Nose cowling

[48RagwingPilot]

Thanks, David. Much appreciated.

[GAHorn]

That appears to be a180 nose cowl.
In any case it's not a170 cowl of any type, which could complicate your quest for easy, fast legality.
Youre best opportunity might be to have your IA/AP visit with the FSDO
to inquire a to their attitude toward a field approval for an existing, successful,
and flight proven alteration using Cessna cowl, part number yada yada yada

The last annual inspector has a vested interest in finding a legitimate solution, since hes been signing off on this. He should pony up for a large part of the effort. IMO

[Bruce Fenstermacher]

Dave,

Looks like a nice job. The lower lip has also been virtually removed. It should be 2-1/2" but looks like 3/4". And of course that spinner is not a '48 as well as the one piece windshield

I'm afraid lots of people including the important people in the FAA will consider it major. Here is why. The shape of the cowl could change the aerodynamics of the aircraft and it may not meet the standards that it meet for certification. Along those same lines the changes made to the cooling of the engine have never been certified with the current mix of parts. Had they removed the internal air box and completely installed the later 172 cowl and baffles one could at least say it had been approved on a like aircraft.

If you talk to the Feds you will want to know and tell them how long the aircraft has been this way with out ill effect. And you probably don't want to elaborate all the other changes that were not made when the bowl was substituted. Or mention anything about aerodynamic changes. Let them figure it out.

Of course I'd try to argue the cowl mods are a minor alteration.

[48RagwingPilot]

All--

Thanks for the comments and analysis. The fact it's a C-180 nose bowl changes things a bit since my A&P/IA has been laboring under the impression it's an early C-172 nose bowl. I'll keep y'all posted as this matter evolves.

Dave

[bat443]

The nose cowl shown in the photo is NOT at 180 nose cowl. None of the 180 cowls have the opening for the oil pan cooling air inlet, nor do they have the engine air intake mounted in the O300 location. Looking at sales brochure photos posted on the Cessna Pilot Association web site it appears to be a nose cowl for a 1961 or 1962 C172 which I verified in the pre 1963 C172/175 parts manual as correct. The nose cowl depicted in the photos is from a C172 serial numbers 17247747
thru 17249544 and actually includes the cut out above the crankshaft with the top cowl attaching aft of the nose cowl. Hope this helps.

Tim

[48RagwingPilot]

Tim,

That info helps a lot. Thanks so much. More to follow.

Dave

[Bruce Fenstermacher]

Dave,

You should also know this is not the first 170 with this nose bowl as it was a required change for a front mounted belt driven vacuum pump. Though I'd venture to say many folks changed out the entire cowl.

This is another good piece of info to have for the Feds as it shows somewhere someone else approved the change. This can be big because they would only be agreeing it was ok in this case not necessarily approving all the other aspects but relying on that having been done for the STC'd pump approval. With some time and he groups help we might be able to identify the STC number and maybe even a drawing or instructions. (might be in our library but I don't remember it)

[GAHorn]

"Looks like"....does not equate to "is".
In fact...it only"looks like" an early 172 nose cowl.
The air box intake is rivetted on, and the sump intake also.
Those could just as easily been added to several versions of early
nose cowls produced by Cessna.
My point is, The FSDO might be the best solution for an approval for
this.
If you do seek that route, Do not hide anything or any minor detail about the cowling...show it all. You do not want only the nose to be approved....then
later find yourself owning an unapproved lower cowl, with an unapproved
lower lip.

[Bruce Fenstermacher]

George is correct you want to identify all the different parts used if one can. I meant by my earlier statement don't put ideas in anyone's head as to why it shouldn't be approved.

[48RagwingPilot]

Bruce & George,

Can you help me find the STC for the vacuum pump that includes the C-172 nose bowl? Thx.

Dave

[Bruce Fenstermacher]

It is for an Airborne STC SA15CE, SA3-664, and SA3-663 for a vacuum pump installation. One of these STCs covers a 170B and none of them may cover a 170. The STC has not been supported for 5 or more years and can not be bought. You will have to find someone with the STC paperwork to see what it all involved. You will not be able to get that from the FAA which will give you only the cover sheet.

I looked in our library and we do not have the actual installation drawings.

I'm not even sure the 172 nose bowl was actually part of the STC but it is the mod that one sees the 172 nose bowl installed.

[DaveF]

In any case it's not a170 cowl of any type

So the cowl of the airplane on the cover of the first quarter 2012 170 News has also been modified?

[Bruce Fenstermacher]

Yes Dave that is another example of a 172 cowl on a 170 but this one is a later B model and so it is likely the entire cowl, not just the nose bowl, has been changed.