Aircraft System Protection
© 2017 General Electric Company – All Rights Reserved. ADTS 405 R/F Mk2 Instruction Manual-English | 35
4.6.1 Auto Recovery Facilities
If, during a leak test, a leak in the system produces a rate of climb greater than the rate set in
limits or a rate of change of airspeed greater than the rate set in limits, then the pressure
controllers automatically regain control to minimize damage to the aircraft system. This
AUTO LEAK RECOVERY facility can be disabled.
If a leak causes the system pressures to exceed any limit during a leak test, the pressure
controllers automatically regain control. This AUTO LIMIT RECOVERY facility can be disabled.
If negative airspeed (or Qc) occurs in measure mode, the zero valve is automatically opened
for 1 second to balance the airspeed. This only applies when the minimum CAS (or Qc) limit is
zero.
Limits cannot be changed with SETUP switched off or Limit Lock enabled.
4.6.2 Limit Checking
The system checks all data entered against minimum and maximum limits set for the
particular limit set in use. If these limits are exceeded, the data entry is ignored and a warning
message displayed showing the minimum and maximum values that can be entered. The
system also checks all limits of associated parameters. If these limits are exceeded when a
new value is entered, the display shows the name of the associated parameter, e.g. If a Mach
limit is exceeded when entering an airspeed value the display shows “Mach” and the
equivalent maximum and minimum limits as airspeed values.
Similarly, if an ARINC 565 limit is exceeded when entering a value and ARINC limits are
enabled, the display shows ‘ARINC’.
Select the limits in use:
a. Press SETUP.
b. Select [LIMITS].
c. Use [NEXT] or [PREV] to select the limits required. Each set of limits is identified by its
name, including the predefined sets of limits (“Standard“, “Civil” and “Max” see
Section 1.3, “Operating Limits,” on page 2).
d. Select [SEL] to select the limits.
e. Press QUIT/CLEAR to return to the pressure display.
Using the CONFIG function, new sets of limits can be created and existing sets of limits can be
edited. In addition, the set of limits in use at power-up can be selected. If required, this
selection can be locked to prevent unauthorized changing of the limits.
Using the SETUP function, previously stored sets of limits can be recalled for use. Each set of
limits is stored under an aircraft name. Three predefined sets of limits “Standard“, “Civil” and
“Max” limits are supplied with the ADTS 405 Mk2.
Note: The ADTS 405 Mk2, when delivered, contains “Standard” and “Civil” limits; to set
and store “Max” limits, for the first time, enter configuration. The “Max” limits depend on
INFORMATION The pressure controllers in the ADTS 405 Mk2 can
“feed” a leak in an aircraft system. When first testing an aircraft system, a
leak test must be carried out at low altitude and airspeed.
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