AD 2015-20-04

This AD becomes effective November 18, 2015.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of November 18, 2015.

For service information identified in this AD, contact Pratt & Whitney Canada Corp., 1000 Marie-Victorin, Longueuil, Quebec, Canada, J4G 1A1; phone: 800-268-8000; fax: 450-647-2888; Web site: http://www.pwc.ca. You may view this service information at the FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA. For information on the availability of this material at the FAA, call 781-238-7125. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2015-0486.

Barbara Caufield, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781-238-7146; fax: 781-238-7199; email: barbara.caufield@faa.gov.

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to the specified products. The NPRM was published in the Federal Register on June 19, 2015 (80 FR 35260). The NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:

Five incidences of incorrect engine torque indication have been reported for PT6B-37A engine installations on AW119MKII helicopters. A lower than actual engine torque indication due to a faulty indication system, particularly on a helicopter being operated at max allowable torque (90 to 110%) range, may result in undetected over-torque condition.

Repeated over-torque conditions that are undetected and consequently are not corrected in accordance with conditional inspection requirements of original equipment manufacturer (OEM) Instructions for Continued Airworthiness (ICAs), may have a negative impact on the operational safety of the aircraft. Investigation by P&WC has determined the root cause of the subject torque indication anomaly to be the axial migration of part number (P/N) 3310433-03 bearings at the engine torque sensing gear location.

The axial migration of the No. 10 bearing is caused by non-optimal bearing internal clearance. This migration may cause an erroneous torque reading, possibly leading to engine overtorque and engine failure. We are also requiring replacement of the No. 9 bearing since it may also migrate, has the same part number as a No. 10 bearing, and could be installed in the same location as a No. 10 bearing.

We gave the public the opportunity to participate in developing this AD. We received no comments on the NPRM (80 FR 35260, June 19, 2015).

We reviewed the available data and determined that air safety and the public interest require adopting this AD as proposed.

P&WC has issued Service Bulletin (SB) No. PT6B-72-39095, Revision No. 3, dated December 29, 2014. The service information describes procedures for inspecting affected bearings. 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 final rule.

P&WC has also issued SB No. PT6B-72-39092, Revision No. 4, dated December 29, 2014. The service information describes procedures for removing affected bearings.

We estimate that this AD affects 83 engines installed on rotocraft of U.S. registry. We estimate that it will take about 3 hours per engine to comply with this AD. We also estimate that it would take about 1 hour per engine to replace the affected bearings. The average labor rate is $85 per hour. Required parts cost about $49,800 per engine. Based on these figures, we estimate the cost of this AD on U.S. operators to be $4,161,620.

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.

We determined that this AD will not have federalism implications under Executive Order 13132. This AD will 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 this AD:

(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.

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

1. The authority citation for part 39 continues to read as follows:

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):