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Honeywell TFE731: Accessory Gearbox Carbon Seal Improvements

September 2014

If you fly with Honeywell TFE731-20,-40,-50,-60 engines, you may have noticed oil leaking from the accessory gearbox drive cover. More specifically, from the starter and alternator gearshaft air-oil seals (P/N 3072784-2).

This is due to high heat that produces coking and carbon build up on the seals.

Honeywell is aware of this and in March of this year released Service Bulletin (SB) TFE731-72-5227 that introduces a reconfigured accessory gearbox cover and a new hydrodynamic carbon face seal that will reduce starter and alternator gearshaft leaks.

These changes now require shimming the gearshafts to ensure they are properly positioned when the gearbox is assembled.

Compliance of this SB will change the accessory gearbox assembly part number from PN 3060827-2 to PN 3060827-4.

Honeywell recommends you incorporate this bulletin during your next scheduled Compressor Zone Inspection. Under certain conditions, a special/warranty program may be available for this modification. Consult the SB for details.

The following SBs should be complied with prior to or at the same time as SB TFE731-72-5227

  • TFE731-72-5124: Install/Rework Accessory Drive Gearbox
  • TFE731-72-5216: Install Improved Plain Encased


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

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