Airworthiness Directive · Amendment 39-17388 · Rotorcraft tailboom
Hughes Helicopters, Inc., and McDonnell Douglas Helicopter Systems (Type Certificate Is Currently Held by MD Helicopters, Inc.) Helicopters
This AD applies to Model 369D, E, F, and FF helicopters with tailboom assembly, part number 369D23500-505, -507, -511, or -513 with a serial number prefix of “7604” and -0001 through -0003, -0006 through -0047, -0049 through -0082, or -0084 through -0113, installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for MD Helicopters, Inc. (MDHI) Model 369D, 369E, 369F, and 369FF helicopters with certain serial-numbered tailboom assemblies. This AD requires measuring the distance between aft longeron rivets and the outboard edge of frame rings. If the distance is too short to ensure a safe flight, the AD requires installing a doubler. This AD was prompted by the discovery of short-edge margin conditions on two tailboom assemblies. The actions are intended to detect a short-edge margin condition, prevent failure of the tailboom and 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.
(1) Within 6 months or 100 hours time-in-service, whichever occurs first, measure the distance from the aft face of the station 209.78 frame ring to the center of rivet No. 1 and rivet No. 2 at the four locations where the frame ring attaches to the tailboom longeron as depicted in Figure 2 of MD Helicopters Service Bulletin (SB) No. SB369D-207, SB369E-102, and SB369F-087, dated July 20, 2010. SB369D-207 applies to Model 369D helicopters; SB369E-102 applies to Model 369E helicopters; and SB369F-087 applies to Model 369F and FF helicopters.
(2) If either the No. 1 or No. 2 aft rivet at a frame-ring-to-tailboom-longeron location is more than 0.50 inches (12.7 millimeters) from the aft face of the station 209.78 frame ring, before further flight, modify that location by fabricating and installing a doubler over the location as depicted in Figures 3 and 4 and by following the Accomplishment Instructions, paragraph 2.C., of the SB for your model helicopter.
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.
