[Federal Register Volume 65, Number 96 (Wednesday, May 17, 2000)]
[Rules and Regulations]
[Pages 31259-31260]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-12353]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2000-SW-04-AD; Amendment 39-11730; AD 2000-10-06]
RIN 2120-AA64


Airworthiness Directives; MD Helicopters Inc. Model MD900 
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) for 
MD Helicopters Inc. (MDHI) Model MD900 helicopters. This action 
requires visually inspecting the drive shaft to determine the assembly 
part number 
(P/N) and marking the drive shaft assembly P/N and serial number (S/N) 
on any unmarked drive shaft. This AD also requires creating a component 
history card or equivalent record for certain drive shaft assemblies 
and replacing any drive shaft assembly that has reached its life limit. 
This amendment is prompted by the discovery of several drive shafts 
with no assembly P/N marked on the part, which could result in a drive 
shaft remaining in service past its life limit. The actions specified 
in this AD are intended to prevent failure of the drive shaft due to 
fatigue, which could result in total loss of drive to the main rotor 
hub and subsequent loss of control of the helicopter.

DATES: Effective June 1, 2000.
    Comments for inclusion in the Rules Docket must be received on or 
before July 17, 2000.

ADDRESSES: Submit comments by mail in triplicate to the Federal 
Aviation Administration (FAA), Office of the Regional Counsel, 
Southwest Region, Attention: Rules Docket No. 2000-SW-04-AD, 2601 
Meacham Blvd., Room 663, Fort Worth, Texas 76137. You may also send 
comments electronically to the Rules Docket at the following address: 
[email protected].

FOR FURTHER INFORMATION CONTACT: Elizabeth Bumann, Aviation Safety 
Engineer, FAA, Los Angeles Aircraft Certification Office, Propulsion 
Branch, 3960 Paramount Blvd., Lakewood, California 90712-4137, 
telephone (562) 627-5265, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: This amendment adopts a new AD for MDHI 
Model MD900 helicopters. On February 19, 1999, the FAA issued AD 99-05-
08, Amendment 39-11056 (64 FR 10209, March 3, 1999), for MDHI Model 
MD900 helicopters to establish or reduce life limits for various parts, 
including the drive shaft assembly. That AD was prompted by analysis 
that indicated a need for establishing or reducing life limits to avoid 
fatigue failure of certain parts. Since issuance of that AD, several 
drive shaft assemblies were found without a P/N marked on the drive 
shafts. This could result in the drive shaft remaining in service past 
its life limit since operators may mistakenly use the subassembly P/N 
for determining whether the life limit listed in AD 99-05-08 applies. A 
drive shaft in operation past its life limit could fail due to fatigue. 
This condition, if not corrected, could result in total loss of drive 
to the main rotor hub and subsequent loss of control of the helicopter.
    The FAA has reviewed MDHI Service Bulletin (SB) SB900-062 R1, dated 
December 16, 1999, which describes procedures for visually inspecting 
the drive shaft to determine the assembly 
P/N and marking the drive shaft assembly P/N and serial number (S/N) on 
any unmarked drive shaft. The SB also specifies creating component 
history cards for certain drive shaft assemblies, verifying the life 
limit, and replacing the drive shaft assembly, if necessary.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other MDHI Model MD900 helicopters of the same type 
design, this AD is being issued to prevent failure of the drive shaft. 
This AD requires visually inspecting the drive shaft to determine the 
assembly P/N and marking the drive shaft assembly P/N and S/N on any 
unmarked drive shaft. This AD also requires creating component history 
cards for certain drive shaft assemblies and replacing the drive shaft 
assembly if the drive shaft assembly has reached its life limit. The 
short compliance time involved is required because the previously 
described critical unsafe condition can adversely affect 
controllability of the helicopter. Therefore, the actions of this AD 
are required prior to accumulating 1,450 hours time-in-service (TIS) on 
the drive shaft or before further flight if TIS equals or exceeds 1,450 
hours, 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 this AD will affect 28 helicopters, that it 
will take approximately 2 work hours to accomplish the required 
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 $3,360.

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

[[Page 31260]]

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 mailed 
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. 2000-SW-04-AD.'' The postcard will be date 
stamped and returned to the commenter.
    The regulations adopted herein will not have a substantial direct 
effect 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, it 
is determined that this final rule does not have federalism 
implications under Executive Order 13132.
    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, 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 
to read as follows:
AD 2000-10-06  MD Helicopters Inc.: Amendment 39-11730. Docket No. 
2000-SW-04-AD.

    Applicability: Model MD900 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 
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 (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 prevent failure of the drive shaft due to fatigue, which 
could result in total loss of drive to the main rotor hub and 
subsequent loss of control of the helicopter; accomplish the 
following:
    (a) Before accumulating 1,450 hours time-in-service (TIS), 
visually inspect the drive shaft assembly to determine which part 
number (P/N) is installed. If necessary, remove the drive plate 
cover to access the P/N located on the top edge of the drive shaft 
assembly. If the number of hours TIS on the drive shaft assembly is 
unknown, use the total hours TIS on the helicopter.

    Note 2: Do not confuse the P/N of the drive shaft subassembly, 
P/N 900D2436028-101, 900D2436026-101, or 900D2436030-101 as the P/N 
of the drive shaft assembly.

    (1) If a drive shaft assembly, P/N 900D2436530-101, is 
installed, no further action is required by this AD.
    (2) If a drive shaft assembly other than P/N 900D2436530-101 is 
installed and is not marked with a P/N, before further flight, use 
an indelible ink fine tip marking pen to mark the following 
information on the edge of the drive shaft assembly in line with the 
engraved subassembly number:
    (i) P/N 900D2436528-101 and the serial number (S/N) of the drive 
shaft subassembly if the subassembly is P/N 900D2436028-101. When 
the ink dries, apply a clear coat over the P/N and S/N, or
    (ii) P/N 900D6400004-101 and the S/N of the drive shaft 
subassembly if the subassembly is P/N 900D2436026-101. When the ink 
drives, apply a clear coat over the P/N and S/N.
    (b) For a drive shaft assembly with 1,450 or more hours TIS, 
before further flight, accomplish paragraph (a) of this AD.

    Note 3: MD Helicopters Inc. Service Bulletin SB900-062 R1, dated 
December 16, 1999, applies to the subject of this AD.

    (c) After accomplishing the requirements of paragraph (a) of 
this AD, before further flight, determine the hours TIS of the drive 
shaft assembly. Record the hours TIS on a current or newly created 
component history card or equivalent record. If the drive shaft 
assembly has reached or exceeded its life limit, replace the drive 
shaft assembly with an airworthy drive shaft assembly before further 
flight.

    Note 4: The Airworthiness Limitations Section, section 04, of 
the MD-900 Rotorcraft Maintenance Manual (CSP-900RMM-2), Revision 6, 
dated December 23, 1999, 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 5: 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 
Secs. 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) This amendment becomes effective on June 1, 2000.

    Issued in Fort Worth, Texas, on May 5, 2000.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 00-12353 Filed 5-16-00; 8:45 am]
BILLING CODE 4910-13-U