Learjet 60 - Apr; APR ARM Light; APR Switch

Pilot's
Manual

Learjet 60
AUTOMATIC
PERFORMANCE
RESERVE
(APR)
The
APR system
provides
for an automatic
change from
the takeoff
Ni rating
to the APR
rating for
the operative engine
in the
event of
loss
of thrust from
one engine
during
takeoff . Theamount
of thrust
change
will depend on
ambient
conditions .
Since the engines
in-
stalled on the
Learjet 60
are flat rated,
the difference
between takeoff
and
APR thrust
will be very
small under
some ambient
conditions .
The system
consists of
an APR
switch on the
forward pedestal,
APR
ARM and
APR ON lights
on the
glareshield, and
associated aircraft
wiring
. To detect
loss of
thrust, the
Full Authority Digital
Electronic
Control
(FADEC)
continuously
monitors the
opposite
engine's Ni
and N2
signals . Loss of
thrust is
defined by the
FADEs as
meeting
one
or more
of the following
criteria :
" The Ni of
one engine
differs more than
15% from the
Ni of the
other engine .
" The
N2 of one
engine differs
more than 7 .5%
from the N2 of
the
other
engine .
" The Ni of
one engine
differs more
than 4% from the
Ni of the
other
engine and
Ni is
decreasing at a
rate greater than 5%
per
second
.
" The N2
of one engine
differs more than
2% from the
N2 of the
other engine
and N2 is decreasing
at a rate
greater than 2%
per
second
.
APR SWITCH
APR
system automatic
operation is
pilot controlled
through the APR
ARM-OFF
switch located on
the right side
of the pedestal adjacent
to
the thrust levers
. The switch
is recessed to
prevent inadvertent
APR
activation . The switch
has two
positions : OFF and ARM .
For automat-
ic
operation the switch is
set to ARM .
When ARM is selected,
the
APR ARM light
will illuminate
provided no faults
exist which affect
the
APR function .
When a loss of thrust
is detected by
one of the FA-
DECs, an
uptrim of the
operative engine is
commanded . The FADEC
checks that the
change to the
appropriate APR N1 setting
has been
triggered and
if it has, the
APR
ON
light will
illuminate . Should auto-
matic activation of
APR fail to occur,
APR thrust can be
manually ob-
tained by setting
the thrust
lever to the APR detent .
In this case, the
APR ON light
will not illuminate . Once
invoked, the APR
thrust
schedule will
remain active until the
APR switch is set to
OFF .
APR
ARM LIGHT
The green APR
ARM light on the
glareshield annunciator
panel will
illuminate when the APR
switch is in the ARM
position provided no
faults
exist which affect the
APR function .
2- 6
PM-123
Change 2