Operators of aircraft with Honeywell RE100 APUs installed (Cessna Latitude, Sovereign, Excel, G150, and Learjet 45/75) may want to revisit SB 49-8303. The HP Turbine wheel is limited to 4,000 cycles — so operators with the RE100 APU may be unaware of this cycle limitation.

Originally issued in April 2020 by Honeywell, this Service Bulletin related to reports of an unusual smell in the cabin during operation and addressed solutions to the issue.

Honeywell has designed new components and uses a new compressor seal technology that will reduce the possible leakage of oil into the bleed air system.

This SB gives authorization and instruction for the APU maintenance facilities to rework and repair the RE100 APU to incorporate the hydrodynamic carbon face seals.

Simultaneously, it’s important to review how many cycles are on the turbine rotor for possible replacement. (See limit and applicability info below.)

RE100CS APU’s installed in the Cessna Latitude, Sovereign, and G150

RE100XL — Installed in the Citation Excel

RE100LJ — Installed in the Learjet 45/75

RE100CS — Compressor: 36,000 cycles; turbine rotor: 12,000 cycles

RE100LJ — Compressor: 12,000 cycles; turbine rotor: 4,000 cycles

RE100XL — Compressor: 12,000 cycles; turbine rotor: 4,000 cycles

For your convenience, West Star can address this AD and other APU-related issues on location at all of our facilities, including satellites or through our AOG team for removal and reinstallations.