[Federal Register Volume 64, Number 55 (Tuesday, March 23, 1999)]
[Proposed Rules]
[Pages 13936-13938]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-7025]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-16-AD]


Airworthiness Directives; McDonnell Douglas Helicopter Systems 
Model 600N Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to McDonnell Douglas Helicopter 
Systems (MDHS) Model 600N helicopters. This proposal would require 
applying serial numbers to several life-limited components related to 
pitch control and removing and replacing the components according to 
new life-limits. This proposal is prompted by fatigue tests that 
indicate a need for shorter service lives for these components. The 
actions specified by the proposed AD are intended to prevent failure of 
the collective pitch control tubes, collective stick housings, and 
collective pitch tube assemblies, which can cause loss of collective 
pitch control, and subsequent loss of control of the helicopter.

DATES: Comments must be received by May 24, 1999.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-16-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137. Comments may be inspected at this location 
between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.
    The service information referenced in the proposed rule may be 
obtained from McDonnell Douglas Helicopter Systems, Technical 
Publications, Bldg. 530/B11, 5000 E. McDowell Road, Mesa, Arizona 
85205-9797. This information may be examined at the FAA, Office of the 
Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort 
Worth, Texas.

FOR FURTHER INFORMATION CONTACT: Frederick A. Guerin, Aerospace 
Engineer, Airframe Branch, Los Angeles Aircraft Certification Office, 
3960 Paramount Blvd., Lakewood, California 90712, telephone (562) 627-
5232, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All

[[Page 13937]]

communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this notice must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket No. 98-SW-16-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 98-SW-16-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

Discussion

    This document proposes the adoption of a new AD that is applicable 
to MDHS Model 600N helicopters. This proposal would require three 
actions: (1) applying serial numbers to the collective pitch control 
tubes, part number's (P/N's) 369A7348 and 369H7809, and collective 
stick housings, P/N's 369A7347 and 369A7820; (2) adding the co-pilot 
collective pitch control tube, P/N 369A7809, to the Airworthiness 
Limitations section, Component Mandatory Replacement Schedule (CMRS), 
of the maintenance manual; and (3) reducing the service lives from 
those stated in the Airworthiness Limitations section, CMRS, of the 
pilot collective pitch control tube, P/N 369A7348, collective stick 
housings, P/N's 369A7347, 369A7820, and 369H7837, and collective pitch 
tube assemblies, P/N's 369H7354-3 and 369H7838-3. The following table 
shows the current life-limits and the proposed life-limits.

----------------------------------------------------------------------------------------------------------------
                                                                      Proposed life-
                                                                       limit (hours    Current life-limit (hours
                P/N                             Component                time-in-          time-in-service)
                                                                         service)
----------------------------------------------------------------------------------------------------------------
369A7347...........................  Housing, collective stick......             450  Unlimited
369A7348...........................  Tube, collective pitch control.             400  Unlimited
369H7354-3.........................  Tube assembly, collective pitch             600  1,500
                                      (pilot).
369A7809...........................  Tube, collective pitch (co-               1,800  Not Determined
                                      pilot).
369A7820...........................  Housing, collective stick......             450  Unlimited
369H7837...........................  Housing, collective stick......             450  Unlimited
369H7838-3.........................  Tube assembly, collective pitch           1,000  1,500
                                      (co-pilot).
----------------------------------------------------------------------------------------------------------------

This proposal is prompted by fatigue tests that indicate a need for 
shorter service lives for these components. The actions specified by 
the proposed AD are intended to prevent failure of the collective pitch 
control tubes, collective stick housings, and collective pitch tube 
assemblies, which can cause loss of collective pitch control, and 
subsequent loss of control of the helicopter.
    The FAA has reviewed McDonnell Douglas Helicopter Systems Service 
Bulletin SB600N-009, dated February 24, 1998, that lists the service 
numbers to be applied to the four components for the listed aircraft 
serial numbers.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other MDHS Model 600N helicopters of the same type 
design, the proposed AD would require applying serial numbers to 
several life-limited components related to pitch control and removing 
and replacing several components according to new life-limits. The 
actions would be required to be accomplished in accordance with the 
service bulletin described previously.
    The FAA estimates that 16 helicopters of U.S. registry would be 
affected by this proposed AD, that it would take approximately 0.5 work 
hour per helicopter to apply the serial numbers, and that the average 
labor rate is $60 per work hour. Based on these figures, the total cost 
impact of the proposed AD on U.S. operators is estimated to be $480.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) is not a ``significant regulatory action'' under 
Executive Order 12866; (2) is not a ``significant rule'' under the DOT 
Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); 
and (3) if promulgated, 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 copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting 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.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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:

McDonnell Douglas Helicopter Systems: Docket No. 98-SW-16-AD.
    Applicability: Model 600N helicopters, certificated in any 
category.

    Note 1: This AD applies to each helicopter identified in the 
preceding applicability

[[Page 13938]]

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 (e) 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 as indicated, unless accomplished 
previously.
    To prevent failure of the collective pitch control tubes, 
collective stick housings, and collective pitch tube assemblies, 
loss of collective pitch control, and subsequent loss of control of 
the helicopter, accomplish the following:
    (a) On or before reaching 400 hours time-in-service (TIS), apply 
the serial number (S/N) listed in McDonnell Douglas Helicopter 
System Service Bulletin No. 600N-009, dated February 24, 1998 (SB), 
to the two collective stick housings, P/N's 369A7347 and 369A7820; 
the pilot collective pitch control tube, P/N 369A7348; and the co-
pilot collective pitch control tube, P/N 369A7809, in the most 
visible spot for the specified aircraft S/N.
    (b) Remove and replace the following flight control components 
according to the stated life-limits:

------------------------------------------------------------------------
                                                            Life-Limit
             P/N                       Component            (hours TIS)
------------------------------------------------------------------------
1369A7347....................  Housing, collective stick             450
369A7348.....................  Tube, collective pitch                400
                                control (pilot).
369H7354-3...................  Tube assembly, collective             600
                                pitch (pilot).
369A7809.....................  Tube, collective pitch              1,800
                                control (co-pilot).
369A7820.....................  Housing, collective stick             450
369H7837.....................  Housing, collective stick             450
369H7838-3...................  Tube assembly, collective           1,000
                                pitch (co-pilot).
------------------------------------------------------------------------

    (c) Create a component history card or equivalent record in the 
helicopter log and record the helicopter TIS at installation for 
each of the components listed in paragraph (b) of this AD.

    (d) This AD revises the Airworthiness Limitations Section of the 
maintenance manual by reducing the life-limits of the pilot 
collective pitch control tube, the collective stick housings, and 
the collective pitch tube assemblies, and adding the co-pilot 
collective pitch control tube to the Airworthiness Limitations 
section, Component Mandatory Replacement Schedule.

    (e) 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.

    (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.

    Issued in Fort Worth, Texas, on March 16, 1999.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.

[FR Doc. 99-7025 Filed 3-22-99; 8:45 am]

BILLING CODE 4910-13-U