<s>
In	O
aviation	O
,	O
an	O
electronic	B-Device
flight	I-Device
instrument	I-Device
system	I-Device
(	O
EFIS	B-Device
)	O
is	O
a	O
flight	O
instrument	O
display	O
system	O
in	O
an	O
aircraft	O
cockpit	O
that	O
displays	O
flight	O
data	O
electronically	O
rather	O
than	O
electromechanically	O
.	O
</s>
<s>
An	O
EFIS	B-Device
normally	O
consists	O
of	O
a	O
primary	O
flight	O
display	O
(	O
PFD	O
)	O
,	O
multi-function	B-Device
display	I-Device
(	O
MFD	O
)	O
,	O
and	O
an	O
engine	O
indicating	O
and	O
crew	O
alerting	O
system	O
(	O
EICAS	O
)	O
display	O
.	O
</s>
<s>
Early	O
EFIS	B-Device
models	O
used	O
cathode	B-Device
ray	I-Device
tube	I-Device
(	O
CRT	O
)	O
displays	O
,	O
but	O
liquid	B-Device
crystal	I-Device
displays	I-Device
(	O
LCD	B-Device
)	O
are	O
now	O
more	O
common	O
.	O
</s>
<s>
The	O
complex	O
electromechanical	O
attitude	O
director	O
indicator	O
(	O
ADI	O
)	O
and	O
horizontal	O
situation	O
indicator	O
(	O
HSI	O
)	O
were	O
the	O
first	O
candidates	O
for	O
replacement	O
by	O
EFIS	B-Device
.	O
</s>
<s>
On	O
the	O
flight	O
deck	O
,	O
the	O
display	O
units	O
are	O
the	O
most	O
obvious	O
parts	O
of	O
an	O
EFIS	B-Device
system	O
,	O
and	O
are	O
the	O
features	O
that	O
lead	O
to	O
the	O
term	O
glass	B-Device
cockpit	I-Device
.	O
</s>
<s>
Multi-function	B-Device
displays	I-Device
can	O
render	O
a	O
separate	O
navigation	O
display	O
unnecessary	O
.	O
</s>
<s>
The	O
PFD	O
and	O
navigation	O
display	O
(	O
and	O
multi-function	B-Device
display	I-Device
,	O
where	O
fitted	O
)	O
are	O
often	O
physically	O
identical	O
.	O
</s>
<s>
LCD	B-Device
units	O
generate	O
less	O
heat	O
than	O
CRTs	O
;	O
an	O
advantage	O
in	O
a	O
congested	O
instrument	O
panel	O
.	O
</s>
<s>
The	O
MFD	O
(	O
multi-function	B-Device
display	I-Device
)	O
displays	O
navigational	O
and	O
weather	O
information	O
from	O
multiple	O
systems	O
.	O
</s>
<s>
EFIS	B-Device
provides	O
pilots	O
with	O
controls	O
that	O
select	O
display	O
range	O
and	O
mode	O
(	O
for	O
example	O
,	O
map	O
or	O
compass	O
rose	O
)	O
and	O
enter	O
data	O
(	O
such	O
as	O
selected	O
heading	O
)	O
.	O
</s>
<s>
The	O
EFIS	B-Device
repeats	O
this	O
selected	O
altitude	O
on	O
the	O
PFD	O
,	O
and	O
by	O
comparing	O
it	O
with	O
the	O
actual	O
altitude	O
(	O
from	O
the	O
air	O
data	O
computer	O
)	O
generates	O
an	O
altitude	O
error	O
display	O
.	O
</s>
<s>
The	O
EFIS	B-Device
visual	O
display	O
is	O
produced	O
by	O
the	O
symbol	O
generator	O
.	O
</s>
<s>
This	O
receives	O
data	O
inputs	O
from	O
the	O
pilot	O
,	O
signals	O
from	O
sensors	O
,	O
and	O
EFIS	B-Device
format	O
selections	O
made	O
by	O
the	O
pilot	O
.	O
</s>
<s>
Traditional	O
(	O
electromechanical	O
)	O
displays	O
are	O
equipped	O
with	O
synchro	B-Algorithm
mechanisms	O
that	O
transmit	O
the	O
pitch	O
,	O
roll	O
,	O
and	O
heading	O
shown	O
on	O
the	O
captain	O
and	O
first	O
officer	O
's	O
instruments	O
to	O
an	O
instrument	O
comparator	O
.	O
</s>
<s>
With	O
EFIS	B-Device
,	O
the	O
comparator	O
function	O
is	O
simple	O
:	O
Is	O
roll	O
data	O
(	O
bank	O
angle	O
)	O
from	O
sensor	O
1	O
the	O
same	O
as	O
roll	O
data	O
from	O
sensor	O
2	O
?	O
</s>
<s>
More	O
advanced	O
EFIS	B-Device
systems	O
have	O
more	O
comparator	O
monitors	O
.	O
</s>
<s>
This	O
computed	O
roll	O
attitude	O
is	O
then	O
compared	O
with	O
the	O
roll	O
attitude	O
input	O
to	O
the	O
symbol	O
generator	O
from	O
the	O
INS	O
or	O
AHRS	B-Device
.	O
</s>
<s>
Under	O
normal	O
conditions	O
,	O
an	O
EFIS	B-Device
might	O
not	O
display	O
some	O
indications	O
,	O
e.g.	O
,	O
engine	O
vibration	O
.	O
</s>
<s>
In	O
similar	O
fashion	O
,	O
EFIS	B-Device
is	O
programmed	O
to	O
show	O
the	O
glideslope	O
scale	O
and	O
pointer	O
only	O
during	O
an	O
ILS	O
approach	O
.	O
</s>
<s>
EFIS	B-Device
,	O
on	O
the	O
other	O
hand	O
,	O
removes	O
invalid	O
data	O
from	O
the	O
display	O
and	O
substitutes	O
an	O
appropriate	O
warning	O
.	O
</s>
<s>
The	O
electronic	O
display	O
technology	O
of	O
EFIS	B-Device
has	O
no	O
such	O
restriction	O
and	O
uses	O
color	O
widely	O
.	O
</s>
<s>
Typical	O
EFIS	B-Device
systems	O
color	O
code	O
the	O
navigation	O
needles	O
to	O
reflect	O
the	O
type	O
of	O
navigation	O
.	O
</s>
<s>
EFIS	B-Device
provides	O
versatility	O
by	O
avoiding	O
some	O
physical	O
limitations	O
of	O
traditional	O
instruments	O
.	O
</s>
<s>
Software	O
updates	O
can	O
update	O
an	O
EFIS	B-Device
system	O
to	O
extend	O
its	O
capabilities	O
.	O
</s>
<s>
A	O
degree	O
of	O
redundancy	O
is	O
available	O
even	O
with	O
the	O
simple	O
two-screen	O
EFIS	B-Device
installation	O
.	O
</s>
<s>
In	O
the	O
late	O
1980s	O
,	O
EFIS	B-Device
became	O
standard	O
equipment	O
on	O
most	O
Boeing	O
and	O
Airbus	O
airliners	O
,	O
and	O
many	O
business	O
aircraft	O
adopted	O
EFIS	B-Device
in	O
the	O
1990s	O
.	O
</s>
<s>
Recent	O
advances	O
in	O
computing	O
power	O
and	O
reductions	O
in	O
the	O
cost	O
of	O
liquid-crystal	B-Device
displays	I-Device
and	O
navigational	O
sensors	O
(	O
such	O
as	O
GPS	O
and	O
attitude	B-Device
and	I-Device
heading	I-Device
reference	I-Device
system	I-Device
)	O
have	O
brought	O
EFIS	B-Device
to	O
general	O
aviation	O
aircraft	O
.	O
</s>
<s>
Notable	O
examples	O
are	O
the	O
Garmin	O
G1000	O
and	O
Chelton	O
Flight	O
Systems	O
EFIS-SV	O
.	O
</s>
<s>
Several	O
EFIS	B-Device
manufacturers	O
have	O
focused	O
on	O
the	O
experimental	O
aircraft	O
market	O
,	O
producing	O
EFIS	B-Device
and	O
EICAS	O
systems	O
for	O
as	O
little	O
as	O
US$	O
1,000	O
-2000	O
.	O
</s>
<s>
Uncertified	O
EFIS	B-Device
systems	O
are	O
also	O
found	O
in	O
Light-sport	O
aircraft	O
,	O
including	O
factory	O
built	O
,	O
microlight	O
,	O
and	O
ultralight	O
aircraft	O
.	O
</s>
