It actually happened today!! Vacuum failure in IMC.

Victor J. Osborne, Jr. wrote:


That's why I'm looking at the Mid-Continent Sporty's electric AI
replacement T/C.

And what will you do if that AI tumbles for some reason in IMC? That's been
my big concern about replacing the TC with an AI, and the relevent AC
doesn't even refer to that particular vulnerability.

Are there tumble-free AIs?

BTW, the Sporty's unit is not the Mid-continental; it's a Castle-something
(IIRC). The Mid-continental is more expensive than the Sporty's.

[...]
Keep in mind that even George w/ bail on you if the vacuum/pressure goes.
(S-Tec aside)

If George is, like most (all?) S-Tec units, rate-based then it'll survive a
vacuum failure in NAV mode. HDG mode, of course, will be unavailable
(unless you want to circle with the DG {8^).

Or is my understanding incorrect?

- Andrew