Glider pilot enters inadvertent spin attempting to avoid another glider.

Attributes
ACN	302632
Time
Date	199504
Day	Sun
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : hio
State Reference	OR
Altitude	msl bound lower : 4500 msl bound upper : 4500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : personal
Make Model Name	Sail Plane
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Aircraft 2
Make Model Name	Sail Plane
Operating Under FAR Part	Part 91
Flight Phase	cruise other
Flight Plan	None
Person 1
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Experience	flight time last 90 days : 20 flight time total : 800 flight time type : 90
ASRS Report	302632
Person 2
Affiliation	Other
Function	flight crew : single pilot
Qualification	pilot : private
Events
Anomaly	conflict : nmac other anomaly
Independent Detector	other other : unspecified cockpit
Resolutory Action	flight crew : regained aircraft control flight crew : took evasive action
Consequence	Other
Miss Distance	horizontal : 200 vertical : 0
Supplementary
Air Traffic Incident	other

Narrative:

While thermaling with several other gliders in 1 thermal, 1 additional glider approached to join the thermal at my altitude. In this thermal, gliders were at varying altitudes from approximately 3000-5000 ft. The approaching glider was coming toward me as I was turning clockwise. As he was coming in, I lost sight of him (my left wing up in the turn). As I tightened the radius of my turn to assure more space between us, the glider began to stall. I pushed the stick hard forward just as it started to turn into a spin and dove away from the conflict. A spin would have resulted I am sure had I not already committed to diving out. I am used to being in relatively close proximity to other gliders in thermaling, so always have an 'out' in reserve. This event reinforced my belief in good spin training for everyone who flies.

Original NASA ASRS Text

Title: GLIDER PLT ENTERS INADVERTENT SPIN ATTEMPTING TO AVOID ANOTHER GLIDER.

Narrative: WHILE THERMALING WITH SEVERAL OTHER GLIDERS IN 1 THERMAL, 1 ADDITIONAL GLIDER APCHED TO JOIN THE THERMAL AT MY ALT. IN THIS THERMAL, GLIDERS WERE AT VARYING ALTS FROM APPROX 3000-5000 FT. THE APCHING GLIDER WAS COMING TOWARD ME AS I WAS TURNING CLOCKWISE. AS HE WAS COMING IN, I LOST SIGHT OF HIM (MY L WING UP IN THE TURN). AS I TIGHTENED THE RADIUS OF MY TURN TO ASSURE MORE SPACE BTWN US, THE GLIDER BEGAN TO STALL. I PUSHED THE STICK HARD FORWARD JUST AS IT STARTED TO TURN INTO A SPIN AND DOVE AWAY FROM THE CONFLICT. A SPIN WOULD HAVE RESULTED I AM SURE HAD I NOT ALREADY COMMITTED TO DIVING OUT. I AM USED TO BEING IN RELATIVELY CLOSE PROX TO OTHER GLIDERS IN THERMALING, SO ALWAYS HAVE AN 'OUT' IN RESERVE. THIS EVENT REINFORCED MY BELIEF IN GOOD SPIN TRAINING FOR EVERYONE WHO FLIES.

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.