AD 2002-21-07
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sikorsky Aircraft Corporation | S-76A | Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, S-76B and S-76C Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-76B | Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, S-76B and S-76C Helicopters |
| aircraft | Sikorsky Aircraft Corporation | S-76C | Airworthiness Directives; Sikorsky Aircraft Corporation Model S- 76A, S-76B and S-76C Helicopters |
Unsafe Condition
Improper bolts installed on the main rotor spindle attachment could result in reduced hub or bolt fatigue life, separation of the main rotor blade at the spindle attachment, and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Remove and inspect each main rotor spindle attachment bolt to ensure the correct bolts are installed.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Before further flight.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sikorsky Aircraft Corporation Model S-76A, S-76B, and S-76C helicopters.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
This amendment adopts a new airworthiness directive (AD) for the specified Sikorsky Aircraft Corporation (Sikorsky) model helicopters that requires removing and inspecting each main rotor spindle attachment bolt (bolt) to ensure that the correct bolts are installed. This amendment is prompted by the discovery of improper bolts installed on a helicopter during its production. The actions specified by this AD are intended to detect installation of incorrect bolts, which could result in reduced hub or bolt fatigue life, separation of the main rotor blade at the spindle attachment, and subsequent loss of control of the helicopter.
Document Text
Show stored source text (verify against official source)
[Federal Register Volume 67, Number 203 (Monday, October 21, 2002)]
[Rules and Regulations]
[Pages 64519-64520]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 02-26590]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2001-SW-59-AD; Amendment 39-12913; AD 2002-21-07]
RIN 2120-AA64
Airworthiness Directives; Sikorsky Aircraft Corporation Model S-
76A, S-76B and S-76C Helicopters
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) for
the specified Sikorsky Aircraft Corporation (Sikorsky) model
helicopters that requires removing and inspecting each main rotor
spindle attachment bolt (bolt) to ensure that the correct bolts are
installed. This amendment is prompted by the discovery of improper
bolts installed on a helicopter during its production. The actions
specified by this AD are intended to detect installation of incorrect
bolts, which could result in reduced hub or bolt fatigue life,
separation of the main rotor blade at the spindle attachment, and
subsequent loss of control of the helicopter.
DATES: Effective November 25, 2002.
FOR FURTHER INFORMATION CONTACT: Kirk Gustafson, Aviation Safety
Engineer, Boston Aircraft Certification Office, Engine and Propeller
Directorate, FAA, 12 New England Executive Park, Burlington, MA 01803,
telephone (781) 238-7190, fax (781) 238-7170.
SUPPLEMENTARY INFORMATION: A proposal to amend 14 CFR part 39 to
include an AD for Sikorsky Model S-76A, S-76B and S-76C helicopters was
published in the Federal Register on June 20, 2002 (67 FR 41875). That
action proposed to require removing and inspecting each bolt to ensure
that the correct bolts are installed.
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 with one change. A ``note'' has been added
following paragraph (b)(3) referencing the alert service bulletin that
pertains to the subject of the AD. The FAA has determined that this
change will neither increase the economic burden on any operator nor
increase the scope of the AD.
The FAA estimates that 165 helicopters of U.S. registry will be
affected by this proposed AD, that it will take approximately 6 work
hours per helicopter to accomplish the required actions, and that the
average labor rate is $60 per work hour. Required parts will cost
approximately $240 per helicopter. Based on these figures, the total
cost impact of the AD on U.S. operators is estimated to be $99,000,
assuming all 40 bolts (per helicopter) are replaced.
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.
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, 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
[[Page 64520]]
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:
2002-21-07 Sikorsky Aircraft Corporation: Amendment 39-12913. Docket
No. 2001-SW-59-AD.
Applicability: Model S-76A, S-76B and S-76C helicopters, except
those having a serial number of 760501, or 760506 through 760515,
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 1,250-hours time-in-service or 2
years, whichever comes first, unless accomplished previously.
To detect installation of an incorrect main rotor spindle
attachment bolt (bolt), which could result in reduced hub or bolt
fatigue life, separation of the main rotor blade at the spindle
attachment, and subsequent loss of control of the helicopter,
accomplish the following:
(a) Remove and measure each bolt to ensure that the length is
1.181 +/-.015 inches. There are 10 bolts per rotor spindle and 40
bolts per helicopter that require inspection.
(1) If 1 or 2 bolts are found on any spindle that are longer
than 1.196 inches (1.181 inches + .015-inch permissible tolerance),
visually inspect the main rotor hub internal threads for distortion
and the hole-bottoms for scoring.
(i) If thread distortion or hole-bottom scoring is found, remove
the rotor hub from service.
(ii) If no thread distortion or hole-bottom scoring is found,
replace all 10 bolts with new airworthy bolts.
(2) If 3 or more bolts that exceed 1.196 inches are found on any
spindle, remove and replace the main rotor hub with an airworthy
main rotor hub.
(3) If any bolt is found that is shorter than 1.166 inches
(1.181 inches -.015 permissible tolerance), replace it with a new
airworthy bolt.
(b) Report the results of the inspections of the main rotor hubs
whenever the bolts exceed 1.196 inches in length, within 5 calendar
days of the inspection, to the Manager, Boston Aircraft
Certification Office, FAA, Engine and Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803-5299; telephone: (781)
238-7150; fax: (781) 238-7170. Include the following information in
the report:
(1) Serial number of the helicopter.
(2) Quantity of incorrect bolts.
(3) Description of thread distortion or hole-bottom scoring
caused by each bolt. Information collection requirements contained
in this AD have been approved by the Office of Management and Budget
(OMB) under the provisions of the Paperwork Reduction Act of 1980
(44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number
2120-0056.
Note 2: Sikorsky Aircraft Corporation Alert Service Bulletin No.
76-65-52 (321), dated July 24, 2001, 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, Engine and Propeller Directorate, 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 3: 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 November 25, 2002.
Issued in Fort Worth, Texas, on October 4, 2002.
Eric D. Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 02-26590 Filed 10-18-02; 8:45 am]
BILLING CODE 4910-13-P
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Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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