Questionable Practice…?

[GAHorn]

How many times have we known instances where automotive parts have been substituted for “genuine” aircraft parts on our airplanes?

I can think of several instances where I personally have accepted an auto-part in lieu of a “genuine” aircraft part.
One example is the brushes in my Delco-Remy 35A generator. The “genuine aircraft” part from El Reno and other “aviation” sources was difficult to locate 400 hrs or so ago. So I researched (and posted) my resultant discovery of the genuine Delco-Remy part-number and found a source of the identical part from an autoparts store. I installed them and have had zero problems, as expected.
Same thing with Delco-Remy starter parts. (and support for this logic is found in an AC 23-27 which has been discussed in other threads)

The recent “party-line” discussion amongst some callers has been seeking a replacement part for spin-on oil filters for the Stratus/Tempest/FM-Enterprises/El Reno adaptor. There are reports that replacement filters are so far backordered as to result in grounded aircraft.
It has been asked “Is it OK to substitute an auto filter?”

What would YOU do?

There exists an automotive filter which appears to meet the design features of the Champion 48108. Thread 3/4 X 16, Anti-drain-back valve, By-pass valve spec (8-11 psi), same filter media, same filtration 21 microns, burst-pressure 275 psi (vs 300). The K&N HP-2004 filter even has the spot-welded nut and accommodation for safety-wire.

https://www.amazon.com/dp/B000C3YTK2/?c ... _lig_dp_it

So, what would YOU do? (This is purely a rhetorical question…No need to incriminate oneself for this discussion.)

(I have the good fortune of having on-hand a case of the 48108 filters because I order those quantities for the two airplanes we have which use that filter.
But I also kept the original TCM pressure-screen in my parts-cabinet, so I can always return the aircraft/engine to original configuration. And frankly, since I did not alter the original 25-hr oil change period,…{the FM Enterprises STC did not address any extension of that}…..inspecting and cleaning that screen is no more trouble than replacing and inspecting spin on filters, without the trouble and expense, IMO.)

[voorheesh]

The automotive oil filter you mention sounds equivalent to the aviation part so the installation, while technically improper sounds safe. Oil changes are eligible for preventive maintenance, so an owner can make the call but still bears responsibility for return to service and making a maintenance record. I would not recommend making a record that is inaccurate as to the part used.

Would a certified mechanic use this part and sign off? If a mechanic spotted an unapproved oil filter during unrelated maintenance, should he/she look the other way? Using unapproved parts opens up some really tricky questions. On some levels (not your example) it can be a criminal matter. So I wonder how professional maintenance technicians would answer your question.

If it were me and the approved filter was unavailable, I would install the automotive part I have ensured is equivalent and enter it in the maintenance record with a brief explanation. (In my own airplane). That would include documentation of the specifications and why using that part was necessary. Realistically, who will ever know? (Don’t put it on YouTube). The chances are you would not be found out, and even if you did, you get credit for being honest and using care. It seems there is minimum safety risk in this “questionable practice”.

[GAHorn]

An example of how this AC 23-27 may prove useful is when selecting bearings. Some fairly energetic arguments have occurred when the subject of wheel bearing replacements have been discussed, especially as regards FAA-PMA substitutions. Some vociferous opposition to the use of over-the-auto-parts-counter Timken bearings versus those sourced from aviation suppliers…. as well as the substitution of foreign manufactured bearings of different mfr’r but which otherwise meet the same ANSI spec. (A vigorous discussion transpired when some bearings made in China were selected for my 172 nosewheel which cost less than $7 each instead of back-ordered/unavailable OEM (Goodyear wheel) bearings priced at $65 ea.)

Here are excerpts of the AC 23-27 which directly apply.

From pg 7:
“ 1) You may use the substitute part/material on secondary structures. Examples of these would include fuselage formers and stringers (typically on steel tube fabric covered aircraft), side windows, material on fabric covered aircraft, and wheel bearings.”

And (pg 12):
“ BEARINGS. Bearing catalogs from general bearing supply houses state in their introductions that the bearings listed in their catalog meet ANSI (American National Standards Institute) specifications or exclusions. They also give cross-references. Usually, they list bearings for aviation applications. You must use the appropriate part from the cross-reference matrix.
Approval: This is a minor alteration and you may document it by a logbook entry. The logbook entry must reference the manufacturer's identification and industry specification for the original and replacement bearing.” (pg 12)

It’s important to note that the AC does not grant blanket approval to substitute non-standard parts, and it’s also important to remember the AC 23-27 applies to aircraft certificated Prior to January 1, 1980.

[rschreiber]

This oil filter shortage has piqued my curiosity. What about removing the STC’d oil filter adapter and replacing the original oil screen? Would that require another 337 to be legal?

[redacted]

Just get a Challenger oil filter. Reusable washable screen. STC available. Have one on my Lancair and installing on the 170 next oil change.

[Bruce Fenstermacher]

The key often is what makes the part being replaced with the substitute part, the legal part. Why is a Champion or a Tempest accepted as OK but not the K&N. Sometimes it is only a perception, not reality. I’ve only seen Tempest and Champion installed, that doesn’t make others not legal.
I apply the “if it looks like a duck and quacks like a duck, it just might be a duck” rule. Then I look for reasons this duck is not a duck or a duck I care to use.
Often the decision comes down to the cost to be different. How many times did I want to answer the questions from naysayers? Or how strong of a legal argument I think I would have and what are the chances I’d. See to present my case.

[GAHorn]

This oil filter shortage has piqued my curiosity. What about removing the STC’d oil filter adapter and replacing the original oil screen? Would that require another 337 to be legal?

Is it a Major Alteration or Repair to return the engine to OEM status? (I personally don’t think so and it doesn’t require a complex operation or procedure.)

[voorheesh]

Removing the oil filter assembly and replacing it with the oil screen is not a major alteration since the OEM parts can be installed in their original design position without the need for modification. It would require an entry in the maintenance records and return to service. I don’t see any reason why it would not come under preventive maintenance which could be accomplished by the aircraft owner (or operator) who holds at least a Pilot Certificate/License (except Sport Pilot). I have known 170 owners who prefer the original set up.

[n2582d]

The key often is what makes the part being replaced with the substitute part, the legal part. Why is a Champion or a Tempest accepted as OK but not the K&N. Sometimes it is only a persecution not reality. I’ve only seen Tempest and Champion installed, that doesn’t make others not legal.
I apply the “if it looks like a duck and quacks like a duck, it just might be a duck” rule. Then I look for reasons this duck is not a duck or a duck I care to use.
Often the decision comes down to the cost to be different. How many times did I want to answer the questions from naysayers? Or how strong of a legal argument I think I would have and what are the chances I’d. See to present my case.

Bruce,
To see if an oil filter, or most any part on an aircraft, is technically legal and its basis for approval, one needs to look at the PMA for that part. Take for example the reusable Challenger oil filter currently being discussed. It is p/n CP-48108C if using the Aero Accessories/Tempest/Stratus/El Reno/F&M adapter*. Plug that into the FAA’s website and this comes up:

PMA Part Number : CP-48108C
PMA Holder Name: Challenger Aviation Products Inc
Status: Current CFR Part Reference: Part 21 PMA Holder Number: PQ2646CE Office of Primary Responsibility: AIR-886: Vandalia/Cleveland/Detroit MIDO Section Supplement Number: 5 Supplement Date: 11/21/2006 Part Name: Oil Filter Assembly Approved Replacement for Part Number: Modification Part Make: Miscellaneous Model: See AML SE02352CH FAA Approval Basis: STC SE02352CH DWG No: CP-48108C

There are many other oil filter PMA replacements for CH48108 manufactured by companies such as Puroflow, Purolator, Kelly Aerospace, Aero Accessories, etc. Nearly all of them are approved, not by STC, but by “test and computation per 14 CFR 21.303 … .” This allows them to be installed on whatever engine the PMA specifies. None of them list the O-300 or C-145 as it never came with a oil filter adapter from the factory. Aero Accessories (Tempest) filter AA48108 is approved for “any type certificated engine where Champion p/n CH48108 … (is) installed.”

Getting back to the Challenger filter that is approved by STC. STC SE02352CH lists a lot of engines on its AML but the O-300/C-145 is not among them. Therefore, unless the FAA’s database is out of date, one would have to install the Challenger oil filter with a field approval.

*The oil filter used on the Cessna adapter for the C-172 was CH48110. There are several other brands of filters with PMA approval to be used on the O-300 without an STC because of their similarity to the Champion CH48110 filter. If one has the Cessna adapter, the Challenger CP-148110 would be the appropriate filter. But the STC for this filter, SA01280CH, is approved by airframe rather than engine. It's approved for the early C-172s but not C-170s. So, as with the Stratus filter adapter, the Challenger filter on the Cessna oil filter adapter would require a field approval.

What a can of worms!