Airworthiness Directive · Amendment 39-18282 · Pratt & Whitney Canada Corp. Turboshaft Engines
Pratt & Whitney Canada Corp. Turboshaft Engines
Superseded. A later AD replaced this one: AD 2019-22-03. Comply with the one in force.
This AD applies to Pratt & Whitney Canada Corp. (P&WC) PT6B-37A turboshaft engines with engine serial numbers identified in Table 1 of paragraph 4, Appendix, in P&WC Service Bulletin (SB) No. PT6B-72-39095, Revision No. 3, dated December 29, 2014.
We are adopting a new airworthiness directive (AD) for certain Pratt & Whitney Canada Corp. (P&WC) PT6B-37A turboshaft engines. This AD requires 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 was prompted by reports of incorrect engine torque for PT6B-37A engines. We are issuing this AD to prevent axial migration of the No. 10 bearing in the engine RGB assembly, which could result in engine overtorque, failure of the engine, in-flight shutdown, and loss of the rotorcraft.
(i) Within 50 flight hours (FHs) time in service after the effective date of this AD, inspect the No. 10 bearing, part number (P/N) 3310433-03, in the RGB assembly for axial movement. Use paragraphs 3.A. to 3.C. in the Accomplishment Instructions in P&WC SB No. PT6B-72-39095, Revision No. 3, dated December 29, 2014, to do the inspection. If the bearing fails the inspection, replace the No. 9 and No. 10 bearings before further flight.
(i) For engines with 500 FHs or less total time since new (TSN), repeat the inspection required by paragraph (e)(1) of this AD every 100 FHs time since last inspection (TSLI) until 500 hours total TSN, and, thereafter, every 200 FHs TSLI until removal.
(ii) For engines with more than 500 FHs total TSN perform the inspection required by paragraph (e)(1) to this AD within 200 FHs TSLI, and, thereafter, every 200 FHs TSLI until removal.
(i) For engine serial numbers (S/Ns) PCE-PU0192, PU0193, PU0201, PU0208, PU0209, PU0212, PU0213, PU0214, PU0216, PU0219, and PU0220, remove the No. 9 and No. 10 bearings, P/N 3310433-03, within 450 FHs or 42 months after the effective date of this AD, whichever occurs first, and replace with parts eligible for installation.
(ii) For all engine S/Ns identified in Applicability paragraph (c) of this AD, other than those listed in paragraph (e)(3)(i) of this AD, remove the No. 9 and No. 10 bearings, P/N 3310433-03, and replace with parts eligible for installation within 42 months after the effective date of this AD.
(iii) Replacement of the No. 9 and No. 10 bearing, P/N 3310433-03, with the No. 9 and No. 10 bearing, P/N 3310233-03 or P/N 3310533-03, is terminating action for this AD.
You do not have to contact your Local Field Service Representative as discussed in paragraph 3.C.(3) of P&WC SB No. PT6B-72-39095, Revision No. 3, dated December 29, 2014.
If you previously replaced the No. 9 and No. 10 bearings in accordance with the instructions contained in P&WC SB No. PT6B-72-39092, Revision No. 2, dated August 8, 2014, or earlier revisions, then you have complied with this AD.
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.
