AD 48-52-01

48-52-01 DOUGLAS: Applies to All DC-6 Aircraft.

To be accomplished not later than June 1, 1949.

1. Revise method of connecting power leads to main bus through Burndy limiters.

2. Reroute generator and starter cables in No. 4 nacelle to eliminate possibility of abrasion of power cables.

3. Install stainless steel combustion air intake ducting on all heaters.

4. Revise wing heater exhaust outlets to preclude nacelle fluids contacting exhaust piping.

5. Install expansion turbine oil drain and filling drain.

6. Install ducting from the wing and tail heater combustion air blowers to the outside skin of the nacelles and tail section. Ducting within the nacelles to be of stainless steel.

7. Delete present wing heater 1.4 pounds CO2 bottles and eject the fuselage nose CO2 banks to either wing heater. CO2 to go into the heater deicing and combustion air and into the area surrounding the heaters. Controls for the new system to be grouped with and worked in the same sequence as the tail and cabin heater fire extinguisher system.

(Douglas DC-6 Service Bulletins No. 220, revised February 18, 1948; 270, dated March 8, 1948; 231, revised January 19, 1948; 259, revised March 12, 1948; 255, revised February 26, 1948; 256, revised February 12, 1948; and 272, revised April 8, 1948; cover the above items consecutively.)