Airworthiness Directives; Sikorsky Aircraft Corporation (Sikorsky) Model S-70A and S-70C Helicopters

[Federal Register Volume 75, Number 221 (Wednesday, November 17, 2010)]
[Rules and Regulations]
[Pages 70101-70102]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-28458]


-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0490; Directorate Identifier 2010-SW-037-AD; 
Amendment 39-16514; AD 2010-23-24]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation 
(Sikorsky) Model S-70A and S-70C Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: This amendment adopts a new airworthiness directive (AD) for 
the Sikorsky Model S-70A and S-70C helicopters. This AD requires an 
ultrasonic test (UT) inspection of the tail gearbox output bevel gear 
(gear) for a crack. If you find a crack, replacing the gear with an 
airworthy gear is required before further flight. This AD is prompted 
by three gear cracking incidents, one of which resulted in the tail 
rotor separating from the helicopter. The actions specified by this AD 
are intended to detect a crack in the gear to prevent a tail rotor 
separating, loss of tail rotor control, and subsequent loss of control 
of the helicopter.

DATES: Effective December 22, 2010.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of December 22, 2010.

ADDRESSES: You may get the service information identified in this AD 
from Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical 
Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone 
(203) 383-4866, e-mail address [email protected], or at http://www.sikorsky.com.
    Examining the Docket: You may examine the docket that contains this 
AD, any comments, and other information on the Internet at http://www.regulations.gov or at the Docket Operations office, West Building 
Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, 
DC.

FOR FURTHER INFORMATION CONTACT: Michael Schwetz, Aviation Safety 
Engineer, Boston Aircraft Certification Office, 12 New England 
Executive Park, Burlington, MA 01803, telephone (781) 238-7761, fax 
(781) 238-7170.

SUPPLEMENTARY INFORMATION: A proposal to amend 14 CFR part 39 to 
include an AD for the specified model helicopters was published in the 
Federal Register on May 13, 2010 (75 FR 26888). That action proposed to 
require a UT inspection of the gear for a crack and replacing any 
cracked gear before further flight. The proposal was prompted by three 
gear crack incidents, one of which resulted in the tail rotor 
separating from the helicopter. The tail gearbox on the helicopter 
where the tail rotor separated from the helicopter experienced a 
fracture of the output shaft spline that drives the tail rotor blades. 
An investigation into the cause of the cracks is ongoing. The unsafe 
condition described previously, if not corrected, could result in a 
tail rotor separating, loss of tail rotor control, and subsequent loss 
of control of the helicopter.
    We have reviewed Sikorsky Alert Service Bulletin No. 70-06-28A, 
Revision A, dated May 21, 2009 (ASB), which refers to procedures for a 
UT inspection of the gear in accordance with Special Service 
Instructions (SSI) No. 70-121A or latest revision.
    This unsafe condition is likely to exist or develop on other 
helicopters of the same type design. Therefore, this AD requires a UT 
inspection of the gear, part number 70358-06620, for a crack. If a 
crack is found, this AD requires replacing the gear with an airworthy 
gear before further flight. The actions are required to be to be done 
by following the SSI described previously.
    We provided the public the opportunity to participate in developing 
this AD. We received no comments on the proposal or on the 
determination of the cost to the public. Therefore, we are adopting the 
action as proposed with only minor non-substantive changes.
    We estimate that this AD affects 5 helicopters in the U.S. 
registry. The actions will take about 4 work hours per helicopter at an 
average labor rate of $85 per work hour. Required parts cost about 
$20,000 for each gear. Based on these figures, we estimate the total 
cost impact of this AD on U.S. operators to be $101,700, assuming the 
gear is replaced on the entire fleet.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will not have a 
substantial direct effect 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.
    For the reasons discussed above, I certify that the regulation:
    1. Is not a ``significant regulatory action'' under Executive Order 
12866;
    2. Is not a ``significant rule'' under the 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.
    We prepared an economic evaluation of the estimated costs to comply 
with this AD. See the AD docket to examine the economic evaluation.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, Section 106 describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the agency's authority.
    We are issuing this rulemaking under the authority described in 
Subtitle VII, Part A, Subpart III, Section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this AD.

List of Subjects in 14 CFR Part 39

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

Adoption of the Amendment

0
Accordingly, under 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:

[[Page 70102]]

PART 39--AIRWORTHINESS DIRECTIVES

0
1. The authority citation for part 39 continues to read as follows:

    Authority: 49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. FAA amends Sec.  39.13 by adding the following new AD:

2010-23-24 Sikorsky Aircraft Corp.: Amendment 39-16514; Docket No. 
FAA-2010-0490; Directorate Identifier 2010-SW-037-AD.

    Applicability: Model S-70A and S-70C helicopters with a tail 
gearbox output bevel gear (gear), part number 70358-06620, 
certificated in any category.
    Compliance: Required as indicated.
    To prevent a tail rotor separating, loss of tail rotor control, 
and subsequent loss of control of the helicopter, do the following:
    (a) Within 500 hours time-in-service (TIS), unless accomplished 
previously, and thereafter at intervals not to exceed 500 hours TIS, 
remove the tail rotor servo control and pitch beam shaft, and using 
a Level II Ultrasonic Testing Technician or equivalent, ultransonic 
inspect the gear for a crack. Ultrasonic inspect the gear by 
following paragraphs A.(5)a. through A(5)n. of Special Service 
Instructions No. 70-121A, Revision A, dated May 21, 2009. If you 
find a crack, before further flight, replace the gear with an 
airworthy gear.
    (b) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Contact the Manager, Boston Aircraft Certification Office, FAA, 
Attn: Michael Schwetz, Aviation Safety Engineer, Boston Aircraft 
Certification Office, 12 New England Executive Park, Burlington, MA 
01803, telephone (781) 238-7761, fax (781) 238-7170, for information 
about previously approved alternative methods of compliance.
    (c) The Joint Aircraft System/Component (JASC) Code is 6520: 
Tail rotor gearbox.
    (d) The inspections shall be done in accordance with the 
specified portions of Sikorsky Special Service Instructions No. 70-
121A, Revision A, dated May 21, 2009. The Director of the Federal 
Register approved this incorporation by reference in accordance with 
5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from 
Sikorsky Aircraft Corporation, Attn: Manager, Commercial Technical 
Support, mailstop s581a, 6900 Main Street, Stratford, CT, telephone 
(203) 383-4866, e-mail address [email protected], or at http://www.sikorsky.com. Copies may be inspected at the FAA, Office of the 
Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas or at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html.

    (e) This amendment becomes effective on December 22, 2010.

    Issued in Fort Worth, Texas, on November 1, 2010.
Kim Smith,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 2010-28458 Filed 11-16-10; 8:45 am]
BILLING CODE 4910-13-P

The complete text was extracted from the official GovInfo HTML edition for this publication. Acquired 2026-10-09T03:12:09.081520+00:00. Text extraction preserves the recorded source wording; it does not determine current requirements.

Open the captured official edition

Source SHA-256

44b04c50ed635a787c31f097ee00d4537e67a8c20b1f036c7a317b70ba9c168c

Text SHA-256

f04e27352eee5a773e9d991d1203d620cd908a33aa03c877a809e465b67bcdb3