MIL-PRF-27197E
back of the indicator (see Figure 1). The MAEAS pointer adjustment shall be protected by a
cover. The cover shall be removable without the use of special tools.
3.5.3 Concentricity of pointers. The MAEAS pointer and the IAS pointer shall be concentric
within 0.010 inch total indicator reading (TTR). The MAEAS pointer shall be nearest the dial.
3.5.4 Indicator range. The indicator shall operate over an IAS range of 80 to 850 knots and at
mach number ranges of 0.50 to 2.2 at altitudes of -1,000 to 80,000 feet.
3.5.5 System safety. The indicator shall present no danger of minor injury to operating and
service personnel or minor damage to the weapon system.
3.5.6 IAS range of indication. The IAS pointer movement shall be limited by stops. The pointer
shall rotate no more than 355o clockwise from 0o when the indicator is subjected to overpressure.
3.5.7 Magnetic effect. The indicator shall not cause a free compass to deflect more than 1o
when revolved about a short bar magnetic compass with a field intensity of 0.17 to 0.19 oersted.
3.5.8 Seal.
3.5.8.1 Case leakage. Case leakage shall be no more than 0.01 inch Hg per minute when
mounted in an instrument panel or mock-up panel.
3.5.8.2 Low temperature case leakage. The case leakage shall be no more than 0.025 inch Hg
per minute at -31oF.
3.5.8.3 Static pressure. The static pressure of the case shall change no more than 0.15 inch of
Hg.
3.5.9 Weight. The weight of the indicator shall be 2.5 pounds or less.
3.5.10 Damping. The time for the indicator to change indication from full scale to 90 knots
shall be greater than 0.8 seconds and less than 2.0 seconds.
3.5.11 Seasoning. The AVU-8B/A and ME-4 shall withstand 250 hours of pressure cycling at a
rate of 4 cycles per hour. The AVU-8C/A shall withstand 1,000 hours of pressure cycling at a
rate of 4 cycles per hour.
3.5.12 Scale error. The IAS, mach number, and MAEAS scale errors shall be within the
tolerances in Tables II, III, and IV.
3.5.13 Friction error.
3.5.13.1 IAS friction error. The IAS friction error shall be less than 3 knots for airspeeds less
than 200 knots and less than 5 knots for airspeeds greater than 20 knots.
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