Airworthiness Directive · Amendment 39-19803 · Empennage structure
Bell Helicopter Textron Canada Limited Helicopters
This AD applies to Bell Helicopter Textron Canada Limited Model 427 helicopters with a vertical fin part number (P/N) 427-035-840-105 or P/N 427-035-840-109 installed, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for Bell Helicopter Textron Canada Limited (BHTC) Model 427 helicopters. This AD requires inspecting the inboard skin of the vertical fin around the four tailboom attachment points. This AD was prompted by reports of cracked vertical fin skins that resulted from metal fatigue. The actions of this AD are intended to prevent an unsafe condition on these products.
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 before the helicopter has accumulated 1,500 hours TIS, whichever occurs later, and thereafter at intervals not to exceed 100 hours TIS:
(1) Remove the vertical fin and clean the vertical fin attachment area with a soap solution to remove all traces of dirt, stains, exhaust residue, and oil. Rinse the area with water and let dry.
(i) Using a 10X power magnifying glass, visually inspect the inboard skin of the vertical fin for a crack around the four tailboom attachment points as depicted in Figure 1 of Bell Helicopter Alert Service Bulletin 427-15-38, Revision A, dated November 14, 2016. Pay particular attention to the upper aft attachment point.
(ii) If there is a crack, replace the vertical fin before further flight.
(2) If the vertical fin does not have a serial number, assign a serial number using the helicopter serial number, and permanently mark the new serial number on the vertical fin data plate. Create a component history card or equivalent record and annotate the serial number.
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.
