[Federal Register Volume 64, Number 81 (Wednesday, April 28, 1999)]
[Proposed Rules]
[Pages 22818-22819]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-10619]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-42-AD]


Airworthiness Directives; McDonnell Douglas Helicopter Systems 
Model MD-900 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to supersede an existing airworthiness 
directive (AD), applicable to McDonnell Douglas Helicopter Systems 
(MDHS) Model MD-900 helicopters, that currently requires applying 
specified serial numbers and establishing life limits for certain 
parts. This proposal is prompted by additional analysis that supports 
an increase in the life limits of certain parts. The actions specified 
by this AD are intended to increase the life limits for various parts.

DATES: Comments must be received on or before June 28, 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-42-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas. Comments may be inspected at this location between 
9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal 
holidays.

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:

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 
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-42-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-42-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.

Discussion

    On June 17, 1997, the FAA issued AD 97-13-09, Amendment 39-10056 
(62 FR 34163), applicable to MDHS Model MD-900 helicopters. The AD 
required applying a specified serial number (S/N) to the following 
parts: For helicopters with S/N 0002 through 0012, to the mid-forward 
truss assembly, Part Number 
(P/N) 900F2401200-102, and to the forward and aft deck fitting 
assemblies, P/N 900F2401500-103 and 900F2401600-103; for helicopters 
with S/N 0002 through 0048, to the vertical stabilizer control system 
(VSCS) bellcrank assemblies, P/N 900F2341712-101, 900FP341712-103, and 
to the mid-aft truss strut assembly, P/N 900F2401300-103. The AD 
required reducing the life limits for the nonrotating swashplate 
assembly, P/N 900C2010192-105, -107, -109, and -111, to 554 hours time-
in-service (TIS); the collective drive link assembly, P/N 900C2010207-
101, to 1,480 hours TIS; and the self-aligning, spherical/slider main 
rotor bearing P/N 900C3010042-103, to 480 hours TIS. The AD required 
establishing life limits for the VSCS bellcrank assembly, P/N 
900FP341712-103, and the bellcrank arm, P/N 900F2341713-101 (used in 
the VSCS bellcrank assembly, P/N 900F2341712-101), of 2,700 hours TIS. 
That action was prompted by the need to establish life limits for 
various parts and to reduce the life limits on other parts to prevent 
fatigue failure of those parts and subsequent loss of control of the 
helicopter.
    Since the issuance of that AD, additional analysis supports an 
increase in the life limits for certain parts. The action in that AD of 
applying S/N's to certain parts and establishing a life limit for the 
VSCS bellcrank assembly, P/N 900FP341712-103, of 2,700 hours TIS 
remains the same except that the correct P/N for the bellcrank arm is 
P/N 900F2341712-101. This document proposes increasing the life limits 
for the nonrotating swashplate, P/N 900C2010192-105, -107, -109, and -
111, to 1,800 hours TIS; the collective drive link assembly, P/N 
900C2010207-101, to 3,307 hours TIS; and the self-aligning, spherical/
slider main rotor bearing, P/N 900C3010042-103, to 2,030 hours TIS. The 
new life limits are based on modified fatigue spectrums, fatigue tests, 
and flight strain data. The actions specified in this proposal would 
increase the life limits for various parts.
    Since an unsafe condition has been identified that is likely to 
exist or

[[Page 22819]]

develop on other MDHS Model MD-900 helicopters of the same type design, 
the proposed AD would supersede AD 97-13-09 to increase the life limits 
for certain parts and correct the P/N for the bellcrank, and, as in AD 
97-13-09, require applying S/N's to certain parts and establishing a 
life limit for the VSCS bellcrank assembly,
    The FAA estimates that 27 helicopters would be affected by this 
proposed AD, that it would take approximately 2.5 work hours per 
helicopter to accomplish the proposed actions, 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.
    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 removing Amendment 39-10056 (62 FR 
34163, June 25, 1997), and by adding a new airworthiness directive (AD) 
to read as follows:

McDonnell Douglas Helicopter Systems: Docket No. 98-SW-42-AD. 
Supersedes AD 97-13-09, Amendment 39-10056, Docket No. 96-SW-35-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 request approval for an 
alternative method of compliance in accordance with paragraph (d) 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 establish appropriate life limits for various parts, 
accomplish the following:
    (a) On or before attaining the following life limits, remove 
from service:
    (1) The nonrotating swashplate assembly, part number (P/N) 
900C2010192-105, -107, -109, or -111, on or before 1,800 hours TIS.
    (2) The collective drive link assembly, 
P/N 900C2010207-101, on or before 3,307 hours TIS.
    (3) The self-aligning, spherical/slider main rotor bearing, P/N 
900C3010042-103, on or before 2,030 hours TIS.
    (4) The vertical stabilizer control system (VSCS) bellcrank 
assembly, P/N 900FP341712-103, and bellcrank arm, P/N 900F2341712-
101, on or before 2,700 hours TIS.
    (b) On or before 100 hours TIS after July 10, 1997, or before 
October 31, 1999, whichever occurs first:
    (1) For Model MD-900 helicopters with serial numbers (S/N) 900-
00002 through 900-00012, apply the appropriate S/N to the mid-
forward truss assembly, P/N 900F2401200-102, and the forward and aft 
deck-fitting assemblies, P/N 900F2401500-103 and 900F2401600-103.
    (2) For Model MD-900 helicopters with 
S/N 900-00002 through 900-00048, apply
S/N to the left and right VSCS bellcrank assemblies, P/N 
900F2341712-101 and 900FP341712-103, and the mid-aft truss strut 
assembly, P/N 900F2401300-103.
    (3) Apply the S/N as specified in paragraphs (b)(1) and (b)(2) 
of this AD adjacent to the existing P/N in accordance with the 
Accomplishment Instructions of MDHS Service Bulletin No. 900-039, 
Revision 2, dated March 12, 1997.
    (c) This AD revises the Airworthiness Limitations Section of the 
MD-900 Maintenance Manual by increasing the retirement lives for 
certain parts.

    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. 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 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.

    Issued in Fort Worth, Texas, on April 21, 1999.
Henry A. Armstrong,
Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-10619 Filed 4-27-99; 8:45 am]
BILLING CODE 4910-13-U