TM 1-1520-238-T-6
9–107
9–7.
SYSTEM DESCRIPTION (cont)
9–7
NOTE
The PLT/GND ORIDE switch can be used to override the squat switch in all
modes and the CPG switch can be used to control SAFE/ARM power.
(17) Squat Switch System.
The squat switch system (fig. 9–96) indicates to the helicopter when flight
mode (weight off wheels) or ground mode (weight on wheels) conditions exist. The squat switch acts as a safety
device which deactivates certain functions of some systems and enables fault detection of other systems via
squat relays: K4-1/2 and K4-9/10.
(a) In the flight mode the squat relays perform the following functions:
Removes the ground supplied to the generator control circuits which deactivates generators 1
and 2 underfrequency controls to prevent loss of electrical power due to low generator rpm.
Disables intercommunication system (ICS) wing communications.
Enables all DASEC channels and disables the backup control system (BUCS) self-test.
Enables the ON position of the TADS/PNVS switch and disables the GND position on the pilot
ANTI ICE panel.
(b) In the ground mode the squat relays perform the following functions:
Supplies a ground to the generator control circuits which activates generator 1 and 2
underfrequency controls.
Supplies a ground to the audio junction box ICS wing disable circuit which enables ICS wing
communications.
Removes the ground supplied to the DASEC which deactivates the YAW command augmentation
system (CAS) and activates the BUCS self-test.
Supplies a ground to the KIT 1A/TSEC computer. The IFF code is zeroized unless the CODE
switch on the IFF panel is set to HOLD in flight mode before landing.
Causes 28 VDC to be applied through the CPG FIRE CONTROL panel and the LH fab MRTU
type II which activates FD/LS verification of proper CPG FIRE CONTROL panel connection and
deactivates weapons systems arming.
Sends 28 VDC to the external stores controller which moves the pylons to the ground stow
position.
Supplies a ground to the gun turret control box which disables gun movement.
Enables the GND position and disables the ON position of the TADS/PNVS switch on the pilot
ANTI ICE panel.
