53-19-01 DOUGLAS: Applies to All DC-4 and C54-DC Series Aircraft Utilizing Eclipse-Pioneer Type 901 Generators. \n\n\tTo be accomplished by the next engine overhaul, but not later than April 1, 1954. \n\n\tIn view of the fire hazard existing in the use of the magnesium cooling fan in the Eclipse Type 901 generator in the DC-4 and C-54 Series aircraft installations, the magnesium fan as a unit must be removed and Eclipse-Pioneer spacer P/N 866570 installed in its place. \n\n\t(Eclipse-Pioneer Service Bulletin No. 505 covers the above subject.)