Hot section inspection: what it is, when it is due and what it finds

What the inspector is looking for

• Combustor liner and dome: cracks, burn-through, erosion, carbon build-up, distortion around the fuel nozzles.
• HPT nozzle guide vanes: cracks at the leading edge and platform, thermal barrier coating (TBC) spallation, burning, blocked cooling holes.
• HPT blades: tip rub and wear, cracks, TBC loss, erosion, nicks and dents from foreign or domestic object damage, cooling-hole blockage.
• LPT first stages: cracks, missing material, deposits.

Every finding is measured or sized and compared with the limit in the Aircraft Maintenance Manual (AMM) for that engine, stage and location. The limit, not the picture, decides what happens next.

When a hot section inspection is due

• At the interval in the operator's maintenance program (based on the AMM and the engine manufacturer's recommendations).
• After an exceedance: EGT overtemperature, hot start, hung start, overspeed.
• After an event: bird strike, FOD, surge or stall.
• Before an engine changes hands — pre-purchase, lease delivery, lease return and mid-lease checks almost always include one.
• When trend monitoring shows EGT margin eroding faster than expected.

How long it takes

On a narrowbody turbofan such as the CFM56 or V2500, the inspection itself usually takes a few hours on wing once the engine has cooled and the cowls are open. Findings that need measurement or a second camera angle add time. The write-up has traditionally taken as long again; InspectView's goal is to bring that part down to one or two hours by sorting the footage, drafting the findings and filling the report for the inspector to check and sign.

What the report must contain

Port-by-port images and video references, each finding with its size and the AMM reference it was judged against, a status per module (serviceable, repetitive inspection or reduced cycles, unserviceable), the engine identity (model, ESN, TSN/CSN), the borescope equipment used, and the name and authorization of the inspector who signed it.

What the outcomes mean

Within limits: the engine stays in service. Within limits but close: the inspector sets a repetitive inspection at a shorter interval. Beyond limits: the engine comes off wing for a shop visit, or the manufacturer is consulted for a repair or a concession. The AI never makes that call; a qualified inspector does.