Narrative:

I was flying from provincetown (pvc) to north central (sfz), heading 265 degrees, to overfly pym as chkpoint. At that point I changed heading to 285 degrees for sfz. I set the ADF frequency in the aircraft to 241 kh for the sfz NDB and my VOR to putnam VOR, 117.4. Both needles centered as I flew 285 degrees (it should be noted that I periodically reset directional gyroscope during this flight). I made visual contact with tan on my left and soon afterwards 1b9 on my right as I held 285 degrees. All was as it should be. As an additional NAVAID I had a 2ND VOR tuned to 112.7, bos, and set to 240 degrees. When I intercepted the bos 240 degree radial I would make a left turn to 240 degrees and be lined up for runway 23 sfz. After passing 1b9, my directional gyroscope and compass had different numbers and resetting directional gyroscope did not help. With all the vertical haze and my apparent now close proximity to sfz I turned left, centered the CDI on 240 degrees and flew to what I believed was sfz. I saw a 'crossed runway' field dialed 122.7 (sfz unicom) and broadcast downwind, base, and final. My defective directional gyroscope indicated my runway alignment for runway 23 so all seemed fine. I did not hear much on 122.7 except that runway 23 was active. Lack of communication at uncontrolled airports is not unusual. I landed, taxied back, at this point I saw a blinking green light 'cleared to taxi' -- ok. (This was first hint that this might not be sfz.) as I took off, waiting for crosswind traffic, I noticed the other end of runway was runway 17 not runway 5 -- only then when in the air did I realize I had landed inadvertently at owd, apparently while tracking 240 degrees outbound direct sfz. Followed inbound to sfz. This was my primary direction indicator with directional gyroscope out and not sure of compass.

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Original NASA ASRS Text

Title: AN SMA PVT PLT LANDS AT THE WRONG ARPT AFTER HIS ACFT SUFFERS A PROB WITH ITS DIRECTIONAL GYROSCOPE NOT AGREEING WITH THE ACFT'S COMPASS.

Narrative: I WAS FLYING FROM PROVINCETOWN (PVC) TO NORTH CENTRAL (SFZ), HDG 265 DEGS, TO OVERFLY PYM AS CHKPOINT. AT THAT POINT I CHANGED HDG TO 285 DEGS FOR SFZ. I SET THE ADF FREQ IN THE ACFT TO 241 KH FOR THE SFZ NDB AND MY VOR TO PUTNAM VOR, 117.4. BOTH NEEDLES CTRED AS I FLEW 285 DEGS (IT SHOULD BE NOTED THAT I PERIODICALLY RESET DIRECTIONAL GYROSCOPE DURING THIS FLT). I MADE VISUAL CONTACT WITH TAN ON MY L AND SOON AFTERWARDS 1B9 ON MY R AS I HELD 285 DEGS. ALL WAS AS IT SHOULD BE. AS AN ADDITIONAL NAVAID I HAD A 2ND VOR TUNED TO 112.7, BOS, AND SET TO 240 DEGS. WHEN I INTERCEPTED THE BOS 240 DEG RADIAL I WOULD MAKE A L TURN TO 240 DEGS AND BE LINED UP FOR RWY 23 SFZ. AFTER PASSING 1B9, MY DIRECTIONAL GYROSCOPE AND COMPASS HAD DIFFERENT NUMBERS AND RESETTING DIRECTIONAL GYROSCOPE DID NOT HELP. WITH ALL THE VERT HAZE AND MY APPARENT NOW CLOSE PROX TO SFZ I TURNED L, CTRED THE CDI ON 240 DEGS AND FLEW TO WHAT I BELIEVED WAS SFZ. I SAW A 'CROSSED RWY' FIELD DIALED 122.7 (SFZ UNICOM) AND BROADCAST DOWNWIND, BASE, AND FINAL. MY DEFECTIVE DIRECTIONAL GYROSCOPE INDICATED MY RWY ALIGNMENT FOR RWY 23 SO ALL SEEMED FINE. I DID NOT HEAR MUCH ON 122.7 EXCEPT THAT RWY 23 WAS ACTIVE. LACK OF COM AT UNCTLED ARPTS IS NOT UNUSUAL. I LANDED, TAXIED BACK, AT THIS POINT I SAW A BLINKING GREEN LIGHT 'CLRED TO TAXI' -- OK. (THIS WAS FIRST HINT THAT THIS MIGHT NOT BE SFZ.) AS I TOOK OFF, WAITING FOR XWIND TFC, I NOTICED THE OTHER END OF RWY WAS RWY 17 NOT RWY 5 -- ONLY THEN WHEN IN THE AIR DID I REALIZE I HAD LANDED INADVERTENTLY AT OWD, APPARENTLY WHILE TRACKING 240 DEGS OUTBOUND DIRECT SFZ. FOLLOWED INBOUND TO SFZ. THIS WAS MY PRIMARY DIRECTION INDICATOR WITH DIRECTIONAL GYROSCOPE OUT AND NOT SURE OF COMPASS.

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.