74-20-07 R5 SIKORSKY AIRCRAFT: Amendment 39-1971 as amended by Amendments 39- 1989, 39-2152, and 39-2439 is further amended by Amendment 39-4895. Applies to S-61L, S- 61N, S-61NM, and S-61R helicopters certificated in all categories, and S-61A (aircraft S/N's 61083, 61087, 61094, and 61161) and S-61V (aircraft S/N 61271) helicopters certificated in the restricted category.
Compliance is required as indicated (unless already accomplished).
To prevent operation with fatigue cracks in the spar of a main rotor blade, accomplish the following:
(a) Remove from service within the next 10 hours time in service from the effective date of this amended AD:
(1) Any main rotor blade which does not comply with Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions, excluding Section 2, Accomplishment Instructions, Part II, Operation, Pilot Information. For main rotor blades which are in compliance, the service life limits are:
(i) 8,000 hours total time in service for S6117-20101 series blades;
(ii) 9,400 hours total time in service for S6115-20501, S6115-20601, S6188-15001, and 61170-20201 series blades;
(2) Any military main rotor blade installed on a helicopter certificated in the restricted category which is not equipped with a visual blade pressure inspection system equivalent to that specified in Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions. For military blades which are in compliance, the service life limits shall be those specified in the restricted category approval.
(b) Inspect main rotor blades equipped with approved visual blade pressure indicators but not equipped with an in-cockpit blade inspection system, or if equipped, with the system inoperative, in accordance with paragraphs (c) and (d). For helicopters equipped with an operative in-cockpit blade inspection system, inspect the main rotor blades in accordance with paragraphs (e) and (f).
(c) Within the next 3 hours time in service after the effective date of this amended AD, unless already accomplished, inspect the visual blade pressure indicators of the following blades of helicopters not equipped with an in-cockpit blade pressure monitoring system (see Sikorsky Service Bulletin No. 61B15-20D), or equipped with such system inoperative:
S6115-20501 Series
S6115-20601 Series
S6117-20101 Series
S6188-15001 Series
61170-20201 Series
61170-20201-062 (S-61A aircraft S/N's 61083 and 61094)
S6115-20201-2 (S-61A aircraft S/N's 61087 and 61161)
61170-20201-060 (S-61V aircraft S/N 61271),
according to the procedures set forth in Section 2, Part IV, of Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions, and as supplemented by paragraph (d) of this AD.
(1) Conduct visual inspections or checks of blade-mounted pressure indicators from the transmission work platform of the helicopter to ensure that an accurate visual check is conducted.
(2) The visual inspections or checks ofblade-mounted pressure indicators shall be conducted by an individual who holds a pilot certificate with appropriate rating or a mechanic certificate with airframe rating or by a certificated maintenance entity. The person performing this inspection or check shall make entries of the results in the aircraft maintenance record including a description and date of the inspection and the name of the individual performing the inspection along with the certificate number, kind of certificate, and signature.
(3) Each blade with any black or red indication visible in the blade pressure indicator is considered to be unsafe and is restricted from further flight until the cause of the indication is determined and corrected in accordance with the procedures given in Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions.
NOTE: The inspections that are required by paragraph (c) to be performed and recorded may be considered to be "airworthiness checks."
If preventivemaintenance action in accordance with Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions, is required as a result of these inspections (airworthiness checks), the subsequent inspections required are considered preventive maintenance that may be performed by persons authorized to perform preventive maintenance under Part 43 of the FAR.
(d) After the initial inspections in accordance with paragraph (c), conduct further inspections in accordance with paragraph (c) prior to the first flight of each day and at intervals not to exceed 3 hours time in service from the last inspection, except for blades identified with yellow or white circles which are limited to inspection intervals of 1 and 2 hours, respectively.
Helicopter time in service for any single flight in excess of the specified inspection interval is not permitted, and if the time in service since the last inspection will exceed the specified interval during the next flight, the visual inspection mustbe conducted prior to the flight.
Yellow or white circles and attendant speed restrictions of AD 74-25-05 may be removed if the main rotor blade is refurbished by Sikorsky in accordance with FAA-approved procedures of June 16, 1975.
(e) Prior to the first flight of the day and every 8 hours time in service thereafter for helicopters equipped with an operable in-cockpit blade pressure monitoring system (see Sikorsky Service Bulletin No. 61B15-20D), and with main rotor blades with serial numbers of 61M-6350- 6105 or greater, or which have been refurbished by Sikorsky in accordance with FAA-approved procedures of June 16, 1975, inspect the main rotor blade pressure indicators and pressure transducers of the blades specified in paragraph (c) according to the procedures set forth in Section 2, Part IV of Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions.
(1) The visual inspections or checks of blade-mounted pressure indicators are to be conducted from the transmission work platform of the helicopter to ensure that an accurate visual check is conducted.
(2) The required functional tests and visual checks shall be conducted by an individual who holds a pilot certificate with appropriate rating or a mechanic certificate with airframe rating or by a certificated maintenance entity. The person performing these tests and checks shall make entries of the results of the inspections in the aircraft maintenance record including a description and date of the inspection and the name of the individual performing the inspection along with the certificate number, kind of certificate, and signature.
(3) Each blade with any black or red indication visible in the blade pressure indicator or whose transducer activates the cockpit warning light is considered to be unsafe and is restricted from further flight until the cause of the indication is determined and corrected in accordance with procedures given in Sikorsky Service Bulletin No. 61B15-6P, orlater FAA- approved revisions.
(f) After the initial inspections in accordance with paragraph (e):
(1) Conduct functional tests in accordance with the procedures of paragraph (e) of all visual blade pressure indicators and in-cockpit blade inspection system transducers every 8 hours time in service.
(2) Check the in-cockpit blade inspection system electrical circuit every 3 hours time in service by use of the system test switch located in the cockpit. An in-flight indication of a failure of the system electrical circuit must be treated in the same manner as an in- cockpit system warning light indication as provided in the Emergency Procedures section of the Rotorcraft Flight Manual.
(g) Alternate inspections, repairs, modifications, or other means of compliance which provide an equivalent level of safety to this AD must be approved by the Manager, Boston Aircraft Certification Office, FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803. In accordance with FAR Section 21.197, flight is permitted to a base where the requirements of this AD may be accomplished.
(h) For helicopters equipped with an operable in-cockpit blade pressure monitoring system (see Sikorsky Service Bulletin No. 61B15-20D), inspect the main rotor blade pressure indicators and transducers of the blades specified in Paragraph (f) according to the procedures set forth in Section 2, Part IV of Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions, and as supplemented by the inspection intervals specified in paragraph (g).
(1) The required visual checks may be performed by the pilot.
(2) Each blade whose transducer activates the cockpit warning light is considered to be unsafe and is restricted from further flight until the cause of the indication is determined and corrected in accordance with procedures given in Sikorsky Service Bulletin No. 61B15-6P, or later FAA-approved revisions.
(i) Alternate inspections, repairs, modifications, or other means of compliance which provide an equivalent level of safety to this AD must be approved by the Manager, Boston Aircraft Certification Branch, FAA, New England Region, 12 New England Executive Park, Burlington, Massachusetts 01803. In accordance with FAR 21.197, flight is permitted to a base where the requirements of this AD may be accomplished.
The manufacturer's specifications and procedures (Sikorsky Service Bulletin No. 61B15- 6P Revision No. 16, 12/3/81 including Revision No. 12, 6/2/77 and Revision No. 15, 4/21/80; Sikorsky Service Bulletin No. 61B15-20 Revision No. 4, 11/9/77) identified in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer may obtain copies upon request to United Technologies Corporation, Sikorsky Aircraft Division, North Main Street, Stratford, Connecticut, 06601, Attn: S-61 Commercial Product Support Dept. These documents also may be examined in the Rules Docket at the Office of the Regional Counsel, Southwest Region, Federal Aviation Administration, Room 156, Building 3B, 4400
Blue Mound Road, Fort Worth, Texas 76106.
This supersedes Amendment 39-283 (31 FR 11714), AD 66-22-5, as amended by Amendment 39-809 (34 FR 12563), Amendment 39-828 (34 FR 13969), Amendment 39-981 (35 FR 6858) and Amendment 39-1178 (36 FR 5674).
Amendment 39-1971 became effective October 4, 1974.
Amendment 39-1989 became effective October 24, 1974.
Amendment 39-2152 became effective April 16, 1975.
Amendment 39-2439 became effective December 23, 1975.
This Amendment 39-4895 becomes effective September 26, 1984, as to all persons including those persons to whom part was made immediately effective by priority letter AD 74- 20-07 R4 issued December 30, 1983, which contained part of this amendment.