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Minnesota Wing Aircrew Training: Tasks P-2021, P-2022. Scanning Techniques and Sighting Characteristics. Scanning Techniques and Sighting Characteristics. Scanning. Scanning is the process of investigating, examining, or checking by systematic search
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Minnesota Wing Aircrew Training: Tasks P-2021, P-2022 Scanning Techniques and Sighting Characteristics
Scanning • Scanning is the process of investigating, examining, or checking by systematic search • The scanner uses a systematic eye movement pattern • Most commonly used eye movement pattern involves moving the eyes and pausing every few degrees – this is known as “fixation”and should cover about 10 degrees a second
Vision • For central vision to be effective, the eye must be focused properly • When you are not actively focusing, your focal point will be about 30 feet out • Peripheral vision is not as sharp, but can be effective if you concentrate (especially at night) • For example: with central vision you may see an object one mile (5000 feet) away, but peripheral vision could only pick up the object 500 feet away
Vision Physiology • The maximum visual acuity is a circle 10° in diameter around a fixation point. This is the area where “concentrated looking” takes place. • All else constitutes peripheral vision • A fist at arms length approximates the area of central vision • Most effective looking straight ahead (otherwise nose is in the way) • 180 degrees of lateral binocular vision • 160 degrees vertical range 10 degrees
Vision Physiology (Continued) • At night • Dark adaptation requires 30 minutes • Use off-center vision • Fewer scans • Rest between scans • Lighting conditions • Shadows
Scanning Range • The distance from an aircraft at which a scanner has a good chance to sight the search object • Don’t confuse with “search visibility” range • Distance at which an object the size of a car can be seen and recognized • CAP rarely credits a search visibility greater than three or four nm • Debris is usually not as large as a car and may not be recognizable, especially from an aircraft going 100 mph. • Therefore, scanning range may be less than but never greater than the search visibility
Surface coverage scanning from the air (no flight motion) Scanning Technique Farther Fixation area 3 • Follow a routine pattern • Cover area systematically • Pause to “fix” on a point every 3° to 4° • When scanning… • Stop at each fixation point long enough to focus clearly (about 1/3 second) • Successive central vision areas should overlap slightly 2 1 Focus points First Fixation Area Nearer the Airplane
Effect of flight path • Movement of the aircraft across the ground can adversely affect coverage
Scanning from RIGHT REAR Window 15 14 13 12 11 10 9 8 7 6 5 Scanning Range 4 3 2 1 Direction of Flight AircraftGroundTrack 1000’ AGL ( 1/2 - 1 mile ) 500’ AGL (1/4 - 1/2 mile)
Scanning from the LEFT REAR WINDOW 15 14 13 12 11 10 9 8 7 6 Scanning Range 5 4 3 Direction of Flight 2 1 1000’ AGL ( 1/2 - 1 mile ) Aircraft Ground Track 500’ AGL (1/4 - 1/2 mile)
Vertical Scanning Pattern • Less effective • Use only from a rear seat position • Typically used by one scanner if there are two on the same side of the aircraft • Provides good coverage of the surface near the search aircraft
Scanning Range • For a 500 Ft AGL search, expect scanning range to be ¼ to ½ mile. • At 1000 Ft AGL, expect ½ to 1 mile scanning range.
Sighting DistanceAverage Visibility ObjectDistance Person in life jacket (open water or moderate seas) 1/2 mile Person in small life raft (open water or moderate seas) 3/4 mile Person in open meadow within wooded area 1/2 mile or less Crash in wooded area 1/2 mile Crash on desert or open plain 2 miles Person on desert or open plain 1 mile or less Vehicle in open area 2 miles or less
Scanning Range Factors • Atmospheric conditions • Position of sun • Clouds and shadows • Terrain and ground cover • Surface conditions (like snow) • Cleanliness of window • Altitude • Condition of scanner • Use of binoculars • Use of sunglasses
Lighting Conditions • Use of binoculars can rapidly bring on eye fatigue and lead to disorientation and even airsickness. • Use only for brief periods to check sightings and for detailed viewings of an assessment area or target. • Looking through a camera or camcorder viewfinder for extended periods can be equally as discomforting. Take breaks. • Sunglasses reduce eye fatigue and glare, but can: • lead to reduced retinal image. • lead to reduced color discrimination. • Don’t wear sunglasses under reduced visibility conditions!
Fighting Fatigue • Change positions every 30 minutes if the size of the aircraft permits • Switch sides of the aircraft (rear seat) • Find a comfortable scanning position • Ensure aircraft windows are clean • Keep inside lighting low to reduce reflections • Only use binoculars to check sightings • Focus on close objects periodically
Atmospheric and Lighting Conditions CLOUD SHADOWS
Atmospheric and Lighting Conditions DUST STORM
Atmospheric and Lighting Conditions CLOUDS & HAZE
Atmospheric and Lighting Conditions HAIL (AVOID IT)
Visual Clues • Light colored or shiny objects • Smoke, fire, blackened areas • Disturbed or discolored foliage • Fresh bare earth • Breaks in cultivated field patterns • Disturbances in water and snow (discoloration, oil slick, debris) • Birds and animals • False clues • Signals and messages (fires, groups of 3’s, mirrors, panels, etc.)
Visual Clues • Don’t expect to find anything that looks like an aircraft • Most wrecks look like discarded trash • There is also a lot of discarded trash out there • If there is any doubt, check it out
Directing the Pilot • Clock Position • High, Low, Level • Maneuvers • Straight ahead • Stop turn • Small Corrections • 5 degrees right • 10 degrees left bank • External References 12 1 11 2 10 3 9 4 8 5 7 6
Wreckage Patterns • Hole in the ground • Cork screw or auger • Creaming or smear • The four winds • Hedge-trimming • Splash
