Borescope Inspection Report: Maintaining Reliable Aircraft Engines

What is a Borescope Inspection Report?

Borescopes are visual inspection tools that are used in areas that are hard to access because they are narrow or small such as engines and turbines. Another reason for using a borescope is that it saves a lot of time and resources of taking apart complex equipment like an engine just to visually inspect its insides.

Generally, a borescope has a long narrow tube with a camera attached to one end. During inspections, this tube is inserted into the narrow space and then sends video feedback to the monitor on its body. For advanced applications, some borescopes have extra attachments like light sources, infrared scanners, and fiber optics.

A borescope inspection report is a formal document that contains all the methodologies, findings, and decisions that took place during an aircraft engine inspection using a borescope. It also contains significant images that were taken to show the general condition of the aircraft engine. This report is crucial because it shows if the rotating parts of the engine are still reliable for flights.

In this article, you will learn:

1. What a General Borescope Inspection Looks Like

2. The Most Common Defects to Look Out For During a Borescope Inspection

3. How A Digital Checklist Maker Can Help You Create Borescope Inspection Reports

General Procedures of Borescope Inspection for Aircraft Engines

During a borescope inspection, there are four general procedures done. Below are the details for each procedure and some critical points to consider during each phase based on the Flight Aviation Administration’s (FAA) Visual Inspection for Aircrafts.

1. INITIATE THE INSPECTION

The first generic procedure is initiating the inspection. This means carefully planning the inspection task which includes considering the access points and proper borescope selection.

Using the right borescope will greatly determine the accuracy of your borescope inspection report since different aircraft engines have different builds and access points. So, when selecting the right borescope, consider the points below:

• Access Opening Inside Diameter – Knowing what the smallest diameter of the access point is will ensure that the borescope camera can easily pass through the access point.
• Travel Path Geometry – Knowing the travel path shape will help in deciding whether to use a straight or curved borescope. This also determines if there is a need to use a guide tube.
• Borescope Length – Knowing how far the inspection point is from the access point will enable proper borescope length selection. To effectively do so, it is recommended to review the plans and structure of the engine. Also, the longer the borescope length is, the harder it is to control. That is why it is recommended to consider other access points or use guide tubes.
• Resolution – Higher resolution means more details which greatly aids in getting better inspection results. Also, depending on the inspection level and requirements, high-resolution images might be needed.
• Type of Documentation - Again, depending on the inspection level and requirements, images might not be enough. As such, some instances might require video recording capabilities.

2. ACCESS THE INSPECTION TASK

The second procedure in the borescope inspection is accessing and preparing the working area. This is critical since it greatly influences the results of the borescope inspection report as it affects the inspector’s motivation, decision-making, and interpreting ability.

Access is constituted by two aspects: primary access and secondary access. Primary access refers to the act of going to the inspection point whereas secondary access refers to the act of actually performing the inspection.

For both of these acts, mobility should be unhindered and uncomfortable positions should be avoided. Safety should also always be a priority. Staging equipment such as stairs, scaffolding, and platforms should always be used to prevent accidents and protective measures against sharp corners and edges should be implemented. All of these preparations should be reflected in the borescope inspection report.

3. SEARCH FOR INDICATIONS

During the actual inspection of the aircraft, the goal is to search for “indications” or any unusual physical defects that can be seen through the camera. All these “indications” need to be properly documented in the inspection report and should be specified with a description that indicates the type of the defect, blade count, as well as the defect location. It is important to not rely on memory when searching for indications. Currently, blade counting can be done easier by using a computer program that helps record and mark defects. But it can also be done manually by logging it into a notebook.

To effectively search for indications, it is recommended for inspectors to continuously ask themselves “What is wrong with this picture?” while looking for any abnormalities. It is also recommended to adjust light sources and the camera angle to get a better understanding of the area under scrutiny.

Typical Defects Detected Through a Borescope Inspection

There are various types of defects that can be detected through visual inspection. Below is a list of the most common defects found during borescope inspections:

• Corrosion – Corrosion is an obvious defect caused by the electrochemical reaction of the metal with its environment, as it is the case with oxidation, for example. For aircraft engines, there are some corrosion types that are not easily distinguishable and need to be detected via special tools and attachments.
• Discoloration – Discoloration can be caused by various factors such as burns, manufacturing issues, as well as corrosion.
• Cracks – Cracks can be caused by fatigue failure or by impacts caused by external elements. Large cracks can be easily noticeable but for hairline cracks, a borescope will need special borescope attachments.
• Surface Finishes – Typically, problems with surface finishes on the aircraft engine are caused by the manufacturing process. Some examples are blemishes, pits, and granules.

Perform Borescope Inspections With a Digital Checklist

For confirming indications, recommendations for repair, overhaul, or replacement need to be done in response to the borescope inspection. These responses are to be documented in the borescope inspection report and then submitted to the top management for review.

With Lumiform’s audit app you can easily perform a multitude of safety and quality inspections on the go from your smartphone or tablet - online or offline and easily create a full report without the fear or worry of having forgotten anything. Create checklists for your borescope inspection and easily collect data in the field to reduce errors and threats in aviation and ensure equipment longevity.

These benefits await you, if you choose to come aboard the Lumiform-family:

• Lumiform’s extensive template library offers thousands of ready-made templates to choose from, so that you can go digital in the blink of an eye.
• Of you prefer to create your own templates and checklists, Lumiform’s flexible form builder helps you convert any paper-based borescope inspections into a digital format in a quick and uncomplicated manner.
• With our easy-to-use mobile app you and your inspectors can perform borescope inspections efficiently.
• All inspection results are automatically summarised by the Lumiform software in a report and can be sent to responsible with a simple click - don’t lose time and save money.
• Comprehensive and automated analyses help you uncover threats and errors fast and effectively and thus allow you to concentrate on improving processes continuously.