IN HANGAR DESIGN STRIKING
By Pat Brown, RA, LEED AP
Big, clear-span, open-box designs are impressive, and, at first
glance, seem very flexible. But while those large, open hangars
might provide adequate space, they likely aren’t providing the
accessibility to aircraft you thought you’d be getting. A clear-span design is the single most significant hangar cost driver,
and the return on investment may not pay off like you hope.
Flexibility should be balanced with efficiency. Sacrificing
efficient operations for flexible space is a poor trade. If that
huge expensive hangar is inefficient, you have overpaid to
build it and you keep overpaying in utility costs and extended
maintenance turn times for the life of the facility.
Design Hangars for Your Fleet
The key to balancing hangar flexibility and efficiency is to define
the mission. In general, use long spans for line maintenance
and short spans for heavy maintenance in two separate
hangars. While separate hangars may seem counterproductive
to creating a flexible hangar, flexibility comes in the form of
more efficient maintenance schedules and less risk.
Most airline fleets include more narrow-body aircraft than wide-body aircraft. Hangar space is always at a premium, and there
is a greater need to get three or four narrow-body aircraft back
on line compared to one wide-body aircraft. So a large, tall,
long-span hangar built for wide-body aircraft that is primarily
used for narrow-body aircraft maintenance can equate to a
huge waste of space and money.
Mixing line and heavy maintenance in a huge open hangar
raises damage risk. The aircraft in heavy maintenance is more
at risk with line maintenance aircraft arriving and departing the
hangar several times a day, exposing the open airframe and
components to weather, windblown foreign object debris (FOD),
hangar rash bumps and scrapes, and repeated exposure of
workers to the outdoor conditions.
Suit Hangars to Aircraft Needs
Line and heavy maintenance operations are distinctly different
in that line maintenance rarely opens the airframe to expose
major internal elements and systems, while heavy maintenance
opens the airframe in many locations to gain access to the
major components and systems concurrently. Dwell times in the
hangar for line maintenance range from an hour to overnight,
while an aircraft in a C-check could be in the hangar, on jacks,
for 20 days or more.
Line maintenance hangar space is defined by that mission:
continuous demand for access, fast turns several times a day,
or overnight. Since maintenance work is less detailed but more
time critical, there is no time to set up the work docks needed