AD 2013-12-05

We are adopting a new airworthiness directive (AD) for Eurocopter Deutschland GmbH (Eurocopter) Model MBB-BK 117 C-2 helicopters. This AD requires determining if a certain serial-numbered bevel gear is installed in the tailrotor intermediate gear box (IGB). If such a bevel gear is installed in the IGB, this AD requires recording the bevel gear's reduced life limit in the Airworthiness Limitations section of the maintenance manual and on the component history card or equivalent IGB record. If the bevel gear's life limit has been reached or exceeded, this AD requires, before further flight, replacing the bevel gear with an airworthy bevel gear. This AD is prompted by the discovery that the tooth foot fillets in certain bevel gears fall below the minimum dimensions required in the design documents to ensure safe functioning of the bevel gear until it reaches its approved life limit. This AD's actions are intended to prevent failure of a bevel gear before it reaches its currentlyapproved life limit, failure of the IGB, and subsequent loss of helicopter control.

Final rule.

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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 adding the following new airworthiness directive (AD):

2013-12-05 Eurocopter Deutschland GmbH Helicopters: Amendment 39- 17483; Docket No. FAA-2013-0018; Directorate Identifier 2010-SW-060- AD.

(a) Applicability

This AD applies to Model MBB-BK 117 C-2 helicopters with a bevel gear, part number (P/N) 4639 310 065, installed in the tail rotor intermediate gear box (IGB), P/N 4639 002 007, certificated in any category.

(b) Unsafe Condition

This AD defines the unsafe condition as failure of a bevel gear, failure of the tail rotor IGB, and subsequent loss of control of the helicopter.

(c)Effective Date

This AD becomes effective August 20, 2013.

(d) 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.

(e) Required Actions

Within 30 days, do the following:
(1) Determine if a bevel gear with a serial number (S/N) listed in Table 1 of Eurocopter Alert Service Bulletin MBB BK117 C-2-04A- 005, Revision 2, dated April 28, 2010 (ASB), is installed in the IGB.
(i) If a bevel gear listed in Table 1 of the ASB is installed in the IGB, record the reduced life limit of the bevel gear onto the component history card or equivalent record of the IGB.
(ii) If the bevel gear life limit has been reached or is exceeded, before further flight, replace the bevel gear with an airworthy bevel gear.
(2) Revise the Airworthiness Limitations section of the maintenance manual by reducing the retirement life for each IGB bevel gear, P/N4639 310 065, that has a S/N listed in Table 1 of the ASB to the life limit corresponding to that S/N.

(f) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Safety Management Group, FAA, may approve AMOCs for this AD. Send your proposal to: Chinh Vuong, Aviation Safety Engineer, Safety Management Group, Rotorcraft Directorate, FAA, 2601 Meacham Blvd., Fort Worth, Texas 76137; telephone (817) 222-5110; email chinh.vuong@faa.gov.
(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.

(g) Additional Information

The subject of this AD is addressed in European Aviation Safety Agency (EASA) AD No. 2010-0096, dated May 25, 2010. You may view the EASA ADat http://www.regulations.gov by searching for and locating it in Docket No. FAA-2013-0018.

(h) Subject

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

(i) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.
(i) Eurocopter Alert Service Bulletin MBB BK117 C-2-04A-005, Revision 2, dated April 28, 2010.
(ii) Reserved.
(3) For Eurocopter service information identified in this AD, contact American Eurocopter Corporation, 2701 N. Forum Drive, Grand Prairie, TX 75052; telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775; or at http://www.eurocopter.com/techpub.
(4) You may view this service information at FAA, Office of the Regional Counsel, Southwest Region, 2601 Meacham Blvd., Room 663, Fort Worth, Texas 76137. For information on the availability of this material at the FAA, call (817) 222-5110.
(5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call (202) 741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html.

Discussion

EASA, which is the Technical Agent for the Member States of the European Union, issued EASA AD No. 2010-0096 on May 25, 2010, to correct an unsafe condition for Eurocopter Model MBB-BK 117 C-2 helicopters. EASA advised that during a recent review of the production documents for the bevel gears of the IGB, it was discovered that certain production batch numbers have tooth foot fillets below the required minimum values that would ensure the approved life limits for this part.
On January 18, 2013, at 78 FR 4090, the Federal Register published our notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR part 39 to include an AD that would apply to Eurocopter Model MBB- BK 117 C-2 helicopters. The NPRM proposed to require determining if a certain serial-numbered bevel gear was installed in the IGB. If such a bevel gear was installed in the IGB, the NPRM proposed to require recording the bevel gear's reduced life limit in the Airworthiness Limitations section of the maintenance manual and on the component history card or equivalent IGB record. If the bevel gear's life limit was reached or exceeded, the NPRM proposed to require, before further flight, replacing the bevel gear with an airworthy bevel gear. The proposed requirements were intended to prevent failure of a bevel gear before it reached its currently approved life limit, failure of the IGB, and subsequent loss of helicopter control.

Comments

We gave the public the opportunity to participate in developing this AD, but we received no comments on the NPRM (78 FR 4090, January 18, 2013).

FAA's Determination

These helicopters have been approved by the aviation authority of Germany and are approved for operation in the United States. Pursuant to our bilateral agreement with Germany, EASA, its technical representative, has notified us of the unsafe condition described in the EASA AD. We are issuing this AD because we evaluated all information provided by EASA and determined the unsafe condition exists and is likely to exist or develop on other helicopters of these same type designs and that air safety and the public interest require adopting the AD requirements as proposed.

Differences Between This AD and the EASA AD

This AD does not require sending a copy of the form in Eurocopter's Alert Service Bulletin No. MBB BK117 C-2-04A-005, Revision 2, dated April 28, 2010 (ASB), to the manufacturer. This AD does not require sending the IGB to an overhaul facility. Also, this AD does not specify a single ferry flight not to exceed 20 hours time-in-service to a maintenance facility if the bevel gear has exceeded the reduced life limit.

Related Service Information

Eurocopter's ASB specifies determining whether certain serial- numbered bevel gears are installed in the IGB. The ASB specifies recording the reduced life limit for each affected bevel gear on the log card of the IGB and on the list of life-limited parts. If a bevel gear has one of the serial numbers listed in Table 1 of the ASB, the ASB specifies filling out a reply form and copying and sending it to Eurocopter. The ASB also specifies sending the IGB to a certified overhaul facility for replacing the bevel gear if it has reached or exceeded its life limit. EASA classified this ASB as mandatory and issued AD No. 2010-0096, dated May 25, 2010, to ensure the continued airworthiness of these helicopters.

Costs of Compliance

We estimate that this AD affects 107 helicopters of U.S. registry and that the labor rate averages $85 per work-hour. We also estimate that it takes about a half hour to determine whether the IGB is affected and to enter the reduced life limit on the component history card or the equivalent record and to revise the Airworthiness Limitations section of the maintenance manual. Based on these figures, we estimate that the cost per helicopter totals about $43, about $4,601 for the U.S. fleet.

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

[[Page 42411]]

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 helicopters identified in this rulemaking action.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This ADwill 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 this AD:
(1) Is not a ``significant regulatory action'' under Executive Order 12866;
(2) Is not a ``significant rule'' under 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 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.