[Federal Register Volume 59, Number 227 (Monday, November 28, 1994)]
[Unknown Section]
[Page ]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-28938]
[Federal Register: November 28, 1994]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-SW-13-AD; Amendment 39-9077; AD 94-24-04]
Airworthiness Directives; McDonnell Douglas Helicopter Systems
and Hughes Helicopters, Inc. Model 369D, E, F, and FF Series
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 and Hughes
Helicopters, Inc. Model 369D, E, F, and FF series helicopters. This
action requires an initial inspection of the pitch control assembly
lockwasher (lockwasher) for dents at the inner tang inside radius,
application of a torque stripe on the tail rotor swashplate and
locknut, and repetitive inspections of the torque stripe to detect any
locknut slippage. This amendment is prompted by a report that a
lockwasher failed in service and allowed a locknut to loosen. The
actions specified in this AD are intended to prevent failure of the
inner tang of the lockwasher, loss of the locknut, disengagement of the
pitch control assembly, loss of tail rotor control, and subsequent loss
of control of the helicopter.
DATES: Effective December 13, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of December 13, 1994.
Comments for inclusion in the Rules Docket must be received on or
before January 27, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), Office of the Assistant Chief Counsel, Attention:
Rules Docket No. 94-SW-13-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, Technical Publications, Bldg.
543/B111, 5000 E. McDowell Road, Mesa, Arizona 85205-9797. This
information may be examined at the FAA, Office of the Assistant Chief
Counsel, 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.
FOR FURTHER INFORMATION CONTACT: Mr. Brent Bandley, Aerospace Engineer,
Airframe Branch, ANM-123L, Northwest Mountain Region, FAA, Los Angeles
Aircraft Certification Office, 3229 E. Spring Street, Long Beach,
California 90806-2425, telephone (310) 988-5237, fax (310) 988-5210.
SUPPLEMENTARY INFORMATION: This amendment adopts a new airworthiness
directive (AD) that is applicable to McDonnell Douglas Helicopter
Systems (MDHS) and Hughes Helicopters, Inc. (Hughes) Model 369D, E, F,
and FF series helicopters. MDHS received a report that indicated a
pitch control assembly lockwasher (lockwasher), part number (P/N)
MS172209, had failed in service. A subsequent investigation revealed
that some lockwashers appear to have dents at the inner tang inside
radius. The FAA has reviewed the reports and determined that failure of
this tang could allow the locknut to loosen and eventually allow the
pitch control assembly to disengage from the tail rotor assembly.
Should these two tail rotor components separate, the rotorcraft crew
would lose the capability of making necessary anti-torque corrections
through the tail rotor to maintain adequate control of the helicopter.
This condition, if not corrected, could result in failure of the inner
tang of the lockwasher, loss of the locknut, disengagement of the pitch
control assembly, loss of tail rotor control, and subsequent loss of
control of the helicopter.
The FAA has reviewed McDonnell Douglas Helicopter Systems Service
Information Notice (SIN) No. DN-185, EN-78, and FN-64, dated September
23, 1994, which describes procedures for an inspection of the
lockwasher, P/N MS172209, application of a torque stripe on the tail
rotor swashplate and locknut, and repetitive inspections of the pitch
control assembly to detect slippage of the locknut.
Since an unsafe condition has been identified that is likely to
exist or develop on other McDonnell Douglas Helicopter Systems and
Hughes Helicopters, Inc. Model 369D, E, F, and FF series helicopters of
the same type design, this AD is being issued to prevent failure of the
inner tang of the lockwasher, loss of the locknut, disengagement of the
pitch control assembly, loss of tail rotor control, and subsequent loss
of control of the helicopter. This AD requires an initial inspection of
the lockwasher for dents in the inner tang inside radius, application
of a torque stripe on the tail rotor swashplate and locknut, and
repetitive inspections of the torque stripe to detect slippage of the
locknut. Due to the critical need to ensure the integrity of the
lockwasher and the short time-in-service before the initial inspection
is required, this rule must be issued immediately to correct an unsafe
condition in the affected helicopters. The actions are required to be
accomplished in accordance with the SIN described previously.
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.
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. 94-SW-13-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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding a new airworthiness directive
to read as follows:
94-24-04 McDonnell Douglas Helicopter Systems (MDHS) and Hughes
Helicopters, Inc. (Hughes): Amendment 39-9077. Docket No. 94-SW-13-
AD.
Applicability: Model 369D, E, F, and FF series helicopters with
pitch control assembly, part number (P/N) 369D21800 or P/N
369D21820, installed, certificated in any category.
Compliance: Required as indicated, unless accomplished
previously.
To prevent failure of the inner tang of the pitch control
assembly lockwasher (lockwasher), loss of the locknut, disengagement
of the pitch control assembly, loss of tail rotor control, and
subsequent loss of control of the helicopter, accomplish the
following:
(a) Within 25 hours time-in-service or 90 calendar days after
the effective date of this AD, whichever occurs first, remove the
tail rotor (T/R) assembly and pitch control assembly from the T/R
gearbox in accordance with the applicable maintenance manual.
(b) Inspect the lockwasher, P/N MS172209, for dents in either
side of the inner tang inside radius as shown in Figure 1 of MDHS
Service Information Notice (SIN) No. DN-185, EN-78, and FN-64, dated
September 23, 1994, using a 5x or higher magnifying glass.
(c) Apply a 0.125 inch-wide torque stripe to the surface of the
locknut and swashplate in accordance with paragraph B and C of Part
II of MDHS SIN No. DN-185, EN-78, and FN-64, dated September 23,
1994, and reinstall the T/R assembly and pitch control assembly into
the T/R gearbox in accordance with the applicable maintenance
manual.
(d) Inspect the torque stripe for slippage at intervals not to
exceed 100 hours time-in-service. If any slippage is detected,
replace the lockwasher with an airworthy lockwasher in accordance
with the applicable maintenance manual. Reapply the 0.125 inch-wide
torque stripe to the surface of the locknut and swashplate.
(e) An alternative method of compliance or adjustment of the
compliance time that provides an acceptable level of safety may be
used when 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: 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.
(f) 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.
(g) The inspections shall be done in accordance with McDonnell
Douglas Helicopter Systems Service Information Notice No. DN-185,
EN-78, and FN-64, dated September 23, 1994. 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, Technical
Publications, Bldg. 543/B111, 5000 E. McDowell Road, Mesa, Arizona
85205-9797. Copies may be inspected at the FAA, Office of the
Assistant Chief Counsel, 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.
(h) This amendment becomes effective on December 13, 1994.
Issued in Fort Worth, Texas, on November 16, 1994.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 94-28938 Filed 11-25-94; 8:45 am]
BILLING CODE 4910-13-P
