On a flight on the titan few days back, the engine started to sound funny, n heli started to wobble alot. I landed and found that the high end needle was loose! It got unscrewed while in flight probably due to all the vibrations. The black clip was not pressing onto the needle tight enough. Those using TT50 engine may want to take note. Unscrewed the high end needle out and bend the black clip to tighten the hold on the needle.