[Federal Register Volume 64, Number 41 (Wednesday, March 3, 1999)]
[Rules and Regulations]
[Pages 10209-10211]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-5038]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-34-AD; Amendment 39-11056; AD 99-05-08]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Helicopter Systems 
Model MD-900 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 MD-
900 helicopters. This action requires establishing or reducing certain 
life limits, applying serial numbers (S/N's), determining hours time-
in-service (TIS), and creating component history cards or equivalent 
records for various parts. This amendment is prompted by analysis that 
indicates a need for establishing or reducing life limits to avoid 
fatigue failure of certain parts. The actions specified by this AD are 
intended to apply appropriate life limits to various parts.

DATES: Effective March 18, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of March 18, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before May 3, 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-34-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. 
530/B11, 5000 E. McDowell Road, Mesa, Arizona 85205-9797, telephone 1-
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; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Greg DiLibero, Aerospace Engineer, 
Aircraft Certification Office, Airframe Branch, FAA, 3960 Paramount 
Blvd., Lakewood, CA 90712, telephone 562-627-5231, fax number 562-627-
5210.

SUPPLEMENTARY INFORMATION: This amendment adopts a new AD that is 
applicable to MDHS Model MD-900 helicopters. Analysis indicates a need 
for establishing life limits, applying S/N's, determining hours time-
in-service (TIS), and creating component history cards or equivalent 
records for various parts. This AD requires (1) establishing a life 
limit for the main rotor drive shafts, P/N's 900D2436528-101, 
900D6400004-101, 900DF436026-101, and 900DF400100-101 to 1,450 hours 
TIS; reducing the life limit for the NOTAR pitch plate assembly, P/N 
900R2443000-105, from 10,000 to 3,527 hours TIS; and establishing a 
life limit for the spherical/slider main rotor bearings, P/N 
900C3010042-105, of 12,807 hours TIS; (2) determining the hours TIS and 
creating a component history card or equivalent record for the NOTAR 
tension-torsion fan blade strap assembly, P/N 500N5311-5 or 
900R3442009-101, and NOTAR pitch plate assembly, P/N 900R2443000-105; 
and (3) applying appropriate S/N's to the NOTAR pitch plate assembly, 
P/N 900R2443000-105, on each helicopter S/N's 900-00002 through 900-
00057.

[[Page 10210]]

This amendment is prompted by the FAA's determination, after reviewing 
the manufacturer's analysis, that a reduction in life limits is 
necessary. The actions specified in this AD are intended to establish 
appropriate life limits for certain parts.
    The FAA has reviewed MDHS Service Bulletin (SB) 900-058R1, dated 
July 6, 1998, which provides procedures for applying life limits and S/
N's to certain parts.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other MDHS Model MD-900 helicopters of the same 
type design, this AD requires reducing or establishing life limits, 
adding S/N's, determining hours TIS, and creating component history 
cards or equivalent records for various parts. The actions are required 
to be accomplished in accordance with the SB previously described. The 
short compliance time is required because the previously described 
critical unsafe condition can adversely affect the controllability and 
structural integrity of the helicopter. Therefore, establishing 
appropriate life limits for various parts is required because several 
helicopters are approaching life limits, 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 27 helicopters will be affected by this 
proposed AD, that it will take approximately 2.5 work hours to add S/
N's to the parts and create component history cards or equivalent 
records, and that the average labor rate is $60 per work hour. Based on 
these figures, the total cost impact of the AD on U.S. operators is 
estimated to be $4,050 assuming no parts will be replaced as a result 
of this AD.

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. 98-SW-34-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 
(AD) to read as follows:

AD 99-05-08  McDonnell Douglas Helicopter Systems: Amendment 39-
11056. Docket No. 98-SW-34-AD.

    Applicability: McDonnell Douglas Helicopter Systems (MDHS) MD-
900 helicopters, 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 establish life limits and place a serial number (S/N) on 
various critical parts, accomplish the following:
    (a) Remove from service:
    (1) Main rotor drive shaft, part number (P/N) 900D2436528-101, 
900D6400004-101, 900DF436026-101, or 900DF400100-101, on or before 
attaining 1,450 hours time-in-service (TIS).
    (2) NOTAR pitch plate assembly, P/N 900R2443000-105, on or 
before attaining 3,527 hours TIS.
    (3) Spherical/slider main rotor bearing, P/N 900C3010042-105, on 
or before attaining 12,807 hours TIS.
    (b) On or before attaining 600 hours TIS after the effective 
date of this AD or by June 30, 1999, whichever occurs first,
    (1) Apply the specified S/N to the pitch plate assembly, P/N 
900R2443000-105, on each Model MD-900 helicopter with S/N's 900-
00002 through 900-00057, as specified in MDHS Service Bulletin SB 
900-058R1, dated July 6, 1998.
    (2) Determine the hours TIS and create a component history card 
or equivalent record for the NOTAR tension-torsion fan blade strap 
assembly, P/N 500N5311-5 or 900R3442009-101, and NOTAR pitch plate 
assembly, P/N 900R2443000-105.

[[Page 10211]]

    (c) This AD revises the Airworthiness Limitations Section of the 
MD-900 Maintenance Manual by establishing new retirement lives and 
adding parts to the life-limited parts list.

    Note 2: The Airworthiness Limitations Section of the MD-900 
Rotorcraft Maintenance Manual, Reissue 1, Revision 2, dated July 24, 
1998, pertains to the subject of this AD.

    (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 3: Information concerning the existence of approved 
alternative methods of compliance with this AD, if any, may be 
obtained from the Rotorcraft Standards Staff.

    (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 corrective action in paragraph (b)(1) shall be 
accomplished in accordance with McDonnell Douglas Helicopter Systems 
Service Bulletin SB 900-058R1, dated July 6, 1998. 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. 530/B11, 5000 E. McDowell 
Road, Mesa, Arizona 85205-9797, telephone 1-800-388-3378, 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 March 18, 1999.

    Issued in Fort Worth, Texas, on February 19, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-5038 Filed 3-2-99; 8:45 am]
BILLING CODE 4910-13-U