Aileron Inspection and Modification

Effectivity: Learjet 40/45/70/75/60 aircraft 

ATA Code: ​27 - Flight Controls​

By: Kevin Ensminger – Technical Services  

Bombardier would like to inform operators of a recent service bulletin regarding the inspection and modification of the ailerons on Learjet 40/45/70/75 aircraft. Corrosion has been found in the aileron leading edge, internal structure and common to the leading edge balance weights and attached structure.   

Recommended Service Bulletin 45-27-53 was released on Jan. 17, 2025, and is applicable to Learjet aircraft 45-005 through 45-200. This service bulletin provides instructions for a borescope and eddy current inspection of the leading edge. Temporary Revision No. 27-3 to the Learjet 40 aircraft series NDI (Nondestructive Inspection Manual) was released as well and provides inspection procedures for the eddy current process on the aileron leading edge skin. In addition to the inspection, additional drainage holes are opened in the leading edge, where existing tooling holes and structure bend relief sealant applied during manufacture is removed. Time of compliance for the service bulletin is six (6) months from date of release, or July 17, 2025.  

Accompanying the service bulletin is a questionnaire to be completed and returned to Learjet Field Support Engineering (FSE), along with inspection results from the service bulletin. FSE will then provide the necessary repairs based on inspection results, following the normal repair request submittal. 

Additional service bulletins for Learjet 40/70/75, and the remainder of the Learjet 45 aircraft (45-201 thru 45-455) are scheduled to be released on June 30, 2025. These service bulletins will have the same inspection/modification instructions and time of compliance as the original service bulletin.   

Learjet 40/45/70/75 aircraft Maintenance Manuals will be revised to incorporate a 48-month recurring inspection of the aileron leading edges, mirroring the inspection procedure in the service bulletin.   

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