EP-3E ARIES II Description
The EP-3E ARIES II Aircraft replaced the EP-3B BATRACK and the EP-3E ARIES DEEPWELL Aircraft. The EP-3E ARIES II is a modified P-3C Non-Update (NUD) Aircraft. Modifications to the EP-3E ARIES II Aircraft began in March 1996. External upper and lower canoes are added to house antenna installations. The bottom forward cargo bay has been modified to accept the AN/APX-134 Radar Antenna and radome.
The EP-3E ARIES II is a shore-based, long range, fixed wing aircraft powered by four T-56-A-14 turboprop engines. The EP-3E uses a complex combination of receivers, antennas, computers, displays, and recording devices to accomplish its primary mission of Electronic Support (ES). The aircraft provides near real-time SIGINT capabilities to Battle Group and Joint Commanders. The avionics package of the EP-3E is designated the Mission Avionics System (MAS). The MAS provides mission support through detection and analysis of significant ES signals.
The fuselage is pressurized in the cabin area. Personnel loading and unloading is accomplished through use of an electromechanically operated folding ladder, which is stored in the cabin when not in use. There are four cabin emergency escape hatches. Two over-wing hatches (port and starboard) are located on the sides of the fuselage, one hatch aft of the pilot's port side windshield panel, and overhead hatch in the top of the flight station. The lavatory and galley are located in the aft cabin fuselage. The largest radome on the aircraft is 12 feet in diameter, 3 feet deep, elliptical, and retractable. It houses the Big Look antenna and is located just aft of the nose gear. The upper and lower canoe assemblies house additional antennas. The upper canoe consists of three sections located on top of the fuselage, forward of and in-line with the vertical stabilizer. The lower canoe, also in three sections, is located on the lower fuselage center, just aft of the Big Look antenna.
There are two independent (primary and secondary) hydraulic power systems located in the Hydraulic Service Center (HSC) that operate at 3,000 pounds per square inch of pressure. The HSC is accessible from outside the aircraft through a door in the bottom of the fuselage and from the cabin through the deck hatch. In addition to the number one and two hydraulic power systems, the normal brake valve, accumulator, emergency brake modulator valves, air brake bottle, in-flight brake pressure reducer, aileron boost package, wing flaps, and landing gear components are located in the HSC. The system is identical to the original P-3C hydraulic system, except for the EP-3E ARIES II modification that deleted bomb bay doors and installed the retractable radome.
The landing gear system is comprised of two main gears and one nose gear. Each assembly consists of dual wheels and forward-retracting struts. The gears are designed to free fall and lock in the down position in the event hydraulic pressure is lost.
The EP-3E ARIES II is powered by four Allison T-56-A-14 turboprop engines. Each engine develops 4,600 Shaft Horsepower (SHP) at 1,077 degrees Celsius Turbine Inlet Temperature. The aircraft propellers are four-bladed Hamilton-Standard 54H60-77, which convert SHP into thrust. Propeller modes of operation are flight range, including take-off roll (after power levers are moved forward) and all flight regimes, and ground operating range (Beta) where power levers are aft of the flight-idle stop. Propeller spinners, blade cuffs, and islands are heated to control ice build-up. When the system is engaged, the spinner nose is heated continuously. A hydraulic, speed-sensitive pitchlock is included in the propeller control assembly to prevent overspeed.
The Auxiliary Power Unit (APU) consists of a Gas Turbine Compressor (GTC) which drives a 60 Kilovolt Ampere (KVA) generator identical to the engine-driven generators. The GTC has a two-stage centrifugal compressor and a single-stage inward flow radial turbine. Bleed air is used for engine starting, ground air conditioning, and heating. The APU can be operated in flight for generating emergency electrical power; however, bleed air is not available.
During ground and flight operations, environmental control for the aircrew and electronic equipment is provided by the air conditioning and pressurization system. The system employs engine bleed air and electrical power to achieve anti-icing (preventive) and de-icing (removal).
The aircraft electrical Alternating Current (AC) power is supplied by three 60 KVA generators mounted on, and driven by engines number two, three, and four. In normal operation, generators two and three work independently, each providing power to one of two main AC buses, A or B. Generator four serves as a standby, supplying power in the event of a malfunction with generators two or three. Generator switching is completely automatic and is indicated by advisory lights in the flight station. The APU is a fourth generator that may be used in flight, if necessary, as well as on the ground. Direct Current (DC) power is provided by three 200 ampere transformer rectifiers which convert AC to DC, supplying power to the DC buses.
The fuel system includes five tanks, a fueling system, and transfer, cross-feed, and dump systems. The fuel system allows conventional over the wing fueling, or pressure fueling and defueling under the wing. There are four wing tanks and an auxiliary tank, identified as tank five. Tank five is a bladder type tank, located in the unpressurized area of the lower fuselage. The fueling system provides the capability to pressure fuel any tank to any desired quantity if electrical power is available. Tank five can be fueled only through the pressure fueling system.
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