Maybe you can help settle a bet. I'm in the process of having a between-the-ankles radio box and transponder installed in my experimental-certified Pitts (I am not the builder, so I don't have a repairman's certificate). I think this work requires only an A&P signoff, but others think this modification will require a Form 337. Who's right?

Also, I'm planning to have just the empty box installed first- no transponder, no wiring, no nothing (I'll fly it to the avioncs shop later on to finish the work). What signoffs, if any, are needed to fly the airplane in this state?

Thanks in advance.

Tom P.

• RE: Mods to an Experimental,ChipB727, 20:54z, 04-02-03
  • RE: Mods to an Experimental,TomParsons, 15:15z, 04-05-03

Most FAA offices only require an A&P Sign-off, Weight and balance amendment, and equipment list update. If the aircraft "could" potentially become "Standard Category" Then a Form 337 must be executed by an IA or Repair Station if the installation is considered a "Major Alteration" as well as the Weight and balance amendment, and equipment list update.

This has happened to me with the Extra's where it was issued a standard category then taken to experimental for some reason, and the aircraft could potentially be returned to Standard Category. Hope this helps......

Chip

Thanks, Chip. I have no intention of mutating my airplane to a Standard Category certificate (in fact, I can't think of a reason why anyone would want to, in a single-hole airplane that can never be used for flight instruction).

Sounds like your answer is sort of FSDO-specific. Do you think I should go ahead and ask the local FSDO, or just keep my mouth shut?

Tom P.