spring2022 - 11

COVER STORY
manually flown CAT III approaches and
low-visibility takeoffs (LVTO). This is an
alternative to autoland systems that are more
costly to install and maintain.
One trend is the growth of HUDs to include
Enhanced Flight Vision System (EFVS) technology.
EFVS builds on HUD functionality by
adding a camera sensor mounted on the nose
of the aircraft. Nate Kowash, Rockwell Collins
program manager, said these EVS sensors
are sophisticated LRUs that contain multiple
infrared and visible light cameras, complex
image processing, and other functions like
sensor window deicing heat. When displayed
on the HUD, the EFVS video provides an augmented
reality view that allows pilots to " see
through " low visibility conditions like fog,
snow, rain, smoke, or even just night VFR.
" As these EVS sensors are exposed on the
exterior aircraft, they add a new element to
HUD maintenance, " he said. " To maintain
the best optical performance of these cameras,
special care should be taken to avoid
scratching EVS windows when cleaning.
Additionally, these LRUs can be subject to
external damage from hail, bird strikes or
lightning strikes. "
Keep HUDs in Service
MyGoFlight works with the MROs, maintenance
facilities and avionics for repair and
support of the product line, Biggs said.
The SkyDisplay has an embedded watchdog
feature checking the functionality of the
HUD for the pilot. If the watchdog detects a
problem with the video image, then the HUD
will display a large Red X for the pilot to alert
there is a problem.
" In most cases, simply cycling the power
will solve the problem. No troubleshooting
is really required, " Biggs said. " There are
brightness and contrast buttons to adjust
during bright and low light situations. The
HUD simply projects existing flight data and
sensor information onto the combiner. "
HUDs have a long life span since the basic
required functionality has remained very
consistent over the years. Aging electronics
tend to have reduced MTBF, and a failure of
mission critical equipment such as the HUD
would cause the mission to be aborted.
Head-Up Displays (HUD) are an increasingly popular avionics option for all
grades of aircraft.
" We specialize in HUD upgrade programs,
allowing its customers the benefit
of increased MTBF, Diminishing Manufacturing
Sources (DMS) and prolonged operational
life, Olivastri said. " Additionally with
modern electronics calibration and diagnostic
routines become more automatic making
maintenance easier, all these factors reducing
life cycle costs. "
Due to the visual nature of the system,
Kowash said the pilot will quickly see if
there is maintenance required. Until then,
maintenance generally does not need to be
concerned. Many of the models are part of
the MSG-3 process with no preventive maintenance
determined.
" Many operators include the HUD in
their Minimum Equipment List as a system
eligible for deferred maintenance, " he said.
" The system does not cause AOG unless it
is operationally needed for low-visibility
operations. And it is optional equipment on
many airframes. "
Kowash said there's a large amount of
built-in test (BIT) that is useful for troubleshooting.
Information on BIT for Collins
HUDs can be found in the maintenance manuals
published by Collins Aerospace.
The system is typically maintained " on
condition, " with no preset inspection intervals.
Some systems need a desiccant inspection
of the Overhead Unit. Some operators
have a Category III landing approval specification
that requires interval testing.
The majority of inside the box repairs are
done at a Collins Service Center. Collins has
an extensive global network of engineers that
help customers with troubleshooting faults or
other maintenance issues.
" Collins offers flight line maintenance
training for maintenance personnel that
will be operating, maintaining, and troubleshooting
our HUD systems, Kowash said.
" These courses are about 2 days and can be
offered either at customer sites or at Collins
facilities. "
Elbit Systems provides Intermediate Level
Maintenance and Depot Level Maintenance
for HUDs at its maintenance facilities. Repair
of the optics assemblies requires a clean environment
and the circuit cards use automated
test equipment (ATE) to repair. The complete
HUD requires very sophisticated test and
alignment equipment.
" The Head Up Display is a very precise
optical/electrical piece of equipment that
SPRING 2022* e-Military Product News For Aviation 11
MyGoFlight
spring2022

Table of Contents for the Digital Edition of spring2022
