AD 62-12-01

62-12-01 BOEING: Amdt. 441 Part 507 Federal Register May 23, 1962. Applies to All Models 707 and 720 Series Aircraft With DC Type Toilet Flushing Motor Installed.

Compliance required as indicated.

There have been several cases of fires originating in the electrical system of the d.c. type toilet flushing motor. To eliminate this unsafe condition, rework of the toilet motor electrical circuit and added protection against moisture entering the circuit components in the toilet area are required. Within the next 360 hours' time in service for paragraph (a) and 1,000 hours' time in service for paragraphs (b), (c), and (d) after the effective date of this AD, unless already accomplished, the following shall be accomplished in accordance with Modification Instructions of Monogram Precision Industries' Service Bulletin No. 35 BAC, dated February 22, 1962, or an FAA approved equivalent.

(a) Reduce the exposure of the system to d.c. voltage by changing the wiring inside the timer so that voltage is applied to the flushing motor during the flushing operation only.

(b) Increase the protection from moisture of the connector attached to the pigtail of the flushing motor by moving the connector from the bracket on the flushing motor to a bracket mounted behind the vertical shroud support.

(c) Provide an improved moisture seal where the wires enter the flushing motor by trimming back the shielding and installing thermo fit sleeving over the wires, and repotting.

(d) Reduce the susceptibility of moisture entering connectors by replacing the potting compound of the connectors attached to the harness and to the motor pigtail with resilient inserts and grommets and supporting the wires with cable clamps attached to the connectors.

(Monogram Precision Industries' Service Bulletin No. 35 BAC, covers this same subject.)

This directive effective May 23, 1962.