were maintained as certified (and operated as certified) while being "temporarily" installed in some experimental aircraft: proper logbook with all annuals sign-offs, AD signoffs...these evidences can show compliance with original TCDS, however, one still need IA or some FSDO to buy this story....

A bit off-topic, are there casese of FAA ADs that are applicable to  experimental aircrafts? or experimental parts? 

Edited Saturday at 05:40 PM by Ibra

[Aerodon]

Certifying engine and propeller combinations is difficult.  Just look how many installations have yellow arcs, and you cannot 'feel' the vibrations they are concerned about - its all internal to the engine / crankshaft / counterbalance weights etc.

Once a propeller has been installed on an 'unapproved' combination, there is no telling what damage has been done.  Yes I get it that it might be the same engine / prop combination that you might find on a certified plane.  And yes that might be an approved combination.  And my guess is the engine is more at risk than the propeller for hidden damage.

Garmin sell 'experimental' G5's for less than certified.  Lycoming sell 'experimental' engines for less than certified.  Hartzell?  Their approval and insurance costs are probably less for Experimental?

So why would you expect 'free trade' between certified and experimental?

Be grateful that you got all this information before buying.  And thanks for sharing, it is a good learning experience for all of us.