Narrative:

While en route to oak from madera, encountered deteriorating WX conditions. Was able to remain VFR without difficulty, however, primary navigation VOR began behaving erratically while flying between layers, and then became completely unreliable. Was not worried because was also using a portable GPS model. Attempted to enter identifier for tracy airport (tcy) so as to fly direct from last known position. The GPS model does not have an alpha-numeric keypad to enter desired waypoint identifiers, etc. It has, instead, arrow keys that require the pilot to scroll through all 26 letters of the alphabet and through various symbols and numbers, at which point the pilot releases the up-down arrow keys on the correct letter/number -- a very time- consuming process at best (but has a great airport data base). As I attempted to go direct to tracy, a feature that is designed to be helpful by guessing what the last letter of the airport you are entering is, prevented me from entering the 'Y' in (tracy) 'tcy.' I struggled with this communist GPS computer logic for a good 5 mins before I gave up and attempted to enter new jerusalem airport's nearby numeric airport identifier. Same problem. Another 5 mins at least wasted inside the cockpit. Found a hole in the deck, spiraled down and found new jerusalem airport, but cannot be sure I missed the restr airspace as all ground reference was obscured. I feel the user unfriendliness of the GPS's logic and lack of an alpha-numeric keypad was a major factor in this incident.

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Original NASA ASRS Text

Title: SMA PLT DISORIENTED, MAY HAVE ENTERED RESTR AREA.

Narrative: WHILE ENRTE TO OAK FROM MADERA, ENCOUNTERED DETERIORATING WX CONDITIONS. WAS ABLE TO REMAIN VFR WITHOUT DIFFICULTY, HOWEVER, PRIMARY NAV VOR BEGAN BEHAVING ERRATICALLY WHILE FLYING BTWN LAYERS, AND THEN BECAME COMPLETELY UNRELIABLE. WAS NOT WORRIED BECAUSE WAS ALSO USING A PORTABLE GPS MODEL. ATTEMPTED TO ENTER IDENTIFIER FOR TRACY ARPT (TCY) SO AS TO FLY DIRECT FROM LAST KNOWN POS. THE GPS MODEL DOES NOT HAVE AN ALPHA-NUMERIC KEYPAD TO ENTER DESIRED WAYPOINT IDENTIFIERS, ETC. IT HAS, INSTEAD, ARROW KEYS THAT REQUIRE THE PLT TO SCROLL THROUGH ALL 26 LETTERS OF THE ALPHABET AND THROUGH VARIOUS SYMBOLS AND NUMBERS, AT WHICH POINT THE PLT RELEASES THE UP-DOWN ARROW KEYS ON THE CORRECT LETTER/NUMBER -- A VERY TIME- CONSUMING PROCESS AT BEST (BUT HAS A GREAT ARPT DATA BASE). AS I ATTEMPTED TO GO DIRECT TO TRACY, A FEATURE THAT IS DESIGNED TO BE HELPFUL BY GUESSING WHAT THE LAST LETTER OF THE ARPT YOU ARE ENTERING IS, PREVENTED ME FROM ENTERING THE 'Y' IN (TRACY) 'TCY.' I STRUGGLED WITH THIS COMMUNIST GPS COMPUTER LOGIC FOR A GOOD 5 MINS BEFORE I GAVE UP AND ATTEMPTED TO ENTER NEW JERUSALEM ARPT'S NEARBY NUMERIC ARPT IDENTIFIER. SAME PROB. ANOTHER 5 MINS AT LEAST WASTED INSIDE THE COCKPIT. FOUND A HOLE IN THE DECK, SPIRALED DOWN AND FOUND NEW JERUSALEM ARPT, BUT CANNOT BE SURE I MISSED THE RESTR AIRSPACE AS ALL GND REF WAS OBSCURED. I FEEL THE USER UNFRIENDLINESS OF THE GPS'S LOGIC AND LACK OF AN ALPHA-NUMERIC KEYPAD WAS A MAJOR FACTOR IN THIS INCIDENT.

Data retrieved from NASA's ASRS site as of July 2007 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.