What is one borescope inspection finding on a high-cycle CFM56-7B or LEAP-1B that most often changes your on-condition plan? Can you give a quick example of when you chose an in-situ blend versus a module swap and what drove that call?

What Borescope Inspection Finding Most Often Changes the On-Condition Plan on High-Cycle CFM56-7B and LEAP-1B Engines? In-Situ Blend vs Module Swap Explained Introduction Borescope inspections are essential to on-condition maintenance for high-cycle aircraft engines. For engines such as the CFM56-7B and LEAP-1B, inspection findings often determine whether an engine remains on wing or requires early removal. One finding consistently drives this decision more than any other. The Key Finding: HPT Blade Distress The borescope inspection finding that most often changes the on-condition plan is high-pressure turbine (HPT) blade cracking or advanced thermal distress. HPT blades operate in the hottest section of the engine and experience extreme mechanical stress. As cycle counts increase, these blades become vulnerable to cracking, tip distress, and coating loss. When inspectors find damage nearing or exceeding allowable limits, operators usually revise maintenance plans immediately. Unlike minor compressor wear, HPT blade damage can progress rapidly. Once cracks begin to grow, the margin for safe continued operation shrinks quickly, making this finding especially critical. In-Situ Blend vs Module Swap: How the Choice Is Made In-Situ Blend Example A high-cycle CFM56-7B shows shallow cracking and minor tip distress on a limited number of HPT blades. The damage remains within approved blend limits. An in-situ blend is selected to remove stress concentrations and restore acceptable geometry. This option allows the engine to remain on wing while maintaining safety and performance. Module Swap Example A LEAP-1B inspection reveals multiple HPT blades with cracking near critical areas, some beyond blend limits. Engine performance trends also show reduced temperature margin. A module swap is chosen because the extent and distribution of damage reduce confidence in remaining blade life. Replacing the turbine module restores durability and operational margin. Conclusion For high-cycle CFM56-7B and LEAP-1B engines, many borescope findings are manageable. HPT blade cracking and advanced distress are not. This finding most often forces a change in the on-condition plan and drives the decision between an in-situ blend and a module swap. The right choice balances safety, remaining life, and operational reality.