the system. A green power indicator lamp will illuminate when external power is applied to the DAU and
the DAU power switch is in the ON position. The green light is not an indication of correct connections,
only that the switch is on and power is applied. The green light will also light if connected backwards.
Installing Universal Tracking Device
Installation of the UTD assembly on the nose mount
(tracker mount) will cause the wirestrike protection
system to be ineffective. All flights with the UTD
installed are limited to areas where wire strikes are
The installation of the UTD is critical to its proper operation and correct measurement. Figure 2 provides
a diagram of the required aircraft mounting. The exact mounting position of the UTD and the installation
angle are determined by the aircraft setup file, and the aircraft specific UTD bracket. To mount the UTD
to the aircraft under test, attach the UTD bracket to the airframe at the required position. After the bracket
is secured, attach the UTD to the bracket. There is a critical consideration to observe during installation
for accurate measurements, the arrow on the body of the UTD must point in the direction of blade
The UTD lens should be cleaned periodically with optical
tissue or soft cloth for optimum performance.
3. Installing Magnetic RPM Sensor
The Magnetic RPM Sensor must be installed in the
prescribed position or an incorrect blade may be
used as the reference blade. Blade color-coding
must be determined if correct prior to starting work
The position and gap of the Magnetic RPM Sensor is critical to the operation of the AVA. The Magnetic
RPM Sensor must be installed in the position prescribed by the appropriate aircraft work package or
adjustments will be recommended for the wrong blade.
(a) Mount the Magnetic RPM Sensor from below the bracket with a jam nut on either side.
(b) Adjust the Magnetic RPM Sensor for a gap specified in the specific work package. Tighten jam nuts.
(c) Rotate the main rotor by hand and align the interrupter and the Magnetic RPM sensor. Check the
clearance at the Magnetic RPM Sensor. Some aircraft will have a single interrupter at one position
on the swashplate and other aircraft will have one double interrupter and a single interrupter for each
other blade position. The aircraft setup file will prescribe either a single or double bladed interrupter.
It is important to use the correct type of interrupter consistent with the aircraft setup file or tachometer
frequency errors will occur. Consult the appropriate aircraft work package.
Always install lockwire after tightening the jam nut.
A loose jam nut could cause aircraft damage.
(d) Install lockwire on jam nuts.