80 FR 53024 - Airworthiness Directives; Airbus Helicopters (Previously Eurocopter France (Eurocopter) Helicopters)

DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration

Federal Register Volume 80, Issue 170 (September 2, 2015)

We propose to supersede airworthiness directive (AD) 2007-25- 08 for Eurocopter Model SA-365 N1, AS-365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters. AD 2007-25-08 currently requires checking the tail rotor gearbox (TGB) oil level, inspecting the magnetic plug for chips and either replacing the TGB or further inspecting for axial play in the tail rotor hub pitch change control spider (spider), and if axial play is found in the spider, replacing the pitch control rod assembly double bearing (bearing). Since we issued the AD 2007-25-08, we have received reports of new occurrences of loss of yaw control due to failure of the control rod bearing. This proposed AD would retain some of the requirements of AD 2007-25-08, revise the inspections for play in the double bearing to improve the detection of play, require replacing the TGB control shaft guide bushes, clarify the criteria concerning particle detection, and change the inspection for play in the double bearing after the guide bushes have been replaced. The proposed actions are intended to prevent damage to the bearing resulting in end play, loss of tail rotor pitch control, and subsequent loss of control of the helicopter.

[Federal Register Volume 80, Number 170 (Wednesday, September 2, 2015)]
[Proposed Rules]
[Pages 53024-53028]
From the Federal Register Online  [www.thefederalregister.org]
[FR Doc No: 2015-21689]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2015-3657; Directorate Identifier 2012-SW-069-AD]
RIN 2120-AA64


Airworthiness Directives; Airbus Helicopters (Previously 
Eurocopter France (Eurocopter) Helicopters)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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[[Page 53025]]

SUMMARY: We propose to supersede airworthiness directive (AD) 2007-25-
08 for Eurocopter Model SA-365 N1, AS-365N2, AS 365 N3, SA-366G1, EC 
155B, and EC155B1 helicopters. AD 2007-25-08 currently requires 
checking the tail rotor gearbox (TGB) oil level, inspecting the 
magnetic plug for chips and either replacing the TGB or further 
inspecting for axial play in the tail rotor hub pitch change control 
spider (spider), and if axial play is found in the spider, replacing 
the pitch control rod assembly double bearing (bearing). Since we 
issued the AD 2007-25-08, we have received reports of new occurrences 
of loss of yaw control due to failure of the control rod bearing. This 
proposed AD would retain some of the requirements of AD 2007-25-08, 
revise the inspections for play in the double bearing to improve the 
detection of play, require replacing the TGB control shaft guide 
bushes, clarify the criteria concerning particle detection, and change 
the inspection for play in the double bearing after the guide bushes 
have been replaced. The proposed actions are intended to prevent damage 
to the bearing resulting in end play, loss of tail rotor pitch control, 
and subsequent loss of control of the helicopter.

DATES: We must receive comments on this proposed AD by November 2, 
2015.

ADDRESSES: You may send comments by any of the following methods:
     Federal eRulemaking Docket: Go to http://www.regulations.gov. Follow the online instructions for sending your 
comments electronically.
     Fax: 202-493-2251.
     Mail: Send comments to the U.S. Department of 
Transportation, Docket Operations, M-30, West Building Ground Floor, 
Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590-0001.
     Hand Delivery: Deliver to the ``Mail'' address between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov or in person at the Docket Operations Office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the European 
Aviation Safety Agency (EASA) AD, the economic evaluation, any comments 
received and other information. The street address for the Docket 
Operations Office (telephone 800-647-5527) is in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.
    For service information identified in this proposed AD, contact 
Airbus Helicopters, Inc., 2701 N. Forum Drive, Grand Prairie, TX 75052; 
telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at 
http://www.airbushelicopters.com/techpub. You may review service 
information at the FAA, Office of the Regional Counsel, Southwest 
Region, 10101 Hillwood Pkwy, Room 6N-321, Fort Worth, Texas 76177.

FOR FURTHER INFORMATION CONTACT: Matt Wilbanks, Aviation Safety 
Engineer, Rotorcraft Certification Office, Rotorcraft Directorate, FAA, 
10101 Hillwood Pkwy, Fort Worth, Texas 76177; telephone (817) 222-5110; 
email [email protected].

SUPPLEMENTARY INFORMATION: 

Comments Invited

    We invite you to participate in this rulemaking by submitting 
written comments, data, or views. We also invite comments relating to 
the economic, environmental, energy, or federalism impacts that might 
result from adopting the proposals in this document. The most helpful 
comments reference a specific portion of the proposal, explain the 
reason for any recommended change, and include supporting data. To 
ensure the docket does not contain duplicate comments, commenters 
should send only one copy of written comments, or if comments are filed 
electronically, commenters should submit only one time.
    We will file in the docket all comments that we receive, as well as 
a report summarizing each substantive public contact with FAA personnel 
concerning this proposed rulemaking. Before acting on this proposal, we 
will consider all comments we receive on or before the closing date for 
comments. We will consider comments filed after the comment period has 
closed if it is possible to do so without incurring expense or delay. 
We may change this proposal in light of the comments we receive.

Discussion

    On November 27, 2007, we issued AD 2007-25-08, Amendment 39-15290 
(72 FR 69604, December 10, 2007) for Eurocopter (now Airbus 
Helicopters) Model SA-365 N1, AS-365 N2, AS 365 N3, SA-366G1, EC 155B, 
and EC155B1 helicopters. AD 2007-25-08 requires repetitively checking 
the TGB oil level to ensure it is at the maximum level. AD 2007-25-08 
also requires repetitively inspecting the magnetic plug for chips, and 
depending on the quantity of chips found, either replacing the TGB or 
further inspecting for axial play in the spider. If axial play is found 
in the spider, AD 2007-25-08 requires replacing the bearing. AD 2007-
25-08 was prompted by EASA Emergency AD No. 2006-0258R1-E, dated August 
29, 2006, as well as the finding that metal chips were not detected on 
the magnetic plug due to insufficient oil flow because the oil in the 
TGB was being maintained at the minimum level. The actions of AD 2007-
25-08 are intended to detect metal chips on the magnetic plug and to 
prevent damage to the bearing resulting in end play, loss of tail rotor 
pitch control, and subsequent loss of control of the helicopter.

Actions Since AD 2007-25-08 Was Issued

    Since we issued AD 2007-25-08 (72 FR 69604, December 10, 2007), we 
have received reports of new occurrences of loss of yaw control due to 
failure of the control rod bearing.
    EASA, which is the Technical Agent for the Member States of the 
European Union, has since superseded EASA Emergency AD No. 2006-0258R1-
E with several ADs, the most recent being EASA AD No. 2012-0170R2, 
dated June 20, 2014, to correct an unsafe condition for these Airbus 
Model helicopters. After receiving reports of several new occurrences 
of damage to the bearings and subsequent investigations of the 
incidents, EASA advises of implementing additional, revised inspection 
and corrective actions; reducing the interval between inspections; a 
modification replacing both guide bushes and improving the tolerance 
between the control shaft and the TGB wheel to limit the friction loads 
on the control bearing; and requiring the play measurement of the TGB 
to control rod, shaft assembly double bearing to be measured according 
to the type of fenestron installed. EASA AD 2012-0170R2 also excludes 
helicopters modified in accordance with modification (MOD) 07 65B63.

FAA's Determination

    These helicopters have been approved by the aviation authority of 
France and are approved for operation in the United States. Pursuant to 
our bilateral agreement with France, EASA, its technical 
representative, has notified us of the unsafe condition described in 
its AD. We are proposing this AD because we evaluated all known 
relevant information and determined that an unsafe condition is likely 
to exist or develop on other products of the same type design.

[[Page 53026]]

Related Service Information Under 1 CFR Part 51

    We reviewed ASB No. AS365-05.00.61, Revision 4, dated April 8, 
2014, for FAA-certificated Model SA 365 N1, AS 365 N2, and AS 365 N3 
helicopters and for non-FAA-certificated Model AS355F, F1, and F2 
helicopters; ASB No. SA366-05.41, Revision 4, dated April 8, 2014, for 
FAA-certificated Model SA-366G1 and non-FAA-certificated Model SA-366GA 
helicopters; and ASB No. EC155-05A022, Revision 4, dated April 8, 2014, 
for FAA-certificated Model EC 155B and EC155B1 helicopters. All three 
ASBs describe procedures for monitoring the behavior of the bearing by 
checking its axial play by dimensional measurement and by maintaining 
the operating oil at the maximum level. EASA classified this service 
information as mandatory and issued EASA AD No. 2012-0170R2 to ensure 
the continued airworthiness of these helicopters. This service 
information is reasonably available because the interested parties have 
access to it through their normal course of business or by the means 
identified in the ADDRESSES section of this NPRM.

Proposed AD Requirements

    This proposed AD would require:
     Checking the TGB oil level at specified intervals. An 
owner/operator (pilot) may perform this visual check and must enter 
compliance into the helicopter maintenance records in accordance with 
14 CFR Sec. Sec.  43.9(a)(1) through (4) and 91.417(a)(2)(v). A pilot 
may perform this check because it involves only a visual check for the 
oil level in the TGB and can be performed equally well by a pilot or a 
mechanic. This check is an exception to our standard maintenance 
regulations.
     Inspecting the magnetic plug of the TGB for chips at 
specified intervals.
     Within 300 hours time-in-service (TIS), replacing each 
affected part-numbered TGB guide bush with an airworthy guide bush, 
inspecting the bearing of the TGB control shaft and rod assembly for 
M50 type particles, and performing measurements of play in the TGB 
control shaft and rod assembly.
     Within 110 hours TIS after replacing the guide bush, and 
thereafter at intervals not to exceed 55 hours TIS, performing certain 
measurements for play in the TGB control shaft and rod assembly.
    This proposed AD would not apply to helicopters with TGB part 
number 365A33-6005-09 installed. Airbus Helicopters refers to the 
installation of this part-numbered TGB as MOD 07 65B63.

 Differences Between the Proposed AD and the EASA AD

    The calendar times in the EASA AD have already passed and are not 
included in this proposed AD.

Costs of Compliance

    We estimate that this proposed AD would affect 133 helicopters of 
U.S. Registry. We estimate that operators may incur the following costs 
in order to comply with this AD. The estimated labor cost is $85 per 
work-hour. We estimate .5 work-hour to check the TGB oil level for a 
cost of $43 per helicopter and $5,719 for the fleet each inspection 
cycle. We estimate .5 work-hour to inspect the magnetic plug on the TGB 
for chips for a cost of $43 per helicopter and $5,719 for the fleet 
each inspection cycle. We estimate 3 work-hours to measure the play in 
the TGB control shaft and rod assembly for a cost of $255 per 
helicopter and $33,915 for the fleet each inspection cycle. Replacing 
the TGB control shaft guide bushes would take 4 work-hours and required 
parts would cost $565, for an estimated total of $905 per helicopter 
and $120,365 for the U.S. operator fleet. Inspecting the TGB control 
shaft and rod assembly for steel particles would take 6 work-hours for 
a cost per helicopter of $510 and a fleet cost of $67,830. If 
necessary, it would cost about $30,000 per helicopter to replace the 
TGB and $24,000 for overhaul of the TGB to replace the bearing.

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.

Regulatory Findings

    We determined that this proposed AD would not have federalism 
implications under Executive Order 13132. 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, I certify this 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);
    3. Will not affect intrastate aviation in Alaska to the extent that 
it justifies making a regulatory distinction; and
    4. 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 an economic evaluation of the estimated costs to comply 
with this proposed AD and placed it in the AD docket.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

The Proposed Amendment

    Accordingly, under the authority delegated to me by the 
Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by removing Airworthiness Directive (AD) 
2007-25-08, Amendment 39-15290 (72 FR 69604, December 10, 2007), and 
adding the following new AD:

Airbus Helicopters (Previously Eurocopter France Helicopters): 
Docket No. FAA-2015-3657; Directorate Identifier 2012-SW-069-AD.

(a) Applicability

    This AD applies to Model SA-365N1, AS-365N2, AS 365 N3, SA-
366G1, EC 155B, and EC155B1 helicopters, with a tail rotor gearbox 
(TGB) pitch control rod assembly double bearing (bearing) installed, 
certificated in any category, except helicopters with TGB part 
number (P/N) 365A33-6005-09 installed.

(b) Unsafe Condition

    This AD defines the unsafe condition as damage to the bearing, 
which could result in end play, loss of tail rotor pitch control, 
and subsequent loss of control of the helicopter.

[[Page 53027]]

(c) Affected ADs

    This AD supersedes AD 2007-25-08, Amendment 39-15290 (72 FR 
69604, December 10, 2007).

(d) Comments Due Date

    We must receive comments by November 2, 2015.

(e) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

(f) Required Actions

    (1) Check the TGB oil level at the following intervals:
    (i) For Model SA-365N1, AS-365N2, AS 365 N3 helicopters, at 
intervals not to exceed 10 hours time-in-service (TIS).
    (ii) For Model SA366G1 helicopters, at each daily flight check.
    (iii) For Model EC 155B and EC155B1 helicopters, at intervals 
not to exceed 15 hours TIS or 7 days, whichever occurs first.
    (iv) The actions required by paragraph (f)(1) of this AD may be 
performed by the owner/operator (pilot) holding at least a private 
pilot certificate and must be entered into the aircraft records 
showing compliance with this AD in accordance with 14 CFR Sec. Sec.  
43.9(a)(1) through (4) and 14 CFR 91.417(a)(2)(v). The record must 
be maintained as required by 14 CFR Sec. Sec.  91.417, 121.380, or 
135.439.
    (2) If the oil level is not at maximum, before further flight, a 
qualified mechanic must fill it to the maximum level.
    (3) Inspect the magnetic plug of the TGB for any chips as 
follows:
    (i) At intervals not to exceed 25 hours TIS for helicopters with 
a magnetic plug without a chip electrical indication in the cockpit, 
or
    (ii) At intervals not to exceed 100 hours TIS and after any 
illumination of the TGB ``CHIP'' warning light for helicopters with 
a chip electrical indication in the cockpit.
    (4) If you find any chips during the inspection in paragraph 
(f)(3) of this AD, determine whether the quantity of chips is within 
the removal criteria.
    (i) If the quantity of chips on the magnetic plug is at or above 
the removal criteria, before further flight, replace the TGB with an 
airworthy TGB.
    (ii) If the quantity of chips on the magnetic plug is below the 
removal criteria, comply with paragraph (f)(6) of this AD before 
further flight.
    (5) Within 300 hours TIS, without removing the TGB:
    (i) Replace each TGB control shaft guide bush (guide bush), P/N 
365A33-6189-20 and 365A33-6189-21, with guide bush, P/N 365A33-6223-
20, and replace each guide bush, P/N 365A33-6188-20, with guide 
bush, P/N 365A33-6222-20.

    Note 1 to paragraph (f)(5)(i) of this AD:  Airbus Helicopters 
refers to the replacement of the guide bushes as Modification 
0765B58.

    (ii) Inspect the bearing of the TGB control shaft and rod 
assembly for M50 type particles (particles) as shown in Figures 1 
through 3 of Airbus Helicopters Alert Service Bulletin (ASB) No. 
AS365-05.00.61, Revision 4, dated April 8, 2014, for Model SA 365 
N1, AS 365 N2, and AS 365 N3 helicopters (AS365-05.00.61); ASB No. 
SA366-05.41, Revision 4, dated April 8, 2014, for Model SA 366G1 
helicopters (SA366-05.41); or ASB No. EC155-05A022, Revision 4, 
dated April 8, 2014, for Model EC 155B and EC155B1 helicopters 
(EC155-05A022). Inspect the bearing by separating the control shaft 
(item q of Figure 3) from the control rod (item p of Figure 3), 
rinse the bearing with white spirit or equivalent, collect the 
product on a blotting paper, and inspect for particles inside the 
control shaft, around the bearing, and on blotting paper.
    (A) If there are no particles, clean the control shaft and 
control rod with white spirit or equivalent and install the control 
shaft and control rod.
    (B) If there are any particles, replace the bearing with an 
airworthy bearing.
    (iii) Perform measurements of play in the TGB control shaft and 
rod assembly bearing as follows:
    (A) For the TGB side:
    (1) Remove the cover and inspect the positioning of the locking 
of the 3 screws, as shown in the two positioning for measurement 
photographs in the Accomplishment Instructions under paragraph 
3.B.4.a.(1) of ASB AS365-05.00.61, SA336-05.41, or EC155-05A022. 
Correctly lock the screws if the positioning is inconvenient for 
measurement. Set the pedal unit to the neutral position and rig the 
tail servo-control using a 6 mm diameter pin. Remove any primer and 
paint from the support casing face of the servo-control using 600 
grit sand paper. Apply DOW 19 or equivalent protection and a coat of 
primer P05 or equivalent. Do not reapply primer and paint to the 
support casing face of the servo-control.
    (2) Perform a measurement ``M1'' using a caliper gage, between 
the end of the control rod (item p in the three photographs in the 
Accomplishment Instructions under paragraph 3.B.4.a.(1) of ASB 
AS365-05.00.61, SA336-05.41, or EC155-05A022) and the seating face 
of the servo-control on the casing. Mark the position of the caliper 
gage on the support casing face of the servo-control as ``R1'' using 
a permanent felt tip pen. Position the caliper gage on R1 (shown in 
the first of the three photographs in the Accomplishment 
Instructions under paragraph 3.B.4.a.(1) of ASB AS365-05.00.61, 
SA336-05.41, or EC155-05A022) and on the screw (item ac in the first 
of the three photographs in the Accomplishment Instructions under 
paragraph 3.B.4.a.(1) of ASB AS365-05.00.61, SA336-05.41, or EC155-
05A022) of the universal joint of the servo-control. Set the mobile 
part of the caliper gage against the end of the control rod. Shift 
the caliper gage against the control lever (item ab in the last 
photograph in the Accomplishment Instructions under paragraph 
3.B.4.a.(1) of ASB AS365-05.00.61, SA336-05.41, or EC155-05A022) 
while remaining in contact with the end of the control rod.
    (3) Record measurement M1 indicated on the caliper gage on the 
component history card or equivalent record.
    (B) For the TRH side:
    (1) Perform a measurement ``M2'' using a caliper gage between 
the flat face of the center plate (item c in the photograph in the 
Accomplishment Instructions under paragraph 3.B.4.a.(2) of ASB 
AS365-05.00.61, SA336-05.41, or EC155-05A022) and the face of the 
inner web (item ad in the photograph in the Accomplishment 
Instructions under paragraph 3.B.4.a.(2) of ASB AS365-05.00.61, 
SA336-05.41, or EC155-05A022) of the rotor hub on which the inner 
bearings of the TRH blades are installed. Position the caliper gage 
flat across the opening (item ae in the photograph in the 
Accomplishment Instructions under paragraph 3.B.4.a.(2) of ASB 
AS365-05.00.61, SA336-05.41, or EC155-05A022) of the pitch change 
spider. Mark the position of the caliper gage on the flat surface of 
the center plate as ``R2'' and on the opening as ``R3'' using a 
permanent felt tip pen.
    (2) Record measurement M2 indicated on the caliper gage.
    (3) Calculate a measurement ``M0'' by adding measurements M1 
(required in paragraph (f)(5)(iii)(A) of this AD) and M2.
    (4) Perform measurements M1 and M2 again by repeating the 
requirements in paragraphs (f)(5)(iii)(A) and (f)(5)(iii)(B) of this 
AD and calculate a second measurement M0.
    (5) Calculate the difference between the two M0 measurements. If 
the difference is not less than 0.25 mm (0.01 inch), calculate the 
two M0 measurements again.
    (6) Calculate the mean value of the two M0 measurements and 
record it on the component history card or equivalent record. This 
M0 measurement will be the reference measurement enabling you to 
evaluate any increase in the play in the bearing of the control 
shaft and rod assembly during later inspections.
    (6) Within 110 hours TIS after replacing the guide bush, and 
thereafter at intervals not to exceed 55 hours TIS, perform 
measurements for play in the TGB control shaft and rod assembly as 
follows.
    (i) On the TGB side:
    (A) Remove the TGB fairing, set the pedal unit to the neutral 
position and rig the tail servo-control using a 6 mm diameter pin.
    (B) Perform measurement ``M1'' using a caliper gage between the 
end of the control rod (item p in the three photographs in the 
Accomplishment Instructions under paragraph 3.B.4.b (1) of ASB 
AS365-05.00.61, SA336-05.41, or EC155-05A022) and the seating face 
of the servo-control on the casing. Position the caliper gage on 
mark R1 and the bearing against the screw (item ac as shown in the 
first of the three photographs in the Accomplishment Instructions 
under paragraph 3.B.4.b.(1) of ASB AS365-05.00.61, SA336-05.41, or 
EC155-05A022) of the universal joint of the servo-control. Set the 
mobile part of the caliper gage against the end of the control rod. 
Shift the caliper gage against the control lever (item ab as shown 
in the last of the three photographs in the Accomplishment 
Instructions under paragraph 3.B.4.b.(1) of ASB AS365-05.00.61, 
SA336-05.41, or EC155-05A022) while remaining in contact with the 
end of the control rod.

[[Page 53028]]

    (C) Record measurement M1 indicated on the caliper gage on the 
component history card or equivalent record.
    (ii) On the tail rotor hub (TRH) side:
    (A) Remove the fairing and perform a measurement ``M2'' using a 
caliper gage between the flat face of the center plate (item c in 
the photograph in the Accomplishment Instructions under paragraph 
3.B.4.b.(2) of ASB AS365-05.00.61, SA336-05.41, or EC155-05A022) and 
the face of the inner web (item ad in the photograph in the 
Accomplishment Instructions under paragraph 3.B.4.b.(2) of ASB 
AS365-05.00.61, SA336-05.41, or EC155-05A022) of the rotor hub on 
which the inner bearings of the TRH blades are installed. Position 
the caliper gage flat across the opening of the pitch change spider 
on R2 and R3 as shown in the right photograph in the Accomplishment 
Instructions under paragraph 3.B.4.b.(2) of ASB AS365-05.00.61, 
SA336-05.41, or EC155-05A022.
    (B) Record measurement M2 indicated on the caliper gage on the 
component history card or equivalent record.
    (C) Calculate a measurement ``M3'' by adding measurements M1 and 
M2.
    (D) Calculate the difference between measurement ``M0'' 
indicated on the TGB component history card or equivalent record and 
M3.
    (1) If the difference between measurement M0 and M3 is less than 
0.5 mm (0.02 inch), perform an additional inspection for play in the 
bearing of the TGB control shaft and rod assembly by following the 
Accomplishment Instructions, paragraph 3.B.6., of ASB AS365-
05.00.61, SA366-05.41, or EC155-05A022. If there is no axial play at 
the TRH pitch change spider, record value M3 on the component 
history card or equivalent record. If there is axial play at the TRH 
pitch change spider, replace the bearing with an airworthy bearing 
and perform a new reference measurement by following the 
requirements of paragraph (f)(6) of this AD.
    (2) If the difference between the measurements is equal to or 
greater than 0.5 mm (0.02 inch), replace the bearing with an 
airworthy bearing and perform a new reference measurement by 
following the requirements of paragraph (f)(6) of this AD.

(g) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Safety Management Group, FAA, may approve AMOCs 
for this AD. Send your proposal to: Matt Wilbanks, Aviation Safety 
Engineer, Rotorcraft Certification Office, Rotorcraft Directorate, 
FAA, 10101 Hillwood Pkwy, Fort Worth, Texas 76177; telephone (817) 
222-5110; email [email protected].
    (2) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, we suggest that you 
notify your principal inspector, or lacking a principal inspector, 
the manager of the local flight standards district office or 
certificate holding district office before operating any aircraft 
complying with this AD through an AMOC.

(h) Additional Information

    The subject of this AD is addressed in European Aviation Safety 
Agency (EASA) AD No. 2012-0170R2, dated June 20, 2014. You may view 
the EASA AD on the internet at http://www.regulations.gov in Docket 
No. FAA-2015-3657.

(i) Subject

    Joint Aircraft Service Component (JASC) Code: 6520 Tail Rotor 
Gearbox.

    Issued in Fort Worth, Texas, on August 21, 2015.
Lance T. Gant,
Acting Directorate Manager, Rotorcraft Directorate, Aircraft 
Certification Service.
[FR Doc. 2015-21689 Filed 9-1-15; 8:45 am]
BILLING CODE 4910-13-P