We recently had the opportunity to try three Lenox Instrument borescopes, a 9-inch 6700K Rigid Autoscope, a 9-inch 6600K-900 Rigid Autoscope, and a Rigid Fiberoptic swing-prism borescope. All of these borescopes delivered a sharp, clear image and were easy to use.

For many applications, the handiest of the three is the 6600K-900, which features a 5/16-inch (8mm) diameter 9-inch-long probe with fixed focus from 1/4 inch to infinity and a 70-degree field of view. Power is provided by a tubular handle that holds three C-cell type batteries. A power wire is included, and the user can either attach the handle directly to the probe or attach the wire and place the handle in a pocket or other convenient location. The advantages of this Autoscope are that it is portable and the batteries can easily be changed. It would also make sense to use rechargeable C-cells. A rheostat on the top of the battery tube is used to adjust the light level. Retail price for the 9-inch Autoscope 6600K-900 is $995. Lenox offers an off-angle viewer attachment for areas where it is difficult to look straight into the eyepiece ($325). For another $1,875, users can opt for the Lenox Color Video System, which includes a borescope-to-camera adapter, power supply, color video camera, 13-inch monitor, and carrying case.

"We've sold thousands of these," said Lenox Instrument director of marketing William Lang. The 6600K is also recommended by Teledyne Continental Motors for compliance with TCM Service Bulletin SB03-3 (differential pressure test and borescope inspection procedures for cylinders).

The 6mm 6700K borescope offers a slightly wider field of view, at 90 degrees, and better focal length, from the surface to infinity. With a quartz lamp in the tip of the probe, the 6700K offers a brighter view than the 6600K-900. The 6700K is attached to a rechargeable NiCad battery pack with a wire, so the probe is easy to rotate for viewing a wide area. The battery pack has to be plugged in to 120-volt electrical supply for recharging, but once charged, the 6700K is fully portable.

A handy clip allows the user to attach the small battery pack to a belt or pocket.

The Rigid Fiberoptic Borescope delivered a bright view that was enhanced by the swing prism's ability to flip the view up and down to make it easier to see inside a piston engine cylinder without having to move the probe around too much. The Rigid Fiberoptic Borescope also features full rotation by turning a ring near the eyepiece, again making it easier to look around without moving the probe tip. This borescope uses a light cable from the probe to the Lenox Light Source, a 150-watt unit. The $1,875 camera adapter also works with the Rigid Fiberoptic Borescope. With a 12-inch swing prism probe (8mm diameter), 72-inch light cable, and Lenox Light Source, this rigid package retails at $3,222.

All of the Lenox borescopes can be used to take digital photographs, Lang said, without a camera adapter. Just hold the digital camera lens up to the borescope viewer, zoom to maximum, and take the picture. When doing this, I found that it worked well when holding the front of the camera lens directly against the probe viewer, then taking the photo with the camera's flash turned off because the borescope provides all the necessary light.

RVI Tools Improve Maintenance Quality

To say that the development of remote visual inspection (RVI) tools and, in particular, borescopes has come a long way is a technological understatement. "While you will still find plenty of uses for the original types, today a toolbox full of rigid borescopes can be replaced with a single flexible videoscope," said Joe Lopez, product manager for Everest VIT. "These systems will accomplish a number of tasks. They offer a greater economy of scale because a technician can do a lot more in less time.

"Today's ‘scopes not only make it easier for technicians to see things, they make it easy to document what they see," he added. "With built-in digital cameras, high-resolution photos can be taken instantly without the added workload of connecting a camera or video recorder."

"I've been doing borescoping for over 25 years and the ‘scopes we have today are what I have been hoping for all that time," said Mike Fitzgerald, manager of engine services for Stevens Aviation. "The biggest technological leap has been the video borescopes.

"They offer a lot of benefits," he continued. "But by far the biggest is you can instantly capture images in a very high resolution way. And because they are digital, you can share them with anyone, anywhere. With an old optical ‘scope, if you took your eye off to hand the ‘scope to someone else, they may not be able to find the exact location again. It was inefficient."

With the ability to e-mail images around the world, Fitzgerald said it is just like having the engine opened up with the customer standing right there looking at it. "It's a tremendous time savings," he added.

Ty Harrison, borescope primary training instructor for Delta Air Lines, shared Fitzgerald's enthusiasm for the video capabilities and added, "video capture has been a great benefit, but equally as important, I think, has been the very small diameters that today's ‘scopes come in. I can sum that up by saying, if there's a hole, there's a potential to do a remote visual inspection."

Harrison added that while the use of borescopes for engine inspections is well documented and understood, today's tiny ‘scopes are making big headway in increasing the efficiency and decreasing the time it takes to do airframe inspections. "It's an efficiency thing," he said. "Our technicians can get in and look at things without having to take them apart."

Harrison used the inspection of control surfaces to illustrate one role borescopes play today. "We used to have to remove them and take them apart to look for damage or a serial number if there is an AD or service bulletin," he explained. "Now, if there's a hole there, we just run a ‘scope in to look for the serial number or whatever. It saves us over eight hours of tear-down time on each part."

Another example of using RVI to save time was shared by Percival Francis, manager, aircraft quality control for FedEx. With more than 380 aircraft, it's critical for FedEx's maintenance people to have every time-saving tool available. "We have a Section 41 inspection we do on our 747s," Francis said. "We used to have to take the cockpit apart and galleys out. It would take the aircraft out of service for two or three months at a time.

"Now we go in there with the RVI stuff, remove some fasteners or drill some holes in the non-structural areas, and snake the probe inside there," he continued. "We can see all over inside the structure. The ‘scopes have 360 degrees of articulation so we can drive them all over. We do almost the entire Section 41 inspection with the cameras and we do it in a lot less time."

Francis also said that by using the RVI tools, FedEx has been able to cut back on unnecessary teardowns and save millions on maintenance costs. "We can go in and capture high-quality video images that we can send to our engineers or to the engine or airframe manufacturers," he said. "The engineers see exactly what is going on and make the calls. If a part doesn't need changing, we can find out right away instead of having to wait weeks for paperwork to go back and forth."

Stevens Aviation's Fitzgerald recounted a situation where RVI definitely saved a customer money and probably something priceless. "We were doing a routine borescope inspection on a King Air's engines. It had no reported problems but when we were doing the fuel nozzle inspection, we found a thin black line on a turbine blade," he said. "We also saw a tiny dent on the leading edge of the blade. If it weren't for the dent we would have thought nothing of it.

"We conferred with the owner and decided to take the engine apart for a thorough inspection," he continued. "We found the blade was cracked and so we sent the disc to an NDT facility for an inspection. They found that 35 of the blades had cracks in them."

"How much money did we save the customer by finding the cracked blades? What is avoiding a catastrophic failure worth?" he asked. "It was expensive, but a lot less expensive and dangerous than it would have been if one of those blades would have let loose when the engine was running."

While today's video borescopes are amazing, the manufacturers are always looking for ways to make them better. For example, Karl Storz Endoscopy America recently introduced a new laser-measurement capability. "The primary advantages are that it is more accurate, easier to use, and cuts the overall cost of the inspection," explained Taylor Hunter, Storz's general manager, industrial endoscopy. "With the laser a technician can do a real-time measurement on demand.

"The old way was to take the probe out and attach a special measurement tip. That not only added time, it was often difficult for the technician to find the same spot," he added. Now he just flips a switch and can do a measurement in seconds without the need to reposition the scope. The technician now has an effective tool to help make go/no-go decisions on critical parts."

Midcoast Boasts In-house RVI Training

Remote visual inspection (RVI) tools are supposed to help technicians do engine and airframe inspections faster and more effectively, but when Midcoast Aviation's senior director, technical services Morris Smith and manager, technical support Tom Hilboldt saw the overall cost of their company's RVI inspections skyrocket, they decided to take dramatic action.

The first thing Midcoast did was limit use of borescopes. "Our borescope operating costs were skyrocketing because of the high repair costs from damage caused by technicians not having proper training," Hilboldt said. "Besides having a training issue, with so many technicians using the units, none of them had an opportunity to really become proficient with the tools."

So they limited access to borescopes to only a handful of technicians and only after those had received specialized training. "We've limited the training," Hilboldt said, "to our crew chiefs and lead inspectors who not only had the return to service authorization on our repair station certificate, but also because they had the experience to visually inspect critical components and make judgment calls. We have around 127 technicians and only about 30 of them are qualified to do borescope inspections."

Smith explained that the majority of Midcoast's RVI training is completed on the job and relies heavily on mentoring. "When one of our technicians is doing an engine inspection, they have another technician assist them to see the proper way to do the procedure," he said. "Engine borescoping is very specialized work so to do it a technician not only has to be very skilled with the ‘scope, they have to receive specialized training from the engine manufacturer."

By pairing a younger technician with a more experienced one, the skills and procedures can be passed along at a comfortable pace. Hilboldt also said that this process also gives each technician enough recurrent use of the borescope to keep his or her skills sharp. "Lack of currency was a major contributor to misuse and handling accidents," he said.

Since the program began in 1995, Midcoast's in-house RVI training program has been a success, taking technicians from novices to masters of the art of borescope inspections. "We've developed a very effective training program," Smith said. "The only outside training we use is when we buy a new piece of equipment. After initial training the knowledge is mentored back to all the other technicians who will use the borescope."