GLIDER PLT DRAGS WING TIP ATTEMPTING CROSSWIND TKOF. PLT RELEASES TOW ROPE TO ABORT; BUT GLIDER CONTINUES TO GROUND LOOP; AND STRIKES PARKED ACFT.

Date: 2007-05 · Aircraft: Sail Plane · Phase: takeoff

Anomalies: ground-event-encounter-loss-of-aircraft-control|ground-excursion-runway

Synopsis

GLIDER PLT DRAGS WING TIP ATTEMPTING CROSSWIND TKOF. PLT RELEASES TOW ROPE TO ABORT; BUT GLIDER CONTINUES TO GROUND LOOP; AND STRIKES PARKED ACFT.

Narrative

ON MAY/SUN/07; I BEGAN A LCL FLT IN MY ASW20 GLIDER. THE VISIBILITY WAS CLR; ABOUT 10 MI VISIBILITY WINDS GUSTING 10-15 KTS FROM 290 DEGS TO 300 DEGS WITH OCCASIONAL GUSTS FROM A HDG OF ABOUT 330 DEGS. AERO TOW OPS WERE UNDERWAY USING RWY 27R AT THE ACTIVE RWY. SEVERAL OTHER GLIDERS WERE LINED UP AHEAD OF ME. ALL TKOFS PROCEEDED WITHOUT INCIDENT PRIOR TO MY TKOF. I DISCUSSED WITH OTHER PLTS AND THE LINE BOY THAT THE WINDS WERE GETTING SHIFTIER AND THAT THE R XWIND WAS BECOMING GREATER. THE LINE BOY HOOKED MY GLIDER TO THE TOW ROPE; WE DID A TEST RELEASE; RECONNECTED THE TOW ROPE AND DID A PULL TEST ON THE TOW ROPE. THE TOW ROPE RELEASE ON MY GLIDER IS COMMONLY REFERRED TO AS A 'CG HOOK;' OR CTR OF GRAVITY RELEASE; LOCATED INSIDE THE MAIN LNDG GEAR WHEELWELL. I COMPLETED THE REMAINING ITEMS ON MY BEFORE TKOF CHKLIST; AND CHKED THE WINDS ONE MORE TIME BY LOOKING TO THE WINDSOCK AND WIND-TEE AT MY L ON THE S SIDE OF THE PARALLEL RWYS. I DETERMINED THE WINDS WERE STILL GUSTY AND SHIFTY BUT WITHIN LIMITS OF A SAFE AERO TOW TKOF. THE LINE BOY WAS ALSO ON MY L SIDE AT THE WINGTIP WAITING FOR ME TO GIVE THUMBS UP SIGNAL FOR HIM TO CHK TFC AND BRING THE WINGS TO THE LEVEL POS. HE ACKNOWLEDGED THAT THE PATTERN WAS CLR AND LEVELED THE WINGS. I SIGNALED THE TOW PLANE THAT I WAS READY FOR TKOF BY GIVING HIM A RUDDER WAGGLE; THE TOW PLT ACKNOWLEDGED WITH A RUDDER WAGGLE AS WELL. WE BEGAN A NORMAL TKOF ROLL. AFTER APPROX 100 FT FROM THE START OF THE TKOF ROLL THE R WINGTIP IMPACTED THE GND AND A STRONG R YAW MOTION STARTED TO DEVELOP. MY CORRECTIVE ACTION OF FULL L RUDDER AND L AILERON HAD NO EFFECT TO CORRECT EITHER THE R ROLL OR THE R YAW. IT BECAME APPARENT THAT A GND LOOP WAS IMMINENT SO I RELEASED THE TOW ROPE. THE TOW PLANE CONTINUED AND MADE A NORMAL TKOF. I CONTINUED TO TURN SHARPLY TO THE R WITH THE R WINGTIP STILL FIRMLY DRAGGING ON THE GND. I IMMEDIATELY PULLED FULL SPOILER AND FULL BRAKE TO TRY AND STOP THE GND LOOP. I CONTINUED TO GND LOOP TO THE R AND IMPACTED THE L WING OF A PARKED ACFT (AEROMOT XIMANGO; MOTORGLIDER) WITH THE L WING OF MY GLIDER. THE XIMANGO WAS PARKED; TIED DOWN ON A SOUTHERLY HEADING (APPROX 180 DEGS). AT THIS TIME MY GLIDER CAME TO A STOP AT A HDG OF APPROX 90 DEGS COMPLETING A DIRECTION CHANGE OF APPROX 180 DEGS FROM THE START OF THE TKOF. MY L WING WENT OVER THE TOP OF THE XIMANGO L WING. THE IMPACT CREATED A GASH ON THE LEADING EDGE AND UPPER SURFACE OF THE XIMANGO L WING AND DAMAGED THE L LOWER WING SURFACE AND TRAILING EDGE FLAP OF MY GLIDER. NO OTHER IMPACT WITH OTHER PARTS OF BOTH GLIDERS OR WITH THE ADJACENT TIED DOWN XIMANGO WAS EVIDENT. THERE WERE NO INJURIES TO ME (PIC); NO ONE WAS IN OR NEAR THE XIMANGO; AND NO OTHER BYSTANDERS WERE NEAR THE INCIDENT. AFTER REVIEW WITH OTHER PLT WITNESSES AND THE LINE BOY IT WAS DETERMINED THAT I MAY HAVE OVER-COMPENSATED FOR THE R XWIND BY ALLOWING THE R WING TO DROP ON TKOF ROLL; AND THAT THE TOW PLANE PROP WASH WAS OBSERVED (DUST) TO BE BLOWN ONTO THE L SIDE UNDER MY L WING ALSO CONTRIBUTING TO THE R WING DROP. ANOTHER CONTRIBUTING FACTOR IS THE CTR OF GRAVITY TOW HOOK USED ON THE ASW20. THIS TOW HOOK ARRANGEMENT DOES NOT PROVIDE A STRAIGHTENING EFFECT AS SEEN ON NOSE HOOK INSTALLATIONS. AEROTOW OPS STOPPED TO PERMIT SAFE REMOVAL OF THE ASW20 FROM THE TIE-DOWN AREA. SHORTLY AFTER THE INCIDENT OCCURRED IT WAS OBSERVED THAT THE WINDS SETTLED DOWN; BECAME LESS INTENSE; LESS SHIFTY; LESS GUSTY AND MORE INLINE WITH THE RWY HDG OF 270 DEGS. CORRECTIVE ACTION: I WILL BE MORE WARY OF XWIND TKOFS IN GLIDERS EQUIPPED WITH CTR OF GRAVITY TOW HOOKS. I WOULD ALSO SUGGEST THAT PARKED ACFT ALONG AN ACTIVE GLIDER RWY HAVE GREATER CLRNC OR USE THE PARALLEL RWY FURTHER AWAY FROM THE PARKED ACFT. I AM ALSO CONCERNED THAT THIS INCIDENT COULD HAVE BEEN MUCH WORSE IF THE XIMANGO HAD HAD ITS ENG RUNNING. I WOULD SUGGEST THAT ALL AEROTOW OPS BE STOPPED IF ANY ACFT ARE IDLING; PROP TURNING OR PREPARING TO TAXI; IF THEY ARE LOCATED BEYOND THE START OF THE AEROTOW TKOF POS.

Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.