Alternate Static Source

[Mark Anderson]

Does anyone know if there is any STC or FAA paperwork required to install an alternate static source on a Comanche that did not have one from the factory? Also do you have to make a change to the checklist?

Thanks

Mark

[Zach Grant L1011jock]

It is a minor alteration so a simple logbook sign off is all you need. I guess I don't understand the checklist question. There is nothing approved about the checklists most people use, so whatever works for you.
Zach

[Mark Anderson]

Zach, thanks. With the checklist, I guess I was confusing part 121 requirements for a FAA approved heck list.

[Mark Anderson]

I just talked to my local avionics shop (Alabama) and they said the FAA is telling them that installing an alternate static source is a major alteration and a form 337 is required. Not sure if this interpreted differently by different FISDO's ?

Thanks

Mark

[Zach Grant L1011jock]

Well Mark, all I can tell you is that the configuration exists in the Piper data, does not affect the weight, balance, structural strength, performance, power plant operation, flight characteristics, or other qualities affecting airworthiness, and it can be done using elementary operations of accepted practices. If that sounds like I just regurgitated an FAR definition, well not quite, but close. The true definition is the negative of the above statement describing a Major alteration, and by process, the lack of the negative as stated presents as a minor alteration. It is still however up to the guy who is going to sign the book as to the final interpretation. I would think a 337 for this would be a nobrainer as all the data exists in the service/parts manual, and if they insist, you can cite the original Piper data, however, if the Feds choose to be unreasonable, then all bets are off, and I suggest you shop for an A/P with a more "liberal" interpretation of major vs. minor alterations.

Zach

[Mark Anderson]

Zach, agreed. They said the 337 will be no problem.

Thanks

Mark