Hi Mark,
I just did the same update. Here’s a lead for you:
I read FAA Policy Statement PS-ACE-28-08-R1 titled, “Replacement of Vacuum Driven Attitude Indicators in 14 CFR, Part 23/CAR 3 Airplanes,” for guidance on removal of the vacuum driven instruments. I deemed the removal to be a minor alteration.
I also found the following paragraph in the Notes in the Type Certificate Data Sheet (TCDS) for Mooney singles:
“NOTE 24: Aircraft models that originally were certified with vacuum powered attitude systems that have those systems
replaced with a non-vacuum powered attitude system: If the Primary Attitude system has been replaced with an
FAA Approved STC’d installation that meets the requirements of 14 CFR 23.1303(f)(i)(ii)(iii)(iv)(v)(vi),
23.1311(a)(1)(2)(5)(6)(b)(c), 23.1321(a)((c)(d)(1), 23.1331(a)(b)(1)(2)(c), thereby leaving no operational systems
dependent on a Primary or Standby (if equipped) Vacuum system, then the Primary and Standby (if equipped)
Vacuum pumps and associated lines, manifolds, etc may be removed from the aircraft. Refer to engine
manufacturer’s instructions of removal and capping off of engine driven vacuum pumps.”
I have asked Piper to insert the same paragraph in its TCDS. I’m not sure if they have.
The approval for installing a blank off plate over the vacuum pump pad is the illustration in the Lycoming Direct drive service manual.
Steve
