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|  FIGURE 3. Sinusoidal excitation amplitude.
4.7.11.1.2 Resonance dwell. The automatic air vent valve shall be
vibrated along each axis at the four most severe resonant frequencies based on
the results of the resonant search. Dwell time shall be 30 minutes at each
frequency and the amplitude shall be as shown on Figure 3. The dwells may be
performed simultaneously. If a change occurs in the resonant frequency during
the test, its time of occurrence shall be recorded, and the frequency shall be
immediately adjusted to maintain the peak resonant condition. The final
resonant frequency shall be recorded.
4.7.11 .1.3 Cycling. The automatic air vent valve shall be vibrated along
each axis for 3 hours. The cycling time shall be 3 hours minus the total
resonance dwell time. The test levels are shown on Figure 3 and the frequency
shall be swept over the range of 5 to 2000 Hz, logarithmically. Sweep time
for the 5 to 2000 to 5 Hz cycle shall be 20 minutes.
4.7.11.2 Random excitation. Random excitation shall be applied for 1
hour along each axis conforming to MIL-STD-81O, Method 514, Section I, Category
5 - Jet aircraft and tactical missiles and the curve shown in this document on
Figure 4.
4.7.11.3 Test inspections. During the sinusoidal and random excitation
testing, the automatic air vent valve under test shall be continuously
monitored for signs of oil leakage. 0il leakage in excess of one drop during
any of the individual vibration procedures shall be considered a failure.
Following the vibration test, the valve shall be subjected to the functional
test 4.7.4 without failure.
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