Duncan Aviation logo

Honeywell Issues An AS907 Series Service Bulletin To Enhance Bearing Life

February 2019

Honeywell issued a second revision to SB (Service Bulletin) AS907-72-9045 that gives instructions on the installation of an improved annular ball (tower shaft) bearing.

This Reliability SB is applicable to the following Honeywell AS907 series engines:

Challenger 300/350

AS907-1-1A (HTF7000)


Challenger 350

AS907-2-1A (HTF7350)

Prior to S/N 136556

Gulfstream G280

AS907-2-1G (HTF7250)

Prior to S/N 130389

Embraer Legacy 450/500

AS907-3-1E (HTF7500)

Prior to S/N 131309

Honeywell developed an improved annular ball (tower shaft), PN 3033024-2, -4 and -6, bearing that utilizes stainless steel rivets to secure the two halves of the bronze cage. Stainless steel provides 60x increased strength that contributes to longer bearing life. The appropriate bearing should be installed when the tower shaft upper bevel gear housing assembly is removed from the engine.

Consult the attached Service Bulletin for more details. 

Honeywell also recommends you comply with SB AS907-72-9080, improved No. 4 Roller Bearing, at the same time.


Shawn Schmitz Engine Tech Rep Astra, Challenger, Citation, Embraer, Falcon, Global, Gulfstream, Hawker, King Air, Learjet, Westwind Lincoln, NE (LNK) +1 402.479.8166

Related Tech Articles

Gulfstream GIV: Troubleshooting High Engine RPMs
March 2023

Another Option To Complete Honeywell Service Bulletin Before Deadline
January 2023

Honeywell Bimodal Service Bulletin Update
May 2022

Challenger 300: Recommended ECU Update For Honeywell HTF7000 Engines
May 2022

Authorized NDT Services For Honeywell TFE731 Service Bulletins
November 2021

View All Engine & APU Tech Articles