[Federal Register Volume 59, Number 122 (Monday, June 27, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-15146]


[[Page Unknown]]

[Federal Register: June 27, 1994]


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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39

[Docket No. 93-SW-07-AD; Amendment 39-8935; AD 94-12-07]

 

Airworthiness Directives: Sikorsky Aircraft Model S-58T Series 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to Sikorsky Aircraft Model S-58T series helicopters, 
that currently requires a one-time inspection of the engine drive shaft 
assembly (drive shaft assembly) for cracks and loose balance weights. 
This amendment requires initial and repetitive visual and florescent 
penetrant inspections of the drive shaft assembly for cracks and 
improperly installed rivets. This amendment is prompted by three 
reported incidents of loose or missing drive shaft assembly balance 
weights and two reported incidents of fatigue cracks on the drive shaft 
assembly near the balance weight rivet hole. The actions specified by 
this AD are intended to prevent failure of the drive shaft assembly, 
loss of power to the rotor system, and a subsequent forced landing of 
the helicopter.

DATES: Effective August 1, 1994.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of August 1, 1994.

ADDRESSES: The service information referenced in this AD may be 
obtained from Sikorsky Aircraft Division, United Technologies 
Corporation, North Main Street, Stratford, Connecticut 06601. This 
information may be examined at the Federal Aviation Administration 
(FAA), Office of the Assistant Chief Counsel, 2601 Meacham Boulevard, 
Room 663, Fort Worth, Texas; or at the Office of the Federal Register, 
800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Terry Fahr, Aerospace Engineer, 
Boston Aircraft Certification Office, FAA, Engine and Propeller 
Directorate, Aircraft Certification Service, 12 New England Executive 
Park, Burlington, Massachusetts 01803, telephone (617) 238-7155, fax 
(617) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 90-10-02, 
Amendment 39-6590 (55 FR 18305, May 2, 1990), which is applicable to 
Sikorsky Aircraft Model S-58T series helicopters, was published in the 
Federal Register on August 31, 1993 (58 FR 45859). That action proposed 
to require initial and repetitive visual and florescent penetrant 
inspections of the engine drive shaft assembly for cracks and loose 
balance weights, and replacement as necessary.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. No comments were received on the 
proposal or the FAA's determination of the cost to the public. The FAA 
has determined that air safety and the public interest require the 
adoption of the rule as proposed, except for editorial changes.
    The FAA estimates that 58 helicopters of U.S. registry will be 
affected by this AD, that it will take approximately 18 work hours per 
helicopter to accomplish the required actions, and that the average 
labor rate is $55 per work hour. Based on these figures, the total cost 
impact of the AD on U.S. operators is estimated to be $57,420.
    The regulations adopted herein will not have substantial direct 
effects on the States, on the relationship between the national 
government and the States, or on the distribution of power and 
responsibilities among the various levels of government. Therefore, in 
accordance with Executive Order 12612, it is determined that this final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) will not have a 
significant economic impact, positive or negative, on a substantial 
number of small entities under the criteria of the Regulatory 
Flexibility Act. A final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends part 39 of 
the Federal Aviation Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

    1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-6590 (55 FR 
18305, May 2, 1990), and by adding a new airworthiness directive (AD), 
Amendment 39-8935, to read as follows:

AD 94-12-07 Sikorsky Aircraft: Amendment 39-8935. Docket Number 93-
SW-07-AD. Supersedes AD 90-10-02, Amendment 39-6590.

    Applicability: Model S-58T series helicopters, equipped with 
engine drive shaft assembly (drive shaft assembly), part number (P/
N) 58350-10030-045 and subassembly P/N 58350-10030-046, or drive 
shaft assembly, P/N 58350-10030-047 and subassemblies 58350-10030-
048 and -049, certificated in any category. The subassembly part 
numbers will appear adjacent to the 58350-10030-045 and 58350-10030-
047 drive shaft assembly part numbers.
    Compliance: Required as indicated, unless accomplished 
previously. To prevent failure of the drive shaft assembly, loss of 
power to the rotor system, and a subsequent forced landing of the 
helicopter, accomplish the following:
    (a) Within the next 25 hours' time-in-service (TIS) after the 
effective date of this AD, or at the next removal of the drive shaft 
assembly, P/N 58350-10030-045 and subassembly -046, or P/N 58350-
10030-047 and subassemblies -048 and -049, whichever comes first--
    (1) Remove and inspect the drive shaft assembly for proper 
installation of rivets, loose balance weights, and cracks in 
accordance with paragraphs 2.A.(1), (2), and (4) of the 
Accomplishment Instructions of Sikorsky Alert Service Bulletin (ASB) 
No. 58B35-31A, Revision A, dated February 17, 1993.
    (2) If a crack, loose balance weight, or improper rivet 
installation is found, replace the drive shaft assembly with an 
airworthy drive shaft assembly.
    (b) Within the next 25 hours' TIS after compliance with 
paragraph (a) of this AD, and at every 25 hours' TIS thereafter, 
visually inspect the drive shaft assembly for cracks in accordance 
with paragraph 2.B. of the Accomplishment Instructions of ASB No. 
58B35-31A, Revision A, dated February 17, 1993.
    (c) For drive shaft assembly, P/N 58350-10030-045 and 
subassembly -046, that have not been reworked in accordance with 
Sikorsky Overhaul Repair Instruction (ORI) No. 58350-001, Revision 
A, dated November 18, 1992, within 250 hours' TIS after the 
inspections required by paragraph (a) of this AD, and thereafter at 
intervals not to exceed 250 hours' TIS, remove and inspect the drive 
shaft assembly in accordance with paragraph 2.C. of the 
Accomplishment Instructions of ASB No. 58B35-31A, Revision A, dated 
February 17, 1993.
    (d) For drive shaft assembly, P/N 58350-10030-047 and 
subassemblies -048 and -049, and additionally, for drive shaft 
assembly, P/N 58350-10030-045 and subassembly -046, that have been 
reworked in accordance with ORI No. 58350-001, Revision A, dated 
November 18, 1992, within 2,500 hours' TIS after the inspections 
required by paragraph (a) of this AD, and thereafter at intervals 
not to exceed 2,500 hours' TIS, remove and inspect the drive shaft 
assembly in accordance with subparagraph 2.D of the Accomplishment 
Instructions of ASB No. 58B35-31A, Revision A, dated February 17, 
1993.
    (e) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used when approved by the Manager, Boston Aircraft Certification 
Office, FAA. Operators shall submit their requests through an FAA 
Principal Maintenance Inspector, who may concur or comment and then 
send it to the Manager, Boston Aircraft Certification Office.

    Note: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Boston Aircraft Certification Office.

    (f) Special flight permits may be issued in accordance with 
sections 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the helicopter to a location where 
the requirements of this AD can be accomplished.
    (g) The inspections and replacement, if necessary, shall be done 
in accordance with Sikorsky Alert Service Bulletin No. 58B35-31A, 
Revision A, dated February 17, 1993. This incorporation by reference 
was approved by the Director of the Federal Register in accordance 
with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from 
Sikorsky Aircraft Division, United Technologies Corporation, North 
Main Street, Stratford, Connecticut 06601. Copies may be inspected 
at the FAA, Office of the Assistant Chief Counsel, 2601 Meacham 
Boulevard, Room 663, Fort Worth, Texas; or at the Office of the 
Federal Register, 800 North Capitol Street, NW., suite 700, 
Washington, DC.
    (h) This amendment becomes effective on August 1, 1994.

    Issued in Fort Worth, Texas, on June 2, 1994.
Larry M. Kelly,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-15146 Filed 6-24-94; 8:45 am]
BILLING CODE 4910-13-P