Gaseous-discharge lamps for airplane lighting service

FLUORESCENT lamps always have been considered desirable for general lighting within the airplane in order to reduce power consumption and utilize the long thin tubular-light sources that fit in so well in the interior of an airplane. Four-hundred-cycle operation has been found by Hays^1,2 to be excellent for fluorescent lamps, providing about 20 per cent greater efficiency than the 60-cycle alternating current for which these lamps were created originally and reducing the size and weight of the ballasts required. However, uncertainty as to lamp operation at low temperatures and particularly at the extremes of low temperature that might be encountered at tremendous altitudes has prevented the general use of these lamps in this field.