Airworthiness Directive · Amendment 39-19782 · Turbine engine reduction gear
Pratt & Whitney Canada Corp. Turboshaft Engines
This AD applies to Pratt & Whitney Canada Corp. (P&WC) PT6B-37A turboshaft engines with serial number (S/N) PCE-PU0275 or earlier or with engine S/N PCE-PU0278.
The FAA is superseding Airworthiness Directive (AD) 2015-20-04 for certain Pratt & Whitney Canada Corp. (P&WC) PT6B-37A turboshaft engines. AD 2015-20-04 required initial and repetitive inspections until replacement of the No. 10 bearing, and eventual replacement of the No. 9 bearing, both located in the engine reduction gearbox (RGB) assembly. This AD requires removal from service and replacement of the No. 9 and No. 10 position bearings. This AD was prompted by reports of incorrect engine torque for PT6B-37A turboshaft engines. The FAA is issuing this AD to address the unsafe condition on these products.
(1) For affected engines that did not have the bearings replaced in accordance with P&WC Service Bulletin (SB) No. PT6B-72-39092, Revision No. 5, dated October 27, 2017, or earlier revision: Remove from service and replace the No. 9 and No. 10 position bearings at the next engine shop visit after the effective date of this AD, but no later than December 31, 2020, whichever occurs first, in accordance with the Accomplishment Instructions, paragraphs 3.A. and B., of P&WC SB PT6B-72-39108, Revision No. 1, dated September 5, 2017.
(2) For affected engines that had the bearings replaced in accordance with P&WC SB No. PT6B-72-39092, Revision No. 5, dated October 27, 2017, or earlier revision: Remove from service and replace the No. 9 and No. 10 position bearings before December 31, 2020, in accordance with the Accomplishment Instructions, paragraphs 3.A. and B., of P&WC SB PT6B-72-39108, Revision No. 1, dated September 5, 2017.
You may take credit for the No. 9 and No. 10 position bearing replacement required by paragraph (g) of this AD, if you performed the replacement before the effective date of this AD using P&WC SB No. PT6B-72-39108, dated September 30, 2016.
For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the separation of pairs of major mating engine flanges, or any removal of the RGB assembly.
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.
