MIL-PRF-62439 Fuel Control, Main ElectrohydraulicThis specification covers an electrohydraulic main fuel control used in the gas turbine engine of the M1 tank, referred to herein as "assembly." The assembly is an electrohydraulic device which converts electrical commands to fuel flow and power turbine stator \(PTS\) inlet guide vane \(IGV\) actuator flows and pressures. This assembly also contains the PTS and IGV electrical feedback components.

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MIL-PRF-62439B(AT)

b. 4800 MHBF for failures causing fuel restriction resulting in a major fuel schedule

change, defined as a 20% loss of fuel flow [564 - 600 pph] at rated power

c. 1200 MHBF for failures causing unscheduled maintenance action

3.7 Identification and marking. The identification and marking shall include, as a

minimum, the department or agency identification, the registration number, and legend as

specified for the appropriate military agency (see 6.2). Marking shall be permanent and legible.

When specified (see 6.2), concealed marking shall be furnished (see 4.5.2).

4. VERIFICATION

4.1 Classification of inspections. The inspection requirements specified herein are

classified as follows:

a. First article inspection (see 4.3)

1. Preproduction inspection (see 4.3.1)

2. Initial production inspection (see 4.3.2)

b. Conformance inspections (see 4.4)

1. Examination (see 4.4.2)

2. Tests (see 4.4.3)

4.2 Inspection conditions. Unless otherwise specified (see 6.2), all inspections shall be

performed in accordance with the environmental test conditions as follows:

Fuel temperature: 85�5 �F

Air temperature: 73�18 �F

Barometric pressure: 25.5 to 30.5 in. of mercury (Hg)

Relative humidity: 50�30%

4.2.1 Test equipment. The following test equipment shall be used in the performance of

the examinations and test specified herein:

a. Test set, Bendix model EK-31A or equivalent

b. Fixture assembly, Bendix part number 2524777-G1 or equivalent

4.3 First article inspection. First article inspection shall be performed on preproduction

or initial production samples as specified herein. Approval of the first article sample by the

Government shall not relieve the contractor of the obligation to supply assemblies that are fully

representative of those inspected as a first article sample. Any changes or deviation of the

production units from the first article sample shall be subject to the approval of the contracting

officer.

4.3.1 Preproduction inspection. When specified (see 6.2), the preproduction sample

shall consist of two assemblies. Preproduction inspection shall consist of the inspections in the

order listed and as specified in table II, except testing for endurance and reliability. When