[Federal Register Volume 63, Number 194 (Wednesday, October 7, 1998)]
[Rules and Regulations]
[Pages 53800-53802]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-26821]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-SW-47-AD; Amendment 39-10820; AD 98-21-12]
RIN 2120-AA64
Airworthiness Directives; McDonnell Douglas Helicopter Systems
Model 369D, 369E, 369FF, 500N, AH-6, and MH-6 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) that
is applicable to McDonnell Douglas Helicopter Systems (MDHS) Model
369D, 369E, 369FF, 500N, AH-6 and MH-6 helicopters. This action
requires visual inspections of the overrunning clutch retainer,
carrier, housing, and pin for wear from spinning of the bearing outer
race. This amendment is prompted by a report of inflight vibrations and
subsequent investigations of three other overrunning clutches, which
indicated wear of the bearing carrier due to spinning of the bearing
outer race. The actions specified in this AD are intended to detect
wear of other clutch components, excessive vibration which could lead
to failure of the overrunning clutch, wear on the bearing carrier, and
subsequent loss of power to the helicopter rotor drive system.
DATES: Effective October 22, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of October 22, 1998.
Comments for inclusion in the Rules Docket must be received on or
before December 7, 1998.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Regional Counsel, Southwest Region,
Attention: Rules Docket No. 97-SW-47-AD, 2601 Meacham Blvd., Room 663,
Fort Worth, Texas 76137.
The service information referenced in this AD may be obtained from
McDonnell Douglas Helicopter Systems, Field Service Department, 5000 E.
McDowell Road, Mesa, Arizona, telephone (800) 388-3378, fax (602) 891-
6782. This information may be examined at the FAA, Office of the
Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort
Worth, Texas 76137; or at the Office of the Federal Register, 800 North
Capitol Street, NW., suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Mr. Bruce Conze, Aerospace Engineer,
FAA, Los Angeles Aircraft Certification Office, 3960 Paramount
Boulevard, Lakewood, California 90712, telephone (562) 627-5261, fax
(562) 627-5210.
SUPPLEMENTARY INFORMATION: This amendment adopts a new AD that is
applicable to MDHS Model 369D, 369E, 369FF, 500N, AH-6, and MH-6
helicopters. This action requires a visual inspection of the
overrunning clutch retainer, part number (P/N) 369F5460-1, carrier, P/N
369F5461-1, housing, P/N 369F5451-1, and pin, P/N MS16556-801, for wear
due to spinning of the bearing retainer and the outer race of the
bearing. This amendment is prompted by a report of an operator that
experienced inflight vibrations. Subsequent investigation revealed that
the bearing retainer and the outer race of the bearing were spinning,
which led to wear of the bearing carrier and movement of the bearing
outer race. Investigations of three other overrunning clutches with the
same P/N also indicated there had been spinning of the retainer. This
condition, if not corrected, could result in wear on the bearing
carrier, which could lead to failure of the overrunning clutch,
excessive vibration, wear of other clutch components, and subsequent
loss of power to the helicopter rotor drive system.
The FAA has reviewed MDHS Service Information Notice No. DN-190,
EN-83, FN-70, NN-011, dated July 25, 1997, which describes procedures
for visually inspecting the overrunning clutch
[[Page 53801]]
retainer, carrier, and pin for clutch or carrier wear, or pin damage,
and replacing any unairworthy clutch assembly with an airworthy clutch
assembly.
Since an unsafe condition has been identified that is likely to
exist or develop on other MDHS Model 369D, 369E, 369FF, 500N, AH-6, and
MH-6 helicopters of the same type design, this AD is being issued to
detect wear of other clutch components, excessive vibration which could
lead to failure of the overrunning clutch, wear on the bearing carrier,
and subsequent loss of power to the helicopter rotor drive system. This
AD requires visual inspections of the overrunning clutch retainer,
carrier, housing, and pin, for wear from spinning of the bearing
retainer. The actions are required to be accomplished in accordance
with the service information notice described previously.
The short compliance time involved is required because the
previously described critical unsafe condition can adversely affect the
controllability of the helicopter. Therefore, inspections of the
overrunning clutch components is required within 25 hours time-in-
service (TIS) and this AD must be issued immediately.
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 2,200 helicopters of U.S. registry will be
affected by this AD, that it will take approximately 2 work hours to
accomplish the inspection and 14 work hours to accomplish either the
replacement of components, or replacement the entire clutch assembly,
and that the average labor rate is $60 per work hour. Required parts
will cost approximately $1,098 if only components are replaced, or
$7690 if the entire clutch assembly is replaced, per helicopter. Based
on these figures, the total cost impact of the proposed AD on U.S.
operators is estimated to be $4,527,600 to accomplish one inspection
and replace components, or $19,030,000 to accomplish one inspection and
replace the entire clutch assembly.
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 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, both before and after the closing date for comments, 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 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. 97-SW-47-AD.'' The postcard will be date stamped and
returned to the commenter.
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.
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, 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. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
AD 98-21-12 McDonnell Douglas Helicopter Systems: Amendment 39-
10820. Docket No. 97-SW-47-AD.
Applicability: Model 369D, 369E, 369FF, 500N, AH-6, and MH-6
helicopters, with overrunning clutch assembly, part number (P/N)
369F5450-501, installed, certificated in any category.
Note 1: This AD applies to each helicopter identified in the
preceding applicability provision, regardless of whether it has been
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 use the authority
provided in paragraph (d) to request approval from the FAA. This
approval may address either no action, if the current configuration
eliminates the unsafe condition, or different actions necessary to
address the unsafe condition described in this AD. Such a request
should include an assessment of the effect of the changed
configuration on the unsafe condition addressed by this AD. In no
case does the presence of any modification, alteration, or repair
remove any helicopter from the applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To detect wear of other clutch components, excessive vibration
which could lead to failure of the overrunning clutch, wear on the
bearing carrier, and subsequent loss of power to the helicopter
rotor drive system, accomplish the following:
(a) Visually inspect the overrunning clutch retainer, P/N
369F5460-1, carrier, P/N 369F5461-1, housing, P/N 369F5451-1, and
pin, P/N MS16556-801, for clutch or carrier wear or pin damage in
accordance with the Accomplishment Instructions in McDonnell Douglas
Helicopter Systems Service Information Notice No. DN-190, EN-83, FN-
70, NN-011, dated July 25, 1997. For
[[Page 53802]]
helicopters with a clutch assembly having less than 100 hours time-
in-service (TIS), conduct the visual inspection before or upon
reaching 100 hours TIS. For helicopters with a clutch assembly
having 100 or more hours TIS, conduct the visual inspection within
25 hours TIS.
(b) Repeat the inspection required by paragraph (a) at intervals
not to exceed 100 hours TIS.
(c) If the inspections specified in paragraph (a) or (b) reveal
wear or damage to components, replace those components with
airworthy components prior to further flight.
(d) 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, Los Angeles 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, Los Angeles Aircraft Certification Office.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this AD, if any, may be
obtained from the Los Angeles Aircraft Certification Office.
(e) 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.
(f) The inspections shall be done in accordance with McDonnell
Douglas Helicopter Systems Service Information Notice No. DN-190,
EN-83, FN-70, NN-011, dated July 25, 1997. 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 McDonnell Douglas Helicopter Systems, Field Service
Department, 5000 E. McDowell Road, Mesa, Arizona, telephone (800)
388-3378, fax (602) 891-6782. 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 Office of the Federal
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.
(g) This amendment becomes effective on October 22, 1998.
Issued in Fort Worth, Texas, on September 30, 1998. original
signed by
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 98-26821 Filed 10-6-98; 8:45 am]
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