Airworthiness Directive · Amendment 39-17247 · Main rotor
Bell Helicopter Textron Helicopters
This AD applies to Model 412 and 412EP helicopters, serial numbers (S/N) 33001 through 33213, 34001 through 34036, and 36001 and higher; and Model 412CF helicopters, S/N 46400 and higher; with a collective lever part number (P/N) 412-010-408-101 installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Bell Helicopter Textron (BHT) Model 412, 412EP, and 412CF helicopters. This AD requires a repetitive inspection of the collective lever for a crack, and if there is a crack, before further flight, replacing the collective lever with an airworthy collective lever. This AD was prompted by a reported failure of a collective lever. The actions are intended to detect a crack in the collective lever, which could lead to failure of the collective lever and subsequent loss of control of the helicopter.
You are responsible for performing each action required by this AD within the specified compliance time unless it has already been accomplished prior to that time.
Within 25 hours time-in-service (TIS) or 30 days, whichever occurs first, and thereafter at intervals not to exceed 100 hours TIS:
(1) Using cleaning compound (C-318) or equivalent, thoroughly clean the collective lever.
(2) Using a 10X or higher power magnifying glass, inspect the collective lever in the areas shown in Figure 1 of Bell Helicopter Textron Alert Service Bulletin (ASB) 412-11-148, Revision A, dated December 12, 2011 or Bell Helicopter Textron ASB 412CF-11-47, Revision A, dated December 12, 2011, as appropriate for your model helicopter.
(3) If there is a crack in the paint, remove the collective lever from the swashplate assembly.
(i) Remove paint and primer from the area around the crack.
(ii) Fluorescent penetrant inspect the area of the crack.
(4) If there is a crack in the collective lever, before further flight, replace the collective lever with an airworthy collective lever.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
