Narrative:

I was towing a glider at 60-65 mph over los alamitos, ca, as was usual on a sunday. Our tow flight path is chosen to take us over mostly industrial commercial property, fields or golf courses for reasons of noise or possible rope break. At 2000' I felt the glider release. Typically, as the tow plane speeds up after release, the flaps are raised, as the maximum flap extended speed is 86 mph. The tow plane then breaks left and descended quickly to enter the pattern for landing. On this occasion, however, in reaching for the flap handle, I grasped the tow rope release and pulled it aft. It had moved only a fraction of its travel when I realized what I was doing and stopped, but the rope was gone! It was reported to the los alamitos aaf base safety officer. Additional information: the glider releases its end of the tow rope when at 2000' (in our operation) and the tow plane returns to land and drops the rope at the runway threshold of 22R. After release the glider breaks right in a climbing right turn. The glider in this case was already off tow, so was not involved in any way. The ropes used are approximately 1/2' diameter. Light synthetic lines about 200-250' long with a weak-link rope at the glider end, and 2' diameter tow rings at each end. The incident had a physical contributing factor, which is the close proximity of the two rope release handle to the flap handle. The corrective action here is simply to positively identify the handle before moving it. Other factors that were possibly contributory were that it was a pickup flight. I had been instructing in the glider that day. The tow pilot of the day asked me if I would like to take the next tow. I am normally very procedures oriented, but this change of duty mid-operations may have caused some crossed wires. While I intended to raise the flaps, I may have subconsciously released at 2000', as I do on each glider flight at los alamitos. Although the tow itself went like clockwork, the operation isn't over just because the glider has released. The corrective action here is to not accept a job nonchalantly, and maintain the same level of alertness through an entire operation.

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Original NASA ASRS Text

Title: PLT OF GLIDER TOW PLANE INADVERTENTLY RELEASES TOW ROPE WHEN HE MEANT TO REACH DOWN TO RAISE THE FLAPS AFTER THE GLIDER HAD RELEASED.

Narrative: I WAS TOWING A GLIDER AT 60-65 MPH OVER LOS ALAMITOS, CA, AS WAS USUAL ON A SUNDAY. OUR TOW FLT PATH IS CHOSEN TO TAKE US OVER MOSTLY INDUSTRIAL COMMERCIAL PROPERTY, FIELDS OR GOLF COURSES FOR REASONS OF NOISE OR POSSIBLE ROPE BREAK. AT 2000' I FELT THE GLIDER RELEASE. TYPICALLY, AS THE TOW PLANE SPDS UP AFTER RELEASE, THE FLAPS ARE RAISED, AS THE MAX FLAP EXTENDED SPD IS 86 MPH. THE TOW PLANE THEN BREAKS LEFT AND DSNDED QUICKLY TO ENTER THE PATTERN FOR LNDG. ON THIS OCCASION, HOWEVER, IN REACHING FOR THE FLAP HANDLE, I GRASPED THE TOW ROPE RELEASE AND PULLED IT AFT. IT HAD MOVED ONLY A FRACTION OF ITS TRAVEL WHEN I REALIZED WHAT I WAS DOING AND STOPPED, BUT THE ROPE WAS GONE! IT WAS RPTED TO THE LOS ALAMITOS AAF BASE SAFETY OFFICER. ADDITIONAL INFO: THE GLIDER RELEASES ITS END OF THE TOW ROPE WHEN AT 2000' (IN OUR OPERATION) AND THE TOW PLANE RETURNS TO LAND AND DROPS THE ROPE AT THE RWY THRESHOLD OF 22R. AFTER RELEASE THE GLIDER BREAKS RIGHT IN A CLBING RIGHT TURN. THE GLIDER IN THIS CASE WAS ALREADY OFF TOW, SO WAS NOT INVOLVED IN ANY WAY. THE ROPES USED ARE APPROX 1/2' DIAMETER. LIGHT SYNTHETIC LINES ABOUT 200-250' LONG WITH A WEAK-LINK ROPE AT THE GLIDER END, AND 2' DIAMETER TOW RINGS AT EACH END. THE INCIDENT HAD A PHYSICAL CONTRIBUTING FACTOR, WHICH IS THE CLOSE PROX OF THE TWO ROPE RELEASE HANDLE TO THE FLAP HANDLE. THE CORRECTIVE ACTION HERE IS SIMPLY TO POSITIVELY IDENT THE HANDLE BEFORE MOVING IT. OTHER FACTORS THAT WERE POSSIBLY CONTRIBUTORY WERE THAT IT WAS A PICKUP FLT. I HAD BEEN INSTRUCTING IN THE GLIDER THAT DAY. THE TOW PLT OF THE DAY ASKED ME IF I WOULD LIKE TO TAKE THE NEXT TOW. I AM NORMALLY VERY PROCS ORIENTED, BUT THIS CHANGE OF DUTY MID-OPS MAY HAVE CAUSED SOME CROSSED WIRES. WHILE I INTENDED TO RAISE THE FLAPS, I MAY HAVE SUBCONSCIOUSLY RELEASED AT 2000', AS I DO ON EACH GLIDER FLT AT LOS ALAMITOS. ALTHOUGH THE TOW ITSELF WENT LIKE CLOCKWORK, THE OPERATION ISN'T OVER JUST BECAUSE THE GLIDER HAS RELEASED. THE CORRECTIVE ACTION HERE IS TO NOT ACCEPT A JOB NONCHALANTLY, AND MAINTAIN THE SAME LEVEL OF ALERTNESS THROUGH AN ENTIRE OPERATION.

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.