Narrative:

On approach to hbz (heber springs, ar) on IFR flight from axh (houston southwest) I had to execute missed due to low ceilings. On climb out, I noticed the compass rose on EFIS HSI display did not correspond to whiskey compass or to compass indications on alternate HSI on copilot side of panel. But there was no flag to indicate gyro failure. I reported to ZME that I was executing missed approach, had gyro problems and wished to go to little rock for assisted no-gyro approach into adams field. ZME instructed me to climb to 5000 ft and cleared me direct little rock. I climbed to 5000 ft and asked center to verify direction of flight for me just to be sure other instruments were not also failing. Memphis assisted with vectors and turned me over to little rock approach. While flying toward little rock with heading assistance from the approach controllers, I unslaved the pilot gyro and tried to set the HSI to heading as indicated by GPS and copilot HSI. The compass rose would turn but when returned to slaved position would not maintain accurate direction indication when compared to whiskey compass, GPS, and the copilot HSI. My primary attitude indicator as well as the backup indicator appeared to be functioning properly and in agreement one with the other and confirmed by airspeed and vertical speed instruments. Little rock approach did excellent job of vectoring me for ILS runway 4L. But I was having difficulty in holding headings to properly intercept localizer. They did ask that I keep my speed at 180 KTS which probably made it a bit more difficult. I was using horizon on pilot side for attitude and trying to use heading information and localizer data from copilot HSI while also checking GPS and whiskey compass as a xchk. I flew through the localizer on the first attempt and my approach clearance was canceled. With the assistance of the little rock approach controllers giving me no-gyro directional turns, I attempted a second approach and was successful at intercepting localizer, turned over to tower controller, who then canceled my approach clearance as I was having problems tracking the localizer. Keep in mind I'm getting attitude information from my primary horizon while using the copilot HSI crosschecked against the GPS for lateral guidance. During this approach, I think I may have dropped below the assigned altitude as assigned by the approach controller. I think I had been told to maintain 2000 ft until established and in retrospect, I may have dropped below that assigned altitude. I was vectored for a third try and could not intercept to the satisfaction of the controller or myself. The controller then suggested that I use the little rock AFB controllers for a PAR approach to the AFB. I declined and asked if they would locate the nearest VFR airport. They reported the pine bluff WX as 1200 ft broken so I opted for vectors to pine bluff hoping for a visual approach but setting up for the ILS runway 17 approach there. I also set up the GPS and pbf as waypoint and used the small map on the face of the GPS as an additional assist. The vectors given for the short flight to pine bluff were almost straight into runway 17. As I neared pine bluff, I was able to spot breaks in the clouds, given a cruise 2000 ft altitude, and able to approach and land visually in the last 5 mi. I thanked the approach controllers for their efforts, advised them I was on the ground at pine bluff and to close the flight plan. Human performance considerations: on saturday, I returned to the pine bluff airport to check on the plane and found a note on aircraft door asking me to call a mr X at little rock approach control. I called right then, but was advised that mr X would not be back in until later that afternoon. I called at approximately XA15 and mr X and I talked extensively about the flight and the circumstances. I described the sequence of events as I recalled them, even telling him of the fine job his controllers had done in assisting me with the problems and placing the blame for the approach problems on a failed directional gyro and my inability to totally remove the failed HSI from my scan. The entire conversation was cordial, actually very friendly, and we chatted about mutual flying experiences. Mr X asked me for my address, phone number, and certificate number, which I gave him.I advised him I would be at my home for the wkend and that I had no plans to fly the airplane until VFR flight was possible. On dec/sun/01 I returned to the airplane in pine bluff. I pwred up the navigation equipment, checked everything carefully, and found all the navigation instruments appeared to be functioning properly. I flew the airplane in VFR conditions from pine bluff to batesville xchking all the instruments and they all seemed to be working normally. I described the problem to the avionics technicians in batesville and asked that careful attention be paid to the primary directional gyro. On dec/tue/01, I checked my message machine in houston and found that I'd had a call from person Y of the little rock FSDO. I called mr Y and we, too, had a very cordial conversation in which I related to him all the above occurrences, including my suspicion that I had a directional gyro problem. He asked me to facsimile him a copy of my pilot certificate and medical certificate. At this point, I became concerned and I even asked him if I was in trouble. He said he didn't think so. He said he knew how difficult it can be to fly an airplane on partial panel and said he was only gathering information to file a report. He said I had done nothing wrong.

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Original NASA ASRS Text

Title: TBM-7G PLT WAS UNABLE TO FLY AN ILS APCH AFTER EXPERIENCING AN HSI FAILURE.

Narrative: ON APCH TO HBZ (HEBER SPRINGS, AR) ON IFR FLT FROM AXH (HOUSTON SOUTHWEST) I HAD TO EXECUTE MISSED DUE TO LOW CEILINGS. ON CLBOUT, I NOTICED THE COMPASS ROSE ON EFIS HSI DISPLAY DID NOT CORRESPOND TO WHISKEY COMPASS OR TO COMPASS INDICATIONS ON ALTERNATE HSI ON COPLT SIDE OF PANEL. BUT THERE WAS NO FLAG TO INDICATE GYRO FAILURE. I RPTED TO ZME THAT I WAS EXECUTING MISSED APCH, HAD GYRO PROBS AND WISHED TO GO TO LITTLE ROCK FOR ASSISTED NO-GYRO APCH INTO ADAMS FIELD. ZME INSTRUCTED ME TO CLB TO 5000 FT AND CLRED ME DIRECT LITTLE ROCK. I CLBED TO 5000 FT AND ASKED CTR TO VERIFY DIRECTION OF FLT FOR ME JUST TO BE SURE OTHER INSTS WERE NOT ALSO FAILING. MEMPHIS ASSISTED WITH VECTORS AND TURNED ME OVER TO LITTLE ROCK APCH. WHILE FLYING TOWARD LITTLE ROCK WITH HDG ASSISTANCE FROM THE APCH CTLRS, I UNSLAVED THE PLT GYRO AND TRIED TO SET THE HSI TO HDG AS INDICATED BY GPS AND COPLT HSI. THE COMPASS ROSE WOULD TURN BUT WHEN RETURNED TO SLAVED POS WOULD NOT MAINTAIN ACCURATE DIRECTION INDICATION WHEN COMPARED TO WHISKEY COMPASS, GPS, AND THE COPLT HSI. MY PRIMARY ATTITUDE INDICATOR AS WELL AS THE BACKUP INDICATOR APPEARED TO BE FUNCTIONING PROPERLY AND IN AGREEMENT ONE WITH THE OTHER AND CONFIRMED BY AIRSPD AND VERT SPD INSTS. LITTLE ROCK APCH DID EXCELLENT JOB OF VECTORING ME FOR ILS RWY 4L. BUT I WAS HAVING DIFFICULTY IN HOLDING HDGS TO PROPERLY INTERCEPT LOC. THEY DID ASK THAT I KEEP MY SPD AT 180 KTS WHICH PROBABLY MADE IT A BIT MORE DIFFICULT. I WAS USING HORIZON ON PLT SIDE FOR ATTITUDE AND TRYING TO USE HDG INFO AND LOC DATA FROM COPLT HSI WHILE ALSO CHKING GPS AND WHISKEY COMPASS AS A XCHK. I FLEW THROUGH THE LOC ON THE FIRST ATTEMPT AND MY APCH CLRNC WAS CANCELED. WITH THE ASSISTANCE OF THE LITTLE ROCK APCH CTLRS GIVING ME NO-GYRO DIRECTIONAL TURNS, I ATTEMPTED A SECOND APCH AND WAS SUCCESSFUL AT INTERCEPTING LOC, TURNED OVER TO TWR CTLR, WHO THEN CANCELED MY APCH CLRNC AS I WAS HAVING PROBS TRACKING THE LOC. KEEP IN MIND I'M GETTING ATTITUDE INFO FROM MY PRIMARY HORIZON WHILE USING THE COPLT HSI XCHKED AGAINST THE GPS FOR LATERAL GUIDANCE. DURING THIS APCH, I THINK I MAY HAVE DROPPED BELOW THE ASSIGNED ALT AS ASSIGNED BY THE APCH CTLR. I THINK I HAD BEEN TOLD TO MAINTAIN 2000 FT UNTIL ESTABLISHED AND IN RETROSPECT, I MAY HAVE DROPPED BELOW THAT ASSIGNED ALT. I WAS VECTORED FOR A THIRD TRY AND COULD NOT INTERCEPT TO THE SATISFACTION OF THE CTLR OR MYSELF. THE CTLR THEN SUGGESTED THAT I USE THE LITTLE ROCK AFB CTLRS FOR A PAR APCH TO THE AFB. I DECLINED AND ASKED IF THEY WOULD LOCATE THE NEAREST VFR ARPT. THEY RPTED THE PINE BLUFF WX AS 1200 FT BROKEN SO I OPTED FOR VECTORS TO PINE BLUFF HOPING FOR A VISUAL APCH BUT SETTING UP FOR THE ILS RWY 17 APCH THERE. I ALSO SET UP THE GPS AND PBF AS WAYPOINT AND USED THE SMALL MAP ON THE FACE OF THE GPS AS AN ADDITIONAL ASSIST. THE VECTORS GIVEN FOR THE SHORT FLT TO PINE BLUFF WERE ALMOST STRAIGHT INTO RWY 17. AS I NEARED PINE BLUFF, I WAS ABLE TO SPOT BREAKS IN THE CLOUDS, GIVEN A CRUISE 2000 FT ALT, AND ABLE TO APCH AND LAND VISUALLY IN THE LAST 5 MI. I THANKED THE APCH CTLRS FOR THEIR EFFORTS, ADVISED THEM I WAS ON THE GND AT PINE BLUFF AND TO CLOSE THE FLT PLAN. HUMAN PERFORMANCE CONSIDERATIONS: ON SATURDAY, I RETURNED TO THE PINE BLUFF ARPT TO CHK ON THE PLANE AND FOUND A NOTE ON ACFT DOOR ASKING ME TO CALL A MR X AT LITTLE ROCK APCH CTL. I CALLED RIGHT THEN, BUT WAS ADVISED THAT MR X WOULD NOT BE BACK IN UNTIL LATER THAT AFTERNOON. I CALLED AT APPROX XA15 AND MR X AND I TALKED EXTENSIVELY ABOUT THE FLT AND THE CIRCUMSTANCES. I DESCRIBED THE SEQUENCE OF EVENTS AS I RECALLED THEM, EVEN TELLING HIM OF THE FINE JOB HIS CTLRS HAD DONE IN ASSISTING ME WITH THE PROBS AND PLACING THE BLAME FOR THE APCH PROBS ON A FAILED DIRECTIONAL GYRO AND MY INABILITY TO TOTALLY REMOVE THE FAILED HSI FROM MY SCAN. THE ENTIRE CONVERSATION WAS CORDIAL, ACTUALLY VERY FRIENDLY, AND WE CHATTED ABOUT MUTUAL FLYING EXPERIENCES. MR X ASKED ME FOR MY ADDRESS, PHONE NUMBER, AND CERTIFICATE NUMBER, WHICH I GAVE HIM.I ADVISED HIM I WOULD BE AT MY HOME FOR THE WKEND AND THAT I HAD NO PLANS TO FLY THE AIRPLANE UNTIL VFR FLT WAS POSSIBLE. ON DEC/SUN/01 I RETURNED TO THE AIRPLANE IN PINE BLUFF. I PWRED UP THE NAV EQUIP, CHKED EVERYTHING CAREFULLY, AND FOUND ALL THE NAV INSTS APPEARED TO BE FUNCTIONING PROPERLY. I FLEW THE AIRPLANE IN VFR CONDITIONS FROM PINE BLUFF TO BATESVILLE XCHKING ALL THE INSTS AND THEY ALL SEEMED TO BE WORKING NORMALLY. I DESCRIBED THE PROB TO THE AVIONICS TECHNICIANS IN BATESVILLE AND ASKED THAT CAREFUL ATTN BE PAID TO THE PRIMARY DIRECTIONAL GYRO. ON DEC/TUE/01, I CHKED MY MESSAGE MACHINE IN HOUSTON AND FOUND THAT I'D HAD A CALL FROM PERSON Y OF THE LITTLE ROCK FSDO. I CALLED MR Y AND WE, TOO, HAD A VERY CORDIAL CONVERSATION IN WHICH I RELATED TO HIM ALL THE ABOVE OCCURRENCES, INCLUDING MY SUSPICION THAT I HAD A DIRECTIONAL GYRO PROB. HE ASKED ME TO FAX HIM A COPY OF MY PLT CERTIFICATE AND MEDICAL CERTIFICATE. AT THIS POINT, I BECAME CONCERNED AND I EVEN ASKED HIM IF I WAS IN TROUBLE. HE SAID HE DIDN'T THINK SO. HE SAID HE KNEW HOW DIFFICULT IT CAN BE TO FLY AN AIRPLANE ON PARTIAL PANEL AND SAID HE WAS ONLY GATHERING INFO TO FILE A RPT. HE SAID I HAD DONE NOTHING WRONG.

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.