[Federal Register Volume 71, Number 84 (Tuesday, May 2, 2006)]
[Proposed Rules]
[Pages 25789-25793]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 06-4107]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18850; Directorate Identifier 2004-SW-19-AD]
RIN 2120-AA64


Airworthiness Directives; Eurocopter France Model AS-365N2, AS 
365 N3, EC 155B, EC155B1, SA-365N, N1, and SA-366G1 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes to revise an existing airworthiness 
directive (AD) for Eurocopter France (Eurocopter) Model AS-365N2, AS 
365 N3, EC 155B, EC155B1, SA-365N, N1, and SA-366G1 helicopters. That 
AD currently requires inspecting the main gearbox (MGB) base plate for 
a crack and replacing the MGB if a crack is found. This action would 
increase the time intervals for inspecting the MGB base plate. This 
action would also include minor editorial changes throughout the AD. 
This proposal is prompted by crack growth tests that indicate that the 
inspection intervals can be increased without affecting safety. The 
actions specified by the proposed AD are intended to detect a crack in 
an MGB base plate and prevent failure of one of the MGB attachment 
points to the frame, which could result in severe vibration and 
subsequent loss of control of the helicopter.

DATES: Comments must be received by July 3, 2006.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD:
     DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically;
     Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically;
     Mail: Docket Management Facility; U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590;
     Fax: 202-493-2251; or
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    You may get the service information identified in this proposed AD 
from American Eurocopter Corporation, 2701 Forum Drive, Grand Prairie, 
Texas

[[Page 25790]]

75053-4005, telephone (972) 641-3460, fax (972) 641-3527.
    You may examine the comments to this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: Ed Cuevas, Aviation Safety Engineer, 
FAA, Rotorcraft Directorate, Safety Management Group, Fort Worth, Texas 
76193-0111, telephone (817) 222-5355, fax (817) 222-5961.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written data, views, or arguments 
regarding this proposed AD. Send your comments to the address listed 
under the caption ADDRESSES. Include the docket number ``FAA-2004-
18850, Directorate Identifier 2004-SW-19-AD'' at the beginning of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the proposed AD. We will 
consider all comments received by the closing date and may amend the 
proposed AD in light of those comments.
    We will post all comments we receive, without change, to  http://dms.dot.gov, including any personal information you provide. We will 
also post a report summarizing each substantive verbal contact with FAA 
personnel concerning this proposed rulemaking. Using the search 
function of our docket Web site, you can find and read the comments to 
any of our dockets, including the name of the individual who sent or 
signed the comment. You may review the DOT's complete Privacy Act 
Statement in the Federal Register published on April 11, 2000 (65 FR 
19477-78) or you may visit http://dms.dot.gov.

Examining the Docket

    You may examine the docket that contains the proposed AD, any 
comments, and other information in person at the Docket Management 
System (DMS) Docket Office between 9 a.m. and 5 p.m., Monday through 
Friday, except Federal holidays. The Docket Office (telephone 1-800-
647-5227) is located at the plaza level of the Department of 
Transportation NASSIF Building in Room PL-401 at 400 Seventh Street, 
SW., Washington, DC. Comments will be available in the AD docket 
shortly after the DMS receives them.

Discussion

    On August 4, 2004, we issued AD 2004-16-15, Amendment 39-13771 (69 
FR 51358, August 19, 2004), to require visually inspecting the MGB for 
a crack in the MGB base plate, part number (P/N) 366A32-1062-03 or P/N 
366A32-1062-06, close to the attachment hole using a 10x or higher 
magnifying glass. Stripping paint from the inspection area is also 
required, but only before the initial inspection. That action was 
prompted by the discovery of a crack in the MGB base plate of an MGB 
installed in a Model AS-365 N2 helicopter. The crack was located very 
close to the attachment points of one of the laminated pads, and it 
propagated to the inside of the MGB base plate and then continued into 
the MGB casing. That condition, if not detected, could result in 
failure of one of the MGB attachment points to the frame, which could 
result in severe vibration and subsequent loss of control of the 
helicopter.
    When we issued AD 2004-16-15, the cause of crack in the MGB base 
plate was still under investigation; therefore, we considered the 
previously issued AD to be interim action until the cause of the crack 
could be determined. The cause of the crack is still under 
investigation. However, since issuing AD 2004-16-15, crack growth tests 
have shown that the inspection intervals can be increased without 
affecting safety. We made this determination after Eurocopter conducted 
crack growth testing in laboratory bench tests. A cracked base plate 
was loaded with an alternating torque to simulate flight loading and 
cycles. Crack propagation speed was measured and assessed over a longer 
duration than the initial inspection interval and this resulted in 
extending the inspection intervals. The first inspection interval was 
determined using crack striations, which was a quick and conservative 
method used to ensure airworthiness and allow for timely issuance of 
service information by the manufacturer. Based on this additional 
information, we are proposing to increase the time intervals between 
each required inspection, however, the actions specified by this 
proposed AD are still considered to be interim. We are also proposing 
to include minor editorial changes in the AD.
    The Direction G[eacute]n[eacute]rale de L'Aviation Civile (DGAC), 
the airworthiness authority for France, notified the FAA that an unsafe 
condition may exist on Eurocopter Model SA 365N, N1, SA 366 G1, AS 365 
N2, N3, EC 155 B, and B1 helicopters, all serial numbers. The DGAC 
advises that a crack was detected in the MGB base plate of an AS 365 N2 
helicopter. The crack was detected in the MGB base plate web, very 
close to the attachment of one of the laminated pads, and runs to the 
inside of the MGB base plate and then on the MGB casing. In time, the 
growth of the crack may lead to the loss of the transfer of rotor 
torque to the rotorcraft structure.
    Eurocopter has issued Alert Service Bulletin (ASB) No. 05.00.45 for 
Model AS365 N, N1, N2, and N3 helicopters; ASB No. 05.29 for Model 
SA366 G1 helicopters; and ASB No. 05A005 for Model EC155 B and B1 
helicopters. All of the ASBs are dated November 8, 2004 and supersede 
previously issued Eurocopter Alert Telex No. 05.00.45, No. 05.29, and 
No. 05A005, all dated February 5, 2004. The ASBs specify the same 
actions as the alert telexes--visually inspecting the MGB base plate 
for the absence of cracks, using a 10x magnifying glass to facilitate 
the crack inspection, and, if in doubt about the existence of a crack, 
inspecting for a crack using a dye-penetrant crack detection 
inspection. However, for the Eurocopter Model AS365 N, N1, N2, N3, and 
SA366 G1 helicopters, the 15-flying hour check for the MGB base plate 
that is specified in the alert telexes is replaced with check intervals 
not to exceed 55 flying hours. For the EC155 B and B1 helicopters, the 
check after the last flight of each day and without exceeding a 9-
flying hour check interval is replaced with check intervals not to 
exceed 15 flying hours.
    The DGAC classified ASB Nos. 05.00.45, 05.29, and 05A005 as 
mandatory and issued AD No. F-2004-023 R1, dated November 24, 2004, to 
ensure 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 
14 CFR 21.29 and the applicable bilateral agreement. Pursuant to the 
applicable bilateral agreement, the DGAC has kept the FAA informed of 
the situation described above. We have examined the findings of the 
DGAC, reviewed all available information, and determined that AD action 
is necessary for products of these type designs that are certificated 
for operation in the United States.
    This previously described unsafe condition is likely to exist or 
develop on other helicopters of the same type designs. Therefore, the 
proposed AD would revise AD 2004-16-15 to require initial and 
repetitive inspections of the MGB base plate for cracking at various 
short time intervals. The time intervals for doing the inspections 
would be increased from what is required in the existing AD and are 
dependant on the helicopter model and the number of cycles on the MGB 
and whether the MGB has ever been overhauled or repaired.

[[Page 25791]]

    We estimate that this proposed AD would affect 142 helicopters of 
U.S. registry. The initial inspection would take about 0.5 work hour 
and each recurring inspection would take about 0.25 work hour. 
Replacing the MGB, if necessary, would take about 4 work hours. The 
average labor rate would be $65 per work hour. It would cost 
approximately $25,000 to repair a cracked MGB base plate. Based on 
these figures, the total estimated cost impact of the AD on U.S. 
operators would be $56,249, assuming that each of the 135 Model AS 365 
and SA 366 helicopters are inspected 11 times (the initial inspection 
plus 10 recurring inspections) and each of the 7 Model EC 155 
helicopters are inspected 40 times (the initial inspection plus 39 
recurring inspections), and one cracked MGB base plate is found 
requiring the repair and replacement of one MGB. This estimate also 
assumes that a replacement MGB would not need to be purchased while a 
previously-installed MGB is being repaired.

Regulatory Findings

    We have determined that this proposed AD would not have federalism 
implications under Executive Order 13132. Additionally, this proposed 
AD would 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.
    For the reasons discussed above, I certify that the 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. 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.
    We prepared a draft economic evaluation of the estimated costs to 
comply with this proposed AD. See the DMS to examine the draft economic 
evaluation.

Authority for This Rulemaking

    Title 49 of the United States Code specifies the FAA's authority to 
issue rules on aviation safety. Subtitle I, section 106, describes the 
authority of the FAA Administrator. Subtitle VII, Aviation Programs, 
describes in more detail the scope of the Agency's authority.
    We are issuing this rulemaking under the authority described in 
subtitle VII, part A, subpart III, section 44701, ``General 
requirements.'' Under that section, Congress charges the FAA with 
promoting safe flight of civil aircraft in air commerce by prescribing 
regulations for practices, methods, and procedures the Administrator 
finds necessary for safety in air commerce. This regulation is within 
the scope of that authority because it addresses an unsafe condition 
that is likely to exist or develop on products identified in this 
rulemaking action.

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 39-13771 (69 FR 
51358, August 19, 2004), and by adding a new airworthiness directive 
(AD), to read as follows:

Eurocopter France: Docket No. FAA-2004-18850; Directorate Identifier 
2004-SW-19-AD. Revises AD 2004-16-15, Amendment 39-13771.

    Applicability: Model AS-365N2, AS 365 N3, EC 155B, EC155B1, SA-
365N, N1, and SA-366G1 helicopters with a main gearbox (MGB) base 
plate, part number (P/N) 366A32-1062-03 or P/N 366A32-1062-06, 
installed, certificated in any category.
    Compliance: Required as indicated in the following compliance 
table and before installing a replacement main gearbox (MGB).

                                                Compliance Table
----------------------------------------------------------------------------------------------------------------
           For model . . .                     If . . .               Or if . . .              Or if . . .
----------------------------------------------------------------------------------------------------------------
(1) SA-365N, N1 and SA-366G1           An MGB is installed      An MGB is installed      An MGB is installed
 helicopters.                           that has less than       that has 9,900 or more   that is overhauled or
                                        9,900 cycles and has     cycles and has never     repaired, before
                                        never been overhauled    been overhauled or       further flight, unless
                                        or repaired, on or       repaired, before         accomplished
                                        before accumulating      further flight, unless   previously, and
                                        9,900 cycles, unless     accomplished             thereafter, at
                                        accomplished             previously, and          intervals not to
                                        previously, and          thereafter, at           exceed 55 hours TIS.
                                        thereafter, at           intervals not to
                                        intervals not to         exceed 55 hours TIS.
                                        exceed 55 hours time-
                                        in-service (TIS).
(2) AS-365N2 and AS 365 N3             An MGB is installed      An MGB is installed      An MGB is installed
 helicopters.                           that has less than       that has 7,300 or more   that has been
                                        7,300 cycles and has     cycles and has never     overhauled or
                                        never been overhauled    been overhauled or       repaired, before
                                        or repaired, on or       repaired, before         further flight, and
                                        before accumulating      further flight, and      thereafter, at
                                        7,300 cycles, unless     thereafter, at           intervals not to
                                        accomplished             intervals not to         exceed 55 hours TIS.
                                        previously, and          exceed 55 hours TIS.
                                        thereafter, at
                                        intervals not to
                                        exceed 55 hours TIS.
(3) EC 155 B and EC155B1 helicopters.  An MGB base plate is     An MGB base plate is
                                        installed that has       installed that has
                                        less than 2,600          2,600 or more cycles,
                                        cycles, no later than    unless accomplished
                                        2,600 cycles, unless     previously, before
                                        accomplished             further flight, and
                                        previously, and          thereafter, at
                                        thereafter, at           intervals not to
                                        intervals not to         exceed 15 hours TIS .
                                        exceed 15 hours TIS.
----------------------------------------------------------------------------------------------------------------
One cycle equates to one helicopter landing in which a landing gear touches the ground.


[[Page 25792]]

    To detect a crack in the MGB base plate and prevent failure of a 
MGB attachment point to the frame, which could result in severe 
vibration and subsequent loss of control of the helicopter, 
accomplish the following:
    (a) Before the initial inspection at the time indicated in the 
compliance table of this AD, strip the paint from area ``D'' on both 
sides (``B'' and ``C'') of the MGB base plate as depicted in Figure 
1 of this AD.

BILLING CODE 4910-13-P
[GRAPHIC] [TIFF OMITTED] TP02MY06.005

BILLING CODE 4910-13-C

[[Page 25793]]

    (b) At the times indicated in the compliance table, inspect area 
``D'' of the MGB base plate for a crack using a 10x or higher 
magnifying glass. Area ``D'' to be inspected is depicted in Figure 1 
of this AD.

    Note 1: Eurocopter France Alert Service Bulletin (ASB) No. 
05.00.45 for Model AS365 N, N1, N2, and N3 helicopters, ASB No. 
05.29 for Model SA366 G1 helicopters, and ASB No. 05A005 for Model 
EC155 B and B1 helicopters, pertain to the subject of this AD. All 
three ASBs are dated November 8, 2004.

    (c) If a crack is found in a MGB base plate, remove and replace 
the MGB with an airworthy MGB before further flight.
    (d) To request a different method of compliance or a different 
compliance time for this AD, follow the procedures in 14 CFR 39.19. 
Contact the Manager, Safety Management Group, Rotorcraft 
Directorate, FAA, ATTN: Ed Cuevas, Fort Worth, Texas 76193-0111, 
telephone (817) 222-5355, fax (817) 222-5961, for information about 
previously approved alternative methods of compliance.

    Note 2: The subject of this AD is addressed in Direction 
G[eacute]n[eacute]rale de L'Aviation Civile (France) AD F-2004-023 
R1, dated November 24, 2004.


    Issued in Fort Worth, Texas, on April 21, 2006.
Mark R. Schilling,
Acting Manager, Rotorcraft Directorate, Aircraft Certification Service.
[FR Doc. 06-4107 Filed 5-1-06; 8:45 am]
BILLING CODE 4910-13-P