Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

NRCM Study Guide > NVG's > Flashcards

NVG's Flashcards

1
Q

WARNINGS: Limitations

NVG’s require _______ to operate.

A

NVG’s require some ambient light (moonlight, starlight, or artificial light, etc.) to operate. The level of performance depends on the level of light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

WARNINGS: Limitations

Ambient light may be reduced by such factors as

A

passing cloud cover & objects that produce shadows.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

WARNINGS: Limitations

The equipment is less effective viewing into

A

shadows & other darkened areas.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

WARNINGS: Limitations

The equipment is less effective through

A

rain, fog, sleet, snow, smoke, & other reflective material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

WARNINGS: Limitations

When conditions of possible reduction or loss of vision exist

A

Adjust speed & altitude to prevent overflying the field-of-view

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

WARNINGS: Limitations

Exercise extreme caution when flying over low-contrast terrain such as snow-covered territory, sandy desert environments, large bodies of water, grassy hills because

A

Under ambient starlight conditions, low-contrast environments degrade visibility, thereby disguising or masking changes in terrain.

This is especially true under low light conditions.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

WARNINGS: Limitations

Exercise extreme caution when flying from high ambient light conditions to low ambient light conditions because

A

Under low light condition, the goggles lose some resolution that they have under highlight conditions.

Flying from highlight to low light conditions quickly reduces the sharpness & definition of terrain images.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

WARNINGS: Limitations

Some goggles may experience a measurable loss of performance at temperatures above 100F (38 C).

  1. This is caused by
  2. If this begins to occur, it will appear as though you are looking through eye-glasses that
A
  1. ambient heat beginning to increase thermonic emissions of the photocathode.
  2. are starting to fog or develop a slight haze.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

WARNINGS: Limitations

The equipment has a field-of-view limited to

A

40° which requires appropriate continuous side-to-side head movements.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

WARNINGS: Limitations

If eyeglasses are worn, the upper rims of the eyeglasses can

A

obscure the low-battery indicator & reduce the field-of-view.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

WARNINGS: Limitations

  1. Do not attach the lanyard to the flight helmet. Attaching the lanyard to the flight helmet may cause
  2. The only authorized way of attaching the lanyard to the flight helmet is
A
  1. head & neck injuries in a survivable accident.
  2. with the use of fastener tape, hook, & fastener tape, pile.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

The image-intensifiers phosphor screen in each monocular contains toxic material, if it breaks. Don’t inhale, ingest, suck-on, or stick into open wounds. Wash off skin if you contact it. If you inhale/swallow, drink a lot of water, induce vomiting, & call the coroner.

A

inhale, ingest, suck-on, or stick into open wounds.

Wash off skin if you contact it.

If you inhale/swallow, drink a lot of water, induce vomiting, & call the coroner.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Some external lighting below 625 nanometers wavelength (blue-green lighting) cannot be viewed through the ANVIS because

A

of the minus-blue coating on the inside of the objective lenses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Glossary Term

Secondary Battery Compartment.

A

The secondary battery compartment is the lower compartment with respect to the ON-OFF-ON label.

Use only no-time (fresh) batteries in this compartment.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Glossary Term

Ambient Light.

A

The light present in the environment around a night vision device & produced by outside sources such as moon, stars, or reflected light.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Glossary Term

Caution.

A

Condition, practices or procedures that must be observed to avoid damage to equipment, destruction of equipment, or a long-term health hazard.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Glossary Term

Dark-Adapted.

A

Having ones eyes adjusted to the goggles output under low light conditions.

Typically takes 35-45 min. to dark adapt.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Glossary Term

Diopter.

A

A unit of measure used to define eye correction.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Glossary Term

Displacement.

A

A sight picture that deviates from the correct OSAP alignment at 40 degrees field-of-view.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Glossary Term

Image Intensifier Assembly.

A

An electro-optical device inside each monocular that detects & amplifies ambient light to produce a visual image.

It consists of a photocathode, microchannel plate, phosphor screen optics, & integral power supply.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Glossary Term

Infinity Focus.

A

Adjustment of the objective lens so that a distant object, such as a star or the point light on a distant tower, forms the sharpest image.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Glossary Term

Light Interference Filter. (LIF)

A

This is a light protection filter for the binocular.

Use of the filter will result in a slight reduction in system gain.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Glossary Term

Microchannel Plate.

A

A current-multiplying optical disk that intensifies the electron image produced by the photocathode.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Glossary Term

Minus-Blue Coating.

A

A special coating in the objective lens of the ANVIS that filters out light from the instrument panel in aircraft with the correct lighting.

This makes the goggles blind to the instrument lighting so the glare does not interfere with viewing outside the aircraft.

This coating will also eliminate viewing other lights with wavelengths below 625 nanometers, such as blue lights.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Photocathode.

A

The input optic of an image intensifier that absorbs light energy & in turn releases electrical energy in the form of an electron image.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Power Converter.

A

An aircraft component that converts 28 Vdc aircraft power to 3.8 Vdc for use by the ANVIS.

Some aircraft may have this power converter.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Power Pack.

A

A component of the ANVIS that attaches to the back of the helmet & provides power to the goggles.

Power is supplied either from aircraft power converter through the power pack or by batteries contained in compartments inside the power pack.

28
Q

Initial Battery Compartment.

A

The initial battery compartment is the upper compartment with respect to the ON-OFF-ON label.

Batteries in this compartment can be previously used batteries.

29
Q

Scintillation.

A

A faint, random, sparkling effect throughout the image area.

Scintillation is a normal characteristic of the image intensifier assembly & should not be confused with emission points.

Scintillation is more pronounced under low light conditions.

Sometimes called video noise.

30
Q

Warning.

A

Conditions, practices, or procedures that must be observed to avoid personal injury or loss of life

31
Q

Power Pack Low-Battery Indicator:

A

The ANVIS incorporates a red LED at the base of the mount that comes on when active battery voltage drops to 2.2 - 2.4 Vdc.

32
Q

Electrical Data. Using AA Alkaline Batteries.

Cell Life until low-battery indicator turns on @:

  1. 100F
  2. 70F
  3. 0F
  4. -22F
A
  1. 100F ⇒ 10-22 Hours
  2. 70F ⇒ 10-22 Hours
  3. 0F ⇒ 5-10 Hours
  4. -22F ⇒ 1-3 Hours
33
Q

Breakaway Force for NVG’s

A

10G-15G

34
Q

Counterweight can weigh up to

A

22 ounces

35
Q

Objective Focus Range

A

11 (±1”) to ∞

36
Q

Eyepiece Focus Ring

A

± 2 to 6 diopters

37
Q

Magnification of NVG optics

A

Unity (1:1)

Amplification of light, not magnification of image.

38
Q

Do NVG’s correct for astigmatism?

A

No, NVG’s do not correct for astigmatism?

39
Q

Field-of-View: NVG vs. Unaided

A

Field-of-View………………40 vs. 200 deg unaided.

40
Q

Light Amplification

A

2000-3500 times ambient light.

41
Q

NVG Operating Temperature

A
  • 32°C to +52°C
  • 26°F to +126°F
42
Q

Light Interference Filter (LIF)

Why do NVG’s need them?

A

In order to operate in laser threat environments, the ANVIS is equipped with LIFs.

Two types-distinguished by noting the number of lugs & notches around outside of the LIF.

The later type has a lug missing on each side, 180 degrees from each other & provides greater laser protection.

43
Q

Objective lens - How it works:

A

An optical element that gathers light and can be focused for the distance of an object.

  • contains a “minus-blue” coating which filters out light from the aircraft instrument panel. (below 625 nanometers.)
  • Photons enter the monocular assembly through the objective lens & are projected onto the photocathode.
  • The image is inverted due to the shape of the objective lens.
44
Q

Image intensifier (I2) assembly –

An electro-optical device that detects and amplifies light to produce a visual image.

The components include:

A

Photocathode

Microchannel Plate

Phosphors Screen

Fiber Optic Inverter

Power Supply

45
Q

The photocathode - Function:

A

releases electrons proportional to the amount of incoming photons.

The electrons are accelerated by an electrical field in the direction of the phosphor screen.

46
Q

Microchannel Plate - Function:

A

consists of approximately 6.34 million microchannels which are coated with an emissive material on the inside of the channel walls.

The microchannels are tilted approximately five to eight degrees to ensure that the incoming electrons strike the channel walls. Upon contact, the primary electrons cause the creation of secondary electrons which, in turn, strike the walls and create additional electrons, causing a cascade of electrons.

This amplification of electrons exit the microchannel plate in the same pattern that the original electrons entered.

47
Q

Phosphors Screen- Function:

A

A very thin layer of phosphor is applied to the input of the fiber optic inverter & emits light when struck by electrons.

The electrons strike the phosphor screen causing the phosphor to glow, creating a visible image.

48
Q

Fiber Optic Inverter- Function:

A

The image is then reinverted (upright) by the fiberoptic inverter where the image is displayed.

49
Q

Power Supply Function -

A

The power supply converts the 3.0 volts from the power pack to the voltage required by the photocathode, microchannel plate, and phosphor screen.

The power supply also provides automatic brightness control (ABC) and bright-source protection (BSP).

50
Q

ABC- Function:

A

Under high-light conditions, the ABC automatically reduces the voltages to the MCP (micro channel plate) to keep the image intensifier’s brightness within a set limit.

The effect of this function may be seen when rapidly changing from low-light to high-light condition; the image gets brighter and then after a momentary delay, suddenly dims slightly to a constant level.

ABC for you and me.

51
Q

BSP - Function:

A

The BSP function reduces the voltage to the photocathode when the goggles are exposed to bright light sources.

The BSP feature protects the image intensifier from damage and enhances its life; however, it also has the effect of lowering resolution. Therefore, under bright conditions when you would not normally use the goggles, the image produced is not sharp.

BSP - Protects photocathode.

52
Q

Operational Defects

NVG Operational Defects

A

These defects relate to the reliability of the image intensifier and are an indication of instability.

  • Shading
  • Edge Glow
  • Flashing/Flickering/Intermittent Operation
  • Emmission Points
53
Q
A

Shading -

  • Each monocular should present a full circle.
  • Shading is indicative of a dying photocathode caused by a defective vacuum seal of the image intensifier.
  • Shading is very dark and images cannot be seen through it.
  • Shading always begins on the edge and migrates inward eventually across the entire image.
  • Shading is a high contrast area with a distinct line of demarcation.
  • Do not confuse shading with variations in output brightness.
  • NOTE: Make sure the shading is not the result of improper tilt, eye-span adjustment, or vertical adjustment.
54
Q
A

Edge Glow -

  • is a bright area (sometimes sparkling) in the outer portion of the viewing area.
  • is sometimes caused by an emission point (or series of emission points) just outside the field of view or by a defective phosphor screen that permits light feedback to the photocathode.
  • To check for edge glow, block out all light by cupping a hand over the lens. If the image monocular assembly is displaying edge glow, the bright area will still show up
55
Q

Operational Defects

Explain Flashing, Flickering, or Intermittent Operation

A
  • An operational defect
  • The image may appear to flicker or flash.
  • This can occur in either one or both monoculars.
  • If there is more than one flicker, check for loose wires, loose battery cap, or weak batteries. Indicate the rate of flashing or flickering on the maintenance forms.
56
Q
A
  • An operational defect
  • A steady or fluctuating pinpoint of bright light in the image area and does not go away when all light is blocked from the objective lens of that monocular.
  • The position of an emission point within the image area does not move.
  • Make sure any emission point is not simply a point light source in the viewed scene.
  • Not all emission points deadline the ANVIS.
  • Place a cupped hand over the lens to block out all light. If the bright spot remains, return the ANVIS to the maintainer to be checked for tolerances.
57
Q

Cosmetic Blemishes -

A
  • These are usually the result of manufacturing imperfections that do not affect image intensifier reliability and are not normally a cause for rejection.
  • However, some types of blemishes can get worse over time.
  • Cosmetic blemishes are not a cause for rejection unless they become severe enough to interfere with the ability to perform the mission.
58
Q
A

Bright Spots -

  • These are signal-induced blemishes in the image area caused by a flaw in the film on the MCP.
  • A bright spot is a small, non-uniform, bright area that may flicker or appear constant.
  • Bright spots usually go away when the light is blocked out. Not all bright spots make the ANVIS unserviceable. Place a cupped hand over the lens to block out all light.
59
Q
A

Black Spots -

  • These are cosmetic blemishes in the image intensifier or dirt or debris between the lenses.
60
Q
A

Chicken Wire -

  • An irregular pattern of dark lines in the FOV throughout the image area or in parts of the image area.
  • Under the worst case condition, these lines will form hexagonal or square-wave shaped lines.
61
Q
A

Image Distortion -

  • This problem is more easily detected in high-light conditions.
  • It is evidenced by vertical objects, such as trees or poles appearing to wave or bend when your head is moved vertically or horizontally when looking through ANVIS.
  • Ground surfaces in the direction of hover may appear to swell or sink.
  • Distortion does not change during the life of an image intensifier. Each image intensifier has been screened for distortion before the first use; therefore, no action is required if this condition is present unless it interferes with viewing the image and interferes with the operator’s ability to perform the mission.
62
Q
A

Fixed-Pattern Noise (Honeycomb) -

  • This is usually a cosmetic blemish characterized by a faint hexagonal pattern throughout the viewing area that most often occurs at high-light levels or when viewing very bright lights.
  • The pattern can be seen in every image intensifier if the light level is high enough.
63
Q
A

Image Disparity -

  • This condition may exist when there is a difference in brightness between the two image-intensifier assemblies within the same binocular.
64
Q

Need new image example

A

Output Brightness Variation -

  • This condition is evidenced by areas of varying brightness in or across the image area.
  • The lower contrasts do not exhibit distinct lines of demarcation nor do they degrade image quality.
  • Do not confuse output brightness with shading.
65
Q

Optimal Sight Adjustment Procedure: Purpose

A
  • OSAP- is performed to precisely align each monocular to the individual eye by obtaining the optimal sight picture.
  • The optimal sight picture occurs when the optical axes of the monocular is aligned with the visual line of sight and the eyepiece is at the maximum distance from the eye while providing the entire FOV.
66
Q

OSAP Steps

A
  1. Don’t focus objective lens
  2. Use 1/4, 1/2 moon conditions with ø light sources in FOV
  3. Preset all mecanical adj’s to middle position
  4. Rotate goggles down
  5. Turn battery to primary
  6. Use Vert adj to ensure T/B edges are clear
  7. Adj Eye span to ensure L/R edges are clear
  8. Use fore/aft knob to adj away from eye until edges blur
  9. Cover one monocular, make small adj in eye span/vert/fore & aft adjustments, repeat with other monocular
  10. Use fore/aft adjt to bring goggles closer to eye (1/2 turn)
  11. Tilt lever should be adjusted in aircraft
  12. Continue to Outdoor Focusing Proceedure
67
Q

Outdoor Focusing Proceedure

A
  1. Turn both objective focus rings CCW then turn both eyepiece focus rings so dot and 0 Diopter are aligned
  2. Turn on Anvis
  3. Look at high contrast target 100-200feet away (building)
  4. Cover left objective lense (don’t close)
  5. Slowly turn right objective focus ring CW. Stop when sharp.
  6. Turn the right eyepiece focus ring CCW until the image blurs slightly. Then turn the eyepiece slowly CW until you first obtain a clear image, then stop.
  7. Repeat 3-6 for L monocular
  8. Turn the L objective focus ring so it is slightly out of focus and fine details are blurred but not whole objects. While viewing with both eyes open, fine-tune the right eyepiece focus ring. When a clear, sharp image is obtained, turn the left objective focus ring back to its original position.
  9. Repeat step (8) above for the left monocular.
  10. Turn off the ANVIS

NRCM Study Guide (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions