Annual Aviation Borescope Reviewby Duane Sipe | February 16, 2021

A look at the very latest Aviation Borescopes, a little history of Remote Visual Inspection and a comparison table to help aircraft maintenance professionals choose the best scopes for their job.

Introduction

What is the purpose of your Remote Visual Inspection, and what are you inspecting? With today’s RVI being accomplished with borescopes, there is a wide variety of these fantastic pieces of equipment to choose from, but it hasn’t always been this way.

A Little History

The first recorded instance of a remote optical viewing apparatus is dated to 1921, where an eye doctor was asked to develop a device to peer inside an industrial turbine rotor.

Later, during world War II, the members of the military had developed crude visual inspection devices to inspect the barrels of their weapons. This is where the term ‘borescope’ is said to have been born.

It wasn’t until 1960 that the first commercially produced borescope became a reality. It was a rigid tube, with the required optics, to peek straight away inside cavities that were beyond the limits of the human eye to directly observe.

In the mid-1800’s, scientists and inventors had discovered that light could be bent by traveling through streams of water. This was the very beginnings of what is known as fiberoptics.

Fiberoptics allows the internal refraction of light through flexible fibers, usually silica or plastic. This technology is used everywhere today. In the mid-1960’s, fiberoptics was used for the first time in conjunction with borescope optics to produce the first ‘fiberscope’. This allowed inspection not only directly in line with the entry axis, but sideways and around corners.

Now, 60 years later, less than an average lifespan, there is a myriad of choices that will best suit the inspection needs of every type of aircraft and engine.

Today’s Remote Visual Inspection Equipment Choices

The current capabilities of the borescope have advanced through several stages, with each adding a new functionality.

The very first borescope provided just a ‘look-and-remember’ method. It was similar to a microscope, only with the target much further away.

We now have at least four more levels of combined capability:

• Look – Remember – Picture
• Look – Remember – Picture – Video
• Look – Remember – Picture – Video – Audio
• Look – Remember – Picture – Video – Audio – Wi-fi

Benefits to the Aviation Industry

The greatest realized benefit is a near incalculable savings on inspection because disassembly to access inspection points has become either non-existent or is greatly reduced.

Also, scopes used for inspection that utilize picture/video/audio capture particularly useful and important maintenance record entries.

With wi-fi enabled scopes, other technicians can be watching the ongoing inspection, right alongside the operator performing the work. Who doesn’t want a second set of eyes?

Scopes For Piston Engines

An internal inspection of the cylinder and the valves can help assess the cause of a low compression check. In the pre-scope days, if a cylinder was below limits and could not be corrected in some fashion, the jug was usually pulled to determine the flaw. There might have only been a piece of build-up on the exhaust valve that could have corrected itself on the next engine run.

An article published in the May 2017 edition of AOPA Pilot discusses Continental Motors’ 2003 Service Bulletin SB03-3, directing that cylinders with low compression test results be inspected with a scope. This was to determine if the cause was temporary as mentioned, or potentially catastrophic.

They required that if the visual inspection showed nothing major, the aircraft had to be flown for at least 45 minutes, then the compression test done a second time. If it failed again, then the cylinder needed pulled.

It was determined that many pulled cylinders over the years were not necessary, saving aircraft owners millions of dollars in maintenance expenses. Money saved because of the borescope.

In 2016, Continental incorporated the requirements of SB03-3 into their Standard Practice Maintenance Manual.

Scopes For Turbine Engines

With the development of guide tubes, used in conjunction with the fiberscope, the simple removal of fuel injector(s) makes it possible to inspect the hot section. And the compressor section can be viewed with little to no disassembly. Once again, substantial time and cost savings have been realized.

For Airframes

Internal inspection of the wing structure, wiring bundles, cables and connections, push-pull tubes, hoses; everything is available for inspection. The ‘look-and-remember’ method of the flashlight and mirror has been enhanced, creating the ability to add visuals to the maintenance record as needed.

For Avionics

Inspection of wire bundles, cable connections, equipment condition within avionics bays. Taking a close-up high-resolution image of suspect areas on circuit boards, such as possible open solder connections, burnt components, etc.

What mechanic or avionics technician has not found themselves lying on their back in the cockpit, feet propped up on the pilot seat, shoulders scrunched against the rudder pedals with a mirror in one hand, pen in the other, and a flashlight in mouth; all to get a fleeting glimpse of the upside- down and backward serial number of an instrument in the deep dark crevices, high in the panel?

Now, the flashlight and mirror-created visual image are combined into one convenient screen that can be captured and retained, as the probe is snaked through the radios, instruments, wire bundles, pitot tubing, switches, and circuit breakers.

(But unfortunately, the technician must still extract himself, Houdini-like, from the contortion riddled position he found himself in.)

What Should You Look for in a Borescope?

When one searches the borescope world, it will be quickly noticed that many features, options, and resultant benefits are available, across a broad array of choices. How should these variations be prioritized in the decision-making process?

When asked what potential customers should look for in a borescope, Doug Kindred, of Gradient Lens Corporation stated:

“Video borescopes that are intended for turbine engine inspection … the first thing is image quality, of course. Aircraft engine inspection is a critical inspection therefore you really need to be able to see well”.

When asked the same question, Bill French, of USA Borescopes echoed image quality, and added:

“Within aviation, most everyone will require articulation, and articulation refers to the ability to steer or manipulate the tip of the probe, so you can look up, down, left, right. Right now, the most popular is joystick articulation”.

Edward Thomas at SPI Borescopes states the following:

“I think the first two things people are going to want to focus on is great image quality, really excellent design in terms of usability and the ruggedness of the product, to make sure it’s heavy duty enough”.

What Does the Future Hold for RVI?

Mr. Kindred answered this question with a one-word reply:

“Measurement”.

In addition to measurement, Mr. French included:

“More advancements in image quality”.

Mr. Thomas adds:

“I think borescopes in what I am going to call the mid-price point of the market are going to start offering high end features. Things like working channels UV capability, IR capability, all included with a base unit”.

“And even as far as the measurement feature that’s relegated to the big boys at this point, I see that technology becoming more affordable in the middle price point of the market”.

Right now, there are few scopes that have measurement capability, but there seems to be consensus that more choices in the future will include this feature.

It’s a pretty safe bet that borescope technology is not going to go away any time soon. One can only imagine what the future holds.

With the advancement of time, and as with all electronics, the trends show increasingly powerful capabilities in ever shrinking packages, both in size and weight.

Could one possible next step after wi-fi capability be livestream to the internet, directly from the handheld unit? With the launch of Starlink, only time will tell.

Summary

Whether you are a one-man A&P/IA maintenance shop intending to make your first Remote Visual Inspection investment, Accountable Manager of a Part 145 Repair Station, an Operator of a fleet of Part 121 through 137 aircraft, or Military Ops looking to upgrade your current set of RVI tooling, there is undoubtedly a modern variant of the borescope with your name on it.

Aviation Borescope Selection and Review

The comparison table accompanying this article was developed from a basic web search, looking for aviation borescopes, searching from the perspective of a first-time buyer in mind.

The primary goal was to create a table to represent a broad spectrum of choices, with seven to ten vendors listed. The vendors were selected solely because they showed up ‘early’ in the google search term return list.

The table is in no way intended to be an all-inclusive list. Hence, due to space limitations, not every supplier could be included. The purpose is to give the reader a snapshot of the technologies available for their first, or next, piece of RVI equipment.

More research by the reader will be needed to explore beyond the suppliers listed here. The selection methodology after arriving on the vender website followed these steps:

1. The borescope had to be identified as aviation friendly.

2. In some cases, the most predominantly promoted borescope was chosen. But deviating from this step was sometimes done to add a broader variety of items including features, benefits, and cost.

3. The rigid borescopes were deliberately chosen outside the first two criteria to highlight the fact that the rigid type is still available, although the trend in aviation has migrated away from rigid scopes (these vendors also provide flexible scopes). This was a purely random decision.

Borescope Comparison Table

	USA Borescopes	Gradient Lens Corp	SPI Borescopes	Viewtech	ITS Videoscopes	Olympus	Waygate	Vividia	Lenox
Click image to view product details
Model:	USA1000 J-4-1500 Plus	Hawkeye® V3 HD Video Borescope: V3-040-1500-4	Recon 3915	VJ-3	XLED Pro Dual View	Iplex NX	XL Flex	AbleScope VA-400	7E060QV-29050
	See us on	See us on	See us on
Type:	360 Degree, 4-way Articulating Videoscope, with side view	4-way Articulating Videoscope	4-way Articulating Videoscope	360 Degree, 4-way Articulating Videoscope	4-way Articulation Combining 2 cameras in parallel. View (0 degree and 90 degree or both together) Videoscope	4-way Articulating Videoscope	360 Degree All-way Tip Articulation Videoscope	Rigid w/180 Degree Articulation	Swing-Prism Rigid
Diameter:	4.3mm	4.0mm or 6.0mm	3.9mm	3.9mm	4.0mm or 6.mm	4.0mm, 6.0mm, 6.2mm	4.0mm, 6.1mm, 8.4mm	8.5mm	6.0mm
Length:	1.5m	1.5m or 3.0m	1.5m	1.5m	1.5m, 7.5m	3.5m, 5.0m, 7.5m	6.6 feet to 32.8 feet, depending on model	400mm	11 inches
Imaging:	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes*	Yes*
Video:	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes*	Yes*
Audio:	Yes, In and Out	Yes, In and Out	Yes, In and Out	Yes, In and Out	No	No	Yes, In and Out	No	No
WiFi:	No	Yes	No	No	No	No	No	No	No
Measurement:	No	No	No	No	No	Yes	No	No	No
Demos:	Yes	Yes, No Cost	Yes, No Cost	Yes, No Cost	Yes, Limited to ITS Location Only	Yes	Yes, Onsite or Virtual	No	No
Warranty:	1 year	1 year	1 year	1 year	2 years limited warranty	1 year	1 year. Exceptions: Light Source 3 years, Battery 30 days, and where used Servo Motors Lifetime.	1 year	2 years
Price ($US):	$8,995	$11,995+	$11,950	$11,900	$15,232	$55,000+	$20,364+*	$249.98**	$4,862
Notes:						Designed for the largest of turbine engines such as; GE, P&W, RR. Stereo measurement (Distance, Point-to-line, Depth, Area/Lines), 3D Modeling, Scalar measurement.	Available through dealers/distributors. *Priced from Instrumart.	*USB Output to Windows and some Android versions. Available through dealers/distributors. **Priced from Oasis Scientific.	*Video and Digital adaptable.

We hope you found this article useful and please remember to double check any specifications in the borescope comparison table with the vender before you buy.

If you would like us to compare any other borescopes or add any additional specs for comparison, please let us know. Also, if there are any other test equipment products you would like us to compare, please email us at info@puremro.com