PA-44 Seminole/Turbo Seminole
Flight Crew Commercial
Flight Crew Last 90 Days 25; Flight Crew Total 1567; Flight Crew Type 37
Human-Machine Interface
Aircraft Equipment Problem Less Severe; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Flight Crew Became Reoriented; Flight Crew Executed Go Around / Missed Approach
Aircraft; Human Factors
IFR flight plan; VFR conditions. Practice ILS 23 approach to BUF. Given vectors while on the GPS localizer; the needles showed to the right. Followed needle; went to right of approach path. [We] did not see airport. Tower vectored me for another approach. GPS had malfunctioned and did not show proper airport location. On second attempt (successful) GPS was switched back to GPS from OBS but did not automatically switch back to OBS; that is; it did not automatically switch it to the localizer/glide slope off of the #1 NAV. Aircraft has only 1 GPS so no cross checking was available when flying with GPS. Also; I will be sure to check the GPS switches from GPS to OBS. Lesson learned; check everything twice. GPS manufacturers should emphasize checking that the unit switches automatically from GPS to VOR localizer/glide slope.
PA44 pilot discovers late that the OBS has not switched automatically from GPS to LOC during an ILS approach; resulting in a significant course deviation and a go around. The second attempt is successful with the OBS manually switched to LOC.