[Federal Register Volume 64, Number 101 (Wednesday, May 26, 1999)]
[Rules and Regulations]
[Pages 28353-28355]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-13320]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-SW-47-AD; Amendment 39-11182; AD 99-11-11]
RIN 2120-AA64


Airworthiness Directives; Eurocopter France Model SA-365N, N1, 
N2, N3, and SA-366G1 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 Eurocopter France Model SA-365N, N1 and SA-366G1 
helicopters, that currently requires repetitive inspections of the main 
gearbox (MGB) magnetic chip plug and oil filter if certain part number/
modification level MGB's are installed. This new action expands the 
helicopter model and MGB applicability to include the SA-365N2 and N3 
helicopters and all variants of the MGB. It also requires installing a 
MGB planetary gear shaft (gear shaft) vibration level monitoring unit 
(VLMU); inserting procedures into the Rotorcraft Flight Manual (RFM) 
for a preflight vibration check using the VLMU and inserting a related 
emergency procedure and limitation for an inoperative VLMU into the 
RFM. This action is prompted by two occurrences of gear shaft cracks. 
The actions specified by this AD are intended to detect cracks in the 
MGB planetary gear shaft, which could lead to failure of the MGB and 
subsequent loss of control of the helicopter.

DATES: Effective June 10, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of June 10, 1999.
    Comments for inclusion in the Rules Docket must be received on or 
before July 26, 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-47-AD, 2601 Meacham Blvd., Room 663, 
Fort Worth, Texas 76137.
    The service information referenced in this AD may be obtained from 
American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, Texas 
75053-4005, telephone (972) 641-3460, fax (972) 641-3527. This 
information may be examined at the FAA, Office of the Regional Counsel, 
Southwest Region, 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: Shep Blackman, Aerospace Engineer, 
Rotorcraft Standards Staff, Rotorcraft Directorate, FAA, 2601 Meacham 
Blvd., Fort Worth, Texas 76137, telephone (817) 222-5296, fax (817) 
222-5961.

SUPPLEMENTARY INFORMATION: The FAA issued Priority Letter AD 97-15-15 
on July 18, 1997, prompted by two occurrences of MGB planetary gear 
shaft cracks, AD 97-15-15 was published in the Federal Register on 
February 6, 1998 (63 FR 6069). It requires that the magnetic chip plug 
on any MGB that was not modified in accordance with MOD 077244 be 
inspected after every flight and the MGB oil filter be inspected after 
the last flight of each day or at intervals not to exceed 12 hours 
time-in-service (TIS). The presence of any ferrous chips or any reports 
of abnormal vibrations by the flight crew requires a MGB ground 
vibration evaluation before further flight. Eurocopter France has 
recently advised the FAA that the potential for planetary gear shaft 
cracks exists for all MGB variants, regardless of modification level, 
currently authorized for installation on FAA-certified Model SA-365/366 
helicopters. The temporary installation of the VLMU enables the flight 
crew to more easily and accurately assess the vibration level of the 
MGB prior to each flight. The manufacturer is pursuing a redesign of 
the affected MGB that will probably result in a mandatory

[[Page 28354]]

modification of the MGB and constitute a terminating action for the 
requirements of this AD. It is anticipated that after the modification 
is accomplished, the VLMU will no longer be required.
    The Direction Generale de L'Aviation Civile (DGAC), which is the 
airworthiness authority for France, has notified the FAA that an unsafe 
condition may exist on Eurocopter France Model SA-365N, N1, N2, and N3, 
and SA-366G1 helicopters. The DGAC advises that, based on two reports 
of cracks detected on the gear shaft, an AD is necessary to mandate the 
installation and the utilization of an MGB vibration level unit that 
detects vibrations at the shaft rotation frequency and indicates the 
potential for a crack in the gear shaft.
    Eurocopter France has issued Eurocopter AS 365 Service Bulletin No. 
31.00.03, applicable to Model SA-365N, N1, N2, and N3, helicopters; and 
Eurocopter SA 366 Service Bulletin No. 31.01, applicable to Model SA-
366G1 helicopters, both dated June 23, 1998. These service bulletins 
provide for the installation of a VLMU that enables a ground check for 
vibrations amplitude at the shaft rotational frequency and provides an 
indication to the pilot when the amplitude of vibration reaches a level 
that could indicate the existence of a crack in the gear shaft. The 
service bulletins also provide for checks of the MGB chip plug and oil 
filter, and measurements of on-ground vibration levels if the VLMU 
becomes inoperative. The DGAC classified these service bulletins as 
mandatory and issued AD 98-324-045(A), applicable to Model 365N 
helicopters, and AD 98-323-023(A), applicable to Model 366 helicopters, 
both dated August 12, 1998, in order to assure the continued 
airworthiness of these helicopters in France.
    These helicopter models are manufactured in France and are type 
certificated for operation in the United States under the provisions of 
Sec. 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the 
applicable bilateral airworthiness agreement. Pursuant to this 
bilateral airworthiness agreement, the DGAC has kept the FAA informed 
of the situation described above. The FAA has examined the findings of 
the DGAC, reviewed all available information, and determined that AD 
action is necessary for products of this type design that are 
certificated for operation in the United States.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other Eurocopter France SA-365N, N1, N2, and N3, 
and SA-366G1 helicopters of the same type design registered in the 
United States, this AD is being issued to detect cracks in the MGB 
planetary gear shaft, which could lead to failure of the MGB and 
subsequent loss of control of the helicopter. This AD requires 
installing a MGB VLMU to enable a preflight MGB vibration check, 
revising the RFM normal, emergency and limitations sections, and if the 
VLMU becomes inoperative, inspecting the MGB magnetic plug after every 
flight and the oil filter each day in which flights are conducted (not 
to exceed 12 hours time-in-service between inspections). The actions 
are required to be accomplished in accordance with the applicable 
service bulletins described previously. If metallic particles are found 
on the magnetic plug or oil filter, drive system ground vibration 
measurements must be conducted. The short compliance time involved is 
required because the previously described critical unsafe condition can 
adversely affect the structural integrity of the helicopter. Therefore, 
the actions are required within 25 hours time-in-service 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 26 helicopters will be affected by this AD, 
that it will take approximately 10 work hours to install the VLMU, and 
that the average labor rate is $60 per work hour. The manufacturer has 
stated that required parts are available at no cost. Based on these 
figures, the total cost impact of the AD on U.S. operators is estimated 
to be $15,600.

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-47-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

[[Page 28355]]

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 99-11-11  Eurocopter France: Amendment 39-11182. Docket No. 98-
SW-47-AD. Supersedes AD 97-15-15, Amendment 39-10313, Docket No. 97-
SW-23-AD.
    Applicability: Model SA-365N, N1, N2, and N3 helicopters, serial 
numbers up to and including 6538, and SA-366G1 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 detect cracks in the main gearbox (MGB) planetary gear shaft 
(shaft), which could lead to failure of the MGB and subsequent loss 
of control of the helicopter, accomplish the following:
    (a) Within 25 hours time-in-service, install a MGB shaft 
vibration level monitoring unit (VLMU), in accordance with paragraph 
B. of the Accomplishment Instructions of either Eurocopter AS 365 
Service Bulletin No. 31.00.03, applicable to Model SA-365N, N1, N2, 
and N3 helicopters; or Eurocopter SA 366 Service Bulletin No. 31.01, 
applicable to Model SA-366G1 helicopters, both dated June 23, 1998 
(SB's).
    (b) Before further flight, accomplish the following:
    (1) Insert paragraphs 2D1), 2D2), and 2D3) of the SB's into the 
applicable Rotorcraft Flight Manual post-start normal procedures 
section.
    (2) Insert the following statement in the Emergency Procedures 
section of the applicable Rotorcraft Flight Manual: ``If vertical 
vibrations at approximately 4/rev frequency are detected, reduce 
power, land as soon as practicable, and perform a VLMU vibration 
level check.''
    (3) Insert the following statement into the Limitations section 
of the applicable Rotorcraft Flight Manual: ``If the VLMU becomes 
inoperative, it must be returned to service within 30 calendar days 
or the helicopter must be grounded until such repairs are made.''
    (c) If the VLMU becomes inoperative, inspect the MGB magnetic 
plug; it must be inspected before every flight and inspect the MGB 
oil filter each day in which flights are conducted or at intervals 
not to exceed 12 hours time-in-service, whichever occurs first. When 
metallic particles are found on either the magnetic plug or the oil 
filter element, conduct drive system ground vibration measurements 
before further flight.
    (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, Rotorcraft Standards Staff, 
Rotorcraft Directorate, FAA. Operators shall submit their requests 
through a FAA Principal Maintenance Inspector, who may concur or 
comment and then send it to the Manager, Rotorcraft Standards Staff.

    Note 2: 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 actions shall be done in accordance with the Eurocopter 
AS 365 Service Bulletin No. 31.00.03, or Eurocopter SA 366 Service 
Bulletin No. 31.01, both dated June 23, 1998, as applicable. 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 American Eurocopter Corporation, 
2701 Forum Drive, Grand Prairie, Texas 75053-4005, telephone (972) 
641-3460, fax (972) 641-3527. Copies may be inspected at the FAA, 
Office of the Regional Counsel, Southwest Region, 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.
    (g) This amendment becomes effective on June 10, 1999.

    Note 3: The subject of this AD is addressed in Direction 
Generale de L'Aviation Civile (France) AD 98-324-045(A), applicable 
to Model SA-365N helicopters, and AD 98-323-023(A), applicable to 
Model SA-366 helicopters, both dated August 12, 1998.

    Issued in Fort Worth, Texas, on May 18, 1999.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 99-13320 Filed 5-25-99; 8:45 am]
BILLING CODE 4910-13-U