156 



PANEL DESIGN 



limits of reach would have to be confined to 

 the two overlapping circles making up an 

 elliptical area, about 43.9 by 34.8 inches 

 while an area of 60.6 by 51.5 inches could be 

 reached by the largest 5% of the population. 

 At a viewing distance of 10 inches, the values 

 for 95% and 5% of the population were 

 58.1 by 49.0 inches and 71.1 by 62.0 inches, 



vestigation of multi-engine aircraft, the R5D 

 (Navy equivalent of the DC 4), it turned out 

 that most of the controls were beyond the 

 reach of the pilots if they were required to 

 keep their bodies resting against the back of 

 their seats (7). Measurements from the 

 standard reference line on the seat used by 

 King to the midpoints of seven control areas 



OS?^ 



nX>^^ 



52 



46 



l- 

 z 

 o 



Q. 



40 LJ 

 O 



z 



LlI 



34 ^j 



Li. 

 LJ 



28 "= 



22 



16 



10 



SEAT 

 REFERENCE-). 

 POINT 



a- do' 



-2 — 



- -8 



!0 



20 



30 



40 



HORIZONTAL DISTANCE (IN.) FROM VERTICAL 

 THROUGH SEAT REFERENCE POINT 



Fig. 3. Maximum distances which can be reached by 97% of a selected Navy population at angles 

 from degrees to 15 degrees to the right of the midline. (After King et al., 21) 



respectively. This type of information 

 should be invaluable for planning the practi- 

 cal Hmits of the working area on a vertical 

 surface for operators of different body size 

 and at different distances from the panel. 

 The same kind of study should be done with 

 other types of panels and work areas now in 

 current use. 



In actual practice, it has been sho'wn that, 

 in many types of equipment, controls are not 

 within the hmits of reach unless the operator 

 stretches and moves his body. In one in- 



of the cockpit showed that all but one area 

 would be out of the limits of reach of 50% of 

 the population of the subjects used in that 

 study (Table II). Furthermore, photo- 

 graphic records of flight operations with this 

 aircraft showed that pilots actually did a 

 great deal of trunk twisting and stretching 

 to reach controls. In another study of 

 errors made by pilots in flight, it was found 

 that 3% of the errors which they could re- 

 member were due to the inabihty to reach 

 a control at all (13). In most of these cases. 



