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Figure 30 Select ATP Leak Test Profile
The ATP Leak Test provides the following profile options:
a) ALR “Auto Leak Recover” can be “(X)” selected/deselected
b) Ambient Comp can be “(X)” select/deselected
Ambient Comp compensates for local ambient barometric pressure to ensure for
example that a 5,000 ft. leak test is really checked at a pressure altitude
equivalent to 5,000 ft. above the local barometric pressure.
c) Pass Limits can be “(X)” selected /deselected which determines whether or not
pass/fail limits are used. If Pass Limits is selected “(X)”, the user can specify the
pass limit value for each of the 3 possible leak tests.
Note: Regarding the actual Leak Test(s), there are 3 possible leak tests that can
be selected. (1) Pt channel, (2) Ps Low ALT and (3) Ps High ALT.
Note: For the Pt channel leak, the ATP will automatically take the Ps channel to
ground prior to starting the Pt channel leak test.
d) Wait: The wait time is the time allowed for the system under test to settle and
stabilize after the target CAS or ALT has been reached. The general rule is the
higher the target CAS or ALT the longer the wait time. That time should be used
to allow for adiabatic to settle so that the leak measurement truly represents the
systems leak rate and is not influenced by the expansion/contraction of gases in
a closed system. The Pt and Ps Low ALT share the same Wait time value while
the Ps High ALT has its own wait time value specified.
e) Measure: The measure time is simply the amount of time to allow for the leak
measurement cycle. Typically 1:00 minute is used for Pt & Ps Low ALT and a
longer time may be used for Ps High ALT.
f) Run: begins executing the ATP leak test that is presently loaded as defined.
g) Save: simply saves the present ATP leak test parameters as presently defined.
h) Cancel: exits the ATP leak test. Any changes made to the ATP leak test
parameters will not be saved.
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