Avionics News March 2016 - 19

GPS solely to provide position, speed and vector data to
the ADS-B broadcast.
They aren't IFR-approved navigators or, for that matter,
even VFR-useful navigators. Like a blind altitude encoder,
only the transponder or the universal access transceiver
know what the GPS is saying to air traffic control.
To use a WAAS GPS for navigation, it needs to be in a
working navigator; for IFR and approach use, that navigator
needs a database loaded with the approach procedures and
airport data for every airport with an approved approach.
For nearly two decades, one of aviation's most-popular
IFR-GPS solutions came in the form of stand-alone GPS
navigators. Until, that is, Garmin revolutionized cockpit
electronics with its GNS 430 and GNS 530 - the first allin-one.
Upgradable to WAAS GPS as the GNS 430W and GNS
530W, these boxes combine a powerful VHF communications transceiver with a VHF navigation receiver, the IFReligible GPS navigator, and a large eight-color screen to
display moving-map data and, later, traffic and weather.
Today, Avidyne, BendixKing and Garmin all produce
newer versions of the all-in-one avionics package, all with
sharper, more colorful display screens, faster processors
and, the keys to the kingdom, an IFR GPS navigator using
WAAS.
For Avidyne, the IFD440 and IFD540 deliver the goods;
BendixKing's KSN 770 fills the same bill; and Garmin
replaced both original GNS models with the GTN 650 and
GTN 750.
All three of these current models deliver sharper, morecolorful display screens than the GNS models and accuracy good enough to fly precision approaches based solely
on satellite navigation signals.
Any of these options can displace screens dedicated to
weather and traffic sensors - as can the PFDs mentioned
above.
And everything else
Engine instruments similarly advanced during the years
since the first general aviation PFDs came along in the first
half of the 1990s.
Between Electronics International, JP Instruments and
several others, operators enjoy the option to modernize their
instrument clusters, right up to and including fuel-level
monitoring, fuel-flow reporting, along with all the usual
engine health data and electrical-system health and load.
Some of this data may be wired to the MFD or PFD used,
as long as a data-sensor feed exists for routing the information to the digital screens.
Modern, no-moving-parts fuel-level sensors can replace

analog sensors with their wire-mounted floats and variable
impedance sensors; ditto for temperature and pressure sensors, heat sensors and more.
With a little integration planning, new sensors can be
connected to the digital cockpit screens for display, eliminating the need for separate clusters of gauges and instruments reflecting powerplant and electrical-system health.
In reality, the biggest limitation for many pilots will be
their wallets.
But accomplished in steps, the costs can be metered
to make each step more affordable and still achieve the
desired end - a modern, electronic flight deck that saves
weight, reduced power demand on the electrical system,
and frees panel space by combining multiple functions on
one easy-to-read display screen.
The choices are there
Planning a panel makeover need not break the bank if accomplished in steps. Upgrading to a basic glass instrument
can cost in the high four figures range, plus installation.
Planning an avionics step up after a couple of years - and a
similar investment - can help make a tired panel into something closer to the state-of-the-art.
But there remains one non-panel system to consider
when replacing analog instruments and old radios with new
digital systems.
Power; specifically, electrical-system power.
A PFD takes more juice to power than the typical turn indicator - the one flight gyro of the three typically powered
by the electrical system. The air powering the other two
gyros usually comes off an engine-driven air pump using
either pressure or vacuum to spin the gyro wheels.
While not substantial, the power needed to light the
display screens of an all-in-one may, when added to the
power for the GPS and two VHF radios, exceed the demand
imposed by the radios removed.
An early part of the long-term makeover process should
include weighing whether the existing alternator - or generator on many older aircraft - can handle the anticipated
current demand.
This can be of particular importance if the progressive
panel upgrade process throws in an autopilot or redundant
displays.
And somewhere in the process of planning the long-term
upgrade, the owner may want to consider adding some form
of standby electrical power - perhaps an alternator in place
of the newly superfluous air pump that originally drive two
or more flight gyros.
It's all part of the planning for a progressive upgrade, one
partial-panel step after another. q
avionics news

march

2016

Table of Contents for the Digital Edition of Avionics News March 2016