Summary
We propose to supersede an existing airworthiness directive (AD) for Eurocopter Model AS350B, BA, B1, B2, C, D, and D1 helicopters and Model AS355E, F, F1, F2, and N helicopters with certain part- numbered tail gearbox (TGB) control levers installed. The existing AD currently requires repetitive visual inspections of the TGB control lever for a crack and replacing a cracked TGB control lever with an airworthy TGB control lever. Since we issued that AD, we have received reports of cracking on the opposite area of the TGB control lever. This proposed AD would retain the current requirements and would also require inspecting other areas of the TGB control lever not previously inspected and at additional inspection intervals. The proposed actions are intended to prevent failure of the TGB control lever, loss of tail rotor control, and subsequent loss of control of the helicopter.