A/U26U-1 Oxygen Servicing Unit
The A/U26U-1 oxygen-servicing unit (fig. 9-23) is
used to replenish oxygen storage cylinders and
emergency bailout oxygen systems, which are installed
in aircraft. The trailer has two fixed wheels and a
retractable, rotatable caster wheel for movement by
hand or towed by a tow tractor. The unit contains a
nitrogen module, oxygen module, and three cylinders
of gas. Two cylinders of nitrogen are used to drive the
boost pump and one cylinder of oxygen is used for
servicing. The modules contain the gas pressure and
flow controls, boost pump, connectors, and safety
devices within a protective case.
A/M26U-4 (NAN-4) Nitrogen Servicing Unit
The A/M26U-4 (NAN-4) nitrogen-servicing unit
(fig. 9-24) provides a mobile source of compressed
nitrogen to recharge aircraft nitrogen systems. It
consists of a welded steel frame, two-wheel axle, a
front retractable caster wheel, draw bar coupler ring for
towing, tool and storage boxes, six compressed gas
cylinders, and a manual hand brake. Nitrogen under
pressure is transferred from the NAN-4 to the aircraft
through a series of gauges, valves, manifold, filters,
pressure regulator, and hoses. It is equipped with a
boost pump that is capable of boosting nitrogen supply
pressure up to a maximum of 3,500 psi.
9-14
ANF0923
Figure 9-23.—A/U26U-1 oxygen servicing unit.
ANF0924
Figure 9-24.—A/M26U-4 (NAN-4) nitrogen servicing unit.
