59-05-03: Deicer Shutoff And Regulating Valves

59-05-03 FAIRCHILD: Applies to F-27 aircraft Serial Numbers 1 through 11, 14 through 23, and 27 through 35. Compliance required as indicated. A number of malfunctions of Bendix 38E09-3B, 38E09-3C and 38E09-3D deicer shutoff and regulating valves have occurred. These malfunctions have been traced to corrosion of the pilot valve assembly. New valves Bendix P/N 38E09-4E have been designed to eliminate this malfunction, however, until new valves are available, the following must be accomplished: (1) A functional performance check of the pneumatic wing deicing system must be performed prior to each flight into known or suspected icing conditions to ascertain that the pneumatic deicing system is performing satisfactorily. (2) At next inspection period, but not to exceed 100 hours, and every 100 hours thereafter remove Bendix shut-off and regulating valves, P/N 38E09-3B, 38E09-3C and 38E09- 3D, whichever type is installed, from left and right nacelles. Remove pilot valvecap, valve assembly and push rod and inspect for corrosion. Remove any signs of corrosion and apply a light coat of DC-7 Dow-Corning Compound or equivalent to valve assembly and push rod. Reinstall valves in aircraft. (3) Not later than June 1, 1959, replace valves P/N 38E09-3B, 38E09-3C and 38E09- 3D with valve P/N 38E09-4E. When this has been accomplished, the function check and inspection covered by items (1) and (2) can be discontinued. (Fairchild F-27 Service Letter F27-93 dated January 20, 1959, and Service Bulletin 30-2 dated January 20, 1959, revision 1 dated March 5, 1959, cover this same subject.) This supersedes AD 59-3-1.