AD 2001-25-08

[Federal Register Volume 66, Number 243 (Tuesday, December 18, 2001)]
[Rules and Regulations]
[Pages 65102-65103]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-31041]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-SW-18-AD; Amendment 39-12561; AD 2001-25-08]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Model S-70A and S-70C 
Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) for 
Sikorsky Model S-70A and S-70C helicopters. This action requires 
certain inspections of each main landing gear drag beam (beam) for a 
crack and removing any cracked beam before further flight. This action 
also requires reducing the torque of the jackpad mounting bolt 
retention nut (nut) of each beam. This amendment is prompted by failure 
of a beam due to stress corrosion resulting from sustained tensile 
stress due partly to excessive torque of the nut. The actions specified 
in this AD are intended to prevent excessive torque of the nut, failure 
of a beam, and subsequent loss of control of the helicopter during 
takeoff or landing.

DATES: Effective January 2, 2002.
    Comments for inclusion in the Rules Docket must be received on or 
before February 19, 2002.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 2001-SW-18-AD, 2601 Meacham Blvd., Room 
663, Fort Worth, Texas 76137. You may also send comments electronically 
to the Rules Docket at the following address: <a href="/cdn-cgi/l/email-protection#526b7f3321257f3336313d3f3f373c2621123433337c353d24"><span class="__cf_email__" data-cfemail="51687c3022267c3035323e3c3c343f2522113730307f363e27">[email&#160;protected]</span></a>.

FOR FURTHER INFORMATION CONTACT: Terry Fahr, Aviation Safety Engineer, 
Boston Aircraft Certification Office, 12 New England Executive Park, 
Burlington, MA 01803, telephone (781) 238-7155, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: This amendment adopts a new AD for Sikorsky 
Model S-70A and S-70C helicopters. This action requires certain 
inspections of each beam for a crack and removing any cracked beam 
before further flight. This AD also requires reducing the torque of the 
nut on each beam. This amendment is prompted by the failure of a beam 
due to stress corrosion resulting from sustained tensile stress due 
partly to excessive torque on the nut.
    The FAA has reviewed Sikorsky Alert Service Bulletin No. 70-03-2, 
dated July 26, 1999 (ASB). The ASB describes procedures for reducing 
the torque on each nut to 45-50 ft-lbs to reduce stress to the beam.
    We have identified an unsafe condition that is likely to exist or 
develop on other Sikorsky Model S-70A and S-70C helicopters of the same 
type designs. Therefore, this AD is being issued to prevent excessive 
torque on a nut, failure of a beam, and subsequent loss of control of 
the helicopter during takeoff or landing. The short compliance time 
involved is required because the previously described critical unsafe 
condition can adversely affect the controllability and structural 
integrity of the helicopter. Therefore, within 30 hours time-in-
service, the following actions are required for the beam, and this AD 
must be issued immediately:
    <bullet> Visually inspect each beam for a crack.
    <bullet> If a crack is found, remove the beam before further 
flight.
    <bullet> If a crack is suspected, dye-penetrant inspect the beam, 
and if a crack is found, remove the beam before further flight.
    <bullet> If no crack is found, reduce the torque on the nut.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.
    The FAA estimates that 3 helicopters on the U.S. register will be 
affected by this AD, that it will take approximately 2 work hours to 
inspect the beam and to reduce the torque on each nut, and 2 work hours 
to replace a cracked beam. The average labor rate is $60 per work hour. 
Required parts will cost approximately $18,600 per beam. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $56,520, assuming one beam has to be replaced on each affected 
helicopter.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified

[[Page 65103]]

under the caption ADDRESSES. All communications received on or before 
the closing date for comments will be considered, and this rule may be 
amended in light of the comments received. Factual information that 
supports the commenter's ideas and suggestions is extremely helpful in 
evaluating the effectiveness of the AD action and determining whether 
additional rulemaking action would be needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the rule. All comments submitted will be 
available in the Rules Docket for examination by interested persons. A 
report that summarizes each FAA-public contact concerned with the 
substance of this AD will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their mailed 
comments submitted in response to this rule must submit a self-
addressed, stamped postcard on which the following statement is made: 
``Comments to Docket No. 2001-SW-18-AD.'' The postcard will be date 
stamped and returned to the commenter.
    The regulations adopted herein 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. Therefore, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and that it is not a ``significant regulatory 
action'' under Executive Order 12866. It has been determined further 
that this action involves an emergency regulation under DOT Regulatory 
Policies and Procedures (44 FR 11034, February 26, 1979). If it is 
determined that this emergency regulation otherwise would be 
significant under DOT Regulatory Policies and Procedures, a final 
regulatory evaluation will be prepared and placed in the Rules Docket. 
A copy of it, if filed, 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, 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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding a new airworthiness directive 
to read as follows:

2001-25-08  Sikorsky Aircraft Corporation: Amendment 39-12561. 
Docket No. 2001-SW-18-AD.

    Applicability: Model S-70A helicopters, serial numbers 700029, 
701129, 701322, 701325, 701327, 701329, 701331, 701333, 701592, 
701593,701594, 701595, 701613, 701614, 701825, 701835, 702127, and 
702129, and Model S-70C helicopters, serial numbers 70583, 70785, 
70788, 70792, 70793, 70794, 70797, 70798, 70799, 70800, 70811, 
70812, 70813, 70830, 70831, 70836, 70837, 70848, 70855, 70856, 
70867, 70868, 70879, 70884, 70892, 70910, 70918, 70927, 70928, 
70929, 70949, 70950, 70951, 70954, 70957, 70958, 70959, 70965, 
70966, and 701029, certificated in any category.

    Note 1: This AD applies to each helicopter identified in the 
preceding applicability provision, regardless of whether it has been 
otherwise modified, altered, or repaired in the area subject to the 
requirements of this AD. For helicopters that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

    Compliance: Required within 30 hours time-in-service, unless 
accomplished previously.
    To prevent excessive torque on a jackpad mounting bolt retention 
nut (nut), failure of a main landing gear drag beam (beam), and 
subsequent loss of control of the helicopter during takeoff or 
landing, accomplish the following:
    (a) With jackpad installed, using a 10X or higher magnifying 
glass, visually inspect each beam, part number (P/N) 70250-32105, 
for a crack at a 3.0-inch radius around the upper and lower jackpad 
holes.
    (1) If a crack is found, remove the beam.
    (2) If a crack is suspected, dye-penetrant inspect the beam, and 
if a crack is found, remove the beam.

    Note 2: Temporary Revision No. 19 of Sikorsky Aircraft Model S-
70 Maintenance Manual, dated January 23, 2001, pertains to the 
subject of this AD.

    (b) If a crack is not found while accomplishing the requirements 
of paragraph (a) of this AD, retorque the nut, part number (P/N) 
MS21245-L12, on each beam as follows:
    (1) Restrain the jackpad and rotate the nut counterclockwise to 
release the torque on the nut. If movement of the jackpad occurs, 
remove and replace the sealant from the lower surface of the 
jackpad/beam interface.
    (2) Retorque the nut to 45-50 ft-lbs.
    (3) Apply sealant to the nut and the immediate area.
    (4) After sealant has dried, touch up the paint as required.
    (5) After the paint has dried, apply a slippage mark (of a 
contrasting color) to the nut as follows:
    (i) Wipe the area to be marked with a clean-lint-free cloth.
    (ii) Apply F1000 Sentry Seal, or equivalent, with a width of 
approximately one half the diameter of the nut (to a maximum width 
of \3/16\ inch) and extending a minimum of \1/2\ inch on the base 
part (or to the edge of the part, whichever is smaller).

    Note 3: Sikorsky Alert Service Bulletin No. 70-03-2, dated July 
26, 1999, pertains to the subject of this AD.

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Boston Aircraft Certification 
Office, FAA. Operators shall submit their requests through an FAA 
Principal Inspector, who may concur or comment and then send it to 
the Manager, Boston Aircraft Certification Office.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Boston Aircraft Certification Office.

    (d) Special flight permits may be issued in accordance with 14 
CFR 21.197 and 21.199 to operate the helicopter to a location where 
the requirements of this AD can be accomplished.
    (e) This amendment becomes effective on January 2, 2002.


    Issued in Fort Worth, Texas, on December 11, 2001.
David A. Downey,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 01-31041 Filed 12-17-01; 8:45 am]
BILLING CODE 4910-13-U