Cessna 170B IFR

[Mike M]

A TSO is required when the reg says item must meet TSO 12345, as appropriate. Otherwise, not required.

It’s not legal to fly IFR with portable nav gear.

Thanks for affirmation on when a TSO is required, Marty. As to portables?

Question One. Is an installed, TSOd VOR/ILS/LOC navigation receiver required by regulation for IFR operation?


Not this regulation:


§91.205(a) General...no person may operate … unless that aircraft contains the instruments and equipment specified ... and those instruments and items of equipment are in operable condition.
(d) Instrument flight rules. For IFR flight, the following instruments and equipment are required:
(2)Two-way radio communication and navigation equipment suitable for the route to be flown.


And not this regulation:

§91.171 VORequipment check for IFR operations.

(a)(2) Has been operationally checked within the preceding 30 days, and was found to be within the limits of the permissible indicated bearing error...

The Instrument Flying Handbook covers traditional navigation systems beginning on page 9-3. I can’t find a requirement for installed TSOd VOR/ILS/LOC equipment. The Aeronautical Information Manual covers VOR in Paragraph 1-1-3, ILS/LOC in 1-1-9, but I can’t find a requirement for installed TSOd VOR/ILS/LOC equipment there either.


So a VOR/ILS/LOC used for IFR must receive the transmissions needed for the route of flight from takeoff to landing and must have a current ops check. Nothing about being installed or TSOd. If anybody knows an FAA manual, handbook, or regulation that requires an installed TSOd navigation receiver for VOR/ILS/LOC please post that reference?


Question Two, is an installed TSOd GPS receiver required by regulation for IFR operation?


FAA-H-8083-15B Instrument Flying Handbook:
Page9-26: GPS equipment ... under IFR must meet ... Technical Standard Order (TSO) C-129 ...; meet the airworthiness installation requirements; be “approved”for that type of IFR operation; and be operated in accordance with the applicable POH/AFM or flight manual supplement. An updatable GPS database … is required when operating under IFR. Equipment approved in accordance with TSO C-115a... and hand-held GPS systems do not meet the requirements ... and are not authorized for IFR ... or as a principal instrument flight reference.


Aeronautical Information Manual:
Para1−2−3.2. b. ... When installed in accordance with appropriate airworthiness installation requirements... 1. An RNAV system with TSO−C129/ −C145/−C146 equipment, installed in accordance with AC 20−138...or AC 20−130A...and authorized for instrument flight rules (IFR) en route and terminal operations...


So an IFR GPS is required to be TSOd, installed, and approved. But. Manuals and Handbooks aren’t regulations. So does anybody know what regulations drive these requirements?

I'm confident somebody knows the regulation reference , but it's not me.