ALERT SERVICE BULLETIN 

Timken 1st Stage Reduction Sun & Planet Gears 

P/N’s: E3024765 & E3101455-02 

Revision: B Issued: Nov. 7, 2011

File: T-804_Rev_B Page 1 of 2

This specification is property of TIMKEN. Statements such as “as agreed with TIMKEN” or “as approved by TIMKEN” require authorization from TIMKEN Engineering. 

Timken Alcor Aerospace Technologies, Inc. 3110 N. Oakland, Mesa, Arizona 85215

T-804 ALERT SERVICE BULLETIN 

Subject: Increased monitoring of chip detector. Removal of Timken Alcor Aerospace 

Technologies, Inc. (“TAATI”) PMA sun and planet gears 

TAATI Part Number(s): E3024765 & E3101455-02 

Engine Application(s): Pratt and Whitney Canada PT6A-15AG, -27, -28, -34, -34AG, -34B, -36 

Revision History: Rev. B dated 11/07/2011 

REASON: 

Rev. A of T-804 alert service bulletin (issued August 29, 2011) applied to Timken Alcor Aerospace 

Technologies, Inc. (“TAATI”) PMA sun gear (P/N E3024765), serial numbers PC5-091 through PC5-176. 

Subsequently, the FAA issued Airworthiness Directive 2011-20-51 (Sept. 15, 2011) (“AD”), which applied to 

the same serial numbers as initial T-804 alert service bulletin. The FAA AD remains in effect for those serial 

numbers. 

This revision (Rev. B) expands the applicability of the T-804 alert service bulletin to include additional first 

stage reduction sun gears and planet gears manufactured by TAATI. 

Failure of the 1st stage sun or planet gear may result in damage to the reduction gear system and a 

possible In Flight Shutdown, creating a risk of property damage, serious injuries, or fatality. 

APPLICABILITY:

This Rev. B to alert service bulletin T-804 is applicable to TAATI PMA sun gear (P/N E3024765) and PMA

planet gear (P/N E3101455-02). 

Affected serial numbers for each part number are: 

 P/N E3024765: Serial numbers PC5-090 and earlier and SG36-120 and earlier 

 P/N E3101455-02: Set serial numbers EE-197 and earlier, EE-4094 and earlier, and EE-4113 

ACCOMPLISHMENT INSTRUCTIONS: 

1. Inspect chip detector for collected debris within 10 operating hours following receipt of this 

alert service bulletin and at every 25 operating hours thereafter until the affected sun and planet 

gears are removed from service in accordance with instruction #2 and TCH maintenance manual 

instructions. If debris is observed, determine if the debris is allowable or non-allowable according to the 

applicable TCH maintenance manual. If the debris is considered non-allowable, remove the affected sun 

and planet gears in accordance with instruction #2.
ALERT SERVICE BULLETIN 

Timken 1st Stage Reduction Sun & Planet Gears 

P/N’s: E3024765 & E3101455-02 

Revision: B Issued: Nov. 7, 2011

File: T-804_Rev_B Page 2 of 2

This specification is property of TIMKEN. Statements such as “as agreed with TIMKEN” or “as approved by TIMKEN” require authorization from TIMKEN Engineering. 

Timken Alcor Aerospace Technologies, Inc. 3110 N. Oakland, Mesa, Arizona 85215

T-804 ALERT SERVICE BULLETIN 

2. Remove the affected sun gear or planet gears from service in accordance with the TCH 

maintenance manual within the earliest to occur of: (a) 60 operating hours after receipt of this alert

service bulletin, (b) 60 days after receipt of this alert service bulletin, or (c) as required by 

instruction #1. At the same time, remove the interacting (mating) planet or sun gears. Replace the 

removed sun and planet gears with a complete zero time, first stage reduction sun gear and planet gear

matched set. 

Contact TAATI customer service and obtain a RMA number, then return the affected sun gear or planet 

gear to TAATI. 

_________________ 

Record compliance with this alert service bulletin in the applicable section of the engine log book at initial 

and final inspection and at removal of the sun and planet gears. The entry should include part number,

serial number and a reference to SB #T-804 Rev. B. 

You may contact Timken to request a log sheet to help document all intermediate inspections performed in 

accordance with this alert service bulletin. 

APPROVAL: 

This document is FAA approved.