AD 66-07-03 ACTIVE

66-07-03 THOMAS A. EDISON and GARWIN, INC: Amdt. 39-203 Part 39 Federal Register March 4, 1966. Applies to Thomas A. Edison Models 195 and 273 Aircraft Engine Gage Units (Models Manufactured for Military use are Identified as AN 5773-1A or -T1A, AN 5773-2 or -72, MS 28043-1 or -T1, and MS 28043-2 or -T2), and Garwin, Inc. Engine Gage Units, P/N's 22-802-03 through -14 and 22-802-022, with Date Stamp Before April 1, 1961.

Compliance required within the next 300 hours' time in service after the effective date of this AD.

Numerous instances of failure of the fuel pressure diaphragm assembly used in the gages affected have been reported. When the gage is under pressure, the diaphragm ruptures resulting in failure of the fuel pressure indicator portion of the gage, causing a serious fire hazard as well as malfunctioning of the fuel pressure indicating portion of the instrument. To prevent recurrence of this condition, accomplish the following:

(a) Overhaul gage units manufactured prior to June 30, 1962, by replacing the diaphragm and capillary tube assembly, P/N 45010- with a new assembly, P/N 45010- in accordance with T.A. Edison Service Bulletin No. 05-75AB-1-SB-1 or FAA-approved equivalent. The new assemblies are identified by the manufacturer with a 1/4 inch wide white band painted on the capillary tube adjacent to the solder joint of the tube to the diaphragm assembly. Identify gage units overhauled in accordance with this AD by placing a white paint dot approximately 1/4 inch in diameter, directly below the nameplate and between the "fuel" and "vent" bosses on the outside of the instrument nameplate.

(b) All gage units shall be vented overboard by means of fuel drain line leading from the fuel pressure gage vent connection and routed such that it will not terminate at a point where the discharge of fuel from the outlet would constitute a fire hazard or from which fumes could enter personnel compartments.

This supersedes AD 63-15-03.This directive effective April 3, 1966.