Airworthiness Directive · Amendment 39-18429 · Rotorcraft flight control
Sikorsky Aircraft Corporation
This AD applies to Sikorsky Model S-92A helicopters, serial numbers 920006 through 920291, with a main rotor or tail rotor servo input pushrod with a part number (P/N) listed in Table 1 to paragraph (a) of this AD, certificated in any category.
| Name | P/N | Torque value |
|---|---|---|
| Yaw Boost Input Pushrod | 92400-04801-108 | 60-100 inch pounds. |
| Pitch Boost Input Pushrod | 92400-04801-107 | 43 inch pounds. |
| Collective Boost Input Pushrod | 92400-04801-107 | 350 inch pounds. |
| Roll Boost Input Pushrod | 92400-04801-109 | 43 inch pounds. |
| Yaw Boost Out Pushrod | 92400-04802-109 | 40-46 inch pounds. |
| Roll Boost Out Pushrod | 92400-04803-103 | 40-46 inch pounds. |
| Pitch Boost Out Pushrod | 92400-04803-102 | 40-46 inch pounds. |
| Collective Boost Out Pushrod | 92400-04802-108 | 40-46 inch pounds. |
| Limiter Pushrod | 92400-04803-106 | 40-46 inch pounds. |
| Pitch to Roll Pushrod | 92400-04803-107 | 40-46 inch pounds. |
| Left Hand Main Rotor Servo Pushrod | 92400-04801-110 | 350 inch pounds. |
| Forward Main Rotor Servo Pushrod | 92400-04801-111 | 350 inch pounds. |
| Right Hand Main Rotor Servo Pushrod | 92400-04801-112 | 350 inch pounds. |
| Upper Deck Quadrant Pushrod | 92400-04802-105 | 60-100 inch pounds. |
| Tail Rotor Servo Input Pushrod | 92400-04802-107 | 40-46 inch pounds. |
We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This AD requires certain inspections of the main rotor and tail rotor control pushrods (pushrods). This AD is prompted by a Sikorsky investigation that indicated that some pushrods may have incorrectly installed locking mechanisms. These AD actions are intended to detect an incorrectly installed locking mechanism, which if not corrected, could result in a loose jam nut, failure of the pushrod, loss of main rotor or tail rotor flight control, and consequent loss of helicopter control.
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 5 hours time-in-service:
(1) For each control input pushrod (pushrod) adjustable end, except for the upper deck quadrant pushrod:
(i) Remove the safety cable and using finger pressure, inspect each jam nut for movement. If a jam nut moves with finger pressure, remove the pushrod assembly from service.
(ii) Inspect to determine whether a 0.02 inch diameter safety wire can pass through the inspection hole. If the safety wire passes through the inspection hole, repair the pushrod in accordance with the Accomplishment Instructions, paragraphs C.(2)(b) through C.(2)(l) of Sikorsky S-92 Helicopter Alert Service Bulletin ASB 92-67-006, Revision A, dated February 19, 2016 (ASB), which is terminating action for that adjustable end.
(iii) Where locking devices are used, inspect for correct engagement of serrations and keys of the locking device as shown in Figure 4 of the ASB. If a locking device is not correctly engaged, repair the locking device in accordance with the Accomplishment Instructions, paragraphs C.(3)(c) through C.(3)(f) of the ASB, which is terminating action for that adjustable end.
(iv) Torque each jam nut using the torque values listed in Table 1 to paragraph (a) of this AD. Install the safety cable, making sure the right-hand threads have safety cable routed as shown in Figure 2 of the ASB, and the left-hand threads have safety cable routed as shown in Figure 3 of the ASB.
(2) For the upper deck quadrant pushrod, determine whether there is any gap between the jam nut, locking device, and adjustable end.
(i) If there is a gap, gain access to the pushrod, remove the safety cable, and using finger pressure, inspect the jam nut for movement. If the jam nut moves with finger pressure, remove the pushrod assembly from service. If the jam nut does not move, perform the actions in paragraphs (e)(1)(ii) through (e)(1)(iv) of this AD.
(ii) If there is no gap, visually inspect the adjustable end for correct safety cable routing as shown in Figure 2 of the ASB, correct engagement of serrations and keys of the locking device as shown in Figure 4 of the ASB, and to determine whether any thread is visible in the inspection hole. If the safety cable is routed incorrectly, if the locking device is not correctly engaged, or if there is no thread in the inspection hole, gain access to the pushrod. Using finger pressure, inspect the jam nut for movement. If the jam nut moves with finger pressure, remove the pushrod assembly from service. If the jam nut does not move with finger pressure, perform the actions in paragraphs (e)(1)(ii) through (e)(1)(iv) 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.
Aircraft
