A B737-300 captain reported an near midair collision with a glider in cos airspace.

Attributes
ACN	597095
Time
Date	200310
Day	Sat
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : cos.airport
State Reference	CO
Altitude	msl single value : 10500
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : cos.tracon
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude descent : approach
Flight Plan	IFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Commercial Fixed Wing
Flight Phase	cruise : level
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
ASRS Report	597095
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	conflict : nmac
Independent Detector	other flight crewa
Resolutory Action	flight crew : took evasive action
Supplementary
Problem Areas	ATC Human Performance Airspace Structure Flight Crew Human Performance
Primary Problem	Ambiguous

Narrative:

Near midair collision. Approximately 10500 ft, 25 NM of cos descending, an near midair collision with a glider. Aggressive climb to avoid a collision. Notified cos approach. Glider apparently no transponder and was not talking to ATC. Called tower when we got on ground.

Original NASA ASRS Text

Title: A B737-300 CAPT RPTED AN NMAC WITH A GLIDER IN COS AIRSPACE.

Narrative: NMAC. APPROX 10500 FT, 25 NM OF COS DSNDING, AN NMAC WITH A GLIDER. AGGRESSIVE CLB TO AVOID A COLLISION. NOTIFIED COS APCH. GLIDER APPARENTLY NO XPONDER AND WAS NOT TALKING TO ATC. CALLED TWR WHEN WE GOT ON GND.

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.