How to upgrade Learjet nacelle anti-ice tubes

Effectivity: Learjet 40/45/70/75 aircraft 

ATA: 71 - Power Plant 

By: TJ Will – Customer Support Engineering 

Bombardier reminds Learjet 40/45/70/75 operators of several 2017 service bulletins that describe how to modify the engine inlet with an improved anti-ice tube (spray ring). These service bulletins are 40-72-02, 45-72-3, 70-72-01, and 75-72-01 – all released on June 19, 2017.   

IRN Z3020005 in 5-19-00 Special Inspections requires a borescope inspection of the anti-ice tube every 250 hours. Any cracks found during inspection will require incorporation of the service bulletin, since repairs to the older style spray ring are not allowed. Incorporation of these service bulletins will increase the inspection interval to 1200 flight hours (IRN Z3020006).   

Operators are instructed to remove the inlet and send it for modification by the Bombardier Component Repair and Overhaul (CR&O) department in the Wichita Service Center. The modification includes an increase in material thickness at the transition between the bleed air supply tube and the circular spray ring inside the nacelle. 

Other improvements include a new gasket, improved spray ring attach brackets, and an additional doubler at the penetration location of the forward nacelle frame. 

Coordination with CR&O is essential to minimize aircraft downtime. Inlets can be modified independently and do not have to be upgraded at the same time, although the increased inspection interval is only applicable to modified inlets. Modified inlets are reidentified with a new part number that is noted in the service bulletin after work is completed by CR&O.   

For additional information or questions, please contact your regional Field Service Representative.