Observation Sectors With Four-Person Crew
 
 
Figure 4-3 Observation Sectors With Four-Person Crew
 

 
 
Section C. Scanning Procedures

 
Introduction
 To properly scan an area, the following must be considered for greatest success:
. Aircraft obstructions

. Aircraft speed

. Binoculars

. Altitude

. Contrast

. Motivation

. Scan degree

. Procedure

. Repeat scans

 
C.1.  Aircraft Obstructions
 Although aircraft are excellent search platforms, most small civilian aircraft have some obstructions that limit scanning sectors.  This varies with the design of the aircraft and the observer’s position.  Generally, obstructions are more severe in low-wing aircraft than in high-wing aircraft.  The PIC should evaluate the particular aircraft and inform observers of the limitations and how best to compensate for them.
 
C.2.  Aircraft Speed
 The speed of the aircraft affects the efficiency of observers by reducing the time in which they can scan a given sector.  In searching, the slower the speed of the aircraft, the greater the probability of visual detection.
 
C.3.  Binoculars
 Binoculars rapidly bring on eye fatigue in aircraft and may cause nausea.  Binoculars should be used only to confirm sightings made by the naked eye.  Gyro-stabilized binoculars are preferred and may be checked out or borrowed at some air stations.
 
C.4.  Altitude
 When searching at low altitudes, the area closest to the aircraft (where detection probabilities are highest) will be passed quite rapidly.  The rapidity with which this area will pass is dependent upon the masking caused by the design of the aircraft and by the speed of the aircraft.  Low-wing aircraft present a particular problem in this regard.  For a moderate speed low-wing aircraft with considerable masking, it may be necessary for rear seat observers to scan only the area in view behind the wing to obtain maximum effectiveness.
 
C.5.  Contrast
 Most searches by Auxiliary aircraft facilities will involve search over water.  Often, over water searches will provide little or no contrast between sea and sky.  Under these conditions, observers’ eyes may focus short of the surface without the knowledge of the observer, and thus compromise the thoroughness of the search.  To minimize this phenomenon, observers should occasionally focus their eyes on some specific items on the surface such as whitecaps or debris.  If none is visible, the eyes should be focused periodically on some part of the aircraft such as the wing tips.  A short “focusing” period of a second or so will overcome this problem and scanning can be resumed.
　
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