Narrative:

At approximately PM45 hours and approximately 95 NM southwest manassas airport, the aircraft alternator light illuminated. I advised ZDC of the problem. They asked if I wanted to be vectored for an immediate landing. I advised I would continue to manassas and asked for a direct heading. My decision was based on the following factors: WX was VFR at destination, had positive radar contact with handoff capability to dulles approach and manassas tower. Other small airports in my vicinity didn't offer this capability or security. I advised center I was closing down all my navigation and communication equipment except for 1 VHF communication and transponder to conserve the battery. Advised center my xmissions would be short and limited to essential communication. Headings and periodic position were furnished by center. A handoff and frequency change to dulles approach took place approximately 36 mi from manassas. Dulles had been advised of my problem. Descent was given and a visual contact with the airport was made at approximately 5 NM. Contact was made with tower, which said they were advised of my problem. I was cleared to land 16L, however, I only had 1 set of runway lights in sight at approximately 800 ft altitude. Throughout my maneuvering I was using a flashlight to see the instrument lights while flying the aircraft and keeping sight of the runway. All lights were dim and no indication that exterior rotating beacon was operating. Ammeter read near zero. After landing, tower advised me I landed 16R rather than 16L. While rolling out after landing, I saw a helicopter pass approximately 300 ft and 100 ft altitude to my right. I recall tower had cleared him for the 'option.' apparently, he was cleared for the 'option' on 16R, which I mistakenly took for 16L. The 'chopper' pilot was upset because he didn't see me until my rollout on the runway. To conserve battery power, I did not report my progress throughout the traffic pattern. There was no need for evasive action on his part nor was there a near miss. I had no visual contact with the helicopter during my approach since he was apparently flying his pattern inside, below, and behind me. To avert a similar situation and possible accident, I would recommend the tower not have cleared the helicopter for the option until I had completed my landing.

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Original NASA ASRS Text

Title: SMA MAKES WRONG RWY APCH LNDG UNAUTH LNDG. ROTARY WINGED TFC COMPLAINS OF RPTR'S ACFT ON HIS RWY.

Narrative: AT APPROX PM45 HRS AND APPROX 95 NM SW MANASSAS ARPT, THE ACFT ALTERNATOR LIGHT ILLUMINATED. I ADVISED ZDC OF THE PROB. THEY ASKED IF I WANTED TO BE VECTORED FOR AN IMMEDIATE LNDG. I ADVISED I WOULD CONTINUE TO MANASSAS AND ASKED FOR A DIRECT HDG. MY DECISION WAS BASED ON THE FOLLOWING FACTORS: WX WAS VFR AT DEST, HAD POSITIVE RADAR CONTACT WITH HDOF CAPABILITY TO DULLES APCH AND MANASSAS TWR. OTHER SMALL ARPTS IN MY VICINITY DIDN'T OFFER THIS CAPABILITY OR SECURITY. I ADVISED CTR I WAS CLOSING DOWN ALL MY NAV AND COM EQUIP EXCEPT FOR 1 VHF COM AND XPONDER TO CONSERVE THE BATTERY. ADVISED CTR MY XMISSIONS WOULD BE SHORT AND LIMITED TO ESSENTIAL COM. HDGS AND PERIODIC POS WERE FURNISHED BY CTR. A HDOF AND FREQ CHANGE TO DULLES APCH TOOK PLACE APPROX 36 MI FROM MANASSAS. DULLES HAD BEEN ADVISED OF MY PROB. DSCNT WAS GIVEN AND A VISUAL CONTACT WITH THE ARPT WAS MADE AT APPROX 5 NM. CONTACT WAS MADE WITH TWR, WHICH SAID THEY WERE ADVISED OF MY PROB. I WAS CLRED TO LAND 16L, HOWEVER, I ONLY HAD 1 SET OF RWY LIGHTS IN SIGHT AT APPROX 800 FT ALT. THROUGHOUT MY MANEUVERING I WAS USING A FLASHLIGHT TO SEE THE INST LIGHTS WHILE FLYING THE ACFT AND KEEPING SIGHT OF THE RWY. ALL LIGHTS WERE DIM AND NO INDICATION THAT EXTERIOR ROTATING BEACON WAS OPERATING. AMMETER READ NEAR ZERO. AFTER LNDG, TWR ADVISED ME I LANDED 16R RATHER THAN 16L. WHILE ROLLING OUT AFTER LNDG, I SAW A HELI PASS APPROX 300 FT AND 100 FT ALT TO MY R. I RECALL TWR HAD CLRED HIM FOR THE 'OPTION.' APPARENTLY, HE WAS CLRED FOR THE 'OPTION' ON 16R, WHICH I MISTAKENLY TOOK FOR 16L. THE 'CHOPPER' PLT WAS UPSET BECAUSE HE DIDN'T SEE ME UNTIL MY ROLLOUT ON THE RWY. TO CONSERVE BATTERY PWR, I DID NOT RPT MY PROGRESS THROUGHOUT THE TFC PATTERN. THERE WAS NO NEED FOR EVASIVE ACTION ON HIS PART NOR WAS THERE A NEAR MISS. I HAD NO VISUAL CONTACT WITH THE HELI DURING MY APCH SINCE HE WAS APPARENTLY FLYING HIS PATTERN INSIDE, BELOW, AND BEHIND ME. TO AVERT A SIMILAR SIT AND POSSIBLE ACCIDENT, I WOULD RECOMMEND THE TWR NOT HAVE CLRED THE HELI FOR THE OPTION UNTIL I HAD COMPLETED MY LNDG.

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.