Greetings…
An aircraft that I rent often had its transponder and pitot-static checks expire as of 12/1; I was planning to fly the aircraft to work on some VFR maneuvers (I’m chipping away at a commercial rating mostly just to develop the stick and rudder skills) and at first I was pretty sure that I could complete the flight with the checks expired (VFR, not in any airspace that requires a transponder) but then I started looking at the regulations to see if it would be legal. The answer that I came to was NO, but I’m curious if I’ve missed something obvious in parsing this out..
The aircraft has a GTX-345 in it, so it is a combined transponder and ADS-B out unit. There would be no way to make the transponder inoperative but leave the ADS-B out piece functioning (and to be clear, I’d never choose to fly an aircraft with the transponder disabled simply because it was a few days expired — but I’m looking for the by the book answer here)
- 91.215 (ATC Transponder and Altitude reporting equipment and use)
- 91.225 (ADS-B Out equipment and use)
- 91.413 (ATC Transponder tests and inspections)
(f) Except as prohibited in paragraph (i)(2) [drones, N/A] of this section, each person operating an aircraft equipped with ADS-B Out must operate this equipment in the transmit mode at all times unless – [unless exceptions aren’t applicable, text not included here]
§ 91.413 ATC transponder tests and inspections.(a) No persons may use an ATC transponder that is specified in 91.215(a), 121.345(c), or § 135.143(c) of this chapter unless, within the preceding 24 calendar months, the ATC transponder has been tested and inspected and found to comply with appendix F of part 43 of this chapter;
§ 91.215 ATC transponder and altitude reporting equipment and use.(a) All airspace: U.S.-registered civil aircraft. For operations not conducted under part 121 or 135 of this chapter, ATC transponder equipment installed must meet the performance and environmental requirements of any class of TSO-C74b (Mode A) or any class of TSO-C74c (Mode A with altitude reporting capability) as appropriate, or the appropriate class of TSO-C112 (Mode S).
…..jumping to…(c) Transponder-on operation. Except as provided in paragraph (e)(2) [not applicable] of this section, while in the airspace as specified in paragraph (b) of this section or in all controlled airspace, each person operating an aircraft equipped with an operable ATC transponder maintained in accordance with § 91.413 shall operate the transponder, including Mode C equipment if installed, and shall reply on the appropriate code or as assigned by ATC, unless otherwise directed by ATC when transmitting would jeopardize the safe execution of air traffic control functions.
So, to sum up what this looks like to me.. 91.225(f) tells me that I must use the unit if its installed due to ADS-B. 91.413(a) says that I CANNOT use the equipment if it hasn’t had its 24 month checkup. 91.215(a) sets out the TSOs that the installed transponders must meet for all airspace, and 91.215(c) indicates that if I’ve got a maintained and operable transponder in the airplane I need to use it in all controlled airspace (which would include Echo).
At the end of the day, my determination was that I’d be breaking regulations to fly the aircraft unless I advised ATC ahead of time, or unless I were flying the aircraft to a facility to get the transponder checks done. Have I interpreted things correctly, or am I missing something obvious?
