DEFENSE - Abdonline

A Global Hawk sits on the runway before
beginning a nighttime mission. The aircraft is
unmanned, and is used to capture imagery from
high altitudes.
the same company makes the
Integrated Sensor Suite, which includes
the electro-optical, infrared, and
synthetic aperature radar imaging used
on all RQ-4As. To keep them in top
operational order, the seven primary
sensor LRUs on the RQ-4 are hand
massaged on a daily basis.
Maintenance providers need
replacement parts to keep aircraft
flying, and this can be a problem for the
current operational RQ-4, because
there are only nine Block 10 models in
the entire world. U.S. Navy Captain
Robert Dishman, Program Manager for
Persistent Maritime Unmanned Aircraft
Systems, at Patuxent River Naval Air
Station in Maryland, tells us that a daily
report is circulated to all units involved
with RQ-4 operations, providing the
status and availability of critical parts
used on the aircraft.
Cannibalization is a fact of life for
Block 10 RQ-4s, as these UAVs have
been projected to be replaced by more
capable follow-on variants since the
program's inception. This results in a
higher cannibalization rate than
normally is considered acceptable for a
weapons system intended for long-term
use.
The fuselage of the RQ-4 is
aluminum, and the wings and
empennage are composite and, as
such, are pretty standard in terms of
maintenance upkeep. The issue faced
by maintainers is that the RQ-4, like any
new aircraft, still is undergoing damage
tolerance assessment; this results in the
need for engineering dispositions from
Northrop Grumman before making
most related repairs.
Technicians update maintenance
manuals as they encounter and repair
damage to the skin of the RQ-4 in order
to continually improve its capabilities.
For example, U.S. Navy BAMS RQ-4N
aircraft will include leading-edge
modifications, which have undergone
hail and bird strike tests.
Another difference between the
U.S. Navy's planned BAMS version of
the RQ-4B and the U.S. Air Force's
Blocks 20-40 is the addition of leadingedge
anti-icing and de-icing
capabilities. Icing is a definite problem
encountered in RQ-4 operations, so
much so that the Air Force has lost
quite a few sorties due to icing
conditions.
During initial design, the
assumption was made that the aircraft
would transit the icing regime quickly
enough, so that ice buildup would not
be an issue. It took further engineering
analysis and in-flight experience to
determine that was not the case;
however, this still was unknown during
initial reviews of the U.S. Air Force
variants.
As more data was available when
the U.S. Navy went on contract, a
requirement for anti-icing and de-icing
features was added. Since retrofitting
this desirable capability is expensive,
the U.S. Air Force is looking at adding it
to future production models.
U.S. Navy RQ-4Ns also will have
KEEPING THE RQ-4 IN THE AIR
increased wing strength to allow for
greater gust load environments and
increase safety factors. This has been
accomplished by adding several more
layers of composite to the wings, while
taking some of the thickness away from
the wing spars. This tradeoff allows the
wing shape to remain the same.
Despite these subtle model
differences, the U.S. Air Force and the
U.S. Navy are working together in their
RQ-4 operations around the world,
sharing maintenance technicians, parts,
and ground support equipment, such as
the LRE (Launch and Recovery Element).
Most important, the two services are
sharing their experiences and ongoing
information, with the goal of improving
and maximizing the use of the versatile
RQ-4.
This cooperation is exemplified by
the recent 380 Air Expeditionary Wing's
addition of the first operational U.S.
Navy RQ-4A. This joint mission is an
outgrowth of the GHMD program,
known as the Broad Area Maritime
Surveillance Demonstrator.
WWW.ABDONLINE.COM AVIATION AFTERMARKET DEFENSE | SPRING 2010
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Photo by John Schwab, Beale Air Force Base, California