Airworthiness Directive · Amendment 39-17647 · Main rotor head
Sikorsky Aircraft Corporation (Sikorsky) Helicopters
This AD applies to Model S-76A, S-76B, and S-76C helicopters with a serial number up to and including 760822 and with a spindle cuff assembly, part number (P/N) 76102-08001-043, -045 or -046, or a blade fold cuff assembly, P/N 76150-09601-041, installed, certificated in any category.
We are adopting a new airworthiness directive (AD) for Sikorsky Model S-76A, B, and C helicopters to require certain inspections of each spindle cuff assembly or blade fold cuff assembly for a crack. If there is a crack, this AD requires replacing the cracked part. If there is no crack, this AD requires applying white paint to the inspection area to enhance the existing inspection procedure. This AD was prompted by discovery of cracks in the spindle cuffs. The actions are intended to prevent failure of a spindle cuff assembly or blade fold cuff assembly, loss of a rotor blade, 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 150 hours time-in-service (TIS):
(1) For each spindle cuff assembly or blade cuff assembly with 1,900 or more hours TIS, conduct a nondestructive inspection (NDI) by following the Accomplishment Instructions, paragraph 3.B., of Sikorsky S-76 Alert Service Bulletin ASB 76-65-67A, Revision A, dated July 18, 2012 (ASB), except this AD does not require you to contact Sikorsky Aircraft Corporation. This inspection must be done by a level 2 or higher technician with National Aerospace Standard 410 or equivalent certification.
(2) For each spindle cuff assembly or blade cuff assembly with less than 1,900 hours TIS, visually inspect the area indicated in Figure 4 of the ASB as “white paint application area” for a crack by using a 5x or higher power magnifying glass.
(3) If there is a crack, before further flight, replace the cracked part.
(4) If there is no crack, apply white paint by following the Accomplishment Instructions, paragraph 3.D., of the ASB.
(5) Do not install an affected spindle cuff assembly or blade fold cuff assembly on any helicopter unless it has been inspected in accordance with paragraphs (e)(1) through (e)(4) of this AD.
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.
