Gas Turbine Visual Inspections: the Aero Way
In-situ gas turbine engine inspections serve to satisfy airworthiness regulatory requirements to determine the condition of critical engine parts. They are mandated within the Aircraft Maintenance Manual (AMM) for each and every engine type in civil operation today.
The result of such inspections provide the licensed inspector with the necessary information to decide whether a given engine, or Asset, can remain on-wing and continue operation.
Engines are designed to operate with minimal visual inspection intervention. They’re triggered by function of engine lifecycle e.g. flight cycle count or time on condition or in response to an ‘anomalous event’ such as bird strike, heavy landing or engine performance issue etc.
On-wing inspections meticulously adhere to procedures captured within the relevant AMM until it reaches the point when it must be removed and inducted into the Maintenance Repair & Overhaul facility. The engine is either partially or fully stripped for detailed examination. Dependent on its specific stage within its lifecycle, some parts are left in-situ and visually examined using a borescope whereas others are fully dis-assembled, removed and replaced for new. The engine is re-assembled, tested and examined (again!) before returning back to service.
Visual inspection and human intervention
I often refer to ‘in-situ engine inspections’ as serving the need to satisfy Asset Health Monitoring (AHM). Indeed, there are many other forms of conditioning monitoring data that is widely embedded within the Aerospace Industry. All modern gas turbines are equipped with pressure, vibration and temperature monitoring systems that track and trend the performance of the Asset but the visual condition of the engine is the modality today that requires significant Human intervention. The engine must be shutdown; it must be cool enough to permit safe access; staging, tooling and activation of safety systems are necessary before anyone is permitted to begin work on the engine – only until this point can a given inspection begin. Six or more hours could easily elapse before any work can begin.
Yet more time must be factored-in to safely return the engine to a serviceable condition once it has been completed. A lot of planning and logistics is needed to make this happen.
Unplanned or unscheduled engine inspections are highly disruptive to Airline Operators – especially those that require frequent re-inspection in order to satisfy continued safe operation of the Asset.
Using artificial intelligence to reduce downtime and automate data collection and analysis
Technology helps reduce the maintenance burden associated with in-situ visual inspections. Our collaboration with Rolls-Royce has provided a means to leverage Artificial Intelligence to generate the required inspection dataset in a much more efficient manner. Click here for more information relating to the Intelligent Engine Inspection. It has not only provided a means to conduct an inspection much quicker, but the resultant Inspection System enables automated data collection, analyses and reporting, directly on to the borescope.
The licensed inspector remains central to the inspection activity. No decision or sentencing is removed from the inspector’s duties.
Data is presented with the appropriate information in a much more repeatable format with consistency and quality.
Human Factors that affect traditional visual inspection quality are reduced because of the connected intelligence that is now formed between the Borescope and its embedded AI analytic and the connected electronic Turning Tool which provides a trigger that enables automated image capture along with updated blade number annotation.
To the casual observer, the inspection equipment setup appears completely standard. No other supplementary device such as tablet or laptop is required to provide computational power.
Administrative tasks such as filename housekeeping, report generation and even secure connectivity to cloud network can be enabled to further optimise inspection workflow directly on the intelligent borescope.
The data generated during periodic in-situ inspections also serves an important secondary need that is becoming more and more important to Gas Turbine OEM’s and Airline Operators alike.
Fleet Health Management and Waygate Technologies’ Mentor Visual iQ Borescope
Collective AHM data provides Airline Operators and engine OEM’s the ability to perform valuable Fleet Health Monitoring (FHM). Holistic understanding of the visual condition of critical parts of an engine variant throughout its lifecycle is now possible.
Data would be traditionally collected during MRO shop visits whereupon part inspection and data collection would feedback into the design loop. Valuable trending of component degradation and detection of emerging defect anomalies are opportunities not fully realised.
Collecting the visual appearance along with accurate 3-dimensional dimensional data of each aerofoil component can now be considered a proactive maintenance strategy that can be efficiently collected whilst the engine remains in operation i.e. not just in the MRO facility.