160 HP engine and wood spars

AKpilot

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I own a 1974 7GCBC, it has wood spars and I replaced the engine years ago with the LYC O-320 B2B, I didn't realize at the time that only the metal spar 7GCBC's were approved to have the 160 HP O-320 B2B engine. Does anyone have any experience with this situation? I assume I will need to get a field approval, but I've heard it's not as easy as it used to be? Any advice or info would be greatly appreciated!

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Bob Turner

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Yeah - shhh!

Check the type certificate for loopholes. There are some who insist that anything on the type certificate is legal for any aircraft. I view that with some skepticism - the PA11 is on the J3 type sheets, but I hold field approvals for wings, struts, and fuel tanks.

Sorry - I did not see your other thread. Maybe Bart can combine them.
 

AKpilot

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I took the TCDS into the FSDO and asked for their interpretation of the language. They said they didn't know for sure, recommended I call the American Champion for clarification, I did and they confirmed it is required to have metal spars to install a 160 HP engine, however, it also gives you a gross weight increase. I'm wondering if there is someone out there that was able to get a field approval for the engine being installed on a wood spar airplane without the gross weight increase? It seems to me the FAA wouldn't have a problem with that being that it is less than a 10% increase in horsepower?
 

Bob Turner

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You do not have to rely on others' opinions. You only have to rely on express statements.
If the TC says "160 horse is only allowed on factory aluminum spar aircraft" or worse, "only allowed on ser# x and up" then there is no room for opinion. If there is an ambiguity, interpret it in your favor.

People who write this stuff know how to make an express statement. If they don't do that, you have every right to interpret stuff in your favor.

Opinion.
 

Goodyear

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I took the TCDS into the FSDO and asked for their interpretation of the language. They said they didn't know for sure, recommended I call the American Champion for clarification, I did and they confirmed it is required to have metal spars to install a 160 HP engine, however, it also gives you a gross weight increase. I'm wondering if there is someone out there that was able to get a field approval for the engine being installed on a wood spar airplane without the gross weight increase? It seems to me the FAA wouldn't have a problem with that being that it is less than a 10% increase in horsepower?
The factory metal wings give you a gross weight increase but not the Milman metal wings. You can probably buy a new plane for the cost of having factory metal wings shipped to you and installed.
 

AKpilot

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Thanks for the advice and input. I decided to go with the field approval process. The FSDO was pretty helpful and the process was not as bad as I thought it would be. It’s done and approved.
 

Bob Turner

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So do you suppose that service bulletin just backs up the TCDS? Or is ACA assuming that it can issue a service letter and it becomes approved data?
 

Bob Turner

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I just quickly looked at the type certificate. Items 125 and 126 appear to allow the 160, installed per a service bulletin. It also references notes 13 and 15, which do not specify metal wings. So can a service bulletin become part of a type certificate? If so, can it only restrict, or can it expand what is legal?

By the way, Continental has a few early service bulletins that state, up at the top, that they are FAA/CAA approved. That is good enough for me.
 

Bartman

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Thanks for the advice and input. I decided to go with the field approval process. The FSDO was pretty helpful and the process was not as bad as I thought it would be. It’s done and approved.
glad to hear it worked out for you! would you mind starting a new thread and outlining your project? details and photos that might help others to do what you've done would be very much appreciated!
 

Kmcaero

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Thanks for the advice and input. I decided to go with the field approval process. The FSDO was pretty helpful and the process was not as bad as I thought it would be. It’s done and approved.
I am in the same boat as you were, wanting to increase to the 160 hp -B2B, I am in the process of rebuilding a 1970 7GCBC over the last few years. I am in Canada so will be dealing with Transport Canada on this. Could you give me some guidance on what you had to do for the FSDO and what paperwork was required? Maybe a copy of the final approval?. If I can show proof of recent FAA acceptance on this to our guys they will usually green stamp it also.
 

AKpilot

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I am in the same boat as you were, wanting to increase to the 160 hp -B2B, I am in the process of rebuilding a 1970 7GCBC over the last few years. I am in Canada so will be dealing with Transport Canada on this. Could you give me some guidance on what you had to do for the FSDO and what paperwork was required? Maybe a copy of the final approval?. If I can show proof of recent FAA acceptance on this to our guys they will usually green stamp it also.
Sorry for the delay, I do not get on the forum very often. I will send you what I have soon, it's all packed away at the moment.
Can you send me your email address?
 

AKpilot

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glad to hear it worked out for you! would you mind starting a new thread and outlining your project? details and photos that might help others to do what you've done would be very much appreciated!
I will get that done soon!
 

Kmcaero

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Thank you for following up! My engine shop has the bottom end together but the top end still awaits my word on pistons.
Regards,
Todd Kendall
204 391-8944 kmco@shaw.ca
 

Old Blue

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In addition to the above engine modification for a 7GCBC, if your pockets are deep enough, there is an STC ( #SA00096BO ) for conversion to an O 360 C2E. You are essentially becoming a Scout from the firewall forward with a Sensenich 76EM8S9-0-56 prop. There in no requirement for the aluminum spars although I did the Milman with leading edge all as part of a total rebuild a few years back of my '68 7GCBC. I spend most of my time on floats and the boost in performance is as expected.
 

Bartman

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Thank you for following up! My engine shop has the bottom end together but the top end still awaits my word on pistons.
Regards,
Todd Kendall
204 391-8944 kmco@shaw.ca
There was a facebook thread about this about four years ago. I've tried to decipher the gist of it but I'm still not quite sure what the right answer is. @AKpilot got his approved so it's possible but there was a reference to Revision 73 of TCDS A759 which can be found here, https://champcitabriadecathlonforums.com/threads/tcds-a-759-7ac-through-7kcab.5/

I'm not sure if this link will work but here it is if you want to give it a try
https://www.facebook.com/groups/718166378262033/permalink/1140531099358890/
 

BB57

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See item 125 which addresses the O-320B2B on the 7GCBC and refers to Note 13 [emphasis added]:

125. Lycoming O-320-B2B engine (Models 7ECA, 7GCAA, 7GCBC) Installed per Champion Dwg. 7-1289.
Requires aircraft to be outfitted per Note 13 (7GCBC) or Note 15 (7ECA, 7GCAA)
Fuel 100 minimum grade aviation gasoline Engine limits Maximum Continuous 2700 r.p.m. (160 h.p.)
Oil capacity 8 qt. at –36 Required equip.
Landplane: 20(a), 102(f), 103(i), 117(e), 123(a), 201(i)(l), 202(g). Modifications per Champion dwg. 11-1029 (7ECA only). Original Equipment Serial Numbers: 400-97 and up (7GCAA) 1200-94 and up (7GCBC)

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NOTE 13. The following changes apply to 7GCBC aircraft built in 1994 and later (all with 7-1545 wings).

C.G. Range and Maximum Weight changes apply to any 7GCBC that retrofits with 7-1545 wings except for airplanes with optional engine item 122.

C.G. Range: Landplane: (+14.2) to (+19.2) at 1800 lb. (+10.5) to (+19.2) at 1325 lb. or less
When performing acrobatic maneuvers, the C.G. range shall be limited to: (+14.2) to (+16.3) at 1800 lb. (+10.5) to (+16.3) at 1350 lb. or less Straight line variation between points given.
Maximum Weight, Landplane: 1800 lb.
Serial Nos. Eligible 1200-94 thru 1202-94, 1203-95 and up

For Serial Nos. 1360-2004 and up with optional engine item 126 or 127; when performing acrobatic maneuvers (see Note 10) the airplane must be loaded as shown above. The airplane may otherwise be operated in the Normal category as shown below.

C.G. Range Landplane: (+15.4) to (+19.2) at 1950 lb. (+10.5) to (+19.2) at 1325 lb. or less Straight line variation between points given.
Maximum Weight, Landplane 1950 lb.
Required Equipment Item 126 or 127

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The 7-1545 wings mentioned above are the metal spar 7GCBC wings, introduced in 1994.

Item 122 addresses O-235 engines (i.e. no gross weight increase for a 7GCBC with metal wings and downward powered O-235 engine.)

Items 126 and 127 are 180 hp O-360 engines.

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*My* read on this is that in order to install a 160 hp O-320B2B, you do not need metal spar wings, you just would not get the gross weight increase to 1800 pounds noted in Note 13.

That said, the wording "Requires aircraft to be outfitted per Note 13 (7GCBC)" is a little ambiguous and I can see where the reference to Note 13 and that initial wording could be taken to mean that metal spar wings are required. The question would be "Does it mean it must have metal spar wings (and not just any metal spar wings but the ACA 7-1545 wings) or does it mean if not equipped, it doesn't get the 1800 pound gross weight increase? However, since Note 13 is all about metal spar wing gross weight increases and new CG limits, I think it's actually silent on the issue of "requiring" metal spars for the 160 hp engine installation. And that makes sense as the Vne isn't increased anyway, and other than Vne and gross weight, the wings have nothing to do with the effects of a 10 hp increase in power. If there was an issue it would be in terms of the engine mount and fuselage being stressed for 10 more hp, and that issue isn't raised anywhere, even with the 180 hp installations.

Consequently, *my* read on it is that the 7-1545 wings are not required for the reasons noted above, plus the fact that any ambiguity in federal regs and documents goes against the author not the reader (based on 12 years of reg writing and enforcement experience).

However you'll need to find an AP / IA who agrees with that interpretation and will sign off on it.