January-February 2022 - 28

COVER STORY
Head-Up Displays (HUD) are an
increasingly popular avionics
option for all grades of aircraft.
MYGOFLIGHT
" 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 vast majority of inside-the-box
repairs are done at a Collins Service
Center, Kowash said. In the field, Collins
has an extensive global network of customer
support engineers that help customers
with troubleshooting faults or
other maintenance issues.
28 JANUARY/FEBRUARY 2022
" 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 two 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
requires very specific processes, procedures
and equipment for proper alignment and
calibration to achieve optimum accuracy,
Olivastri said. " We support the end user
with hands-on initial training and refresher
training. We assist with in-country troubleshooting
and problem solving to ensure this
essential piece of equipment does not cause
their aircraft to be grounded. "
Elbit Systems HUDs must be certified
by the applicable civil authorities to the
highest design assurance level since they
are utilized as the pilots' Primary Flight
Display. This means that a failure of the
HUD would ultimately cancel the mission
or ground the aircraft.
An improperly calibrated HUD could
result in multiple issues such as blurry or
shifted imagery, display brightness, while
display refresh issues could cause a noticeable
blinking of the image.
For the optics, chips and scratches
could go unnoticed. A chip or scratch
within the field of view (FOV) may seem
like very minor issue but could result in
a profound effect on the pilot's ability to
read the display
" All these calibration and optics issues
may go unnoticed for the untrained maintainer
but could result in critical information
unreadable by the pilot resulting in an unsafe
operating environment, " Olivastri said.
AIRCRAFT MAINTENANCE TECHNOLOGY
January-February 2022

Table of Contents for the Digital Edition of January-February 2022
