51-23-03 PIPER: Applies to Model PA-16 Aircraft, Serial Numbers 16-1 and Up; PA-20 Aircraft, Serial Numbers 20-1 Through 20-802; and PA-22 Aircraft, Serial Numbers 22-1 Through 22-348.
Compliance required as soon as possible, but not later than October 15, 1951.
Install insulators of sufficient area inside the battery box cover over the battery terminals to positively prevent a metallic contact between the wing nuts or terminals and cover. Hard fiber rubber or phenolic insulating materials 1/16-inch minimum thickness may be used.
(Piper Service Bulletin No. 118 covers this same subject.)