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Do You Need An NVG Inspection?
Night Flight Concepts offers in-depth and cost-effective aviation NVG services and inspection procedures. Our highly-trained and experienced technicians utilize calibrated testing equipment and state-of-the-art inspection, servicing, and repair methods to provide the best aviation night vision goggles services. Our team ensures that you have smooth and safe flight operations.
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In-Depth NVG Inspection
Part of our 180-day inspection is a complete and comprehensive assessment of every component of night vision goggles: battery pack, helmet mount adapter, goggle adjustment rages, gain, current draw, image distortion, high/low light resolution, infinity focus, image intensifier, eyepiece diopter settings, binocular collimation, purge, and low battery indicator function.
Once we complete the NVG 180-day inspection, we will return the night vision goggles with a test data sheet, airworthiness compliance certificates, and an NVG maintenance logbook.
Accurate Performance Measurements
To secure the safe use of NVG during helicopter operations, another key service feature we provide is performance measurements for all aviation NVGs. As the night vision goggles come through our inspection facility, we measure their performance and enter the data we collect in our database.
We will then conduct a continued accumulation of data as the goggles rotate through inspections. This step allows us to develop a trend analysis which helps us determine certain NVGs that may be aging and showing signs of reduced performance over time.
Professional Aviation NVG Repair Services
Our aviation night vision goggles specialists and other crew members are experienced and highly trained to handle any NVG issue you may have. If you see any blemishes or defects on your goggles, send them our way for proper inspection or repair. Please complete our shipping form and send it along with your NVG.
LOOK FOR COMMON NVG FAULTS
PRIOR TO EACH FLIGHT BEFORE EACH FLIGHT
Operational Defects
Operational defects are an immediate cause of rejecting NVGs for use. Once detected, the NVGs must be returned to our facility for evaluation and repair. These are the four operational defects NVG users should watch for:
Shading
If there’s shading, you won’t see a full circular image. This situation is caused by a defective vacuum seal of the image intensifier, indicating a dying photocathode.
When there’s shading, it’s completely dark and there’s zero visibility of images through the shaded area. It typically begins on the edge and migrates inward, eventually across the entire picture. Shading is a high-contrast area with a distinct line of demarcation.
However, don’t confuse shading with variations in output brightness. Improper sight adjustment and focusing procedures can also result in the false appearance of shading. Send your NVG to us if you suspect that there’s shading. We can carefully inspect it and correct any shading issues.
Edge Glow
If there’s an emission point (or a series of emission points) outside the field of view or by a defective phosphor screen that permits light feedback to the photocathode, your NVG should be checked for edge glow.
To do so, you’ll need to cup a hand over the objective lens of the NVG. The bright area will remain visible if the image monocular assembly displays an edge glow. Remit your NVG to Night Flight Concepts so we can check them for edge glow.
Emission Points
When checking for emission points, ensure it’s not just any lighting system or light source in the viewed scene. Emission points don’t go away when all light is blocked from the objective lens of that monocular. It can be a steady or fluctuating bright light in the image area.
Place a cupped hand over the objective lens when checking for emission points to block out all light. If the bright spot remains, submit the night vision goggles to Night Flight Concepts for further checking.
Flashing, Flickering, or Intermittent Operation
The image may appear to flicker or flash, either in one or both monoculars. You can commonly see these blinking when adjusting the eye-span knobs. If you experience multiple flickers, check for loose wirings, battery caps, or weak batteries.
For any flashing, flickering, or intermittent operation, send your night vision goggles to us for a comprehensive inspection. Make sure to indicate the amount of flashing or flickering on our inspection and maintenance form.
Cosmetic Blemishes
These are usually manufacturing flaws. Cosmetic blemishes found in night vision goggles don’t necessarily render them ineffective; these flaws do not affect the image intensifier reliability. Nevertheless, some cosmetic blemishes can worsen over time. And while these blemishes are not usually a cause for rejection, they can get severe enough to interfere with the goggles' performance.
If you find any blemish in your NVG, document the specific nature of the problem on the provided maintenance forms. Identify the position of the defect by using the clock method and approximate distance from the center (e.g., 5 o’clock toward the outside, 2:30 near the center, or 1 o’clock midway.) You may then return the NVG for repair to our FAA Part 145 NVG Inspection and Repair Station.
Here are some of the most common cosmetic blemishes you should look out for:
Bright Spots
Flaws in the film on the microchannel plate can cause bright spots in the image area. These spots are usually small, non-uniform, and bright. They may flicker or appear constant, typically disappearing when the light is blocked.
To check if any bright spot you see is a cause for concern, place a cupped hand over the objective lens to block out all light. If the spot remains, there’s a likelihood of an emission point. You may then send the device to us for further checking.
Output Brightness Variation
This is characterized by areas of varying brightness levels in or across the image area in an individual monocular. The lower contrast does not show distinct lines of demarcation. They also don’t degrade image quality.
For more information about our NVG inspection and maintenance repair services, please fill out our contact form so we can adequately assist you.
Image Disparity
This condition may exist when there is a difference in brightness between the two image intensifier assemblies within the same binocular.
Veiling Glare
When light outside the field of view strikes the objective lens of a night vision goggle and scatters rather than passing straight through the lens, then something called veiling glare occurs. This condition produces a reduction in contrast and occurs only under certain circumstances.
It may be caused by excessively scratched, pitted, or chipped objective lenses. Additionally, dust and fingerprints may affect this condition. Thus, you must ensure that your lens is always clean.
During a routine NVG preflight inspection, veiling glare may not be immediately evident. Our experienced specialists will thoroughly check for a veiling glow to see if the image intensifier or objective lens must be replaced.
Image Distortion
When looking through your NVG, do vertical objects such as trees or poles appear wavy or bendy? If so, then your goggles should be screened for distortion. We recommend each image intensifier be checked before the first use.
All Night Flight Concepts aviation NVG undergoes a detailed and meticulous quality assurance check before delivery.
Black Spots
These are usually dirt or debris stuck between the lenses. Generally, you can assume the black spot was there during acceptance. However, occasionally the need may arise to verify the location, size, and number of spots against the allowed specifications for the image intensifier.
Chicken Wire
These are irregular patterns of dark lines found all over or in parts of the image area. Under the worst-case condition, these lines may form hexagonal or square-wave-shaped lines. These lines exist due to the defective fibers not transmitting light at the boundaries of fiber bundles in the output optic of the image intensifier.
Fixed Pattern Noise
This is characterized by hexagonal patterns throughout the viewing area that usually occurs at high-light levels or when trying to view extremely bright lights. All NVG image tubes will display fixed pattern noise if the outside lighting output is high enough.
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