Maintenance/ownership costs of a Vans RV vs. a certified Skyhawk/Cherokee/AA5

[DMD3.]

One of the primary benefits of experimental is being able to do your own maintenance and not having to pay a mechanic. I was browsing VAF, and someone posted that while hiring an A&P would negate the cost savings on maintenance, it still really shouldn’t cost MORE than maintaining a certified spam can. How true would you say this is? If I can live without backseats, would maintenance cost about the same on an RV 6-9 for roughly the same amount?

 

[Bell206]

How true would you say this is?

These discussions need specific context to get viable answers. For example, take a 172 owner who performs all the prevent mx he can and has a mechanic who owner-assists the rest vs an RV non-builder owner who farms out most of his work the costs will be closer. However, with MOSAIC giving a new option to non-builder E/AB owners on the condition inspection, no reason for the E/AB to be solidly on the lower end provided the owner had the skill set and confidence to perform the work.

 

[DMD3.]

These discussions need specific context to get viable answers. For example, take a 172 owner who performs all the prevent mx he can and has a mechanic who owner-assists the rest vs an RV non-builder owner who farms out most of his work the costs will be closer. However, with MOSAIC giving a new option to non-builder E/AB owners on the condition inspection, no reason for the E/AB to be solidly on the lower end provided the owner had the skill set and confidence to perform the work.

In my case I don’t have mechanical skills so I’m having to pay someone for maintenance regardless of it being certified, EAB, LSA, etc.

 

[FORANE]

The only way I see a RV costing more to maintain than a spam can is if the owner treats the RV like a high maintenance mistress.

 

[ateamer]

Costs will be the same or less. The more you get hands-on involved, the more work you’ll be able to do yourself. The only thing that an A&P or LSR-I is mandated for on an Experimental is the condition inspection. Most parts and avionics are cheaper as well. And you’re not stifled by FAA restrictions on parts.

I owned an RV-8A for five years. It was easy to own, doing the work as well as financially. RVs are well-designed and generally have been well-built. Homebuilts can have subpar parts and assembly, such as bad wiring connections, but that happens with certified planes, too.

If I ever sell our current plane (Cessna), I’ll go back to RV and never own a certified aircraft again.

 

[rockyfatcat]

I am an A&P and I own 2 aircraft. A 1965 Aircoupe and a RV7. I share a hangar with 5 other A&P’s who all own certified aircraft. The thing that’ll pop out in cost savings is approved certified parts vs not certified.

Recently one of the guys was rebuilding the nose strut on his 172. He bought one certified o-ring for $65. I could probably buy a pack of the same o-rings 10 for $20 if I wasn’t concerned about it being a certified part. Many of the ‘certified parts’ are identical to non certified except for the sticker.

When I was going through A&P school I worked at Robinson Helicopter in Torrance CA. I would watch a girl across the aisle take a pallet of Ford air filters for example and using a label gun she’d put a RHC sticker on each individual air filter box making it an FAA approved part before putting it on the next pallet. Of course the Ford air filter from RHC was at least 3x the price from your local auto parts store.

The Aeroled landing light and taxi light in my daily driver were probably 3 or 4 hundred each. I could probably find similar PAR 36 LED bulbs on ebay for $40 each.

My RV7 is currently at the avionics shop getting the IFR upgrade. I purchased a previously flying day VFR only aircraft and did a ton of work to bring everything up to snuff. The Garmin price difference between certified and experimental avionics is amazing.

If you aren’t mechanically inclined, you’ll end up paying the same hourly for a mechanic to perform the work. The choices for what you can put into a certified aircraft is limited to what is available with a STC with your make and model on their AML. Field approvals for non standard equipment by the FSDO is more and more ‘I don’t have to’. If you want to avoid a field approval you need to pay 5k to hire a DAR/DER to get it approved in your certified aircraft.

On the other hand if you wanted to modify your Experimental aircraft to install a home brewed night vision thermal camera with the thermal display in the dash…. It’s experimental! You’re good! No approvals needed.

 

[Clip4]

One of the primary benefits of experimental is being able to do your own maintenance and not having to pay a mechanic. I was browsing VAF, and someone posted that while hiring an A&P would negate the cost savings on maintenance, it still really shouldn’t cost MORE than maintaining a certified spam can. How true would you say this is? If I can live without backseats, would maintenance cost about the same on an RV 6-9 for roughly the same amount?

I am curious, how much maintenance do you think there is on fixed gear certified aircraft a year? Keep in mind few owners fly 100 hours a year.

 

[Dana]

I am curious, how much maintenance do you think there is on fixed gear certified aircraft a year? Keep in mind few owners fly 100 hours a year.

In a good year, not much, but a lot of certified aircraft are 50 years old and more, so the chance of a major surprise bill (e.g. Piper wing spar AD, Cub/T-Craft strut AD, Cessna flap track cracks, etc.) is probably higher than a relatively new RV. Have you priced a Bonanza ruddervator lately?

I used to kid a buddy that I bought my airplane for less than he paid for the annual on his Bonanza.

 

[rhkennerly]

The real choke point, I’m reading, is available A&Ps to do certified annual inspections. I just finished the annual condition inspection on the SwampCat (LSA experimental) myself (LSR-I), whereas the two local shops at my airport are booked out through the end of the summer. If you don’t book your next certified annual immediately when paying for your current annual, you’re in for a long wait to get in. That makes it tough to break into the maintenance cycle & pretty much locks you into a single shop.

I’m not a particularly skilled wrench twirler, but generally the tasks aren’t that difficult. Inspection are mostly about attention to detail, unless there is a real problem. But it means investing yourself, too. The LSR-I course is only 2 days, but that is not real skill building. I’ve got a hands-on Rotax course coming up soon & more LSR courses in the works.

if you’re not doing experimental inspections yourself, then you’re competing with certified owners for space at the shop. I don’t think there is much savings then. In fact, the research for ADs, SBs, & SLs on your experimental might make it initially more expensive. And don’t even think about walking in with a non-certified part for you A&P to install. They’ve invested thousands in that certification. They’ll not risk that on your one time or sporadic business.

 

[moparrob66]

Timely topic for me. I just sold my 172 and Im excited to finish my Zenith kit. Its a huge weight of stress off of me. I loved the plane, but the thought of a potential $40k overhaul and waiting 12-18 months for it was miserable. I only had one Annual Airworthiness Extortion, er, I mean Inspection and it really chapped my hide. $3800 to actually fix nothing I wanted fixed.

With my experimental, I control the costs vs paying somebody to find something he doesnt like so he can make me pay him to fix it. No thanks!

 

[Bell206]

And don’t even think about walking in with a non-certified part for you A&P to install.

I think it depends on the mechanic how they approach E/AB aircraft. But what I have found is an increasing number of mechanics who elect to be very conservative in the application of the rules or simply do not understand the rules.

With my experimental, I control the costs vs paying somebody to find something he doesnt like so he can make me pay him to fix it. No thanks!

Interesting. So what happens when you find something you don't like, but it costs $3800 to fix. Will you pay then or defer it?

The choices for what you can put into a certified aircraft is limited to what is available with a STC with your make and model on their AML.

Not really. In previous threads you posted AC 23-27, why not post it here? You, as an A&P, can install whatever you want in a TC aircraft provided you follow the appropriate guidance which the majority of the time is not a major alteration nor would require a field approval. Same goes with o-rings, air filters, or "home brewed night vision thermal camera with the thermal display in the dash." Understanding the rules is one thing, but only wanting to follow certain rules is something completely different, which unfortunately is becoming more mainstream as you exampled above.

 

[moparrob66]

I think it depends on the mechanic how they approach E/AB aircraft. But what I have found is an increasing number of mechanics who elect to be very conservative in the application of the rules or simply do not understand the rules.


Interesting. So what happens when you find something you don't like, but it costs $3800 to fix. Will you pay then or defer it?


Not really. In previous threads you posted AC 23-27, why not post it here? You, as an A&P, can install whatever you want in a TC aircraft provided you follow the appropriate guidance which the majority of the time is not a major alteration nor would require a field approval. Same goes with o-rings, air filters, or "home brewed night vision thermal camera with the thermal display in the dash." Understanding the rules is one thing, but only wanting to follow certain rules is something completely different, which unfortunately is becoming more mainstream as you exampled above.

If I find a problem with my experimental that costs $3800 to fix (and I'm sure at some point I will), I'll fix it. I dont need an auto mechanic to force me to change ball joints on my car; if its broken, its a safety item and it needs fixed, YOU JUST DO IT.

The guy who did my annual doesnt like mogas, so he drained it without my permission and charged me to dispose of it, even though theres an stc from 20+ years ago in the logs. My yoke tube control lock hole was broken and filed flush when I bought it at the previous annual. It was ugly, but airworthy. Mechanic thought it was unsafe, so $400 later its an 1/8 inch shorter and still ugly.

The wheel bearings were fine when I greased them at tire change, but shot 6 months and .5 flight hours later. That was $360. For the same Timken bearings that would have been half that from NAPA.

Im relieved that I wont go through that again, or worse. Sure, it may normal but its definitely not for me.

 

[Bell206]

My yoke tube control lock hole was broken and filed flush when I bought it at the previous annual.

Except this is the only item that would apply to the difference between TC'd vs E/AB. The rest of your issues were strictly within your power as owner to stop. An annual inspection is only an inspection and if mechanic drained your mogas and replaced bearings as disc of that inspection without your approval that is outside the purview of the regulations.

I dont need an auto mechanic to force me to change ball joints on my car; if its broken, its a safety item and it needs fixed,

This is actually one the main differences between TC's vs E/AB aircraft. To determine something airworthy it must conform to its type design AND be in a condition for safe operation. An E/AB only needs to meet the latter as there is no type design. So while it appears to be a no brainer on safety only items for an E/AB, if those "ball joints" were on a TC'd aircraft and worn beyond limits vs broken, they would have to be changed regardless. So there really is no comparison between annuals vs condition inspections even though they use the same guide.

 

[Dixiebluesky]

1/2 the cost and 1/10th the frustration of certified.

 

[rockyfatcat]

I think it depends on the mechanic how they approach E/AB aircraft. But what I have found is an increasing number of mechanics who elect to be very conservative in the application of the rules or simply do not understand the rules.


Interesting. So what happens when you find something you don't like, but it costs $3800 to fix. Will you pay then or defer it?


Not really. In previous threads you posted AC 23-27, why not post it here? You, as an A&P, can install whatever you want in a TC aircraft provided you follow the appropriate guidance which the majority of the time is not a major alteration nor would require a field approval. Same goes with o-rings, air filters, or "home brewed night vision thermal camera with the thermal display in the dash." Understanding the rules is one thing, but only wanting to follow certain rules is something completely different, which unfortunately is becoming more mainstream as you exampled above.

Yes I am an A&P. Yes I do know the differences between certified and experimental and I will stick with certified STC, PMA, etc parts on my certified aircraft.

A couple years ago I was shopping for avionics and was interested in the RC Allen Mini6 Multifunction Digital Instrument. I kept asking STC? AML? Their answer was TSO & 337 field approval. They should have told me read AC 23-27 very carefully. But I did not know that at the time and ended up buying a couple GI 275’s as I didn’t want to go down that rabbit hole.

Choose your battles. I think that there are plenty of same similar, as good or better options that you can rightly use under AC23-27.

If I were to mount that thermal imaging system on my Aircoupe. I think I would mount it similar to that of a GOPRO and have the display on an iPad mounted on the dash like I would for foreflight, Rather than performing a unapproved major alteration to my airframe.

 

[Dixiebluesky]

Your general maintenance parts will be pennies on the dollar compared to certified. Piper, Cessna..... are not producing these parts, they buy them. And in this internet age finding out where the parts were likely sourced is easier than ever. So that 100.00 seal that is back ordered for 8 months with no end in sight can be sourced and shipped for 20.00 same day.

Check out the price of experimental vs certified avionics. Not only are they cheaper but all the modern avionics I have been around and owned were "unlocked" I guess you would call it. Setting and parameters being able to be changed by the user. So if you want to make a change here or there you call the 800 number from your plane and you make the change in a few easy steps, vs taking your certified to a dealer and all that goes with it.

 

[rhkennerly]

Another thing to keep in mind, The Vans Air Force and the wealth of knowledge and experience available to you. There must be a dozen RVs at my little airport. All the owners help each other out. We also have an active EAA chapter.

However, this rah-rah for Experimental is really predicated on you reciprocating. If you’re buying an RV because you’re cheap and you don’t want to help other owners or participate in their projects, you might want to stick to certified.

 

[Bell206]

Yes I am an A&P. Yes I do know the differences between certified and experimental and I will stick with certified STC, PMA, etc parts on my certified aircraft.

Interesting. So what is the FAA definition of an “experimental” part? Same goes for what is a “certified” part? While these words are thrown around in various posts here, in what context do they change things?

For example, in your 172 nose strut “certified” o-ring comment above, what makes the $65.00 certified o-ring any different than an o-ring I buy from a non-descript supply house under the same part number for $5.00?

Also, while its good to prioritize using STC, PMA, TSO, and other approved parts, you’ll find those approvals only cover a small amount of parts. So, what about all the other parts you may need that don’t come with any of the above listed approvals?

A couple years ago I was shopping for avionics and was interested in the RC Allen Mini6 Multifunction Digital Instrument. I kept asking STC? AML? Their answer was TSO & 337 field approval. They should have told me read AC 23-27 very carefully.

Actually, AC23-27 wouldn’t have provided any assistance as it is for existing part substitution vs providing installation guidance for new parts as stated in its applicability paragraph. One option would have been to look at the FAA PS-ACE-23-08 Policy Statement for the Mini 6 installation, which I used to install a number of RC Allen 2610s as minor alterations.

If I were to mount that thermal imaging system on my Aircoupe. I think I would mount it similar to that of a GOPRO and have the display on an iPad mounted on the dash like I would for foreflight, Rather than performing a unapproved major alteration to my airframe.

So what makes you think installing your DIY thermal image system in your Coupe would be a major alteration vs a minor alteration?

 

[Clip4]

In a good year, not much, but a lot of certified aircraft are 50 years old and more, so the chance of a major surprise bill (e.g. Piper wing spar AD, Cub/T-Craft strut AD, Cessna flap track cracks, etc.) is probably higher than a relatively new RV. Have you priced a Bonanza ruddervator lately?

I used to kid a buddy that I bought my airplane for less than he paid for the annual on his Bonanza.

If you choose to buy a Bonaza with a magnesium ruddervator, any maintenance involved should be no surprise. This has been a well known issue for the last 25 years.

Cessna flap track cracks are owner induced (flaps above rated speeds, worn-out rollers, and improper lubrication).

 

[rockyfatcat]

Interesting. So what is the FAA definition of an “experimental” part? Same goes for what is a “certified” part? While these words are thrown around in various posts here, in what context do they change things?

For example, in your 172 nose strut “certified” o-ring comment above, what makes the $65.00 certified o-ring any different than an o-ring I buy from a non-descript supply house under the same part number for $5.00?

Also, while its good to prioritize using STC, PMA, TSO, and other approved parts, you’ll find those approvals only cover a small amount of parts. So, what about all the other parts you may need that don’t come with any of the above listed approvals?


Actually, AC23-27 wouldn’t have provided any assistance as it is for existing part substitution vs providing installation guidance for new parts as stated in its applicability paragraph. One option would have been to look at the FAA PS-ACE-23-08 Policy Statement for the Mini 6 installation, which I used to install a number of RC Allen 2610s as minor alterations.


So what makes you think installing your DIY thermal image system in your Coupe would be a major alteration vs a minor alteration?

I have a stack of aircraft spruce receipts as thick as a telephone book tracking the records of 60 years of certified parts installed on my certified aircraft. In that stack are receipts of all the used parts I have installed on my Aircoupe. EVERY control surface, and critical fastener on my RV uses the same AN, MS, NAS spec hardware and has a receipt in my logs.

When It cones to what is a non certified part on a certified aircraft. You can reference the FAA Suspected Unapproved Parts (SUP) Program for guidance.

As far as modifying my airframe to mount an home brewed FLIR pod on my 65 Aircoupe. That’s not a hill I’m willing to die on.

Depending on the size of the pod to mount the same equipment on my RV might require revisiting phase 1 testing & Notification to FSDO of a Major Change in order to stay legal.

 

[Bell206]

I have a stack of aircraft spruce receipts as thick as a telephone book tracking the records of 60 years of certified parts installed on my certified aircraft.

Interesting again. So no comment on the difference between the $65 “certified” o-ring on a 172 strut you mentioned and the same $5.00 o-ring from Spruce? As I stated earlier, understanding the rules is one thing, but only wanting to follow certain rules is something completely different, which is unfortunate for the average Part 91 owner out there, where mechanics no longer try to provide the best service possible.

 

[rockyfatcat]

Interesting again. So no comment on the difference between the $65 “certified” o-ring on a 172 strut you mentioned and the same $5.00 o-ring from Spruce? As I stated earlier, understanding the rules is one thing, but only wanting to follow certain rules is something completely different, which is unfortunate for the average Part 91 owner out there, where mechanics no longer try to provide the best service possible.

The $65 o-ring was from spruce. I’m pretty sure I could get something similar from McMaster.com

 

[Bell206]

The $65 o-ring was from spruce. I’m pretty sure I could get something similar from McMaster.com

So are you stating you can't use McMaster to buy the o-rings for your 172?

 

[rockyfatcat]

So are you stating you can't use McMaster to buy the o-rings for your 172?

I have never owned a 172. If I did I would play by the rules and find the correct part. It’s not tough to find comparable Mil spec parts. Same similar or better.

 

[Clip4]

Interesting again. So no comment on the difference between the $65 “certified” o-ring on a 172 strut you mentioned and the same $5.00 o-ring from Spruce? As I stated earlier, understanding the rules is one thing, but only wanting to follow certain rules is something completely different, which is unfortunate for the average Part 91 owner out there, where mechanics no longer try to provide the best service possible.

Let’s take another o-ring. Sure, you can source the size o-ring for the fuel primer on a late 70s 172/182 from Spruce, but why pay Spruce’s inflated price when you could get it at the local hardware store?

The compound is not the same as the OEM spec from Spruce or the hardware store and you will be replacing it in a rather short period.

 

[Bell206]

The compound is not the same as the OEM spec from Spruce or the hardware store

Interesting. So, you think your hardware store o-ring of an unknown composition is a legal substitute for your fuel primer? And what makes you so sure the OEM o-ring spec is not the same spec as the Spruce o-ring, or at least an acceptable substitute? A quick check, and I find legit replacement o-rings for your primer for $0.76 each at McFarlane as Spruce doesn't carry that size individually. Or, you can do what I usually do and buy a bag of 50 from a reputable vendor at $0.15 each then sell the rest at a decent profit on eBay.

 

[pfarber]

I am an A&P and I own 2 aircraft. A 1965 Aircoupe and a RV7. I share a hangar with 5 other A&P’s who all own certified aircraft. The thing that’ll pop out in cost savings is approved certified parts vs not certified.

Recently one of the guys was rebuilding the nose strut on his 172. He bought one certified o-ring for $65. I could probably buy a pack of the same o-rings 10 for $20 if I wasn’t concerned about it being a certified part. Many of the ‘certified parts’ are identical to non certified except for the sticker.

When I was going through A&P school I worked at Robinson Helicopter in Torrance CA. I would watch a girl across the aisle take a pallet of Ford air filters for example and using a label gun she’d put a RHC sticker on each individual air filter box making it an FAA approved part before putting it on the next pallet. Of course the Ford air filter from RHC was at least 3x the price from your local auto parts store.

The Aeroled landing light and taxi light in my daily driver were probably 3 or 4 hundred each. I could probably find similar PAR 36 LED bulbs on ebay for $40 each.

My RV7 is currently at the avionics shop getting the IFR upgrade. I purchased a previously flying day VFR only aircraft and did a ton of work to bring everything up to snuff. The Garmin price difference between certified and experimental avionics is amazing.

If you aren’t mechanically inclined, you’ll end up paying the same hourly for a mechanic to perform the work. The choices for what you can put into a certified aircraft is limited to what is available with a STC with your make and model on their AML. Field approvals for non standard equipment by the FSDO is more and more ‘I don’t have to’. If you want to avoid a field approval you need to pay 5k to hire a DAR/DER to get it approved in your certified aircraft.

On the other hand if you wanted to modify your Experimental aircraft to install a home brewed night vision thermal camera with the thermal display in the dash…. It’s experimental! You’re good! No approvals needed.

I'm not trying to argue but just want to point out some of the things that overlooked.

First, that Aeroled landing light WILL work as advertised. You could (for whatever reason the FAA deemed) trace back every part to its original manufacturer. That ebay led? Ming ming isn't tracking anything and you have no idea what the performace of that lamp will be.

Second, the cost difference in avionics is becuase while the units meet the same TSO specs, the certificated units will be locked down to the TCDS of each aircraft its been STCd for. That's gonna be a lot of admin/paperwork on the back end. Then there is the 'resetting' of the GARA clock for 17 more years of liability for the certified unit. That's gonna cost real money.

Will that justify the 2x-3x cost? Well, it seems so. Garmin needs to make money and there are just not a ton of GA AC getting $40k+ avionics upgrades. While the FAA may issue several hundred E/AB airworthiness certs a year (aka a larger pool of customers that can drop $100-$250k on a plane) the average certified AC are still sporting KX-155s and other original equipment because it works.

Remember the 430 is almost 30 years old and they are still widely used. That means Garmin made a few bucks on the sale 30 years ago an may have not seen another penny (other than map updates) from that hardware. Good for the consumer, not great as a revenue stream for Garmin.

 

[schmookeeg]

New Ruddervator PMA skins $7150. You might need a different boogeyman

V-tail Bonanza ruddervator corrosion solved

The American Bonanza Society awarded a prize first announced in 2021 to SRS Aviation, for solving a problem with V-tail ruddervators that was an existential threat to the fleet.

www.aopa.org

 

[AlphaPilotFlyer]

the cost delta between cert and exp/non- cert is significant and inarguable across all categories.

in this o-ring discussion, that's an easy demonstration as cessna and piper, in example, usually list the AN # or it's easily found. these are 1940s era rubber composites and easily replaced with same or with a newer material as viton or other. We replaced all fuel seals on a c172 as to be compatible with ethanol. I think we paid 1/10 the cost for all compatible compared to certified rubber....our rings were from an ISO approved source and milspec.

the real savings comes from using exp engines and avionics, as well as ability for the non certified mechanic-owner to do wider area of mx on AB. When you see the exp version of a garmin G5 cost half of its certified brother, or a exp efis panel or auto pilot cost a fraction of a comparable certified unit it's a stark delta. i would argue that your plane is safer with a proven exp efis and autopilot ....a lot of verified crashes would have been prevented if they had as FAA 's own study determined. Daynon makes a great exp efis for the c172, which is the same as the certified stc version, just a paper makes the difference.

This juxtaposition become to titanic when comparing cert and exp engines. especially auto conversions due to their mass production scales and parts availability. however, it's important to consider supplier here as there are many aftermarket sub standard forgeries in this space so it's best to pay a bit more for a genuine GM, Honda, ect part from dealer that had documented QA and material PCN requirements with suppliers.

i once worked for a manufacturer that had some products made in China and visited the factories there.... our parts came off the exact line as named brands just packaged and distributed differently. just as the ford oil filter example above, there is often no magical difference between faa certified and a regular car part, besides the cost. the stuff the cert part supplier did you can likely do to assure best QC. Without getting into PMA, TSO, STCs, cessna buys stuff from suppliers and demonstrates a QC program which may be as simple of a PCN or random sample test. when we bought our c172 to use as a test bed for an engine development program, the cargo door lock was busted so contacted cessna for a new lock assembly...learning it was over $200, we took it to a local locksmith who looked at it and identified it as a lock barrel used in older file cabinets...we left with a brand new lock matching our key for $30. point is. what did cessna have to show a 1950s FAA to use a file cabinet lock?

i recently bought some foam to redo our planes seat which was getting flat and uncomfortable....the automotive foam stated it was SAE flame retardant which would have met the faa standard (again, we didn't have to meet any requirement as it's exp but we do anyways just maybe not through formal means...I did a quick test and it was nowhere near self extinguishing and sent it back and found another source.

keeping a certified plane flying is way too expensive for most recreational owners, especially with lack of repair shops dwindling. the wider owner mx allowed for exp AB is substantial in final cost comparisons in addition to exp parts and upgrades.

if my c172 was not in exp category, I would never of it owned it or rarely flown it. it's ownership cost decreased by 60% or more with the exp engine and avionics. my hanger mates with certified c172s and other cert aircraft are selling as cost rise and their birds are down for months waiting on service or inspections or waiting for fuel cost to come down ...for most their rec flying is simply going to a cheap gas spot to fuel up now

my insurance is same as a certified c172, and my hanger rent as well. in a sense, my exp c172 is a definitive example in exo vs certified in terms of at least costs. I get that a lot of people like the feeling of flying a certified that's been flying for decades for rational reason and see the value there. but recreational flying, as all things, has a rational price elasticity and most reached it years ago, multiplied by other factors as well no doubt.

there's a lot of pressure on recreational GA and certified aircraft are getting harder to rationalize owning for most. I say you can get a better, safer plane and be able to enjoy it more if you have a proven experimental and discipline to maintain it to a high standard rather than exploit the category's benefits. We believed crossing certified with exp was a solution by installing well designed and tested auto conversion engines on older airframes, and still do...this solution will likely be proven as planes get older and engines (the most expensive part of a plane) get more expensive and A&Ps continue to get scarcer and regulations keep coming.

 

[Bell206]

I think we paid 1/10 the cost for all compatible compared to certified rubber....our rings were from an ISO approved source and milspec.

So what's the difference between the "certified rubber" orings you note and the orings you bought at an ISO source for 1/10th of the cost?

 

[AlphaPilotFlyer]

we use ethanol car gas. ethanol breaks down rubber which original cessna seals are made from... so needed to use seals that were compatible with ethanol. We used ISO and SAE sourced seals certified for ethanol gas compatibility simply because we needed some faa recognized basis , rather than buying the same size seals from eBay or local hardware store.

 

[Bell206]

We used ISO and SAE sourced seals certified for ethanol gas compatibility simply because we needed some faa recognized basis , rather than buying the same size seals from eBay or local hardware store.

I think we paid 1/10 the cost for all compatible compared to certified rubber....our rings were from an ISO approved source and milspec.

Let me rephrase. Why do you imply or believe your ISO orings are not equal to those "certified rubber" orings? For context, you used this as an example for the difference with Cessna and Piper parts.

 

[AlphaPilotFlyer]

this

Let me rephrase. Why do you imply or believe your ISO orings are not equal to those "certified rubber" orings? For context, you used this as an example for the difference with Cessna and Piper parts.

in a nut shell..the c172 type design makes its included parts "certified". for our STC design, or any STC, applicant has to demonstrate a part meets a recognized cert basis or provide approved means acceptable to ACO which will be noted in G1 paper and cert basis. once that STC is issued, all parts become certified.

A good DER will find alternative means of compliance that reduce cost and time. in our case. we needed to replace seals as OE rubber seals were not compatible with flex fuels. We could have found some new material and come up with its own cert plan, but since such o rings were available COTS that already had a cert basis accepted/recognized by FAA, it was path of least resistance.

not sure your reason for asking the difference between cert and non certain parts as o rings....but more direct answer is if you want to change a part from that which was part of type design, regardless of means such as field approval, A&P sign off or even STC, you need to present data that the part is safe which can be multifaceted. example is A&P not being able to get a seal from the manufacturer or other approved source such as McFarlane (which has their own faa part approval)....he is not likely to use a seal from ebay as it's true type/quality/source is unknown. however, sourcing same seal from a milspec or SAE source is easier to show it's comparable and most will supply paperwork with such info.

 

[Hang 4]

Simpler than o-rings. Piper alternator belt. It is made by Gates. Piper puts a sticker on it with a Piper part number, it's now magically worth ~$100 vs $20. It's the exact same darn belt. The sticker is literally on the Gates sleeve they package it in. I doubt there's a Piper engineer in the Gates factory pulling the "best" belts out.

Similarly, you can get a Viton o-ring that matches the size, durometer and exceeds the chemical resistance of the approved one. This is not going to the aviation aisle at Ace Hardware but rather meeting or exceeding the manufacturer spec. I have no idea on the legality of substituting, but I also suspect most A&P's don't either and I also suspect it's not as tight as the SGOTI makes it out to be.

 

[Bell206]

not sure your reason for asking the difference between cert and non certain parts as o rings....but more direct answer is if you want to change a part from that which was part of type design, regardless of means such as field approval, A&P sign off or even STC, you need to present data that the part is safe which can be multifaceted.

This is close enough. But no data needs to be presented as a lot of TC parts like orings fall under standards parts. So to continue with the 172/182 fuel primer example above, take the oring part number and you'll find it was made to a specification. And in the case of this primer's orings that MIL-SPEC was superseded, ie., replaced, by a newer SPEC which covers a newer type oring which in turn allows for the substitution.

In the real world provided you know where to look, this takes about 5 minutes. So where the individual above made the error to buy a hardware store oring instead of paying Spruce's higher costs was to simply find a legal alternate oring and pay a much lower price as shown. So in the case of your ISO vender and SAE orings, more than likely I could use those same orings on a current 172.

 

[Bell206]

Simpler than o-rings. Piper alternator belt. It is made by Gates. Piper puts a sticker on it with a Piper part number, it's now magically worth ~$100 vs $20. It's the exact same darn belt. T

Sure. But there is a reason for that. So why do you think your mechanic can buy the same Gates belt without the Piper sticker and legally install it on your aircraft?

 

[Hang 4]

Sure. But there is a reason for that. So why do you think your mechanic can buy the same Gates belt without the Piper sticker and legally install it on your aircraft?

I didn't say they could. But by the same token, other than a regulation, I'd love to know how that Piper belt is any better.

 

[Bell206]

But by the same token, other than a regulation, I'd love to know how that Piper belt is any better.

Its not simply because its all due to regulation: Part 21.9. Without the Piper sticker they'd violate that rule. And every item sold by Piper get assessed its share of the corporate overhead.

 

[AlphaPilotFlyer]

crazy stuff for sure. For a few more ridiculous examples; we used a Stewart Warner oil pressure sensor that cost us about $30. The distributor says Piper uses same part from them but Piper retails at $160... same part, same supplier (the part has been around for decades and used on everything from farm equipment to industrial equipment). As your drive belt example, I did engineering stuff in boat industry. When you bought an inboard engine it was a car or truck engine modified for marine mission but branded per the boat brand. Mercruiser, a huge marine engine co, used mostly GM engines and sold GM parts for about 3x the cost simply by using their own PN sticker over the GM part # sticker (they changed the GM PN, mostly adding a prefix to GM #). People felt ripped off when peeling it up and seeing the GM PN they could buy for 1/3 at any auto parts store....they eventually started repackaging parts with own branding.

In aviation, the FAA loves creating monopolies that limit the supply side of supply & demand economics. , being it limiting DPEs or increasing new approved parts- especially safety related components- by making certification require hiring teams of expensive DERs and related process which is not feasible for most GA small upstarts. Now that GA is so small there is little interest in investing. In the parts department, once a part, even a commercially available part found on Amazon, cost 5x as the belt you mention and Piper won't even take the time to repackage it or have it made with their own PN inked on it. So the TC holder has a monopoly in a sense. Some like TC holders will buy out small companies that get aftermarket parts certified and sell cheaper then OE only to close them down, to continue the monopoly.

To be fair, we learned that branded auto parts counterfeits is a billion dollar industry and there's some cheap junk out there, so you need to be sure it comes from a reputable source. In our case we advised getting all GM parts from a dealer rather than from ebay or parts store regardless if it came in a GM box. So it's possible, not likely, that the Gates belt from amazon could be of lesser quality or old stock.

That's why experimental and LSA is the future for most GA users.

 

[Hang 4]

Its not simply because its all due to regulation: Part 21.9. Without the Piper sticker they'd violate that rule. And every item sold by Piper get assessed its share of the corporate overhead.

Well that's a darn good sticker