48-13-01 BEECH: Applies to All D18S, D18C Airplanes Equipped With Pilot's Reclining Seats and Having the Generator Control Box Mounted on Bulkhead No. 5.
To be accomplished not later than July 1, 1948.
To prevent a short circuit between the hot terminal of the generator control box and bulkhead No. 5, rivet a 0.016 phenolic sheet 13/4 x 3 inches between the bulkhead web and the first horizontal angle immediately above the generator control box. The sheet should extend downward from the angle to the web cutout and provide positive insulation between the web and the hot post of the generator control box. If a phenolic strip has previously been installed at this point, an additional strip will not be necessary.
(Beech Service Letter No. D18-23 covers this same subject.)