[Federal Register Volume 62, Number 122 (Wednesday, June 25, 1997)]
[Rules and Regulations]
[Pages 34163-34165]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-16568]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 96-SW-35-AD; Amendment 39-10056; AD 97-13-09]
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 applying specified serial numbers 
to the left and right vertical stabilizer control system (VSCS) 
bellcrank assemblies, the forward and aft deck-fitting assemblies, and 
the mid-forward and mid-aft truss strut assemblies; and establishes new 
life limits for the non-rotating swashplate assembly, the collective 
drive link assembly, and the self-aligning, spherical/slider main rotor 
bearing. This amendment is prompted by additional manufacturer's 
analysis which indicates a need for the reduction of the life limit on 
several parts and the addition of non-serialized parts to the life-
limited parts list. The actions specified in this AD are intended to 
establish a life limit for various parts and reduce the current life 
limit on other parts.

DATES: Effective July 10, 1997.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of July 10, 1997.
    Comments for inclusion in the rules docket must be received on or 
before August 25, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Assistant Chief Counsel, Attention: 
Rules Docket No. 96-SW-35-AD, 2601 Meacham Blvd., Room 663, Fort Worth, 
Texas 76137.

[[Page 34164]]

    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. This 
information may be examined at the FAA, Office of the Assistant Chief 
Counsel, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137; or at 
the Office of the Federal Register, 800 North Capitol Street, NW., 
suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Mr. Greg DiLibero, Aerospace Engineer, 
Airframe Branch, Los Angeles Aircraft Certification Office, FAA, 3960 
Paramount Boulevard, Lakewood, California 90712, telephone (562) 627-
5231, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: This amendment adopts a new AD that is 
applicable to MDHS Model MD-900 helicopters. For Model MD-900 
helicopters with serial numbers (S/N) 0002 through 0012, this action 
requires applying serial numbers to the mid-forward truss assembly, 
part number (P/N) 900F2401200-102, and the forward and aft deck-fitting 
assemblies, P/N 900F2401500-103 and P/N 900F2401600-103. For Model MD-
900 helicopters with S/N 0002 through 0048, this action requires 
applying S/N's to the VSCS bellcrank assemblies, part number (P/N) 
900F2341712-101 or P/N 900FP341712-103, and the mid-aft truss strut 
assembly, P/N 900F2401300-103. For all Model MD-900 helicopters, this 
action reduces the life limits for the non-rotating swashplate 
assembly, P/N 900C2010192-105, -107, -109, or -111, from 8,300 hours 
time-in-service (TIS) to 554 hours TIS; the collective drive link 
assembly, P/N 900C2010207-101, from 3,900 hours TIS to 1,480 hours TIS; 
the self-aligning, spherical/slider main rotor bearing, P/N 
900C3010042-103, from 2,100 hours TIS to 480 hours TIS; and the VSCS 
bellcrank assembly, P/N 900FP341712-103, and bellcrank arm, P/N 
900F2341713-101, (used in the VSCS bellcrank assembly, P/N 900F2341712-
101) from no life limit to 2,700 hours TIS. This amendment is prompted 
by additional manufacturer's analysis which indicates a need for the 
reduction of the life limit on several parts and the addition of non-
serialized parts to the life-limited parts list. The actions specified 
in this AD are intended to establish a life limit for various parts and 
reduce the current life limit on other parts.
    The FAA has reviewed McDonnell Douglas Helicopter Systems Service 
Bulletin No. SB900-039, Revision 2, dated March 12, 1997, which 
describes procedures for applying the serial numbers to the life-
limited 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 is being issued to establish a life limit for 
various parts and reduce the current life limit on other parts. This AD 
requires applying specified serial numbers to the left and right VSCS 
bellcrank assemblies, P/N 900F2341712-101 or P/N 900FP341712-103; to 
the mid-forward and mid-aft truss strut assemblies, P/N 900F2401200-102 
and P/N 900F2401300-103; and to the forward and aft deck-fitting 
assemblies, P/N 900F2401500-103 and P/N 900F2401600-103. This AD also 
reduces the life limits for the non-rotating swashplate assembly, P/N 
900C2010192-105, -107, -109, or -111, from 8,300 hours TIS to 554 hours 
TIS; the collective drive link assembly, P/N 900C2010207-101, from 
3,900 hours TIS to 1,480 hours TIS; the self-aligning, spherical/slider 
main rotor bearing, P/N 900C3010042-103, from 2,100 hours TIS to 480 
hours TIS; and 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) from no life limit to 2,700 hours TIS. 
The serial numbers for the VSCS bellcrank assemblies, the mid-forward 
and mid-aft truss assemblies, and the forward and aft deck-fitting 
assemblies are specified in and are required to be accomplished in 
accordance with the service bulletin described previously. The serial 
numbers specified in the service bulletin shall be applied adjacent to 
the existing P/N's. Some Model MD-900 helicopters that are currently in 
service are equipped with helicopter control system parts that are 
approaching the new, lower life limits. Failure of any of these parts 
could result in loss of control of the helicopter. Due to the 
criticality of the components of the helicopter control system, this AD 
is being issued in the form of an immediately-adopted final rule with 
request for comments.
    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. 96-SW-35-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

[[Page 34165]]

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 
to read as follows:

AD 97-13-09  McDonnell Douglas Helicopter Systems: Amendment 39-
10056. Docket No. 96-SW-35-AD.

    Applicability: Model 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 a life limit for various parts and reduce the 
current life limit on other parts, accomplish the following:
    (a) Within 100 hours time-in-service (TIS) after the effective 
date of this AD:
    (1) For Model MD-900 helicopters with serial number (S/N) 0002 
through 0012, apply serial numbers to the mid-forward truss 
assembly, P/N 900F2401200-102, and the forward and aft deck-fitting 
assemblies, P/N 900F2401500-103 and P/N 900F2401600-103.
    (2) For Model MD-900 helicopters with S/N 0002 through 0048, 
apply S/N's to the left and right vertical stabilizer control system 
(VSCS) bellcrank assemblies, P/N 900F2341712-101 or P/N 900FP341712-
103, and the mid-aft truss strut assembly, P/N 900F2401300-103.
    (3) Apply the S/N's as specified in paragraphs (a)(1) and (a)(2) 
of this AD adjacent to the existing P/N's, and in accordance with 
the Accomplishment Instructions of McDonnell Douglas Helicopter 
Systems Service Bulletin No. SB900-039, Revision 2, dated March 12, 
1997.
    (b) Before further flight, remove from service:
    (1) The non-rotating swashplate assembly, P/N 900C2010192-105, -
107, -109, or -111, on or before attaining 554 hours TIS.
    (2) The collective drive link assembly, P/N 900C2010207-101, on 
or before attaining 1,480 hours TIS.
    (3) The self-aligning, spherical/slider main rotor bearing, P/N 
900C3010042-103, on or before attaining 480 hours TIS.
    (4) The VSCS bellcrank assembly, P/N 900FP341712-103, and 
bellcrank arm, P/N 900F2341713-101 (used in the VSCS bellcrank 
assembly, P/N 900F2341712-101), on or before attaining 2,700 hours 
TIS.
    (c) This AD revises the Airworthiness Limitations section of the 
maintenance manual by establishing new retirement lives for these 
parts.
    (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 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.

    (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 modification shall be done in accordance with McDonnell 
Douglas Helicopter Systems Bulletin No. SB900-039, Revision 2, dated 
March 12, 1997. 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. 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.
    (g) This amendment becomes effective on July 10, 1997.

    Issued in Fort Worth, Texas, on June 17, 1997.
Eric Bries,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 97-16568 Filed 6-24-97; 8:45 am]
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