60-24-04 SIKORSKY: Amdt. 221 Part 507 Federal Register November 11, 1960. Applies to All S-58 Helicopters.
Compliance required within the next 50 hours' time in service after effective date.
Complete loss of electrical power and excessive battery fumes have resulted from the breakage of the cable connected to the L(plus) terminal of Eclipse Pioneer Voltage Regulator P/N 1597-1. In order to preclude the breakage of the L(plus) cable and the resulting loss of electrical power, the following is required unless already accomplished:
(a) Remove the existing clamp securing the voltage regulator cables to the airframe at a distance of approximately 12 inches from the regulator base.
(b) Install cable clamp MS 21919DG5, or equivalent, to secure the regulator cables to the regulator base utilizing an existing hole in the corner of the regulator base. This should be accomplished while providing enough cable slack to relieve tension on the terminal lugs but without changing the cable routing.
(c) If, in some installations, there is an unduly long length of unsupported cable existing beyond the voltage regulator after compliance with (a) and (b), an additional clamp of the same type should be provided to attach the cable to the airframe with care being exercised so that the motion of the regulator on its shockmount is not restricted.
(Sikorsky Service Bulletin No. 58B55-1 covers this same subject.)
This directive effective November 28, 1960.