Airworthiness Directive · Amendment 39-16888 · Pratt & Whitney Canada Turboprop Engines
Pratt & Whitney Canada Turboprop Engines
This AD applies to Pratt & Whitney Canada PT6A-15AG, -27, -28, -34, -34AG, -34B, and -36 series turboprop engines that have had maintenance done to the power section module involving the first stage reduction sun gear or planetary gear set replacement since December 22, 2008, and having a:
(1) Timken Alcor Aerospace Technologies, Inc. (TAATI) part manufacturer approval (PMA) replacement first stage reduction sun gear, part number (P/N) E3024765, serial numbers (S/Ns) PC5-051 through PC5-089, or S/Ns SG36-051 through SG36-120, installed; or
(2) TAATI PMA replacement planetary gear set, P/N E3101455-02, S/Ns EE-051 through EE-197, or S/Ns EE-4051 through EE-4094, or S/N EE-4113, installed.
We are adopting a new airworthiness directive (AD) for Pratt & Whitney Canada PT6A-15AG, -27, -28, -34, -34AG, -34B, and -36 series turboprop engines. This AD requires the removal of certain affected part manufacturer approval (PMA) replacement Timken Alcor Aerospace Technologies, Inc. (TAATI) first stage reduction sun gears and/or the interacting planetary gear sets from the propeller reduction gearbox assembly. This AD was prompted by a failure report of a certain TAATI PMA sun gear, installed since December 22, 2008. We are issuing this AD to prevent failure of the sun gear, which will result in an engine in- flight shut down, possible uncontained engine failure, aircraft damage, and serious injuries.
(1) Within 10 operating hours after the effective date of this AD:
(i) Inspect the chip detector on the propeller reduction gearbox assembly for metal debris.
(ii) Do the inspections in accordance with paragraph 1 of the Accomplishment Instructions of Timken Alcor Aerospace Technologies, Inc. Alert Service Bulletin No. T-804, Revision B, dated November 7, 2011. If the amount of metal debris found exceeds the allowable limits then, before further flight, permanently remove from service the affected gears as specified in paragraph (g) of this AD.
(2) Repeat the chip detector inspections within every 25 additional operating hours thereafter, until the affected gears are removed from service.
Within 60 operating hours or 365 days after the effective date of this AD, whichever occurs first, permanently remove from service the PMA replacement TAATI first stage reduction sun gear and the interacting planetary gears, and the PMA replacement TAATI planetary gear sets and interacting gears, listed in paragraph (c) of this AD, from the propeller reduction gearbox assembly.
(1) After the effective date of this AD, do not install on any airplane, any engine or power section module with a TAATI PMA replacement first stage reduction sun gear, P/N E3024765, S/Ns PC5-051 through PC5-089, or S/Ns SG36-051 through SG36-120, or the associated planetary gears in the propeller reduction gearbox assembly.
(2) After the effective date of this AD, do not install on any airplane, any engine or power section module with a TAATI PMA planetary gear set, P/N E3101455-02, S/Ns EE-051 through EE-197, or S/Ns EE-4051 through EE-4094, or S/N EE-4113, or the associated first stage sun gear in the propeller reduction gearbox assembly.
The sun gear and planetary gear sets as-installed are considered to be matched sets. Therefore, the sun gear and planetary gear sets associated as mating parts with an affected gear in the propeller reduction gearbox assembly must also be permanently removed from service.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
