MIL-HDBK 1028/6A
Section 2:
FIXED POINT UTILITY SYSTEMS
2.1
General.
Design of the fixed point utility system (FPUS)
requires determining the number and type of aircraft to be served, ground
support requirements of the particular aircraft, expected diversity of the
aircraft loads and site configuration. Resolving these variables provides
the central facilities utility demands, equipment capacities, line size and
routing of the distribution system, and aircraft service point
requirements.
2.1.1
Planning. The FPUS concept is based upon the economy of
supply of aircraft utilities from a centralized plant of energy-efficient
components. Include the following considerations in FPUS planning for a
particular aircraft maintenance facility:
a) Orderly expansion of the system components to accommodate
probable future hangar bays and parking apron service points.
b) Economic feasibility of supplying adjacent or nearby
facilities (existing or future) from the centralized supply.
c) Relocatability of ground support equipment versus FPUS
installed equipment.
d)
2.1.2
Aircraft Services. Fixed point systems shall supply aircraft
utilities at parking apron service points and maintenance hangar service
points. The FPUS required are compressed air, preconditioned air for
hangar aircraft, and electrical power. Two system design alternatives are
feasible. (See Table 1 for a summary of aircraft utility demands.)
2.1.2.1
Alternate 1. The air start system provides compressed air at the
parking apron service points. Aircraft cooling is provided by mobile
ground carts. The selection of the air start system or environmental
control system (ECS) system is based upon system requirements and economic
factors. Factors affecting the system selection include central plant and
utility distribution construction costs, local environmental conditions,
and local utility rate structures. Manpower requirements, space
limitations, system dependability, and air quality permits to operate fuel
fired yellow gear equipment outdoors must be considered in addition to
economic analysis. The air start system will generally have the lowest
initial cost and shortest payback period while using the least energy of
any current design option.
2.1.2.2
Alternate 2. The ECS, provides compressed air for engine
starting air and ECS compressed air at the parking apron service points
from a central source. The ECS will generally have the lowest operating
2