Mooney cowl stc SA000946AT

[KSMooniac]

1 hour ago, FlyingDude said:

 

Also, I am pretty sure this mod will change flight characteristics.  If a dumb Brake Caliper Swap (TM) speed mod requires a 337, changing the engine cowls would definitely require an STC.  I am sure the plane will handle differently but I am pretty sure that it won't be anything drastic...

 

Just to muddy the waters a bit more... just because something in the past was granted an STC and especially marketed as "STC'd" doesn't necessarily mean one was required to accomplish the change.    It used to be a lot easier to get an STC back when engineering judgment was acceptable, and FAA personnel were more reasonable in their reviews.  I'd hazard a guess that if you proposed doing the caliper swap today, a reasonable IA might consider it a minor mod and be done with it.

[Echo]

On my first E model I bought STC and asked my IA to rotate. He said “somebody already did it”, but I submitted paperwork…sigh (caliper swap)

Edited April 10 by Echo

[FlyingDude]

15 minutes ago, KSMooniac said:

Just to muddy the waters a bit more...

I wrote a response citing CFR 21.93 and the definitions in par. 1.1 but I deleted it.  I don't think I'll ever get a J cowl anyway.

 

[EricJ]

44 minutes ago, KSMooniac said:

Just to muddy the waters a bit more... just because something in the past was granted an STC and especially marketed as "STC'd" doesn't necessarily mean one was required to accomplish the change.    It used to be a lot easier to get an STC back when engineering judgment was acceptable, and FAA personnel were more reasonable in their reviews.  I'd hazard a guess that if you proposed doing the caliper swap today, a reasonable IA might consider it a minor mod and be done with it.

Yeah, there's nothing stopping anyone from rotating their brake calipers.   My hangar neighbor has owned his M20A for many decades, and said they heard directly from Bill Wheat that no STC or 337 was necessary.    There was also nothing stopping anyone from applying for an STC and asking for money for permission to use it.

There's also an STC for sun visors.   Go figure.

[Shadrach]

3 hours ago, FlyingDude said:

I was once trying to see the feasibility of doing this while I was obsessing about the doghouse engine baffles.  Fixed the baffles, plugged tons of gaps and CHTs improved, and I kind of gave up the unicorn hunt.

However, installing J cowls on a pre-J is a major alteration per Appendix A of Part 43.  You can argue that item (iii) won't apply because engine cowls are not part of Fuselage (this is Mooneyspace after all, we argue all day long), however item (viii) clearly lists "cowling". 

Also, I am pretty sure this mod will change flight characteristics.  If a dumb Brake Caliper Swap (TM) speed mod requires a 337, changing the engine cowls would definitely require an STC.  I am sure the plane will handle differently but I am pretty sure that it won't be anything drastic...

 

Appendix A to Part 43—Major Alterations, Major Repairs, and Preventive Maintenance

(a) Major alterations—(1) Airframe major alterations. Alterations of the following parts and alterations of the following types, when not listed in the aircraft specifications issued by the FAA, are airframe major alterations:

(i) Wings.

(ii) Tail surfaces.

(iii) Fuselage.

(iv) Engine mounts.

(v) Control system.

(vi) Landing gear.

(vii) Hull or floats.

(viii) Elements of an airframe including spars, ribs, fittings, shock absorbers, bracing, cowling, fairings, and balance weights.

(ix) Hydraulic and electrical actuating system of components.

(x) Rotor blades.

(xi) Changes to the empty weight or empty balance which result in an increase in the maximum certificated weight or center of gravity limits of the aircraft.

(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems.

(xiii) Changes to the wing or to fixed or movable control surfaces which affect flutter and vibration characteristics.

I don’t know that the brake mod requires a 337. There are loads of 337’s filed every year that are not necessary per the regs. I happen to be close to DC and know several IAs that work for major DOD contractors. Before making their acquaintance, I had never heard the term “courtesy 337”. I am not saying the term is an industry norm, but I am saying that some maintenance facilities file 337s for any alteration, regardless of whether or not it meets the definition of major.

Are the brakes mounted in reverse on later models?

Is installing a used wing a major alteration?

it’s a major job, but it does not meet the definition of a major alteration. Does using a used J wing on an F model make it a major alteration? I don’t think so but I’m open to the rationale. My 67 model has a twist wing. What if I needed to replace it and could only find wing from a 69 model without the twist. Does that qualify as a major alteration? All of those parts are type certificated Mooney parts.

I don’t wish to be deliberately contrary about the process but there are a lot of inconsistencies from FSDO to FSDO with regards to interpretation of the regulations. It’s not a new problem. It is frequently topic of conversation within the agency yet it is never rectified. Every regulatory/approval process should demonstrably contribute to safety.  If it doesn’t, one must ask what it is accomplishing?  I feel obligated to push back sometimes on principle. It is frustrating to install a simple/common modification followed by the submission of a 337 that was copied word for word from someone else’s approved 337, only to have it rejected by the office in your region.

 

[Echo]

LED landing lights are another example of silliness. Better light. Less heat. Less energy draw.  

[Skates97]

7 hours ago, Sabremech said:

I did four cowling modifications initially when I started my project. I’m still working on two different cowlings but am in the process of moving right now. Many other issues with composite shops have hampered progress for quite a while but I am too far into it and too much money invested to walk away from it. 
Thanks,

David

Just waiting to wire the money when the cowling is available... 

[EricJ]

1 hour ago, Shadrach said:

Is installing a used wing a major alteration?

According to our local FAA reps at one of our IA seminars, if the replacement wing is the same part number as the original, tnen, no, it is a logbook entry.   Part number replacements are not major repairs or major alterations.

 

1 hour ago, Shadrach said:

it’s a major job, but it does not meet the definition of a major alteration. does using a used J wing on an F model make it a major alteration? I don’t think so but I’m open to the rationale. My 67 model has a twist wing. What if I needed to replace it and could only find wing from a 69 model without the twist does that qualify as a major alteration? All of those parts are type certificated Mooney parts.

That's a good question.   If the part came from the same model in the TCDS, e.g., the non-twist wing from another F model, I can see arguing that it's a replacement.   If the wing came from a J, I can see somebody arguing that it's a different model in the TCDS and therefore an alteration.   I can also see somebody arguing that if the wing isn't exactly the same part number, that it can't be replaced without a 337.  There will inevitably also be those that say it's a major repair regardless (although we have at least some FAA reps that say otherwise).   And there are some brave souls that say if it came from the same TCDS, regardless of model, it's good to go.

I know Maxwells have done this sort of thing more than once, so they might have an opinion on the matter.   They tend to err on the conservative side sometimes, which is understandable. 

1 hour ago, Shadrach said:

I don’t wish to be deliberately contrary about the process but there are a lot of inconsistencies from FSDO to FSDO with regards to interpretation of the regulations. It’s not a new problem. It is frequently topic of conversation within the agency yet it is never rectified. Every regulatory/approval process should demonstrably contribute to safety.  If it doesn’t, one must ask what it is accomplishing?  I feel obligated to push back sometimes on principle. It is frustrating to install a simple/common modification followed by the submission of a 337 that was copied word for word from someone else’s approved 337, only to have it rejected by the office in your region.

Unless it's the same inspector in the same FSDO on the same day, you really can't count on the same results.    Our most recent IA seminar was last month, and I was at multiple sessions where they were making an illustrative point that if the registration isn't current, then it's not really legally an airplane and you can't really sign off an annual.   A week or so ago I was on an email distribution where one of the senior local FSDO guys said, oops, sorry about that, it turns out that's not right, there was a legal opinion letter from 2012 that says the opposite, so you can sign off an annual regardless of registration status.   D'oh.

If you really want to spin them up, ask whether ADs apply to Experimental category airplanes.   I always thought the applicability statement in the AD was the final word, but apparently that's not even true, or at least that's one of the contentious issues.   This was asked as a question in one of the sessions and what came out of it (from multiple senior FAA folks in the room) was that the bottom line is that there is not agreement on this topic, apparently due to conflicting regs or at least conflicting interpretations of regs.

They have a difficult job in that a) the regs change fairly frequently, b) interpretations of the regs change even more frequently.   Court rulings, legal opinion letters, and even management changes and industry developments can all change how the agency operates as a whole and how individuals operate.   An individual inspector may have gotten burned on a particular topic and now takes a different view than previously, etc., etc.    From all of that I thnk it's the nature of the beast that there will always be differences among inspectors and FSDOs and the whole thing changes with time.    So all you can do is do the best you can at the time given the best info you have at the time.    There's *always* somebody to tell you you're doing it wrong, regardless of what you do.   That's just part of it, too.

[Fly Boomer]

40 minutes ago, EricJ said:

From all of that I thnk it's the nature of the beast that there will always be differences among inspectors and FSDOs and the whole thing changes with time.    So all you can do is do the best you can at the time given the best info you have at the time.   

Excellent summary.  Given the complexities of our pursuit, there is simply no way to write regs that specifically cover all potential situations.  It all comes down to "on any given day".

[Shadrach]

On 4/10/2024 at 6:08 PM, Fly Boomer said:

Excellent summary.  Given the complexities of our pursuit, there is simply no way to write regs that specifically cover all potential situations.  It all comes down to "on any given day".

Perhaps there is no simple way, but it could be better. When there are 50 owners pissing up multiple ropes in order to install an improved landing light that is not STCd but is an OEM part for at least one certified aircraft manufacturer, the agency has lost the plot.

The up side to dealing with multiple resubmissions for the same 337 is that I have never once since landed without a lighting landing light nor ever needed to replace a bulb. I was able to make my plane safer, more visible and more reliable with less draw on the electrical system despite my FSDOs best efforts to make it difficult. 

[Shadrach]

3 hours ago, EricJ said:

According to our local FAA reps at one of our IA seminars, if the replacement wing is the same part number as the original, tnen, no, it is a logbook entry.   Part number replacements are not major repairs or major alterations.

 

That's a good question.   If the part came from the same model in the TCDS, e.g., the non-twist wing from another F model, I can see arguing that it's a replacement.   If the wing came from a J, I can see somebody arguing that it's a different model in the TCDS and therefore an alteration.   I can also see somebody arguing that if the wing isn't exactly the same part number, that it can't be replaced without a 337.  There will inevitably also be those that say it's a major repair regardless (although we have at least some FAA reps that say otherwise).   And there are some brave souls that say if it came from the same TCDS, regardless of model, it's good to go.

I know Maxwells have done this sort of thing more than once, so they might have an opinion on the matter.   They tend to err on the conservative side sometimes, which is understandable. 

Unless it's the same inspector in the same FSDO on the same day, you really can't count on the same results.    Our most recent IA seminar was last month, and I was at multiple sessions where they were making an illustrative point that if the registration isn't current, then it's not really legally an airplane and you can't really sign off an annual.   A week or so ago I was on an email distribution where one of the senior local FSDO guys said, oops, sorry about that, it turns out that's not right, there was a legal opinion letter from 2012 that says the opposite, so you can sign off an annual regardless of registration status.   D'oh.

If you really want to spin them up, ask whether ADs apply to Experimental category airplanes.   I always thought the applicability statement in the AD was the final word, but apparently that's not even true, or at least that's one of the contentious issues.   This was asked as a question in one of the sessions and what came out of it (from multiple senior FAA folks in the room) was that the bottom line is that there is not agreement on this topic, apparently due to conflicting regs or at least conflicting interpretations of regs.

They have a difficult job in that a) the regs change fairly frequently, b) interpretations of the regs change even more frequently.   Court rulings, legal opinion letters, and even management changes and industry developments can all change how the agency operates as a whole and how individuals operate.   An individual inspector may have gotten burned on a particular topic and now takes a different view than previously, etc., etc.    From all of that I thnk it's the nature of the beast that there will always be differences among inspectors and FSDOs and the whole thing changes with time.    So all you can do is do the best you can at the time given the best info you have at the time.    There's *always* somebody to tell you you're doing it wrong, regardless of what you do.   That's just part of it, too.

The AD thing is not that big of a deal as no IA that I know of would be comfortable signing off an experimental aircraft with existing ADs. That would leave it to builders with repaiman authorization inspecting their own planes…most of whom are likely going to comply.

[KSMooniac]

10 minutes ago, Shadrach said:

Perhaps there is no simple way, but it could be better. When there are 50 owners pissing up multiple ropes in order. to install an improved landing light that is not STCd but is an OEM part for at least one certified aircraft manufacturer, the agency has lost the plot.

The up side to dealing with multiple resubmissions for the same 337 is that I have never once since landed without a lighting landing light nor ever needed to replace a bulb. I was able to make my plane safer, more visible and more reliable with less draw on the electrical system despite my FSDOs best efforts to make it difficult. 

Are you describing the XeVision HID light circa 2007-08? 

[EricJ]

22 minutes ago, Shadrach said:

The AD thing is not that big of a deal as no IA that I know of would be comfortable signing off an experimental aircraft with existing ADs. That would leave it to builders with repaiman authorization inspecting their own planes…most of whom are likely going to comply.

Experimental aircraft owners have no need for an IA.   Any A&P can sign off an experimental, and, as you mention, many builders/owners can sign them off as well.  If you think all, or even most, experimental owners are diligent about complying with ADs you are misinformed.   There is widespread opinion that ADs don't apply to Experimentals, which was the basis for the question in the first place.   It is revealing that even the FAA doesn't affirm this specifically.

[Shadrach]

On 4/10/2024 at 8:45 PM, KSMooniac said:

Are you describing the XeVision HID light circa 2007-08? 

I forgot that you were part of the goat rope! Did you get your 337 through on the first try? It’s been an excellent modification in every way accept approval. I wish I could say things had improved but in some ways they’ve gotten worse. There really is no incentive for regional FSDOs to grant field approvals these days.

[Shadrach]

5 minutes ago, EricJ said:

Experimental aircraft owners have no need for an IA.   Any A&P can sign off an experimental, and, as you mention, many builders/owners can sign them off as well.  If you think all, or even most, experimental owners are diligent about complying with ADs you are misinformed.   There is widespread opinion that ADs don't apply to Experimentals, which was the basis for the question in the first place.   It is revealing that even the FAA doesn't affirm this specifically.

I can only go by the ones I know. They are a pretty thorough. They are also pretty independent in mindset. So I could see them willfully ignoring an AD they think is egregious.

[KSMooniac]

I forgot that you were part of the goat rope! Did you get your 337 through on the first try? It’s been an excellent modification in every way accept approval. I wish I could say things had improved but in some ways they’ve gotten worse. There is really is no incentive for regional FSDOs to grant field approvals these days.

I was, and fortunately mine sailed right through in Wichita.

I'm finally changing to an LED right now, so if you'd like some spares let me know! I bought a used kit years ago for spares and ended up needing a cable after I pinched my original. Otherwise, I have two kits available soon.

Sent from my motorola edge plus 2023 using Tapatalk

[Shadrach]

5 minutes ago, KSMooniac said:

I was, and fortunately mine sailed right through in Wichita.

I'm finally changing to an LED right now, so if you'd like some spares let me know! I bought a used kit years ago for spares and ended up needing a cable after I pinched my original. Otherwise, I have two kits available soon.

Sent from my motorola edge plus 2023 using Tapatalk
 

What’s prompting the switch? Looking for a wider beam? Mine has performed flawlessly for more than 15 years and still lights up the water tower 3/4 of a mile away on the other side of the airport when I pass the fuel farm.

[KSMooniac]

I think it will be an upgrade... We'll see. Impulse purchase from a neighbor after he couldn't fit it in his application so I got a deal. I may change my mind!

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