PA44 pilot discovers late that the obs has not switched automatically from GPS to localizer during a...

Attributes
ACN	1087129
Time
Date	201304
Place
Locale Reference	BUF.Airport
State Reference	NY
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	PA-44 Seminole/Turbo Seminole
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	GPS & Other Satellite Navigation
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial
Experience	Flight Crew Last 90 Days 25 Flight Crew Total 1567 Flight Crew Type 37
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Clearance Deviation - Track / Heading All Types

Narrative:

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 navigation. 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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site as of July 2013 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

PA44 pilot discovers late that the obs has not switched automatically from GPS to localizer 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 localizer.