2 small aircraft have near midair collision in traffic pattern.

Attributes
ACN	102267
Time
Date	198901
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : w10
State Reference	VA
Altitude	msl bound lower : 1200 msl bound upper : 1200
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	other
Flight Plan	VFR
Aircraft 2
Make Model Name	Small Aircraft, Low Wing, 1 Eng, Fixed Gear
Flight Phase	other
Person 1
Affiliation	Other
Function	flight crew : single pilot
Experience	flight time last 90 days : 30 flight time total : 950
ASRS Report	102267
Person 2
Affiliation	Other
Function	flight crew : single pilot
Events
Anomaly	conflict : nmac non adherence : far other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 500 vertical : 0
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Entering the traffic pattern to runway 16L I was at 1200' MSL entering on a 45 degree angle to runway 16L. I noticed another aircraft approaching to my left at the same altitude. He looked like he was intending to enter the traffic pattern improperly, via a straight in entry to downwind, rather than a 45 degree angle. When I saw he was getting too close, I made a 360 degree turn to the right to avoid the other aircraft. He never turned at all. I estimate we came within 500' of each other. Observing this aircraft later on the ground, he parked his aircraft on the hold line to runway 16L for an excessively long time causing delay to taxiing aircraft when he had ample time to takeoff between intermittent landing aircraft, and unnecessarily obstructed traffic on the ground as well as in the air.

Original NASA ASRS Text

Title: 2 SMA HAVE NMAC IN TRAFFIC PATTERN.

Narrative: ENTERING THE TFC PATTERN TO RWY 16L I WAS AT 1200' MSL ENTERING ON A 45 DEG ANGLE TO RWY 16L. I NOTICED ANOTHER ACFT APCHING TO MY LEFT AT THE SAME ALT. HE LOOKED LIKE HE WAS INTENDING TO ENTER THE TFC PATTERN IMPROPERLY, VIA A STRAIGHT IN ENTRY TO DOWNWIND, RATHER THAN A 45 DEG ANGLE. WHEN I SAW HE WAS GETTING TOO CLOSE, I MADE A 360 DEG TURN TO THE RIGHT TO AVOID THE OTHER ACFT. HE NEVER TURNED AT ALL. I ESTIMATE WE CAME WITHIN 500' OF EACH OTHER. OBSERVING THIS ACFT LATER ON THE GND, HE PARKED HIS ACFT ON THE HOLD LINE TO RWY 16L FOR AN EXCESSIVELY LONG TIME CAUSING DELAY TO TAXIING ACFT WHEN HE HAD AMPLE TIME TO TKOF BTWN INTERMITTENT LNDG ACFT, AND UNNECESSARILY OBSTRUCTED TFC ON THE GND AS WELL AS IN THE AIR.

Data retrieved from NASA's ASRS site as of August 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.