Trade offs between an F and J model

[EricJ]

28 minutes ago, Hank said:

I have no dog in this race, other than general dislike for people who say that everything not cover3d under PMS, STC, etc., is of coirse a major modification requiring DAR / DER input, 337s, etc. But I did a 1-second google search, the first hit was an AOPA article [https://www.aopa.org/news-and-media/all-news/2014/october/22/aircraft-maintenance-major-vs-minor-alterations-part-2] from which I extractex the following:

It is the responsibility of the installer to determine whether an alteration is minor or major based on the federal aviation regulations. This makes choosing a good shop to do the alteration very important. There are a lot of excellent mechanics out there who understand the regulations, can help you navigate the process, and can get your alteration done in a safe and legal manner. Unfortunately, there are also quite a few shops out there who follow the “No STC = No Alteration” philosophy. This approach has no basis in the regulations, so steer clear of anyone not willing to evaluate your proposed alteration on its own merits. 

The primary regulatory guidance for determining a major vs. a minor alteration can be found in 14 CFR 21.93  and 14 CFR Part 1.1.

According to 14 CFR 21.93, “A ‘minor change’ is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product. All other changes are ‘major changes’ (except as provided in paragraph (b) of this section).”

Definitions provided in 14 CFR Part 1.1 state, “Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications—

(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations.”

And “minor alteration means an alteration other than a major alteration

FWIW, I think that's not quite right.   Part 21 is about certification procedures, so unless somebody is actually seeking a new certification or a change in the certification, I think it isn't really applicable.

However, the definition you cite in 1.1 is certainly applicable, and the other FAR section that matters is Part 43 Appendix A, which lists Major Alterations and Repairs.   Basically, if it does not appear in the list in Part 43 App A and isn't precluded by Part 1.1, it is, by definition, a minor modification and does not require a 337.

I don't see anything in 43 App A or 1.1 that would make me think that particular change should be considered a Major Alteration.   Sounds like the relevant A&Ps and IAs (i.e., the ones that actually write in the logbook for that airplane) agree.

[Yetti]

In case anyone want more reading material.    I think this one is in the download section.

seat_rail.pdf

[mooniac15u]

46 minutes ago, M20Doc said:

When you go to buy Yetti’s airplane, you can make it an issue.  Until then his IA seems content.

Clarence

So, you will do this as a minor mod for your customers?

[mooniac15u]

1 hour ago, Hank said:

I have no dog in this race, other than general dislike for people who say that everything not cover3d under PMS, STC, etc., is of coirse a major modification requiring DAR / DER input, 337s, etc. But I did a 1-second google search, the first hit was an AOPA article [https://www.aopa.org/news-and-media/all-news/2014/october/22/aircraft-maintenance-major-vs-minor-alterations-part-2] from which I extractex the following:

It is the responsibility of the installer to determine whether an alteration is minor or major based on the federal aviation regulations. This makes choosing a good shop to do the alteration very important. There are a lot of excellent mechanics out there who understand the regulations, can help you navigate the process, and can get your alteration done in a safe and legal manner. Unfortunately, there are also quite a few shops out there who follow the “No STC = No Alteration” philosophy. This approach has no basis in the regulations, so steer clear of anyone not willing to evaluate your proposed alteration on its own merits. 

The primary regulatory guidance for determining a major vs. a minor alteration can be found in 14 CFR 21.93  and 14 CFR Part 1.1.

According to 14 CFR 21.93, “A ‘minor change’ is one that has no appreciable effect on the weight, balance, structural strength, reliability, operational characteristics, or other characteristics affecting the airworthiness of the product. All other changes are ‘major changes’ (except as provided in paragraph (b) of this section).”

Definitions provided in 14 CFR Part 1.1 state, “Major alteration means an alteration not listed in the aircraft, aircraft engine, or propeller specifications—

(1) That might appreciably affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness; or

(2) That is not done according to accepted practices or cannot be done by elementary operations.”

And “minor alteration means an alteration other than a major alteration

FWIW, I generally agree that there are a lot of unnecessary 337s filed for minor modifications. In this case it impacts the W&B by changing the range of stations for the seat. It also involves drilling holes in seat rails which are structural. I don't understand why everyone is so reluctant to call this a major mod. 

[Hank]

7 minutes ago, mooniac15u said:

FWIW, I generally agree that there are a lot of unnecessary 337s filed for minor modifications. In this case it impacts the W&B by changing the range of stations for the seat. It also involves drilling holes in seat rails which are structural. I don't understand why everyone is so reluctant to call this a major mod. 

Because the FAA doesn't list it as a major mod. Because the CG is only effected while slid back, and that can be calculated preflight. Kind of like others here who take off then slide their seats all the way back. The seat rails are already full of holes, thenpiece at the back serves no additional structural function affected by another hole. It's not an "appreciable" change. His IA is fine with it.

Should I keep listing reasons, or can I stop?

Why do some people repeatedly insist that everything is a major mod, when the FAA has kindly defined what they think is a Major Mod? Or is your opinion more worthy than the FAA's either because it's more restrictive or because it's your opinion???

[EricJ]

37 minutes ago, mooniac15u said:

I don't understand why everyone is so reluctant to call this a major mod. 

A minor alteration is defined as anything that isn't a major alteration (by Part 1.1), and major alterations are defined by Part 43 App A and Part 1.1, as previously cited.  

Being reluctant to call something a major alteration should be the default.  If it doesn't qualify as a major alteration under the stated regs, it isn't one.   I haven't seen anything close to something I'd call a justification of this being a major alteration.

[gsxrpilot]

2 hours ago, M20Doc said:

When you go to buy Yetti’s airplane, you can make it an issue.  Until then his IA seems content its none of your damn business.

Clarence

Fixed it for ya 

[mooniac15u]

10 hours ago, Hank said:

Because the FAA doesn't list it as a major mod. Because the CG is only effected while slid back, and that can be calculated preflight. Kind of like others here who take off then slide their seats all the way back. The seat rails are already full of holes, thenpiece at the back serves no additional structural function affected by another hole. It's not an "appreciable" change. His IA is fine with it.

Should I keep listing reasons, or can I stop?

Why do some people repeatedly insist that everything is a major mod, when the FAA has kindly defined what they think is a Major Mod? Or is your opinion more worthy than the FAA's either because it's more restrictive or because it's your opinion???

I have never insisted that everything is a minor mod.  That is a strawman that has nothing to do with this particular issue.

With the extra hole any other pilot flying that plane could reasonably make the assumption that they can put the seat in that hole and be within the the CG range described in the POH or the TCDS when calculating the W&B for the plane.  Filing a 337 would at least create a document trail for future owners rather than hoping that they find it buried in a logbook entry.  Realistically I would hope that notations were made in the POH about the change.

Anything that allows a pilot to create a more aft CG without their knowledge is a significant change.  Call it a major mod or call it a minor mod but the impact of this change is potentially greater than most of what the FAA would think of as a minor mod.

[mooniac15u]

9 hours ago, gsxrpilot said:

Fixed it for ya 

This is a public internet forum and this mod has been mentioned several times in the past.  Topics like this deserve some discussion so that anyone else considering this mod is aware of possible implications.  I have no illusions that anyone who has already made up their mind will consider any new information or viewpoints that might be presented.  This is the internet.

[Hank]

4 minutes ago, mooniac15u said:

Filing a 337 would at least create a document trail for future owners rather than hoping that they find it buried in a logbook entry.

Finding a whole sheet of paper in the logbook pile is easier than finding a written entry in the Airframe book itself???

My "logbook" is a zippered notebook, overflowing with papers, including a zippered poich with the Engine, Airframe and Propeller logbooks near the front to find quickly. Anything else must be searched for.

[mooniac15u]

7 minutes ago, Hank said:

Finding a whole sheet of paper in the logbook pile is easier than finding a written entry in the Airframe book itself???

My "logbook" is a zippered notebook, overflowing with papers, including a zippered poich with the Engine, Airframe and Propeller logbooks near the front to find quickly. Anything else must be searched for.

If you submit a 337 it becomes a part of the permanent record on file with the FAA.  When purchasing an aircraft you can (and should) get a copy of the all the 337s from the FAA.

[Yetti]

2 minutes ago, mooniac15u said:

If you submit a 337 it becomes a part of the permanent record on file with the FAA.  When purchasing an aircraft you can (and should) get a copy of the all the 337s from the FAA.

What you should be worried about is how the holes were drilled to conform to the drawing.  a 0.250 hole 1.5" away from the other hole.   If the holes are not drilled properly the pins or only one pin would engage.   Realizing that the new rails come undrilled from Mcfarlane.  The rail is slightly convex.  And they should be drilled to the proper depth.   

[Yetti]

As far as 337s go.  The Grumpy IA thought that changing out the ELT to a 406 required a 337 since it was a new radio.   Nope just a A&P sign off.

[mooniac15u]

3 minutes ago, Yetti said:

What you should be worried about is how the holes were drilled to conform to the drawing.  a 0.250 hole 1.5" away from the other hole.   If the holes are not drilled properly the pins or only one pin would engage.   Realizing that the new rails come undrilled from Mcfarlane.  The rail is slightly convex.  And they should be drilled to the proper depth.   

When it comes to your particular implementation I have no doubt that you did the work properly.  Your attention to detail is well documented here.

[Yetti]

1 minute ago, mooniac15u said:

When it comes to your particular implementation I have no doubt that you did the work properly.  Your attention to detail is well documented here.

Jigs are the answer.   Side note a .250 drill bit spun by hand (not in a drill motor) is quite handy for cleaning out the other holes.   Everyone should clean their holes every couple of years.  to prevent the lack of seat pin engagement.

  The distance between holes was measured on the milling machine so it's really accurate.   tape is placed on the drill bit to show the stop mark to get the proper depth.

[Shadrach]

12 hours ago, mooniac15u said:

FWIW, I generally agree that there are a lot of unnecessary 337s filed for minor modifications. In this case it impacts the W&B by changing the range of stations for the seat. It also involves drilling holes in seat rails which are structural. I don't understand why everyone is so reluctant to call this a major mod. 

Everyone is reluctant because it does not fit the definition of a major alteration (major mod is your term, let’s stick to the FAA’s verbiage). Seat rails are not a structural component of the airframe and that is what is meant by “structural”. By your definition drilling any hole would require a 337 because there is no such thing as a hole that does not affect the structure of the object being drilled. The question revolves around whether the object being drilled is structural to the airframe. The answer in the case of seat rails is no. Your CG argument doesn’t hold water either. Neither the CG range nor the max gross weight of the aircraft is being altered.  Extending the seat’s CG station aft slightly while keeping it within the factory specified CG range does not constitute a major alteration.  It does not affect weight, balance, structural strength, performance, powerplant operation, flight characteristics, or other qualities affecting airworthiness.

It appears as though you’re trying to make this into something that it’s not. I would never try and get in between a man and his desire to generate paperwork. Knock yourself out when it comes to your own aircraft.  I am genuinely confused by your determination to inflate such a minor change made on someone else’s airplane into a Major Alteration. I’m not saying you wouldn’t be able to find a FSDO to except it as such, but there are still quite a few commonsense folks at the FAA that would tell you that this does not meet the definition of a Major Alteration. 

Edited April 19, 2019 by Shadrach

[ArtVandelay]

As far as 337s go.  The Grumpy IA thought that changing out the ELT to a 406 required a 337 since it was a new radio.   Nope just a A&P sign off.

Was the new station noted in the weight & balance section of the POH?


Tom

[Yetti]

27 minutes ago, ArtVandelay said:

Was the new station noted in the weight & balance section of the POH?


Tom

ACK has a 406 that fits the old bracket. which was in the hat rack. Replace the antenna (of course there was some filiform, so I had to scuff and paint)  The 406 has a battery that is good till 2023 so there is a less expense of buying Duracells every other year.      Good point I do think the weight is different, the station should be the same.    I should have increased the weight allowed in the hat rack.

Edited April 19, 2019 by Yetti

[Shadrach]

15 minutes ago, ArtVandelay said:

Was the new station noted in the weight & balance section of the POH?


Tom

Noting the new additional aft station range of the seat would be needed to complete the logbook entry IAW acceptable standards. It’s interesting to note the checking the many online weight & balance calculators for the M20F and J models vary a bit. Some have a provision to change the arm from forward to aft, some take an average, some have a drop down with selectable ARMs. 

[Shadrach]

12 minutes ago, Yetti said:

ACK has a 406 that fits the old bracket. which was in the hat rack. Replace the antenna (of course there was some filiform, so I had to scuff and paint)  The 406 has a battery that is good till 2023 so there is a less expense of buying Duracells every other year.      Good point I do think the weight is different, the station should be the same.    I should have increased the weight allowed in the hat rack.

Ha!  regardless of his quote, I’m pretty sure he was referring to the seat mod. Which should have been noted.

Edited April 19, 2019 by Shadrach

[Yetti]

7 minutes ago, Shadrach said:

Ha!  regardless of his quote, I’m pretty sure he was referring to the seat mod. Which should have been noted.

I've moved on :-)     I think when you read through all the threads, there seems to be a variable number of holes that come from the factory.   The W&B was noted.  and the W&B I run on the phone has my fat furry ass sitting further back.   I think more weight aft makes my plane faster than others.

Edited April 19, 2019 by Yetti

[Shadrach]

1 hour ago, Yetti said:

I've moved on :-)     I think when you read through all the threads, there seems to be a variable number of holes that come from the factory.   The W&B was noted.  and the W&B I run on the phone has my fat furry ass sitting further back.   I think more weight aft makes my plane faster than others.

Indeed there are a variety of holes and a specified range of ARMs for said holes. I agree that this is a minor alteration (takes major mental gymnastics to see it any other way). That being said, there does need to be a way of calculating W&B with your FFA being seated further aft however slight the change may be. The notion that DER would be required to bless it is just silly...

Edited April 19, 2019 by Shadrach

[Marauder]

I’ll add a little commentary about this topic. When I was based further north, my IA approached the local FSDO about adding a sub panel in my plane on the pilot’s side of the panel. The FSDO said nothing was needed other than a log book entry that it was installed.

Fast forward 19 years. I am now located further south and am in the middle of an avionics upgrade. The local FSDO happened to be in the avionics shop reviewing their certification. They see the sub panel and tell the shop it is strictly forbidden. They required the sub panel to be removed. Fortunately I was making space in the panel with the upgrade and was able to move things up and eliminate the sub panel.

So, even the “authorities” don’t agree on these topics. I suspect that is one of the reasons the FAA is trying to consolidate these functions into a central function.


Sent from my iPad using Tapatalk Pro

[Igor_U]

13 hours ago, Yetti said:

In case anyone want more reading material.    I think this one is in the download section.

seat_rail.pdf 613.62 kB · 10 downloads

yeah, seen this before

Is it only me finding this ironic? Quite a few posters are claiming it is minor alteration while supporting documents is filed as Major?

[ArtVandelay]

Indeed there are a variety of holes and a specified range of ARMs for said holes. I agree that this is a minor alteration (takes major mental gymnastics to see it any other way). However, there does need to be a way of calculating W&B with your FFA being seated further aft however slight the change may be. The notion that DER would be required to bless it is just silly...

This^
My Js moment runs 130”lb/1000 fully loaded so assuming 300lbs and 2” further back, it’s still less than 1% difference.


Tom