Instructor and student aboard C172 fail to provide adequate spacing with thermaling sailplane.

Attributes
ACN	790391
Time
Date	200806
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : 92a.airport
State Reference	TN
Altitude	msl single value : 3800
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	general aviation : instructional
Make Model Name	Skyhawk 172/Cutlass 172
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	cruise : level
Flight Plan	VFR
Aircraft 2
Operator	general aviation : personal
Make Model Name	Sail Plane
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	climbout : vacating altitude
Flight Plan	None
Person 1
Affiliation	other
Function	instruction : instructor
Qualification	pilot : atp pilot : cfi pilot : flight engineer
Experience	flight time total : 4850 flight time type : 200
ASRS Report	790391
Events
Anomaly	conflict : airborne less severe
Independent Detector	other flight crewa
Resolutory Action	none taken : anomaly accepted
Miss Distance	horizontal : 1500 vertical : 200
Supplementary
Problem Areas	Flight Crew Human Performance Airspace Structure
Primary Problem	Flight Crew Human Performance

Narrative:

Flight was planned to overfly a glider airport and turn around it to another distant waypoint. Approaching chilhowee airport (92A); an sgs-2-33 was seen thermaling. We climbed from 3500 ft MSL to 3800 ft MSL. Contributing factors: student wanted to deviate slightly left. Discussion was to keep aircraft visible to our left. We climbed 300 ft and pressed forward; right of glider. Glider was on our left. Ridge was a little below us; 600 ft under; to our right; 1500 ft. Instructor should have commanded a 90 degree left turn early enough to have thousands of ft of clearance on the sgs 2-33; not just 1500 ft or so clearance. Student's left turn should have been 90 degrees left. We did maneuver to pass to the right of the 2-33. As we approached; the 2-33 stopped thermaling and rolled out to parallel us. Our wingtip strobes on; flying opposite our direction; passing about 200 or so ft below and about 1500 ft to our left.

Original NASA ASRS Text

Title: INSTRUCTOR AND STUDENT ABOARD C172 FAIL TO PROVIDE ADEQUATE SPACING WITH THERMALING SAILPLANE.

Narrative: FLT WAS PLANNED TO OVERFLY A GLIDER ARPT AND TURN AROUND IT TO ANOTHER DISTANT WAYPOINT. APCHING CHILHOWEE ARPT (92A); AN SGS-2-33 WAS SEEN THERMALING. WE CLBED FROM 3500 FT MSL TO 3800 FT MSL. CONTRIBUTING FACTORS: STUDENT WANTED TO DEVIATE SLIGHTLY L. DISCUSSION WAS TO KEEP ACFT VISIBLE TO OUR L. WE CLBED 300 FT AND PRESSED FORWARD; R OF GLIDER. GLIDER WAS ON OUR L. RIDGE WAS A LITTLE BELOW US; 600 FT UNDER; TO OUR RIGHT; 1500 FT. INSTRUCTOR SHOULD HAVE COMMANDED A 90 DEG L TURN EARLY ENOUGH TO HAVE THOUSANDS OF FT OF CLRNC ON THE SGS 2-33; NOT JUST 1500 FT OR SO CLRNC. STUDENT'S L TURN SHOULD HAVE BEEN 90 DEGS L. WE DID MANEUVER TO PASS TO THE R OF THE 2-33. AS WE APCHED; THE 2-33 STOPPED THERMALING AND ROLLED OUT TO PARALLEL US. OUR WINGTIP STROBES ON; FLYING OPPOSITE OUR DIRECTION; PASSING ABOUT 200 OR SO FT BELOW AND ABOUT 1500 FT TO OUR L.

Data retrieved from NASA's ASRS site as of May 2009 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.