Narrative:

I pulled the helicopter on a platform out of the hangar after a very thorough preflight done in detail to show a potential student how to correctly do it. The start was uneventful and I pulled the collective to a manifold pressure of 21 to get the aircraft light on the skids. Then as I increased slowly to lift off I felt a bump and the helicopter took off suddenly; slightly tilted to the left. I was immediately over the edge of the landing platform; 1 skid over the ground and the other over the platform that is about 3 ft high. I could not control the collective smoothly to get back over the platform and land safely; so I moved forward into the parking lot. Then I lowered the collective and with the same bump the manifold pressure dropped to 19. The helicopter went down fast towards the ground and I pulled back again to avoid a very hard landing and worse. The helicopter jumped up about 20 ft. I switched hands to check the control friction (I was flying from the left seat to allow the potential student to 'enjoy' flying from the captain seat) and found it normally unlocked. Through this struggle I brought the helicopter into a more open space (no airplanes); I lowered the collective again and had the same drop but I was ready and as soon as it started to drop I pulled up and caught the fall at about 5 ft above the surface. Before it started climbing I lowered the collective with the same 'bump' and started sinking. At that point I raised the collective and immediately lowered it to settle amazingly well on the ground. It was not a perfect landing but it was not even a hard landing. When I started the engine my intent was to bring the helicopter down from the platform to reposition in the parking lot and then call tower and get ready to fly off. After I shut down the tower asked for explanations which I provided; similar to this report but less detailed. The controller told me he was very concerned; even more so because I was not talking to him; which would have not helped; could even have distraction me. After this landing we found a broken zip tie sticking out of the left collective boot. After removing the boot completely the rest of the zip tie was found attached to the clip holding the left collective in place (this is an early model with a poorly designed removable collective; difficult to put back in). The presence of the zip tie there remains completely unexplained as it was not there before the aircraft went into a major overhaul. I have no doubt about this issue since I removed the left collective several times and I never had anything attached to the clip. After this unpleasant adventure I removed the landing light that needed change and found inside the bottom of the aircraft 2 washers; 2 cut zip ties; a clip; and a few other miscellaneous small items. I removed all this hardware and performed the landing light change. Overall it was an experience that ended up well by some luck and maybe some skills on my part. I carefully checked the left collective before removing it and after placing it back. The zip tie was sliding freely along the clip and could easily get caught between the collective and the frame; rubbing against the frame of the aircraft in the opening where the collective goes through the firewall. My attempt at controling the aircraft ended up cutting it against the sharp edge and most likely explains that I was able to land in a normal manner after all these out of control movements; more luck than skills I guess. The intent of this report is to insist once more that after a major overhaul there are gremlins. The aircraft had been flown about 7-8 hours before this incident but the zip tie could move freely along the clip and could get caught at any time or never with luck.

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Original NASA ASRS Text

Title: INTERMITTENT LOSS OF COLLECTIVE CONTROL ON R22 HELI DEEMED TO HAVE BEEN THE RESULT OF A ZIP TIE APPARENTLY UTILIZED BY MAINTENANCE DURING OVERHAUL AND NOT REMOVED PRIOR TO RETURN TO SERVICE. THE TIE CAUSED INTERFERENCE BETWEEN THE COLLECTIVE AND THE ADJOINING BODY WORK UNTIL IT WAS CUT DURING THE LOSS AND RECOVERY OF CONTROL MANEUVERING.

Narrative: I PULLED THE HELI ON A PLATFORM OUT OF THE HANGAR AFTER A VERY THOROUGH PREFLT DONE IN DETAIL TO SHOW A POTENTIAL STUDENT HOW TO CORRECTLY DO IT. THE START WAS UNEVENTFUL AND I PULLED THE COLLECTIVE TO A MANIFOLD PRESSURE OF 21 TO GET THE ACFT LIGHT ON THE SKIDS. THEN AS I INCREASED SLOWLY TO LIFT OFF I FELT A BUMP AND THE HELI TOOK OFF SUDDENLY; SLIGHTLY TILTED TO THE L. I WAS IMMEDIATELY OVER THE EDGE OF THE LNDG PLATFORM; 1 SKID OVER THE GND AND THE OTHER OVER THE PLATFORM THAT IS ABOUT 3 FT HIGH. I COULD NOT CTL THE COLLECTIVE SMOOTHLY TO GET BACK OVER THE PLATFORM AND LAND SAFELY; SO I MOVED FORWARD INTO THE PARKING LOT. THEN I LOWERED THE COLLECTIVE AND WITH THE SAME BUMP THE MANIFOLD PRESSURE DROPPED TO 19. THE HELI WENT DOWN FAST TOWARDS THE GND AND I PULLED BACK AGAIN TO AVOID A VERY HARD LNDG AND WORSE. THE HELI JUMPED UP ABOUT 20 FT. I SWITCHED HANDS TO CHK THE CTL FRICTION (I WAS FLYING FROM THE L SEAT TO ALLOW THE POTENTIAL STUDENT TO 'ENJOY' FLYING FROM THE CAPT SEAT) AND FOUND IT NORMALLY UNLOCKED. THROUGH THIS STRUGGLE I BROUGHT THE HELI INTO A MORE OPEN SPACE (NO AIRPLANES); I LOWERED THE COLLECTIVE AGAIN AND HAD THE SAME DROP BUT I WAS READY AND AS SOON AS IT STARTED TO DROP I PULLED UP AND CAUGHT THE FALL AT ABOUT 5 FT ABOVE THE SURFACE. BEFORE IT STARTED CLBING I LOWERED THE COLLECTIVE WITH THE SAME 'BUMP' AND STARTED SINKING. AT THAT POINT I RAISED THE COLLECTIVE AND IMMEDIATELY LOWERED IT TO SETTLE AMAZINGLY WELL ON THE GND. IT WAS NOT A PERFECT LNDG BUT IT WAS NOT EVEN A HARD LNDG. WHEN I STARTED THE ENG MY INTENT WAS TO BRING THE HELI DOWN FROM THE PLATFORM TO REPOSITION IN THE PARKING LOT AND THEN CALL TWR AND GET READY TO FLY OFF. AFTER I SHUT DOWN THE TWR ASKED FOR EXPLANATIONS WHICH I PROVIDED; SIMILAR TO THIS RPT BUT LESS DETAILED. THE CTLR TOLD ME HE WAS VERY CONCERNED; EVEN MORE SO BECAUSE I WAS NOT TALKING TO HIM; WHICH WOULD HAVE NOT HELPED; COULD EVEN HAVE DISTR ME. AFTER THIS LNDG WE FOUND A BROKEN ZIP TIE STICKING OUT OF THE L COLLECTIVE BOOT. AFTER REMOVING THE BOOT COMPLETELY THE REST OF THE ZIP TIE WAS FOUND ATTACHED TO THE CLIP HOLDING THE L COLLECTIVE IN PLACE (THIS IS AN EARLY MODEL WITH A POORLY DESIGNED REMOVABLE COLLECTIVE; DIFFICULT TO PUT BACK IN). THE PRESENCE OF THE ZIP TIE THERE REMAINS COMPLETELY UNEXPLAINED AS IT WAS NOT THERE BEFORE THE ACFT WENT INTO A MAJOR OVERHAUL. I HAVE NO DOUBT ABOUT THIS ISSUE SINCE I REMOVED THE L COLLECTIVE SEVERAL TIMES AND I NEVER HAD ANYTHING ATTACHED TO THE CLIP. AFTER THIS UNPLEASANT ADVENTURE I REMOVED THE LNDG LIGHT THAT NEEDED CHANGE AND FOUND INSIDE THE BOTTOM OF THE ACFT 2 WASHERS; 2 CUT ZIP TIES; A CLIP; AND A FEW OTHER MISCELLANEOUS SMALL ITEMS. I REMOVED ALL THIS HARDWARE AND PERFORMED THE LNDG LIGHT CHANGE. OVERALL IT WAS AN EXPERIENCE THAT ENDED UP WELL BY SOME LUCK AND MAYBE SOME SKILLS ON MY PART. I CAREFULLY CHKED THE L COLLECTIVE BEFORE REMOVING IT AND AFTER PLACING IT BACK. THE ZIP TIE WAS SLIDING FREELY ALONG THE CLIP AND COULD EASILY GET CAUGHT BTWN THE COLLECTIVE AND THE FRAME; RUBBING AGAINST THE FRAME OF THE ACFT IN THE OPENING WHERE THE COLLECTIVE GOES THROUGH THE FIREWALL. MY ATTEMPT AT CTLING THE ACFT ENDED UP CUTTING IT AGAINST THE SHARP EDGE AND MOST LIKELY EXPLAINS THAT I WAS ABLE TO LAND IN A NORMAL MANNER AFTER ALL THESE OUT OF CTL MOVEMENTS; MORE LUCK THAN SKILLS I GUESS. THE INTENT OF THIS RPT IS TO INSIST ONCE MORE THAT AFTER A MAJOR OVERHAUL THERE ARE GREMLINS. THE ACFT HAD BEEN FLOWN ABOUT 7-8 HRS BEFORE THIS INCIDENT BUT THE ZIP TIE COULD MOVE FREELY ALONG THE CLIP AND COULD GET CAUGHT AT ANY TIME OR NEVER WITH LUCK.

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.