The A-10 and
OA-10 Thunderbolt IIs are the first Air Force aircraft specially
designed for close air support of ground forces. They are simple,
effective and survivable twin-engine jet aircraft that can be used
against all ground targets, including tanks and other armored
vehicles.
The primary
mission of the A-10 is to provide day and night close air combat
support for friendly land forces and to act as forward air
controller (FAC) to coordinate and direct friendly air forces in
support of land forces. The A-10 has a secondary mission of
supporting search and rescue and Special Forces operations. It
also possesses a limited capability to perform certain types of
interdiction. All of these missions may take place in a high or
low threat environment.
The
A/OA-10 aircraft was specifically developed as a close air support
aircraft with reliability and maintainability as major design
considerations. The Air Force requirements documents emphasized
payload, low altitude flying capability, range and loiter
capability, low speed maneuverability and weapons delivery
accuracy. The aircraft is capable of worldwide deployment and
operation from austere bases with minimal support equipment.
Specific
survivability features include titanium armor plated cockpit,
redundant flight control system separated by fuel tanks, manual
reversion mode for flight controls, foam filled fuel tanks,
ballistic foam void fillers, and a redundant primary structure
providing “get home” capability after being hit. Design
simplicity, ease of access and left to right interchangeable
components make the A/OA-10 aircraft readily maintainable and
suitable for deployment at advanced bases.
The A-10/OA-10
have excellent maneuverability at low air speeds and altitude, and
are highly accurate weapons-delivery platforms. They can loiter near battle areas for
extended periods of time and operate under 1,000-foot ceilings (303.3
meters) with 1.5-mile (2.4 kilometers) visibility. Their wide combat radius
and short takeoff and landing capability permit operations in and out of
locations near front lines. Using night vision goggles, A-10/ OA-10 pilots
can conduct their missions during darkness.
The A/OA-10 is a single
place, pressurized, low wing and tail aircraft with two General Electric
TF-34-100/A turbo-fan engines, each with a sea level static thrust rating of
approximately 9000 pounds. The engines are installed in nacelles mounted on
pylons extending from the fuselage just aft of and above the wing. Two
vertical stabilizers are located at the outboard tips of the horizontal
stabilizers. The forward retracting tricycle landing gear incorporates short
struts and a wide tread. The nose wheel retracts fully into the fuselage
nose. The main gear retracts into streamlined fairing on the wing with the
lower portion of the wheel protruding to facilitate emergency gear-up
landings. The General Electric Aircraft Armament Subsystem A/A49E-6 (30
millimeter Gun System) is located in the forward nose section of the
fuselage. The gun system consists of the 30mm Gatling gun mechanism,
double-ended linkless ammunition feed, storage assembly and hydraulic drive
system.
Avionics equipment
includes communications, inertial navigation systems, fire control and
weapons delivery systems, target penetration aids and night vision goggles.
Their weapons delivery systems include head-up displays that indicate
airspeed, altitude and dive angle on the windscreen, a low altitude safety
and targeting enhancement system (LASTE) which provides constantly computing
impact point freefall ordnance delivery; and Pave Penny laser-tracking pods
under the fuselage. The aircraft also have armament control panels, and
infrared and electronic countermeasures to handle surface-to-air-missile
threats.
The Thunderbolt II's 30mm
GAU-8/A Gatling gun can fire 3,900 rounds a minute and can defeat an array
of ground targets to include tanks. Some of their other equipment includes
an inertial navigation system, electronic countermeasures, target
penetration aids, self-protection systems, and AGM-65 Maverick and AIM-9
Sidewinder missiles.
Thunderbolt IIs have
Night Vision Imaging Systems (NVIS), compatible single-seat cockpits forward
of their wings and a large bubble canopy which provides pilots all-around
vision. The pilots are encircled by titanium armor that also protects parts
of the flight-control system. The redundant primary structural sections
allow the aircraft to enjoy better survivability during close air support
than did previous aircraft. The aircraft can survive direct hits from
armor-piercing and high-explosive projectiles up to 23mm. Their self-sealing
fuel cells are protected by internal and external foam. Their redundant
hydraulic flight-control systems are backed up by manual systems. This
permits pilots to fly and land when hydraulic power is lost.
The Thunderbolt II can be
serviced and operated from bases with limited facilities near battle areas.
Many of the aircraft's parts are interchangeable left and right, including
the engines, main landing gear and vertical stabilizers.
The first production
A-10A was delivered to Davis-Monthan Air Force Base, Ariz., in October 1975.
It was designed specially for the close air support mission and had the
ability to combine large military loads, long loiter and wide combat radius,
which proved to be vital assets to America and its allies during Operation
Desert Storm. In the Gulf War, A-10s, with a mission capable rate of 95.7
percent, flew 8,100 sorties and launched 90 percent of the AGM-65 Maverick
missiles.
Service Life
The original service life
of the A/OA-10 was 8,000 hours, equating to approximately to FY2005. The
revised service life was projected out to 12,000 hours, equating to
approximately FY2016. The most recent long range plan has the A/OA-10 in the
fleet through FY2028, which equates to approximately 18,000-24,000 hours.
A/OA-10 modifications are
aimed at improving the A/OA-10 throughout the its service life. All
modifications are integrated between ACC, AFRC, and ANG, with the Guard and
Reserve often funding non-recurring engineering efforts for the
modifications and ACC opting for follow-on production buys. Budgetary
constraints are often best overcome by this type of arrangement. Two types
of modifications are conducted on the A/OA-10, those to systems, structures
and engines, and those to avionics. Structure, system and engine
modifications aim at improving reliability, maintainability and
supportability of the A/OA-10 and reducing the cost of ownership. Avionics
modifications continue the metamorphosis of the A/OA-10 from a day visual
flight rules (VFR) fighter to a night-capable integrated weapon system.
A/OA-10 avionics
modifications provide for greater interoperability between the Army and Air
Force by improving situational awareness, tactical communication, navigation
and weapon system accuracy, and providing additional capabilities in the
areas of threat detection and avoidance, low-level flight safety, stores
management and employment of “smart” weapons. In addition, modifications are
sought to reduce cost of ownership and to remove supportability quagmires
such as obsolete parts. Modifications to the A/OA-10 are nearly always
interdependent—interdependence maximizes combat capability of the A/OA-10 by
interconnecting modifications in distributed avionics architecture. Integral
to the improvement of the A/OA-10 is a new acquisition strategy centered on
a recently acquired prime contractor for the weapon system. The prime
contractor will be the integrator of all major weapon system modifications
and provide the continuity necessary to accommodate the downward trend in
organic manpower and relocation of the System Program Office.
A large portion of the
systems sustaining engineering is for contingency use throughout the fiscal
year and is utilized to investigate mishaps, resolve system deficiencies,
develop engineering change proposals, or to establish new operational
limits. Specific requirements cannot be forecast, but general needs can be
predicted based on actual occurrences since the A/OA-10 program management
responsibility transferred to SM-ALC in 1982. The objectives of the
sustaining engineering and configuration management programs are to reduce
spares utilization, reduce hazard potentials and to increase the weapon
system's effectiveness. Sustaining Engineering is mission critical and will
be used to obtain the non-organic engineering services needed to maintain
and improve the design and performance.
The A/OA-10 weapon system
was originally designed for manual pilot operation and control. In 1990, the
aircraft was modified to incorporate the Low Altitude Safety and Targeting
Enhancements (LASTE) System. This system provided computer-aided
capabilities including a Ground Collision Avoidance System (GCAS) to issue
warnings of impending collision with the ground, an Enhanced Attitude
Control (EAC) function for aircraft stabilization during gunfire and a Low
Altitude Autopilot system, and computed weapon delivery solutions for
targeting improvements. The LASTE computer system installation added the
requirement for an Operational Flight Program (OFP) to provide the computer
control software necessary to perform the above functions.
Commencing in 1999, the
A/OA-10 fleet was additionally upgraded with the installation of an Embedded
Global Positioning System/Inertial Navigation System (EGI). In conjunction
with this aircraft modification, a replacement Control Display Unit (CDU)
will be installed with its own separate OFP software.
Operational capability
changes, mission changes, latent system deficiencies, and additional user
requirements dictate the necessity of periodic OFP block change cycles (BCC)
to maintain the weapon system operational requirements. The current BCC
includes the LASTE OFP changes, but will additionally require the CDU OFP
updates to be accomplished concurrently following the installations of EGI/IDM
Modification. Following installation of the original LASTE System,
corrections to original system deficiencies, added user requirements, and
now the pending EGI modification program have increased the total
requirements for the LASTE computer hardware to its maximum design
capability. Implementation of the current OFP software change will result in
maximum utilization of the computer's memory and throughput, precluding any
further operational change requirements from being implemented. In
anticipation of this hardware limitation, engineering Reliability and
Maintainability (R&M) project was initiated in 1993 to develop options to
correct this deficiency. This project is developing an engineering hardware
unit, along with an updated OFP software program, for test and evaluation.
The addition of the LASTE
system and the pending installation of the EGI/CDU system have greatly
increased the complexity of the A/OA-10 weapon system, including the
troubleshooting and maintenance requirements. Also, the implementation of
the 2-level maintenance system, eliminating the intermediate-level
maintenance capabilities at the operating units, has necessitated improved
troubleshooting capabilities at the unit levels to maintain the aircraft
operational readiness requirements. An Operational Test System (OTS) has
been developed to provide a computer test aid for the organizational
maintenance units to expedite their maintenance actions. The OTS contains a
software test program that requires periodic updates to maintain
compatibility with the LASTE and CDU systems, as well as other A/OA-10
avionics systems.
TF-34 engines are
essentially two level maintenance via user Queen Bee sites at Barksdale,
Davis-Monthan and Shaw AFBs. All ACC aircraft TF-34 engines are repaired at
Davis-Monthan or Shaw AFB. Shaw AFB also supports USAFE. PACAF uses a
combination of two and three level maintenance; Osan AB utilizes regional
support provided at Kadena AB, while Eielson AFB performs Jet Engine
Intermediate Maintenance (JEIM) on-sight. Barksdale AFB regionally supports
AFRC. The ANG remains entirely supported by base field JEIM shops. Depot
level engine maintenance is accomplished by the Navy at Jacksonville NAS,
FL. The A/OA-10 has 51 avionics line replaceable units that transitioned to
two level maintenance.
The A/OA-10 was designed
for user maintenance in all normal maintenance inspections and tasks. This
design has been very successful for this aspect and there is every
expectation this will continue for the life of the weapon system. The only
depot level requirements are Analytical Condition Inspection (ACI) and
unscheduled depot level repair.
ACI is a specialized
inspection to check areas, sub-systems or parts that are not checked on any
periodic basis during normal maintenance. The purpose of the ACI is to find
developing problems that might affect the mission or ensure such conditions
do not exist. Problems discovered during ACI result in engineering studies
that determine appropriate corrective action. There are 11 ACI aircraft
selected (by usage, age, flight hours and environment) from different bases
and MAJCOMs that are scheduled per fiscal year. The ACIs are accomplished at
OO-ALC.
Unscheduled depot repair
occurs when an aircraft incident, accident or other unusual occurrence
creates a problem beyond the users ability to correct. Such occurrences
result in a request from the MAJCOM for depot assistance. Depending on the
situation, the aircraft may be inducted into a depot or contractor facility,
or a depot or contractor field team may be dispatched to the location of the
aircraft.
The A/OA-10 has a
requirement for repaint every eight years. The fleet size sets the current
requirement to approximately 65 per fiscal year. While this is not strictly
a depot requirement, the need for a fixed, specialized and environmentally
contained facility limits the user in his choices. The A/OA-10 is primarily
painted atOO-ALC; however, Daimler-Benz AG in Germany paints USAFE aircraft.
For economic reasons the 11 ACI aircraft inducted into OO-ALC each year are
also painted.
In the Gulf War, A-10s
had a mission capable rate of 95.7 percent, flew 8,100 sorties and launched
90 percent of the AGM-65 Maverick missiles.
Sources and
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