A private pilot has an near midair collision while trying to land at hpn.

Attributes
ACN	603403
Time
Date	200312
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hpn.airport
State Reference	NY
Altitude	msl single value : 1500
Environment
Flight Conditions	VMC
Weather Elements	Windshear Turbulence
Light	Dusk
Aircraft 1
Controlling Facilities	tower : hpn.tower tower : tncm.tower
Operator	general aviation : personal
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Flight Plan	None
Aircraft 2
Controlling Facilities	tower : hpn.tower
Operator	general aviation : personal
Make Model Name	Cessna Aircraft Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	descent : approach
Route In Use	approach : traffic pattern
Flight Plan	None
Person 1
Affiliation	other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 10.2 flight time total : 180.5 flight time type : 180.5
ASRS Report	603403
Person 2
Affiliation	other
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took precautionary avoidance action
Consequence	faa : reviewed incident with flight crew
Miss Distance	vertical : 150
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

At approximately XA30 I announced myself to the westchester county tower. Westchester county tower instructed me to report mid downwind for landing runway 29. I repeated the instruction. After a few mins, I noticed several aircraft in the area and much radio chatter and wanted to verify my position and intent. I asked westchester county tower if I could cross mid field and enter runway 29 from a right pattern. This seemed to be a safer approach given the traffic ahead of me. Westchester county tower then indicated that would not be permitted, to stand by for resequencing. I repeated standing by. Westchester county tower then asked if I saw the cessna on base for runway 34 ahead of me. I responded that I had the aircraft in sight. Westchester county then instructed me to follow the aircraft in and that I was cleared to land runway 29. I followed the aircraft and observed it as it began its descent for landing runway 34. I was about to start my descent from tpa 1500 ft MSL while on left base for runway 29, when I noticed an aircraft converging on my position from my rear left quarter, apparently at the end of downwind on runway 34. Immediately I added full power and veered to the left heading northeast. I immediately notified tower that I was continuing northeast to avoid traffic and would be entering runway 29 from a right base. I then heard the other aircraft announce to westchester county tower that a single engine aircraft had crossed its flight path, meaning my aircraft. After completing my right base turn and entering final, westchester county tower cleared an aircraft for takeoff from runway 34. I then notified westchester county tower that I was on final. Westchester county tower cleared me for landing runway 29. I repeated clearance to land runway 29 and did so.

Original NASA ASRS Text

Title: A PVT PLT HAS AN NMAC WHILE TRYING TO LAND AT HPN.

Narrative: AT APPROX XA30 I ANNOUNCED MYSELF TO THE WESTCHESTER COUNTY TWR. WESTCHESTER COUNTY TWR INSTRUCTED ME TO RPT MID DOWNWIND FOR LNDG RWY 29. I REPEATED THE INSTRUCTION. AFTER A FEW MINS, I NOTICED SEVERAL ACFT IN THE AREA AND MUCH RADIO CHATTER AND WANTED TO VERIFY MY POS AND INTENT. I ASKED WESTCHESTER COUNTY TWR IF I COULD CROSS MID FIELD AND ENTER RWY 29 FROM A R PATTERN. THIS SEEMED TO BE A SAFER APCH GIVEN THE TFC AHEAD OF ME. WESTCHESTER COUNTY TWR THEN INDICATED THAT WOULD NOT BE PERMITTED, TO STAND BY FOR RESEQUENCING. I REPEATED STANDING BY. WESTCHESTER COUNTY TWR THEN ASKED IF I SAW THE CESSNA ON BASE FOR RWY 34 AHEAD OF ME. I RESPONDED THAT I HAD THE ACFT IN SIGHT. WESTCHESTER COUNTY THEN INSTRUCTED ME TO FOLLOW THE ACFT IN AND THAT I WAS CLRED TO LAND RWY 29. I FOLLOWED THE ACFT AND OBSERVED IT AS IT BEGAN ITS DSCNT FOR LNDG RWY 34. I WAS ABOUT TO START MY DSCNT FROM TPA 1500 FT MSL WHILE ON L BASE FOR RWY 29, WHEN I NOTICED AN ACFT CONVERGING ON MY POS FROM MY REAR L QUARTER, APPARENTLY AT THE END OF DOWNWIND ON RWY 34. IMMEDIATELY I ADDED FULL PWR AND VEERED TO THE L HEADING NE. I IMMEDIATELY NOTIFIED TWR THAT I WAS CONTINUING NE TO AVOID TFC AND WOULD BE ENTERING RWY 29 FROM A R BASE. I THEN HEARD THE OTHER ACFT ANNOUNCE TO WESTCHESTER COUNTY TWR THAT A SINGLE ENG ACFT HAD CROSSED ITS FLT PATH, MEANING MY ACFT. AFTER COMPLETING MY R BASE TURN AND ENTERING FINAL, WESTCHESTER COUNTY TWR CLRED AN ACFT FOR TKOF FROM RWY 34. I THEN NOTIFIED WESTCHESTER COUNTY TWR THAT I WAS ON FINAL. WESTCHESTER COUNTY TWR CLRED ME FOR LNDG RWY 29. I REPEATED CLRNC TO LAND RWY 29 AND DID SO.

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.