[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]
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