> "Dana Overall" <bo12...@hotmail.com> writes: > The IFR equipment install must be TSO'd equipment to > legally use the system but supporting equipment such as > airspeed, altimeter, and so on, do not have to be TSO'd.
This is a common impression, that avionics must be TSO'd. But which FAR, by number please, requires "TSO'd avionics" under Part-91 operations, IFR or VFR ?? None that I am aware of, but I may be wrong ( ...again :). The Narco MK-12, MK-12A, and MK-12B for instance, full of vacuum tubes and never certified by Narco to satisfy any TSO, were flown by us-oldtimers for many years in the hardest-IFR. Its VOR/LOC nav receiver and indicator were self-certified for IFR use by the pilot using any of several rather crude functional tests at designated time intervals. Some still fly these radios, which FAR prohibits this ? The more recent absurdities of Installation Certifications and TSO's applying to GPS navs are another bag of worms but do not retroactively include the VHF/UHF nav arena ( ie, VOR, LOC, and GS ) or the LF NDB/ADF. The com radio, OTOH, must meet the 0.025 mHz spacing requirements of the 21st century. While this is most easily done by pointing to a TSO, that TSO is not an all-inclusive requirement. See FAR 21.303 and the keywords =may= and =when required=. IMHO, always subject to error and willing to accept the FARs as-written. Art Cacella 1970 American AA-1 N6155L "Dinkie", flying 33 yrs. 1972 KR-1 plans, still not started on <sigh> 2004 Sonerai-I, on gear w/engine, making wings 2004 Moni-m/G, on gear, mounting engine & wings 2004 Polly, mini-RV-6, mounting engine & gear 200? Intrepid, all metal canard pusher, 4-pl, parts Winston-Salem, NC ________________________________________________________________ The best thing to hit the internet in years - Juno SpeedBand! Surf the web up to FIVE TIMES FASTER! Only $14.95/ month - visit www.juno.com to sign up today!