AD 64-07-01

64-07-01 BOEING: Amdt. 702 Part 507 Federal Register March 11, 1964. Applies to All Models 707 and 720 Series Aircraft.

Compliance required within the next 1,000 hours' time in service after the effective date of this AD, unless already accomplished.

To eliminate possible inflight electrical fire in the J6 electrical distribution panel as a result of heat generated by a loose terminal on a generator contactor, modify the J6 electrical distribution center as follows:

(a) Remove the nylon terminal covers from the generator and bus-tie circuit breakers 50086-001, -002 or -003 and external power contactor B102D or B102F.

(b) Replace the vinyl covered braid connections BAC J40D-30-24 between each generator circuit breaker and bus-tie circuit breaker with No. 4 gauge high temperature wire jumpers manufactured from MIL-W-7139A, Type I, Class A wire, or equivalent.

(c) Replace capacitors 28F345 with General Electric capacitors 49F2204 (pyranol) or equivalent.

(d) Replace synchronizing bus radio noise filter capacitors CP53B1EF205K with Sprague Electric 121P20506T13 capacitors (dry metalized paper), or equivalent.

(e) Reroute wiring to the auxiliary negative sequence relays separate from all other wires in the a.c. power shield.

(f) Modifications (a) through (e) shall be accomplished in accordance with Paragraph 3, Modification Data of Boeing Service Bulletin No. 1720, or a method approved by FAA Engineering and Manufacturing Branch Western Region.

(Boeing Service Bulletin No. 1720 covers this same subject.)

This directive effective April 13, 1964.