User Name  
Password    



The Aviation Forum > Aviation > General Aviation > Modifying a Certified Aircraft?
Reply
 
LinkBack Thread Tools Search this Thread Display Modes
Old 09-16-2009, 06:17 PM   #1 (permalink)
Registered User
 
taylorbr's Avatar
 
Join Date: Apr 24, 2006
Location: Desert Country, CA
Posts: 1,284
Modifying a Certified Aircraft?

I know I should consult the EAA about this, but I'm looking for a quick and dirty answer and am hoping someone here has it.

If I wanted to buy a certified aircraft, modify it, and then have it certified under the experimental category, is that possible? We're talking much less than 51% of the aircraft being amateur built...As an example, could you purchase an aircraft, re-engine it, and have it certified in the experimental category without needing an STC if you went through the same engineering and flight test process that homebuilts go through?
__________________
Two dots left of the localizer...
taylorbr is offline   Reply With Quote
Old 09-16-2009, 08:08 PM   #2 (permalink)
Chillin' at .81 mach
 
Inverted's Avatar
 
Join Date: Oct 29, 2006
Location: Walnut Creek CA
Posts: 1,821
I have known several people to do that.
__________________
Lear Driver.
Ex freight dawg.
CFI/CFII/MEI, tailwheel and aerobatic instructor.

InvertedCast, the only podcast best listened to upside down!
www.invertedcast.com
Inverted is offline   Reply With Quote
Old 09-18-2009, 02:00 PM   #3 (permalink)
G Junkie
 
eagledriver's Avatar
 
Join Date: Mar 31, 2006
Location: Seattle
Posts: 836
There are different categories of "Experimental".

Experimental - Amateur Built
Experimental - Research
Experimental - Exhibition
Experimental - Air Racing
Experimental - Training
and more....

Re-engining a certified aircraft would put it in the Research category. The caveat being, once the "research" is done, the aircraft must be put back into its certified condition.

It all depends on what you want to do. For instance...

You buy a 1975 Cessna 172, but want to replace the 150hp engine with a 180hp one. You can either:

1. Purchase an existing Supplemental Type Certificate (STC) kit that's on the market.
2. File a 337 with your local FSDO on your newly designed conversion using the numerous STC's and the fact that Cessna now delivers the 172 with a 180hp engine as supporting documentation. (Good luck.)

If you purchased that same 1975 172 and wanted to stuff a 260hp O-540 in there, then you would end up doing the Experimental - Research route with the hopes of gathering enough information to file a 337 to appease the FSDO to grant you your new Airworthiness Certificate. It would be cheaper to buy a 182 though....

What is the project you have in mind?
__________________
John Smutny

http://northwestskyways.blogspot.com/

Life is not a journey to the grave intending of arriving safely in a well-preserved body, but rather to skid in broadside, used up, worn out, and loudly proclaiming: Damn, what a ride!

Last edited by eagledriver; 09-18-2009 at 05:02 PM.
eagledriver is offline   Reply With Quote
Old 09-18-2009, 08:08 PM   #4 (permalink)
TAF Moderator
 
Bluenose's Avatar
 
Join Date: Jul 09, 2004
Location: Canada's East Coast
Posts: 6,160
Do you guys have the LSTC option? (Limited Supplemental Type Certificate?)

That's what you get when you want to make a mod on your airplane, but have no intention of selling the mod as a kit or plans or whatever. While an STC costs many thousands of dollars of testing/engineering/paperwork hoops because you intend to sell it to the general public for a tidy profit and must therefore prove that it is safe, etc, an LSTC is a one-of for your airplane only. It still needs to be safe (more or less), but it's like the difference between the rules for a privately registered airplane and a commercially reg one....
__________________
Bluenose
TAF Moderator
Bluenose is offline   Reply With Quote
Old 09-18-2009, 09:43 PM   #5 (permalink)
Registered User
 
taylorbr's Avatar
 
Join Date: Apr 24, 2006
Location: Desert Country, CA
Posts: 1,284
Quote:
Originally Posted by eagledriver View Post
What is the project you have in mind?
I've been floating around a few. My least ambitious would be a re-engine of either a Mooney M20F or 1968 Cessna 210 to a TIO-550 with intercoolers. I was even thinking possibly along the lines of liquid cooled since I know the climb performance of the 210 is limited due to CHT. It would also be nice to change the 210's hydraulic system from engine driven to the electric driven system used in the later models.
__________________
Two dots left of the localizer...
taylorbr is offline   Reply With Quote
Old 09-19-2009, 12:25 AM   #6 (permalink)
G Junkie
 
eagledriver's Avatar
 
Join Date: Mar 31, 2006
Location: Seattle
Posts: 836
Yikes, converting a M20F to a M20R? I think that falls under the 172 to 182 mod thing I mentioned. While a lot of components are interchangeable between the two, I doubt you'll find a FSDO to entertain the mod.

And that is the key, you need to talk to your FSDO and see what their tolerance for changes to a certified airframe is. It's odd, but the rules differ from FSDO to FSDO greatly.

Bluenose, the LSTC is a Canadian thing that (unfortunately) is not available down here. There are "Alaska Mods" to many aircraft that are allowed up North, but it's hard to find a FSDO in the Lower 48 that allow similar leeway.
__________________
John Smutny

http://northwestskyways.blogspot.com/

Life is not a journey to the grave intending of arriving safely in a well-preserved body, but rather to skid in broadside, used up, worn out, and loudly proclaiming: Damn, what a ride!
eagledriver is offline   Reply With Quote
Old 09-19-2009, 11:04 AM   #7 (permalink)
Registered User
 
taylorbr's Avatar
 
Join Date: Apr 24, 2006
Location: Desert Country, CA
Posts: 1,284
Quote:
Originally Posted by eagledriver View Post
Yikes, converting a M20F to a M20R? I think that falls under the 172 to 182 mod thing I mentioned. While a lot of components are interchangeable between the two, I doubt you'll find a FSDO to entertain the mod.
Agreed - there is a similar mod called the Mooney Rocket (no longer sold unfortunately), but it took them two years to get the STC through.

It's a shame that there isn't a category of experimental for modifying certified aircraft. You could do the engineering and flight test work required of a homebuilt and put the entire aircraft into the experimental category, but still require the unmodified components to be annualed by an IA.
__________________
Two dots left of the localizer...
taylorbr is offline   Reply With Quote
Old 12-25-2012, 06:54 AM   #8 (permalink)
Registered User
 
MooneyPilot's Avatar
 
Join Date: Dec 16, 2005
Location: summerstown, Ontario,canada
Posts: 360
Smile Modifying Older Planes?

Speed mods pay off with airplanes with cleaner lines to start with. It would never have worked with my old PA-12!

This is a 1964 M20C with a Lycoming 0360A1D (180 hp)
Using a benchmark of 2500 rpm, 25" MP , 50 ROP and at 4500', the speed increased to 158 kts.

An ARI nose & new paint brought it to 154 kts. The last 4 knots were from aileron, flap gap seals, and all the tail mods, hinge covers,long dorsal & horizontal stab farings.

but, you can see "diminishing returns" at work. And 2500rpm & 25" MP aren't the normal power. This is the benchmark suggested by a MAPA Log article.
Attached Thumbnails
Modifying a Certified Aircraft?-tafrji.jpg.jpg  
__________________
http://www.facebook.com/profile.php?id=516160854

I want summer......NOW!!!!
MooneyPilot is offline   Reply With Quote
Old 12-25-2012, 11:48 AM   #9 (permalink)
Administrator
 
Richard's Avatar
 
Join Date: Apr 13, 2002
Posts: 870
MooneyPilot - I think you're exactly right: speed mods on airframes that are already, or potentially, clean are the low-hanging fruit of airframe mods.

And I can't think of any GA airplane that proves the point better than the Mooney line. When Roy LoPresti became President of Mooney, he immediately applied the types of drag clean-up measures you describe and really put Mooney on the map as a real performance leader.

He had some pesky (understatement) cooling problems with the 231, of course, but nonetheless, he got some real-world performance improvements at relatively low cost and low complexity.
Richard is offline   Reply With Quote
Old 12-25-2012, 01:13 PM   #10 (permalink)
Registered User
 
MooneyPilot's Avatar
 
Join Date: Dec 16, 2005
Location: summerstown, Ontario,canada
Posts: 360
Exactly! And all the mods I applied, except the ARI nose, were "201 mods" that came from either LoPresti at the Mooney factory or Lasar after market. There is a real market for "201 mods" that can be put on the older basic airframes.
__________________
http://www.facebook.com/profile.php?id=516160854

I want summer......NOW!!!!
MooneyPilot is offline   Reply With Quote
Reply

Share This Content

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 08:30 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
(c) 2002-2012 The Aviation Forum, All Rights ReservedAd Management plugin by RedTyger

Search Engine Friendly URLs by vBSEO 3.3.1