Learjet 20 Series Pilot Training Manual page 330

RVSM SYSTEM
RVSM system aircraft are equipped with
STC STO 1195WI manufactured by Avcon
Industries.
GENERAL
The existing pilot (servo pneumatic or pneu-
matic) altimeters have been replaced with
IS&S air data display units (ADDUs) that
combine the function of the basic altimeter
with those of the traditional altitude alerter.
The ADDU is a self-sensing unit that has pitot
and static system connections. The existing au-
topilot air data sensor was removed and re-
placed with the analog interface unit (AIU) that
converts digital data from the altimeters to
analog signals to interface with the existing
FC-110 autopilot (Figure 16-12).
The AIU also provides the outputs to other
optional aircraft systems (i.e., long range NAV,
SAT/TAS indicator). The altitude alerter was
removed and replaced with the air data panel.
T h i s p a n e l c o n s i s t s o f a n A D C 1 / A D C 2
switch/annunciator, an AIU FAIL annunciator,
a standby altimeter, and the static source static
port switch (Figure 16-13).
The existing pitot-static system pitot tubes,
static ports, and plumbing are replaced with
Rosemount pitot-static probes and plumbing.
Figure 16-13. Air Data Panel
LEARJET 20 SERIES PILOT TRAINING MANUAL
FOR TRAINING PURPOSES ONLY
References to static ports in the basic Airplane
Flight Manual (AFM) are to be disregarded.
References to pitot heads shall mean pitot-
static probes. The pressurization static port has
not changed in this configuration. A standby
altimeter (pneumatic) has been installed and
plumbed to the aircraft existing shoulder static
ports.
SYSTEM CONTROL
The following circuit breakers are added to
provide protection for the air data equipment:
ALT1—Is a 2-amp, 28-VDC circuit breaker on
the LH main bus. It protects ADDU 1.
ALT2—Is a 2-amp, 28-VDC circuit breaker on
the RH main bus. It protects ADDU 2.
A D C A I U — I s a 1 - a m p , 2 8 - V D C c i r c u i t
breaker on the RH main bus. It provides pro-
tection to the AIU.
A D C A I U — I s a 1 - a m p , 2 6 - VAC c i r c u i t
breaker on the RH 26 VAC bus. It also provides
protection to the AIU.
STATIC SOURCE—Is a 5-amp, 28-VDC cir-
cuit breaker on the LH main bus. It provides
protection to the isolation valves.
STBY ALT—Is a 2-amp, 28-VDC circuit
breaker on the RH main bus. It protects the
standby altimeter vibrator.
INDICATIONS
Refer to Figure 16-14 for the following
indications:
ADC1/ADC2—The ADC1/ADC2 switch/an-
nunciator captions are displayed in green. The
switch/annunciator selects the air data source
for transponder altitude reporting, altitude
preselect, altitude alerting and air data inputs
to the analog interface unit (AIU). The se-
lected air data source becomes the active mas-
ter ADDU.
FlightSafety
international
16-13