Airworthiness Directive · Amendment 39-17301 · Main rotor drive system and 6400: tail rotor system
Sikorsky Aircraft-Manufactured Model S-64F Helicopters
This AD applies to Sikorsky Aircraft Corporation-manufactured Model S-64F helicopters, now under the Erickson Air-Crane Incorporated Model S-64F type certificate, certificated in any category.
We are adopting a new airworthiness directive (AD) for Sikorsky Aircraft Corporation-manufactured Model S-64F helicopters, now under the Erickson Air-Crane Incorporated (Erickson) Model S-64F type certificate. This AD supersedes an existing AD which requires inspections, rework, and replacement, if necessary, of the main gearbox (MGB) second stage lower planetary plate (plate). Since we issued that AD, the manufacturer has conducted a configuration review and analysis, and a review of the service history of certain components. The actions of this AD are intended to establish life limits for certain components, remove various parts from service, and require consistency in the part numbers of certain four bladed tail rotor (T/R) assemblies to prevent fatigue cracking, failure from static overload, 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.
(1) Before further flight:
(i) Remove from service any part with a number of hours time-in-service (TIS) equal to or greater than the part's retirement life as stated in Table 1 to Paragraph (f) of this AD.
| Part name | Part No. (P/N) | Retirement life |
|---|---|---|
| Main Rotor (M/R) Blade Assembly | 6415-20601-045 | 13,280 hours TIS. |
| Main Transmission Support Beam Assembly, LH | 6420-62363-045 | 9,300 hours TIS. |
| Main Transmission Support Beam Assembly, RH | 6420-62363-046 | 9,300 hours TIS. |
| Left Splice Fitting (Transition Fitting), Rotary, Rudder Boom | 6420-66341-101 | 8,300 hours TIS. |
| Right Splice Fitting (Transition Fitting), Rotary, Rudder Boom | 6420-66341-102 | 8,300 hours TIS. |
| M/R Drive Shaft | 6435-20536-101 | 2,200 hours TIS. |
| Pressure Plate Assembly, Rotary Wing Head | 65101-11016-042 | 8,800 hours TIS. |
| Horn and Liner Assembly | 65102-11047-041 | 1,140 hours TIS. |
| Lower Hub Plate Assembly | 65103-11009-041 | 15,500 hours TIS. |
| Horizontal Hinge Pin, Rotary Wing Head | 65103-11020-103 | 5,100 hours TIS. |
| Damper Bracket Assembly, Rotary Wing Head | 65103-11032-043 | 20,000 hours TIS. |
| Hub Subassembly, Rotary Wing | 65103-11310-043 | 21,600 hours TIS. |
| Shaft Assembly, Pitch Control Tail Gearbox | 65358-07035-043 | 9,400 hours TIS. |
| Rod End Assembly, Primary Servo Assembly | 65652-11212-041 | 20,800 hours TIS. |
Note 1 to Table 1 to Paragraph (f) of this AD: The list of parts in Table 1 to Paragraph (f) of this AD contains only a portion of the life-limited parts for this model helicopter and is not an all-inclusive list.
(ii) Revise the retirement life of each part as shown in Table 1 to Paragraph (f) of this AD by making pen and ink changes or by inserting a copy of this AD into the Airworthiness Limitations section of the maintenance manual.
(iii) Record on the component history card or equivalent record the retirement life for each part as shown in Table 1 to Paragraph (f) of this AD.
(2) Before further flight, remove from service any part with a P/N listed in Table 2 to Paragraph (f) of this AD, regardless of the part's TIS. The P/Ns listed in Table 2 to Paragraph (f) of this AD are not eligible for installation on any helicopter.
| Part name | P/N |
|---|---|
| Spindle Assembly, Rotary Rudder | 6410-30302-041. |
| Main Gearbox Second Stage Lower Planetary Plate | 6435-20516-101 or 6435-20516-102. |
| Bracket Assembly, Main Servo | 6435-20527-041 or 6435-20527-042. |
| Primary Servo Link, Tandem Servo, M/R | 6465-62161-042. |
| Shoulder Bolt, Tail Rotor (T/R) | 65111-07001-102. |
| T/R Blade Assembly | 65161-00001-041. |
(3) Before further flight, if a T/R blade assembly, P/N 65160-00001-048, is installed, remove any of the other three T/R blade assemblies that have a different P/N and replace it with a T/R blade assembly, P/N 65160-00001-048. The T/R blade assembly, P/N 65160-00001-048, must be installed in sets of four only.
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
