APART Study Guide Flashcards
NVG NOMENCLATURE, CHARACTERISTICS, LIMITATIONS, AND OPERATIONS
Describe how light passes through the ANVIS.
OPMPFE
* Objective Lens (inverts image, minus blue filter)
* Photocathode (changes photons to electrons)
* Microchannel Plate (multiplies electrons)
* Phospher Screen (electrons to protons, creates the lighted image)
* Fiber Optic Inverter (inverts the image)
* Eyepiece Lens (allows the eye to see the image)
What is Automatic Brightness Protection (ABC)?
ABC automatically adjusts microchannel plate (MCP) voltage to maintain image brightness at preset levels by controlling the amount of electrons that exit the MCP.
ABC is to protect the wearers vision, not to protect the goggles.
What is Bright Source Protection (BSP)?
Reduces the voltage to the photocathode when exposed to bright light sources.
This protects the goggles from damage and enhances its life (however, it lowers resolution).
Exposure to bright light sources could result in damage to the photocathode, MCP, or the operator’s
eye.
What are the ANVIS operational defects?
SEEF
Flashing, Flickering, or Intermittent Operation
Edge Glow
Shading
Emission Point
ANVIS OPERATIONAL DEFECT
Describe Flashing, Flickering or Intermittent Operation.
Light appears to flicker or flash. Can be in either one or both monoculars.
ANVIS OPERATIONAL DEFECT
Describe Edge Glow
A bright area in the outer portion of the viewing area (could be caused by a series of emission points).
Check by covering the light entering from the objective lens. If it remains, it is edge glow.
ANVIS OPERATIONAL DEFECTS
Describe Shading
You will not see a fully circular image, regardless of the adjustment. Begins at the edge and works inward. There will be a high contract area with a distinct line of demarcation.
ANVIS OPERATIONAL DEFECTS
Describe an Emission Point
A steady or fluctuating pinpoint of bright light in the image area and does not go away when all light is
blocked from the OBJ lens.
What are the ANVIS cosmetic blemishes
IF I COB
Image Distortion
Fixed Pattern Noise
Image Disparity
Chicken Wire
Bright Spots
Output Brightness Variation
Black Spots
ANVIS COSMETIC BLEMISHES
Describe Image Distortion
Evidenced by vertical objects (poles / trees) appearing to bend when you move your head vertically or
horizontally.
Ground surfaces may appear to swell or sink as well.
ANVIS COSMETIC BLEMISHES
Explain Fixed Pattern Noise
AKA Honeycomb
Faint hexagonal pattern throughout the viewing area that most often occurs at highlight levels.
ANVIS COSMETIC BLEMISHES
Explain Image Disparity
Difference in brightness between the two image intensifier assemblies within the same binocular.
ANVIS COSMETIC BLEMISHES
Explain Chicken Wire
An irregular pattern of dark thin lines in the field of view either throughout the image or in parts of the image.
Under worst conditions, these lines will form hexagonal shaped lines (think of it as the beginning of
honeycomb)
ANVIS COSMETIC BLEMISHES
Explain Bright Spots
These are SIGNAL induced - a bright spot is a small bright area that may flicker or remain constant.
ANVIS COSMETIC BLEMISHES
Explain Output Brightness Variation
Evidenced by Areas of varying brightness in or across the image area.
DO NOT CONFUSE WITH SHADING. There are no distinct lines of demarcation
ANVIS COSMETIC BLEMISHES
Explain Black Spots
These are blemishes in the image intensifier or dirt, hair or debris between the lenses.
What is the intensification of the ANVIS?
2000-3000 times
What is the visual acuity of the ANVIS
Best is 20/25 when looking through the center of the tubes. At the periphery, the acuity can decrease to 20/70
What is the FOV of the ANVIS with proper OSAP?
40 degrees
What is rhe Breakaway force of the ANVIS?
10-15Gs
What are some limitations of the ANVIS?
Reduction in visual acuity
Color vision decrease/dissapear
Night blind spot
What are the three night vision techniques that can help overcome ANVIS limitations?
SOS
Scanning
Off center viewing
Shapes or Silhouettes
What are the Visual Illusions?
FFSHAVSCC (For Fucks Sake HAVe Some Class Carl)
Fascination/Fixation
False Horizon
Size/Distance Illusion
Height/Depth Perception Illusion
Autokinesis
Vection (Inducted Motion Illusion)
Structural Illusion
Confusion with
VISUAL ILLUSION
Describe Facination/Fixation
**Fascination: **Task Saturation (in cockpit) - so engrossed with a problem or task within the cockpit, they fail to scan outside
Fixation: Target Fixation (out of cockpit) - fixating on object outside the cockpit you fail to scan/crosscheck
Solution: refrain from staring; scan
VISUAL ILLUSION
Describe False Horizon
Aviator confuses cloud formations with the horizon or the ground, thus they may fly the aircraft in a
banked attitude.
Solution: Scan instruments and other visual cues
VISUAL ILLUSION
Describe Size Distance Illusion
- Size Constancy Illusion – an example is landing at an unfamiliar runway. A narrower runway may lead a pilot to believe he/she is higher and further away.
- Shape Constancy Illusion – Commonly encountered with sloping runways. An upsloping runway may give the pilot the illusion of being too high
- Aerial Perspective Illusion – visual cues are of a different size or perspicuity (clarity and discrimination) than expected. An example is mistaking short immature trees for full grown ones. Also, objects within a hazy environment are often thought to be further away than they actual area.
VISUAL ILLUSION
Describe Height/Depth Preception Illusion
The height - depth perception illusion is due to a lack of sufficient visual cues and causes an aircrew to lose depth perception (i.e. flying over desert, snow, water the aviator may fly extremely low due to lack of cues.)
Solution: trust instruments and scan horizon
VISUAL ILLUSION
Describe Autokinesis
Primarily occurs at night when ambient visual cues are minimal and a small dim light is seen against a dark background. Aviator visually fixates on light for 6-12 seconds, the light appears to move up to 20 degrees in any direction and continues to “move”.
Solution: avoid fixating on objects, develop a good scan.
VISUAL ILLUSION
Describe Vection
Falsely perceived self-motion (at a stop light, car next to you starts moving and you think you’re
moving).
**Solution: **proper scanning - experience / knowledge of the occurrence
VISUAL ILLUSION
Describe the Structural Illusion
Caused by effects of heat waves, rain, snow, sleet, or the shape of the windscreen - objects may appear obscure / not their true shape/size.
Solution: experience / knowledge.
VISUAL ILLUSION
Describe Confusion with Ground Lights
Aviator mistakes ground lights for stars - which prompts aviator to place the aircraft in an unusual
attitude to keep the misperceived ground lights above them.
Solution: conduct a proper scan, aided and unaided.
VISUAL ILLUSION
Describe the Crater Illusion
Aviator mistakes ground lights for stars - which prompts aviator to place the aircraft in an unusual
attitude to keep the misperceived ground lights above them.
Solution: conduct a proper scan, aided and unaided.
What are the 5 major components of the eye?
- Cornea
- Iris
- Pupil
- Lens
- Retina
What are the 3 types of vision?
PMS
Photopic - day OR bright/high light levels
Mesopic - dusk/dawn OR medium to low level light
Scotopic - night OR low light levels
What are the Monocular Cues?
GRAM
Geometric Perspective
Retinal Image Size
Aerial Prespective
Motion Parallax
MONOCULAR CUES
What is Geometric Perspective and what cues does it include?
An object may appear to have a different shape when viewed at varying distances and from different angles.
LAV
Linear Perspective
Apparent Foreshortening
Vertical Position in Field
MONOCULAR CUES
Explain Linear Perspective
Parallel lines, such as railroad tracks, appear to converge as distance from the observer increases.
MONOCULAR CUES
Explain Apparent Foreshortening
The true shape of an object or terrain feature appears elliptical (oval and narrowed appearance) when viewed from a distance.
MONOCULAR CUES
Explain Vertical Position in Field
Objects or terrain features farther away from the observer appear higher on the horizon than those
closer to the observer.
MONOCULAR CUES
What is Retinal Image Size and what cues does it include?
An image focused on the retina is perceived by the brain to be of a given size.
KITO
Known Size of Objects
Increasing/Decreasing Size of Objects
Terrestrial Association
Overlapping Contours
MONOCULAR CUES
Explain Known Size of Objects
Familiarity with an object or classification of objects allows us to determine the relative distance to that object. The nearer an object is to the observer, the larger its retinal image.
MONOCULAR CUES
Explain Increasing/Decreasing Size of Objects
If size is increasing, object is coming closer - if size is decreasing the object is moving farther away - if size is constant, object is staying the same distance.
MONOCULAR CUES
Explain Terrestrial Association
Objects normally associated together (helicopter and heliport / airport) are judged to be at about the same distance and assist in determine size.
MONOCULAR CUES
Explain Overlapping Contours
When objects overlap, the overlapped object is farther away.
MONOCULAR CUES
What is Aerial Perspective and what cues does it include?
The clarity of an object and the shadow cast by it are perceived by the brain and are cues for estimating distance.
FLP
Fading of Colors and Shades
Loss of Detail or Texture
Position of Light Source and Direction of Shadows
MONOCULAR CUES
Explain Fading of Colors and Shades
Objects viewed through haze, fog or smoke are seen less distinctly and appear to be at a greater
distance than they actually are.
If light is unrestricted - the opposite is true because you can see the object more distinctly / more details
- so it appears closer.
MONOCULAR CUES
Explain Loss of Detail or Texture
As a person gets farther from an object, discrete details become less apparent (a corn field from high altitude looks like a green blob and everything seems to blur together - but up close, you can tell it is clearly a corn field with distinct rows and patterns).
MONOCULAR CUES
Explain Position of Light Source and Direction of Shaddows
Every object casts a shadow from a light source. The direction in which the shadow is cast depends on
the position of the light source. If the shadow of an object is towards the observer, the object is closer
than the light source is to the observer.
MONOCULAR CUES
Describe Motion Parallax
(Most Important for depth perception) - Apparent relative motion of stationary objects as viewed by an observer who is moving across the landscape
Near objects appear to move against the direction of travel
Far objects appear to move with the direction of travel slightly, or stay stationary.
What benefit does pre-breathing oxygen / having oxygen available have yon your night vision?
You start to lose night vision at 4,000 feet PA because of lack of oxygen to the RODS.
Lack of oxygen to the rods significantly reduces their sensitivity, increasing the time required for dark adaptation and decreasing their ability to see at night. RHODOPSIN IS OXYGEN DEPENDENT.
Describe the Night Blind Spot
Occurs when the fovea becomes inactive under darkness or low level illumination - central vision
becomes less effective and the night blind spot develops.
The night blind spot covers 5-10 degrees of central vision. This is due to the fact that there are no rods on the fovea centralis (the center of vision).
Describe the Day Blind Spot
The day (physiological) blind spot is present all the time (including at night). This blind spot results from
the position of the optic disk on the retina. The optic disk has no light-sensitive receptors.
The physiological blind spot covers an area of approximately 5.5-7.5 degrees and is located about 15
degrees from the fovea.
What are the 4 sections of the engine?
- Hot Section
- Cold Section
- Power Turbine Section
- Accessory (Gearbox) Section
What sensors are located on the aft top portion of the left and right sides of the engine?
Left - Np Sensor
Right - Torque and Overspeed Sensor
What are the functions of the HMU?
Pumps fuel at high pressure
Meters fuel via LDS, PAS and DEC (torque motor)
Collective pitch compensation through LDS
Accel/Decel fuel flow to prevent compressor stall
Ng Limiting
Variable guide veins for optimal performance
DEC lockut via PAS (bypass torque motor from the DEC)
Torque motor trims Ng
Opens vapor vent for fuel priming
PM CAN VDTO
