Narrative:

I just started my first 135 operation employment and was flying a small aircraft X. The day before (in new orleans at moisant) I flew a different small aircraft, one which had a directional gyro compass and dual vors. I am experienced in the operation of this type INS setup, but my experience with HSI's has been limited to low time in multi simulators. I had forgotten that the HSI has a separate remote magnetic compass and this contributed to my error. Upon returning to moisant international airport from lafayette, la. I was cleared for the visibility on runway 6 at moisant. It was quite hazy, but the airport was in sight, however this had only been my second day operating out of moisant airport and I was not yet familiar with the runway layout. Because I did not know that the magnetic compass was off, and because when I slaved the HSI, and the 2 didn't correspond with one another, I unslaved the HSI and set it to the magnetic compass. Upon reaching the TCA, ATC vectored me so that I was approaching the airport from the south, then they cleared me to lower (from assigned altitude 3000') and cleared for visibility runway 6. I had to slip to lose altitude fast and doing so precessed the magnetic compass, and the HSI because it was unslaved. Upon lining up to T/D, all indications on both INS told me I was on heading 060 degrees, however from looking at the airport plan on my approach plate, the runway confign and apparent lengths did not seem right. I, being a conscientious INS pilot, did what I was taught and hence had taught my students, and that was 'trust your INS.' when I lowered my gear and was commencing to put more than approach flaps in, moisant tower controller advised that I was landing on the wrong runway, and instructed me to execute a go around. After I started the go around, the tower controller asked if I could still land on runway 6. (Up to this point, I was landing on runway 10, which was closed due to repairs.) I said I would be able to land on runway 6, which I did. After landing I apologized for the distance on my part, and the tower controller stated that it was all right since I did not touch down. Nothing more was said. I know now that the HSI is independently slaved to another compass, and I am familiar with new's location and confign.

Related reports:

Google
 

Original NASA ASRS Text

Title: GA SMA PART 135 OPERATION WRONG RWY APCH.

Narrative: I JUST STARTED MY FIRST 135 OPERATION EMPLOYMENT AND WAS FLYING A SMA X. THE DAY BEFORE (IN NEW ORLEANS AT MOISANT) I FLEW A DIFFERENT SMA, ONE WHICH HAD A DIRECTIONAL GYRO COMPASS AND DUAL VORS. I AM EXPERIENCED IN THE OPERATION OF THIS TYPE INS SETUP, BUT MY EXPERIENCE WITH HSI'S HAS BEEN LIMITED TO LOW TIME IN MULTI SIMULATORS. I HAD FORGOTTEN THAT THE HSI HAS A SEPARATE REMOTE MAGNETIC COMPASS AND THIS CONTRIBUTED TO MY ERROR. UPON RETURNING TO MOISANT INTL ARPT FROM LAFAYETTE, LA. I WAS CLRED FOR THE VIS ON RWY 6 AT MOISANT. IT WAS QUITE HAZY, BUT THE ARPT WAS IN SIGHT, HOWEVER THIS HAD ONLY BEEN MY SECOND DAY OPERATING OUT OF MOISANT ARPT AND I WAS NOT YET FAMILIAR WITH THE RWY LAYOUT. BECAUSE I DID NOT KNOW THAT THE MAGNETIC COMPASS WAS OFF, AND BECAUSE WHEN I SLAVED THE HSI, AND THE 2 DIDN'T CORRESPOND WITH ONE ANOTHER, I UNSLAVED THE HSI AND SET IT TO THE MAGNETIC COMPASS. UPON REACHING THE TCA, ATC VECTORED ME SO THAT I WAS APCHING THE ARPT FROM THE S, THEN THEY CLRED ME TO LOWER (FROM ASSIGNED ALT 3000') AND CLRED FOR VIS RWY 6. I HAD TO SLIP TO LOSE ALT FAST AND DOING SO PRECESSED THE MAGNETIC COMPASS, AND THE HSI BECAUSE IT WAS UNSLAVED. UPON LINING UP TO T/D, ALL INDICATIONS ON BOTH INS TOLD ME I WAS ON HDG 060 DEGS, HOWEVER FROM LOOKING AT THE ARPT PLAN ON MY APCH PLATE, THE RWY CONFIGN AND APPARENT LENGTHS DID NOT SEEM RIGHT. I, BEING A CONSCIENTIOUS INS PLT, DID WHAT I WAS TAUGHT AND HENCE HAD TAUGHT MY STUDENTS, AND THAT WAS 'TRUST YOUR INS.' WHEN I LOWERED MY GEAR AND WAS COMMENCING TO PUT MORE THAN APCH FLAPS IN, MOISANT TWR CTLR ADVISED THAT I WAS LNDG ON THE WRONG RWY, AND INSTRUCTED ME TO EXECUTE A GAR. AFTER I STARTED THE GAR, THE TWR CTLR ASKED IF I COULD STILL LAND ON RWY 6. (UP TO THIS POINT, I WAS LNDG ON RWY 10, WHICH WAS CLOSED DUE TO REPAIRS.) I SAID I WOULD BE ABLE TO LAND ON RWY 6, WHICH I DID. AFTER LNDG I APOLOGIZED FOR THE DISTANCE ON MY PART, AND THE TWR CTLR STATED THAT IT WAS ALL RIGHT SINCE I DID NOT TOUCH DOWN. NOTHING MORE WAS SAID. I KNOW NOW THAT THE HSI IS INDEPENDENTLY SLAVED TO ANOTHER COMPASS, AND I AM FAMILIAR WITH NEW'S LOCATION AND CONFIGN.

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.