CFM56-7B borescope inspection: what inspectors look for, stage by stage
Fan to LPT, the findings that matter on the world's most common narrowbody engine — and which ones move the value of the asset.
Fan and booster
The fan is inspected visually from the inlet: leading-edge nicks and dents, tip curl, blade shingling, platform and spinner condition. The three-stage booster behind it is reached through its borescope ports and is the first place foreign object damage shows up after it clears the fan.
High-pressure compressor, stages 1 to 9
The front stages take the FOD and erosion; the rear stages run hot and show tip rub, corrosion and airfoil distress. Each stage is indexed blade by blade. Nicks and dents are measured against the stage-specific limits in the engine manual; the limit is not the same for a stage 1 blade as for a stage 9 blade.
Combustor
Liner cracking, burn-through, missing material and fuel-nozzle coking are the headline items. Combustor condition also tells the inspector what to expect one stage downstream, because anything that leaves the combustor goes through the high-pressure turbine.
High-pressure turbine
The HPT nozzle guide vanes and the single stage of HPT blades carry the highest temperatures in the engine. The inspector looks for thermal barrier coating loss, trailing-edge burn and cracking, tip loss and blocked cooling holes. Measurements here are the ones most likely to be compared against a lease return condition or a purchase agreement, so this is where third-generation 3D measurement earns its place.
Low-pressure turbine, stages 1 to 4
Airfoil cracking, platform damage and impact marks from upstream debris. The LPT rarely drives a shop visit on its own, but it tells the story of what has passed through the engine.
What moves the value of the engine
- HPT blade and nozzle condition — the single biggest workscope driver.
- HPC rear-stage distress — points to a heavier compressor workscope.
- Combustor liner cracking beyond limits — adds cost and time at the shop.
- Documented, measured findings with video — the difference between a negotiation and an argument.
Do you inspect CFM56-7B engines on wing or off wing?
Both. On wing on the ramp or in the hangar, and off wing in the shop or in storage, including engines on stands awaiting a trade.
Which CFM56 variants do you cover?
CFM56-5B and CFM56-7B are our daily work, alongside LEAP-1A/1B, V2500, CF6-80, CF34, PW4000, GE90, GEnx, Trent, PW1100G and the 131-9 and GTCP36 APU families.
How is the report delivered?
As a PDF with stage-sorted stills and video links, drafted in InspectView and signed by the JTech inspector, in the format your lessor or buyer already accepts.
JTech Turbines performs borescope, GVI, QEC, pre-purchase and lease return inspections on site in 30+ countries. Reports are drafted in InspectView and signed by the inspector.