Narrative:

I was in contact with boston approach. I had advised I could maintain 140 KTS on final. Boston chose to keep me close to logan and work me into final when separation of aircraft allowed. At 2000 ft MSL, while intercepting ILS 4, my original equipment 1964 directional gyroscope temporarily paused while tracking my left turn onto the localizer. It paused for 2 seconds, then rotated rapidly as if it had hung up and released. My directional gyroscope heading was now incorrect. I chose to notify logan approach of a missed approach. When setting this style directional gyroscope, you must push the set knob in and scroll the horizontal indicator to match the magnetic heading. I thought that I may have inadvertently not pulled the knob back to activate the directional gyroscope. When logan approach started new radar vectors for runway 4R in logan, I noticed a considerable lag in the directional gyroscope maintaining accurate heading changes. At this time, I notified logan approach that my directional gyroscope was malfunctioning. I received radar vectors to beverly, ma (30 mi north). When clear of clouds, landed VFR. No major incident. This was my first missed approach IFR/IMC, actual/non-training. Logan ATC had me call them back once on the ground, beverly. I spoke with the night ATC supervisor. He questioned me. I apologized for any inconveniences caused logan ATC. He stated no problem, that's why they are there. Remedy: I have ordered a new autoplt system with new updated vertical/360 degree face directional gyroscope instead of the old 1964 horizontal scroll directional gyroscope with 30 degree heading window.

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Original NASA ASRS Text

Title: AN SMA PLT'S DIRECTIONAL GYROSCOPE MISBEHAVED AT NIGHT IN THE WX.

Narrative: I WAS IN CONTACT WITH BOSTON APCH. I HAD ADVISED I COULD MAINTAIN 140 KTS ON FINAL. BOSTON CHOSE TO KEEP ME CLOSE TO LOGAN AND WORK ME INTO FINAL WHEN SEPARATION OF ACFT ALLOWED. AT 2000 FT MSL, WHILE INTERCEPTING ILS 4, MY ORIGINAL EQUIP 1964 DIRECTIONAL GYROSCOPE TEMPORARILY PAUSED WHILE TRACKING MY L TURN ONTO THE LOC. IT PAUSED FOR 2 SECONDS, THEN ROTATED RAPIDLY AS IF IT HAD HUNG UP AND RELEASED. MY DIRECTIONAL GYROSCOPE HDG WAS NOW INCORRECT. I CHOSE TO NOTIFY LOGAN APCH OF A MISSED APCH. WHEN SETTING THIS STYLE DIRECTIONAL GYROSCOPE, YOU MUST PUSH THE SET KNOB IN AND SCROLL THE HORIZ INDICATOR TO MATCH THE MAGNETIC HDG. I THOUGHT THAT I MAY HAVE INADVERTENTLY NOT PULLED THE KNOB BACK TO ACTIVATE THE DIRECTIONAL GYROSCOPE. WHEN LOGAN APCH STARTED NEW RADAR VECTORS FOR RWY 4R IN LOGAN, I NOTICED A CONSIDERABLE LAG IN THE DIRECTIONAL GYROSCOPE MAINTAINING ACCURATE HDG CHANGES. AT THIS TIME, I NOTIFIED LOGAN APCH THAT MY DIRECTIONAL GYROSCOPE WAS MALFUNCTIONING. I RECEIVED RADAR VECTORS TO BEVERLY, MA (30 MI N). WHEN CLR OF CLOUDS, LANDED VFR. NO MAJOR INCIDENT. THIS WAS MY FIRST MISSED APCH IFR/IMC, ACTUAL/NON-TRAINING. LOGAN ATC HAD ME CALL THEM BACK ONCE ON THE GND, BEVERLY. I SPOKE WITH THE NIGHT ATC SUPVR. HE QUESTIONED ME. I APOLOGIZED FOR ANY INCONVENIENCES CAUSED LOGAN ATC. HE STATED NO PROB, THAT'S WHY THEY ARE THERE. REMEDY: I HAVE ORDERED A NEW AUTOPLT SYS WITH NEW UPDATED VERT/360 DEG FACE DIRECTIONAL GYROSCOPE INSTEAD OF THE OLD 1964 HORIZ SCROLL DIRECTIONAL GYROSCOPE WITH 30 DEG HDG WINDOW.

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.