Narrative:

I was en route on an IFR flight plan from las cruces, NM (lru) to santa monica, ca (smo). I was flying V186 from the paradise VOR (pdz) to darts intersection, which is the initial approach fix for the VOR-a runway 21 approach to smo. I was using the GPS coupled to the HSI/CDI for navigation. I was having to fly a 245 degree heading or 30 degrees left of my 275 degree course heading for V186 in order to stay on the flight path. I attributed the required correction to a forecast crosswind from the south, however, the amount of correction I was having to maintain was more than the forecast winds. Upon approaching darts intersection socal approach gave me an assigned 245 degree heading to intercept the approach course, which I did. He also cleared me for the approach and instructed me to maintain 4000 ft until established. At this time I also switched to the navigation #1 for navigation. The needle centered and I turned inbound to the approach course of 212 degrees and started my descent from 4000 ft MSL to 2600 ft MSL. Socal approach then advised me that I was right of course. I explained that I was showing the needle centered. They then advised me to turn 30 degrees left which I did to a 182 degree heading. Socal approach then said I was still right of course. At about this time I realized, as did socal approach, that I had a directional gyroscope problem that was reflecting to me 30 degrees left of my actual heading, which he was seeing on his screen. I then noticed that my compass slave unit showed a full deflection error even though it was in the slave mode. Socal approach then advised me to turn further to the left. They then advised me I had intercepted the approach course and to maintain a 182 degree heading on my directional gyroscope card which was the required correction necessary to stay on the approach course. I should have at this time relied on the compass to confirm my being on course but in the rush of things I asked socal approach to continue to give me vectors if needed to stay on the approach course. During the same time that I, along with help from socal approach, was diagnosing the course deviation problem, socal approach issued an altitude alert as I had descended 200 ft below the required altitude of 2600 ft MSL and requested that I immediately climb which I did even though my climb was slowed by my having already dropped my landing gear and approach flaps. Socal approach then advised me that I was at my next step-down fix and I descended to 1100 ft MSL. I was also instructed to go to the tower frequency, which I did. I broke out of the layer of clouds at approximately 1700 ft MSL and was cleared to land.

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Original NASA ASRS Text

Title: AFTER THE PLT OF A BEECH BARON, BE58, WAS CLRED FOR A VOR APCH, HE WAS GIVEN VECTORS TO CORRECT HIS HEADING AND TRACK SINCE HE WAS R OF COURSE IN ADDITION, RPTR DSNDED BELOW THE PUBLISHED STEP DOWN ALT CAUSING APCH CTLR TO GIVE A LOW ALT ALERT.

Narrative: I WAS ENRTE ON AN IFR FLT PLAN FROM LAS CRUCES, NM (LRU) TO SANTA MONICA, CA (SMO). I WAS FLYING V186 FROM THE PARADISE VOR (PDZ) TO DARTS INTXN, WHICH IS THE INITIAL APCH FIX FOR THE VOR-A RWY 21 APCH TO SMO. I WAS USING THE GPS COUPLED TO THE HSI/CDI FOR NAV. I WAS HAVING TO FLY A 245 DEG HDG OR 30 DEGS L OF MY 275 DEG COURSE HDG FOR V186 IN ORDER TO STAY ON THE FLT PATH. I ATTRIBUTED THE REQUIRED CORRECTION TO A FORECAST XWIND FROM THE S, HOWEVER, THE AMOUNT OF CORRECTION I WAS HAVING TO MAINTAIN WAS MORE THAN THE FORECAST WINDS. UPON APCHING DARTS INTXN SOCAL APCH GAVE ME AN ASSIGNED 245 DEG HDG TO INTERCEPT THE APCH COURSE, WHICH I DID. HE ALSO CLRED ME FOR THE APCH AND INSTRUCTED ME TO MAINTAIN 4000 FT UNTIL ESTABLISHED. AT THIS TIME I ALSO SWITCHED TO THE NAV #1 FOR NAV. THE NEEDLE CTRED AND I TURNED INBOUND TO THE APCH COURSE OF 212 DEGS AND STARTED MY DSCNT FROM 4000 FT MSL TO 2600 FT MSL. SOCAL APCH THEN ADVISED ME THAT I WAS R OF COURSE. I EXPLAINED THAT I WAS SHOWING THE NEEDLE CTRED. THEY THEN ADVISED ME TO TURN 30 DEGS L WHICH I DID TO A 182 DEG HDG. SOCAL APCH THEN SAID I WAS STILL R OF COURSE. AT ABOUT THIS TIME I REALIZED, AS DID SOCAL APCH, THAT I HAD A DIRECTIONAL GYROSCOPE PROB THAT WAS REFLECTING TO ME 30 DEGS L OF MY ACTUAL HEADING, WHICH HE WAS SEEING ON HIS SCREEN. I THEN NOTICED THAT MY COMPASS SLAVE UNIT SHOWED A FULL DEFLECTION ERROR EVEN THOUGH IT WAS IN THE SLAVE MODE. SOCAL APCH THEN ADVISED ME TO TURN FURTHER TO THE L. THEY THEN ADVISED ME I HAD INTERCEPTED THE APCH COURSE AND TO MAINTAIN A 182 DEG HDG ON MY DIRECTIONAL GYROSCOPE CARD WHICH WAS THE REQUIRED CORRECTION NECESSARY TO STAY ON THE APCH COURSE. I SHOULD HAVE AT THIS TIME RELIED ON THE COMPASS TO CONFIRM MY BEING ON COURSE BUT IN THE RUSH OF THINGS I ASKED SOCAL APCH TO CONTINUE TO GIVE ME VECTORS IF NEEDED TO STAY ON THE APCH COURSE. DURING THE SAME TIME THAT I, ALONG WITH HELP FROM SOCAL APCH, WAS DIAGNOSING THE COURSE DEV PROB, SOCAL APCH ISSUED AN ALT ALERT AS I HAD DSNDED 200 FT BELOW THE REQUIRED ALT OF 2600 FT MSL AND REQUESTED THAT I IMMEDIATELY CLB WHICH I DID EVEN THOUGH MY CLB WAS SLOWED BY MY HAVING ALREADY DROPPED MY LNDG GEAR AND APCH FLAPS. SOCAL APCH THEN ADVISED ME THAT I WAS AT MY NEXT STEP-DOWN FIX AND I DSNDED TO 1100 FT MSL. I WAS ALSO INSTRUCTED TO GO TO THE TWR FREQ, WHICH I DID. I BROKE OUT OF THE LAYER OF CLOUDS AT APPROX 1700 FT MSL AND WAS CLRED TO LAND.

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.