A PA28 pilot becomes confused about the tower instructions as a metroliner passes directly overhead.

Attributes
ACN	584907
Time
Date	200306
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : hln.airport
State Reference	MT
Altitude	msl single value : 6000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tower : hln.tower tower : pit.tower
Operator	general aviation : personal
Make Model Name	PA-28 Cherokee/Archer II/Dakota/Pillan/Warrior
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : visual
Flight Plan	VFR
Aircraft 2
Controlling Facilities	tower : hln.tower
Operator	common carrier : charter
Make Model Name	SA-227 AC Metro III
Operating Under FAR Part	Part 135
Flight Phase	descent : approach
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : instrument pilot : private
Experience	flight time last 90 days : 7 flight time total : 1200 flight time type : 1000
ASRS Report	584907
Person 2
Affiliation	company : charter
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne critical non adherence : clearance
Independent Detector	aircraft equipment : tcas other flight crewa
Resolutory Action	none taken : detected after the fact
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous

Narrative:

While on a straight in approach to runway 9 as directed by ATC, I heard a metropolitan report straight in and above and behind me. I immediately transmitted my altitude and DME distance. At time my transponder was on mode C and squawking 1200. Tower notified traffic of my existence and the metropolitan said something about TCASII. I transmitted again, but may have been stepped on. The metropolitan passed directly over me, and landed. About the same time, tower instructed me 'enter a left upwind for runway 9.' I turned left, flew upwind and reported a left base for runway 9 behind the metropolitan, which was now on the runway. Tower told me he had instructed me to enter a left upwind for runway 9, and I replied that 'I guess I don't know what a left upwind for runway 9 is.' I was then cleared to land, and proceeded to do so. I was somewhat unnerved by the plane passing over me, and felt that I had complied to the best of my knowledge, given the circumstances, and position of my aircraft. A direction to turn right or left immediately would have been clrer.

Original NASA ASRS Text

Title: A PA28 PLT BECOMES CONFUSED ABOUT THE TWR INSTRUCTIONS AS A METROLINER PASSES DIRECTLY OVERHEAD.

Narrative: WHILE ON A STRAIGHT IN APCH TO RWY 9 AS DIRECTED BY ATC, I HEARD A METRO RPT STRAIGHT IN AND ABOVE AND BEHIND ME. I IMMEDIATELY XMITTED MY ALT AND DME DISTANCE. AT TIME MY XPONDER WAS ON MODE C AND SQUAWKING 1200. TWR NOTIFIED TFC OF MY EXISTENCE AND THE METRO SAID SOMETHING ABOUT TCASII. I XMITTED AGAIN, BUT MAY HAVE BEEN STEPPED ON. THE METRO PASSED DIRECTLY OVER ME, AND LANDED. ABOUT THE SAME TIME, TWR INSTRUCTED ME 'ENTER A L UPWIND FOR RWY 9.' I TURNED L, FLEW UPWIND AND RPTED A L BASE FOR RWY 9 BEHIND THE METRO, WHICH WAS NOW ON THE RWY. TWR TOLD ME HE HAD INSTRUCTED ME TO ENTER A L UPWIND FOR RWY 9, AND I REPLIED THAT 'I GUESS I DON'T KNOW WHAT A L UPWIND FOR RWY 9 IS.' I WAS THEN CLRED TO LAND, AND PROCEEDED TO DO SO. I WAS SOMEWHAT UNNERVED BY THE PLANE PASSING OVER ME, AND FELT THAT I HAD COMPLIED TO THE BEST OF MY KNOWLEDGE, GIVEN THE CIRCUMSTANCES, AND POS OF MY ACFT. A DIRECTION TO TURN R OR L IMMEDIATELY WOULD HAVE BEEN CLRER.

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.