Considering Making a Citabria/Decathlon IFR

Bob Turner said:
Citabria is a CAR4a airplane. For those, any can legally be flown IFR.

Decathlon is certificated under different rules. If an AFM says VFR only, you are going to need more than gyros and a sweep second hand.

By the way, POH is different from an AFM, at least legally.
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For operation in IFR conditions a SuperD must satisfy two Part 23 requirements (or so I've been instructed by our FSDO): 1) a heated pitot tube and 2) an alternate static air source selector valve.

Our SuperD is about two-thirds of the way through the process of installing the 91.205(d) items to make the airplane "IFR equipped", which authorizes flight on an IFR clearance but not flight in IFR conditions. I bought a salvaged but serviceable heated pitot tube and new ACA heated pitot tube mounting bracket. As soon as the airplane is ready for a ferry flight to the fabric shop, a patch will be applied around the new mounting bracket.

The FAA wants an approved alt static air source valve; the switch that Ken Bowersox used in his STC is no longer acceptable (at least to our FSDO). We're installing a surplus Mooney M20K valve (about $120) instead of a Cessna 172 valve (about $550).

Old news to those of you who have had (or performed) major surgery on your airplanes, but it;s like taking apart one of those hollow Russian dolls with more smaller Russian dolls inside, each doll uglier than the last.

The shop discovered that one of the left bulkheads had a failed attach point. They don't know how to remove and replace it with a new or repaired bulkhead. Any advice?
 
Does ac43.13 cover splicing plywood to plywood with doublers over the seam?

Cut off the bottom of the former to allow clearance from the lower mounting tabs so an an ample sized doubler can be glued on each side of the former. Drill it for the mounting hardware and seal it all up before bolting it back in
 
Bulkhead 20.webp
I believe this is Bulkhead 20 (Left) in Figure 10 of the ACA Parts Manual; it's the furthest aft bulkhead.
Bartman said:
Does ac43.13 cover splicing plywood to plywood with doublers over the seam?

Cut off the bottom of the former to allow clearance from the lower mounting tabs so an an ample sized doubler can be glued on each side of the former. Drill it for the mounting hardware and seal it all up before bolting it back in
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Bartman said:
Does ac43.13 cover splicing plywood to plywood with doublers over the seam?

Cut off the bottom of the former to allow clearance from the lower mounting tabs so an an ample sized doubler can be glued on each side of the former. Drill it for the mounting hardware and seal it all up before bolting it back in
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A repair of one of the other bulkheads was completed just before I bought the airplane; I believe that the method you described was used. It's held up well for over five years.
 
Get a tracing of it from the back and include the bolt hole. Cut a piece of plywood to match, bolt it to the former so you can mark the cut line, cut the former and then glue it up but check ac43 to confirm
 
Thanks, guys.

In the meantime the IFR upgrade has been going mostly well...except I'm pretty certain that the Certification Office coordinating/project engineer was likely put on furlough today. The installation will probably be complete by Halloween.
 
Great to hear it Bruce, I respect the hell out of you for going at it as you have
 
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volvo164 said:
Breaking the instrument face for VSI didn't suffice for alternate static?
:)
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The Part 23 reg is, let's say, subject to interpretation. ACA doesn't install an alternate static air source switch or valve. It believes, with great justification IMHO, that dual static ports mitigate the risk of a blocked port. You'd have to suffer a really bad day for both ports to ice over (and even then...you could break the VSI face). However, when Ken Bowersox was performing the flight test the FAA test pilot insisted Ken had to install a switch. He used a simple (unapproved) pneumatic toggle switch. That was my plan, too. The FSDO supporting me insists that I must use an FAA approved part.
 
I was going to install one of those pneumatic valves in my 1951 Cessna 170. The 170 only has 1 static port. My IA suggested it. Maybe I should install a Cessna 172 part - will check with my avionics shop. Indeed - not worried about the Citabria give the 2 ports, on opposite sides of the airframe.
 
volvo164 said:
I was going to install one of those pneumatic valves in my 1951 Cessna 170. The 170 only has 1 static port. My IA suggested it. Maybe I should install a Cessna 172 part - will check with my avionics shop. Indeed - not worried about the Citabria give the 2 ports, on opposite sides of the airframe.
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The difference is whether the airplane is already approved for IFR. The SuperD isn't, so I must apply for a field approval that authorizes an AFM Supplement that adds flight in instrument conditions.
 
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