Airworthiness Directives; McDonnell Douglas Helicopter Systems Model 369 (YOH-6A), 369A (OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, and 500N Helicopters

[Federal Register Volume 63, Number 76 (Tuesday, April 21, 1998)]
[Rules and Regulations]
[Pages 19653-19655]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-10461]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 97-SW-52-AD; Amendment 39-10481; AD 98-09-02]
RIN 2120-AA64


Airworthiness Directives; McDonnell Douglas Helicopter Systems 
Model 369 (YOH-6A), 369A (OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 
369HM, 369HS, and 500N Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to McDonnell Douglas Helicopter Systems (MDHS) Model 
369 (YOH-6A), 369A (OH-6A), 369D, 369E, 369F, 369FF, 369H, 369HE, 
369HM, and 369HS helicopters, that currently requires replacing 
overrunning clutch outer races (outer races) having certain heat 
treatment numbers. This amendment requires replacing all outer races 
with airworthy outer races, regardless of the heat treatment number, 
and is applicable to a particular model helicopter that was not 
included in the existing AD (Model 500N helicopters). This amendment is 
prompted by several reports of failed clutch races having heat 
treatment numbers other than the ones addressed in the earlier AD. The 
actions specified by this AD are intended to prevent failure of the 
overrunning clutch assembly outer race, which could result in loss of 
engine drive to the rotor system and a subsequent forced landing.

DATES: Effective May 6, 1998. The incorporation by reference of certain 
publications listed in the regulations is approved by the Director of 
the Federal Register as of May 6, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before June 22, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), Office of the Regional Counsel, Southwest Region, 
Attention: Rules Docket No. 97-SW-52-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. This 
information may be examined at the FAA, Office of the Regional Counsel, 
Southwest Region,

[[Page 19654]]

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. Bruce Conze, Aerospace Engineer, 
FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 
Paramount Boulevard, Lakewood, California 90712, telephone (562) 627-
5261, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION: On April 15, 1988, the FAA issued AD 88-10-
04, Amendment 39-5897 (53 FR 16384, May 9, 1988) to require replacing 
outer races, part number (P/N) 369A5352, serial number (S/N) 0692 
through 0927, with airworthy outer races in accordance with paragraphs 
a through g of the Procedures section of McDonnell Douglas Helicopter 
Company Service Information Notice HN-215/DN-156/EN-46/FN-34, dated 
March 18, 1988. On March 17, 1989, the FAA issued AD 88-10-04 R1, 
Amendment 39-6173 (54 FR 12590, March 28, 1989), to limit the scope of 
AD 88-10-04, to require replacing only outer races, P/N 369A5352, S/N 
0692 through 0927, having heat treatment (HT) number HT 255534. The 
revision to AD 88-10-04 was prompted by a determination that only outer 
races with heat treatment batch numbers ``HT 255534'' had been 
improperly processed during manufacture. That condition, if not 
corrected, could result in failure of the overrunning clutch assembly 
outer race, loss of engine drive to the rotor system and a subsequent 
forced landing.
    Since the issuance of that AD and the revision to the AD, MDHS has 
received additional reports of failed outer races with heat treatment 
numbers other than HT 255534. Additionally, the FAA has determined that 
the AD should also be applicable to the Model 500N helicopter. This 
model was not in existence when the previous AD was issued.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other MDHS Model 369, 369A, 369D, 369E, 369F, 
369FF, 369H, 369HE, 369HM, 369HS, 500N, YOH-6A, and OH-6A, helicopters 
of the same type design, this AD supersedes AD 88-10-04 and the 
revision, AD 88-10-04 R1, to require, within the next 50 hours time-in-
service (TIS), removing the outer races, P/N 369A5352, S/N 0692 through 
S/N 0927, and replacing it with airworthy outer races, P/N 369A5352-5, 
together with a wave washer, P/N W1593-018. The short compliance time 
involved is required because the previously described critical unsafe 
condition can result in a forced landing of the helicopter. Therefore, 
the replacement of parts is required within the next 50 hours TIS, 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 2000 MDHS Model 369, 369A, 369D, 369E, 369F, 
369FF, 369H, 369HE, 369HM, 369HS, 500N, YOH-6A, and OH-6A helicopters 
of U.S. registry will be affected by this AD, that it will take 
approximately 2 hours to accomplish the parts replacement, and that the 
average labor rate is $60 per hour. Required parts will cost 
approximately $1,614 per helicopter. Based on these figures, the total 
cost impact of the AD on U.S. operators is estimated to be $3,468,000.

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. 97-SW-52-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 removing Amendment 39-5897 (53 FR 
16384, May 9, 1988) and Amendment 39-6173 (54 FR 12590, March 28, 
1989), and by adding a new airworthiness directive (AD), Amendment 39-
10481, to read as follows:

AD 98-09-02 McDonnell Douglas Helicopter Systems: Amendment 39-
10481. Docket No. 97-SW-52-AD. Supersedes AD 88-10-04, Amendment 39-
5897 and AD 88-10-04 R1, Amendment 39-6173.

    Applicability: Model 369, 369A, 369D, 369E, 369F, 369FF, 369H, 
369HE, 369HM,

[[Page 19655]]

369HS, 500N, YOH-6A, and OH-6A 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 (c) 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 within 50 hours time-in-service after the 
effective date of this AD, unless accomplished previously.
    To prevent failure of the overrunning clutch assembly outer 
race, which could result in loss of engine drive to the rotor system 
and a subsequent forced landing, accomplish the following:
    (a) Inspect the overrunning clutch outer race, part number (P/N) 
369A5352, to determine its serial number (S/N) in accordance with 
paragraphs A through C of the Accomplishment Instructions contained 
in McDonnell Douglas Helicopter Systems Service Information Notice 
HN-215.2, DN-156.2, EN-46.2, FN-34.2, NN-010, dated March 18, 1997 
(service information notice).
    (b) Remove any overrunning clutch outer race, P/N 369A5352, 
having a S/N of 0692 through 0927, and replace it with an airworthy 
overrunning clutch outer race, P/N 369A5352-5, together with a wave 
washer, P/N W1593-018, in accordance with the service information 
notice.
    (c) 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.

    (d) 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.
    (e) The inspection and replacement shall be done in accordance 
with McDonnell Douglas Helicopter Systems Service Information Notice 
HN-215.2, DN-156.2, EN-46.2, FN-34.2, NN-010, dated April 11, 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 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.
    (f) This amendment becomes effective on May 6, 1998.

    Issued in Fort Worth, Texas, on April 14, 1998.
Eric Bries,
Acting Manager, Rotorcraft Directorate,
Aircraft Certification Service.
[FR Doc. 98-10461 Filed 4-20-98; 8:45 am]
BILLING CODE 4910-13-U

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