Airworthiness directives: Sikorsky,
[Federal Register: December 18, 2001 (Volume 66, Number 243)]
[Rules and Regulations]
[Page 65102-65103]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18de01-3]
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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: 9-asw-adcomments@faa.gov.
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:
Visually inspect each beam for a crack.
If a crack is found, remove the beam before further
flight.
If a crack is suspected, dye-penetrant inspect the beam,
and if a crack is found, remove the beam before further flight.
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
-
The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
-
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