201: AIRFRAME SYSTEM References:

(a) NAVEDTRA 12338, Aviation Structural Mechanic (H & S) 3 and 2

(b) NAVAIR 01-85ADC-1, NATOPS Flight Manual, Navy Model EA-6B Aircraft

(c) NAVAIR 01-85ADC0-2-6, Organizational Maintenance, Environmental Control Systems, Navy Model EA-6B Aircraft

(d) NAVAIR 01-85ADC-2-5, Organizational Maintenance, Escape and Survival Systems, Navy Model EA-6B Aircraft

(e) NAVAIR 01-85ADC-2-1, Organizational Maintenance, General Information and Servicing, Navy Model EA-6B Aircraft

(f) NAVEDTRA 10401, Aviation Structural Mechanic (E) 2

(g) NAVAIR 01-85ADC-2-3, Organizational Maintenance, Landing Gear and Arresting Gear Systems, Navy Model EA-6B Aircraft

(h) NAVAIR 01-85ADC-2-10, Organizational Maintenance, Instrument Systems, Navy Model EA-6B Aircraft

201.1 Systems components and component parts

Referring to a standard print of this system or the actual equipment, identify the following system component parts and discuss the designated items for each:

A. What is its function?

B. Where is it located?

201.1.1 Aircraft structure:

The Aircraft structure consists of principal parts, and must be fast, maneuverable.

(1) Fuselage:

(a) It provides space for the crew, passengers, cargo, most of the accessories, and other equipment (b) The fuselage is the main structure or body of the aircraft to which all other units attach.

(2) Empennage:

(a) For inspection and maintenance purpose, attachment point for vertical and horizontal stabilizers. (b) The entire tail section is considered a single unit of the airframe, and is referred to as the “Empennage”.

(3) Wings:

(a) The wings of an aircraft are designed to develop lift when they move through the air.

(b) The wings are located on the right and left side of the fuselage.

201.1.2 Flight Control Surfaces:

The Flight Control Surfaces are hinged or moveable airfoils designed to change the attitude during flight.

(1) Flaps:

(a) The wing flaps are semi-fowler type slotted flaps and work with the wing slats to provide additional lift during takeoff and landing.

(b) The flaps are supported by a hinge and carriage assembly in the wing trailing edge.

(2) Slats:

(a) The wing slats work with the flaps to provide additional lift during takeoff and landing.

(b) The wing slats are supported by reversible screw jacks, and guided by rollers in the wing leading edge.

(3) Flaperons:

(a) Flaperons are used for lateral control (ROLL). Stick movement to left results in the left flaperon being used with the right flaperon remaining flush with the wing. Conversely, stick movement to the right results in the right flaperon being used and the left flaperon remaining flush with the wing.

(b) Flaperons are located just forward of the wing flaps. The flaperons are divided on each wing at the wing fold.

(4) Horizontal Stabilizer:

(a) Longitudinal control (PITCH) is provided by the horizontal stabilizer. The slab-type stabilizer responds to fore and aft movement from the stick. Stabilizer movement is limited when flaps and slats are retracted, and is increased when flaps and slat are extended, or with flaps and slats retracted and ASSIST SPIN RECOVERY switch to ON.

(b) Connected to the Empennage, left and right sides that rotate as a unit.

(5) Rudder:

(a) Directional control (YAW) is provided by a single rudder. Rudder control is provided through movement from the rudder pedals in the cockpit. Rudder movement is limited when flaps and slats are retracted, and is increased when flaps and slats are extended, or with flaps and slats retracted and ASSIST SPIN RECOVERY switch to ON.

(b) Connected to the aft edge of the vertical fin at two hinge points, the lower section has an attachment point for rudder actuator

(6) Speed Brakes:

(a) Speed brakes are hinged movable control surfaces used for reducing the speed of the aircraft. Their primary purpose is to keep the aircraft from building up excessive speed during dives.

(b) Surfaces at the trailing tip of each wing tip, outboard of the flaps.

102.1.3 Hydraulics:

Various types of hydraulic components make up a power system.

(1) Reservoirs:

(a) The reservoir is a tank in which an adequate supply of fluid for the system is stored, fluid flows from the reservoir to the pump, where it is forced through the system and eventually returned to the reservoir.

(b) There are two hydraulic reservoirs on the EA-6B, Flight and Combine. The flight reservoir is located on the right side, aft and below the starboard engine intake, below the starboard boarding ladder. The combine reservoir is located under the port wing root, above the port forward engine bay door.

(2) Hydraulic Pumps:

(a) All aircraft hydraulic systems have one or more power-driven pumps and may have a hand pump as an additional source of power. Power-driven pumps are the primary source of energy, and may be either engine-driven or electric motor driven.

(3) Actuators:

(a) Actuating cylinders are the most commonly used actuating units in aircraft hydraulic systems. An actuating unit may be defined as a unit that transforms hydraulic fluid pressure into mechanical force, which performs work (moving some mechanism).

(4) Accumulators:

(a) The purpose of the accumulator in a hydraulic system is to store volume of fluid under pressure. An accumulator acts as a cushion against pressure surges that may be caused by the pulsating fluid delivery from the pump or from system operations.

201.1.4 Landing Gear:

The aircraft has a fully retractable tricycle landing gear. The landing gear system provides the aircraft with complete carrier and land takeoff and landing capability. Also that portion of the aircraft that supports the weight of the aircraft while it is on the ground.

(1) Nose Landing Gear:

(a) The nose gear is hydraulically interconnected with the main gear. The nose gear system includes an air-oil shock strut, duel wheels with tubeless tires, a supporting drag strut, and a nosewheel steering and damper system.

(b) It is located forward, under the cockpit.

(2) Main Landing Gear:

(a) The main gear system consists of an air-oil shock strut that houses a multiple-disk wheel brake, a single wheel and tubeless tire assembly, and a supporting drag brace.

(b) It is located under the port and starboard wing roots.

(3) Wheel Brakes:

(a) The main wheel brakes are hydraulically powered multiple disk brakes. The brake system is designed to retard or stop the aircraft’s motion on the ground. They also aid in controlling the direction of the aircraft while it is taxiing.

(b) The wheel brakes are mounted on the bottom of the main landing gear shock struts, inside the tire assembly.

(4) Nose Tow Catapult system (tow-link):

(a) The components necessary for a catapult launch, serves the dual purpose of guiding the aircraft to the shuttle from the lead-in track and attaching the aircraft to the shuttle.

(b) It is located forward of the nose gear, lower part of the shock strut.

(5) Arresting Hook:

(a) The arresting hook system provides carrier landing capability and arresting landing capability equipped with arresting gear.

(b) It is located in the belly of the Empennage.

201.1.5 Environmental Control Sysmtems:

(a) Cabin Air Conditioning - The cabin air-conditioning system is an air-cycle system used to maintain the forward and aft cockpit temperature within the limits of crew safety and comfort. The system distributes a mixture of dehumidified, refrigerated bleed air and engine hot bleed air through air conditioning ducts in the forward and aft cockpits. The forward refrigeration unit supplies the refrigerated bleed air for the cabin air-conditioning system. The cockpit air-conditioning system can maintain temperature between 60F and 80F and can be operated in three modes; auto, manual, and ram air. Auto Mode: Utilizes a variety of air temperature sensors, shutoff valves and a controller to maintain temperature automatically at a given setting through constant analysis of signals sent from sensors to the controller and then to valves regulating the flow of both hot and cold air to get the desired temperature. Manual Mode: Uses a switch on the air-conditioning control panel placed cold or hot to drive a dual temperature control valve hot or cold depending on the needs of the aircrew. When the switch is released it returns to a hold position and maintains the valve at the last selected position. Ram-Air Mode: Ram air mode is an emergency backup used in the event the forward refrigeration fails. Ram air is brought in from outside the aircraft utilizing the Ram-Air valve and the ducting already in place for normal air-conditioning.

(b) Cabin Pressurization - The cabin pressurization system is used to maintain forward and aft cockpit pressures within the limits of crew safety and comfort. With today’s high performance aircraft the altitudes at which flight is now possible is astounding. The pressures at which the human body operates at peak effectiveness are those maintained when between sea-level and 8,000 feet. The cabin pressurization system is the means to maintain the proper pressures and regulating them in the aircraft. The cockpit pressurization system regulates the out-flow of conditioned air through a set of valves to regulate pressures suitable for aircrew efficiency. These valves are the cabin pressure regulator located outboard of ECMO-3 on the rear bulkhead. The cabin pressure regulator maintains pressure from sea level through 8,000 feet at ambient, 8,000 feet to 23,000 feet is maintained at 8,000 feet and above 23,000 feet a 5-PSI differential is maintained. The cabin safety valve is used the event the cabin pressure fails and then by selecting dump on the cabin dump control panel to dump excessive pressure overboard and also allows for removing smoke in the cockpit.

(c) Defogging - The defogging system provides the inner surfaces of the forward windshield, windshield quarter panels and forward cockpit canopy with a conditioned bleed air blast to defog and defrost these surfaces. The temperature of the conditioned bleed air is automatically maintained by the defog and equipment cooling controller. The system uses hot bleed air from both motors mixed with cooled bleed air supplied by the main heat exchanger of the forward refrigeration unit to automatically supply conditioned bleed air at a temperature of 240F +/- 5F during stabilizer flight and then 240F +/- 10F o transient flights to provide defogging. The system is manually controlled by the defog thumb-wheel on the defog/anti-ice/rain removal panel. This control turns the system on and off and controls the flow by increasing/decreasing the numbers on the thumb-wheel.

(d) Vent Suit - The vent suit system provides the personnel services (vent suit or cushion airflow) of each crewmember with a supply of automatically temperature controlled, conditioned air as desired. This system automatically maintains a selected temperature throughout a continuous range between 50F and 100F within a tolerance of +/- 2F during stabilizer flight conditions and +/- 10F during transient flight. This system uses hot bleed air from both engines and refrigerated air from the forward refrigeration unit. Each crewmember controls the flow of conditioned bleed air or refrigerated bleed air to his/her personal services through the use of an airflow thumb-wheel. The pilot’s suit temperature thumb-wheel controls the temperature of the system to all seat positions.

(e) Equipment Cooling - The equipment cooling system provides specially cooled electronic equipment installed in the forward equipment bays, aft compartment, tail compartment and fin pod with direct ducted conditioned bleed air at a temperature of 75F +/- 5F. The system uses hot bleed air from the engines and refrigerated bleed air from the aft refrigeration unit installed in the aft compartment. The aft refrigeration unit is one of the main components of this system. It consists of a heat exchanger, cooling turbine, mass-flow control valve and mass flow controller all mounted in the right side of the aft compartment. A water separator is installed at the outlet port of the aft cooling turbine to remove most of the water from the refrigerated bleed air produced by the aft cooling turbine. The automatic temperature-control system is used by the equipment cooling system to reheat the refrigerated bleed air. This further reduces the relative humidity and ensures delivery of drier air to the specially cooled electronic equipment. The automatic temperature control system operates as soon as the engines are started and consists of defog and equipment cooling controller and various sensors used to regulate temperatures. Through comparing signals and sending signals to valves to open or close mixing hot and cold air together to maintain the desired temperatures of 75F +/- 5F.

(f) Equipment Pressurization - The equipment pressurization system supplies electronic equipment in the aft forward equipment bay with a supply of dry, pressurized air on aircraft 158029 through 163048. This air is necessary to provide proper performance of the electronic equipment by preventing corrosion and arcing due to accumulation of moisture. The system uses cooled bleed air from the auxiliary heat exchanger of the forward refrigeration unit. The cooled air from the auxiliary heat exchanger is piped to a pressure regulator. The pressure regulator reduces and maintains pressure to the electronic equipment to 30PSI +/- 2PSIG. Tubing downstream of the pressure regulator provides pressurized air for the magnetic tape transport in the right forward equipment compartment. A bleed port in the tubing to the magnetic tape transport provides a collecting and draining point for moisture from the pressurized air supplied to this equipment.

(g) Windshield Washing - The windshield washing system is installed to provide cleaning of the pilot’s windshield. The windshield washing system is controlled by the Windshield switch on the defog/anti-icing/rain removal control panel when selected to WASH. The system cleans the windshield by directing a stream of 50% water-methyl-alcohol mixture is then dried by engine bleed air through the rain removal nozzles (which is selected afterwards by holding the Windshield switch to AIR). The windshield wash system uses cooled bleed air provided by the auxiliary heat exchanger of the forward refrigeration unit to pressurize the windshield washing tank which stores the washing solution. The pressure forces the fluid through a series of five nozzles located at the base of the pilot’s windscreen. The windshield washing shutoff valve controls the flow of cool bleed air to the top of the windshield wash tank to expel the liquid.

(h) Rain Removal - The rain removal system is installed in the aircraft to provide for cleaning the pilot’s windshield. The rain removal system is controlled by the windshield switch, on the defog panel, when selected to AIR. The system uses hot bleed air from both engines to remove ice and rain from the pilot’s windshield. The rain removal pressure regulator shutoff valve controls the airflow to the windshield.

201.1.6 Egress Systems:

(a) Canopy - The canopies for the EA-6B are of a transparent plastic type comprised of two plastic panels on a frame set up with hinges at the rear and canopy actuators (one for each canopy) to assist with the closing and opening. Normal canopy closing and opening can be controlled internally or externally with 2 handles forward of the port boarding ladder set flush in the fuselage and 2 handles, 1 in each cockpit center forward console. In the event the normal canopy system fails to open the canopies an auxiliary system is incorporated which over-rides the primary and opens both forward and aft canopies. In the event of ejection for aircrew while in flight a jettison system is also incorporated which blows the canopies off back and up into the windstream where they are out of the way for ejection (if time permits). Two jettison handles are provided, one in the front cockpit and one in the aft cockpit. The canopies are also made so that during the ejection sequence the seat and occupant go through the glass.

(b) Ejection Seat - There are four Martin Baker MK-GRUEA-7 ejection seats installed in the EA-6B aircraft. Used to provide aircrew members with a comfortable work seat and provide a safe, efficient, completely automatic escape at ground level (zero altitude, 80 knots minimum) and throughtout the entire speed and altitude range of the aircraft. The primary means of ejection is through the canopy glass though if time permits the canopy may be jettisoned (only below 250KIAS) prior to ejection. Once ejection is initiated by command initiated ejection the aircrew members are ejected in a timely order as follows: ECMO-3 first at time 0, ECMO-2 second at .40 sec, ECMO-1 third at .80 sec and last the Pilot at 1.20 seconds. Individual ejections would also have the same times if done separate than command sequenced ejection. Pilot and ECMO-1 seats have 8 safety pins and the two rear seats, ECMO-2 and ECMO-3 have 7 a piece. The difference is for the command ejection capability for both front seats.

201.1.7 Survival Systems:

(a) Liquid Oxygen - The LOX system converts liquid oxygen to gaseous oxygen, and delivers the gaseous oxygen to the crew. This enables them to operate above 10,000 feet altitude and to maintain peak body efficiency at altitudes above 5,000 feet. The system delivers 100% oxygen to each crewmembers chest mounted breathing regulator. At normal atmospheric pressure, liquid oxygen boils at -297F degrees and changes to gaseous oxygen in volumetric ratio of 862 to 1. A low-pressure warning switch activates the OXYGEN caution lamp whenever system pressure drops below 50 psi. Each converter has a capacity of 10 liters and total system capacity is 30 liters.

(b) Emergency Oxygen - In addition to the liquid oxygen supply, each ejection seat is equipped with an oxygen cylinder and is capable of providing gaseous emergency oxygen. There are two types of emergency oxygen supply survival kits, each different in size and oxygen supply time. The RSSK-7 survival kit has a 94 cubic inch capacity that supplies oxygen for approximately 15 minutes. The SKU-2/A survival kit has 100 cubic inches with with about a 20-minute supply of oxygen. Each survival kit is equipped with a pull type lanyard for switching to emergency bottle operation should the aircraft oxygen fail. The emergency bottles are also automatically activated during ejection as the ejection seat travels up the rails, a lanyard attached to the personal services block (which is attached to the deck) actuates the supply of emergency oxygen.

(c) Anti-gravity (Anit-G) - The primary function of the anti-g system is to automatically regulate air pressure flow to the crewmembers g-suits. The system is designed to protect the crew against blackout and grayout and to alleviate fatigue resulting from repeated g-loads below blackout levels. The anti-g valve uses cooled engine bleed air from the auxiliary heat exchanger of the forward refrigeration unit to pressurize the four pressure regulating anti-g valves and their associated lines and fittings. The system works to force blood from the lower extremities of the crewmember to their upper body helping them overcome the effects of g-forces; grayout and blackout.

201.1.8 Main Landing Gear forward door override valve.

(a) A door control override valve, which controls opening and closing of the main gear forward door for ground servicing.

(b) Located in each nacelle aft of the main gear shock strut.

201.1.9 Sate the purpose of the nose landing gear strut lock.

The nose gear strut lock system renders the shock strut almost rigid for a catapult launch. The system is actuated by combine hydraulic system pressure when the CATAPULT GRIP handle is rotated and lifted, activating the strut lock selector switch.

201.1.10 State the purpose of the Landing Gear Emergency system.

The emergency landing gear system is used to lower the main and nose gear using pneumatic pressure when a malfunction occurs in the electrical control or hydraulic power portions of the landing gear systems.

201.1.11 State the purpose of the Integrated Position Indicator (IPI).

The integrated position indicator, located on the left side of the pilot’s panel, displays the position of slats, stabilizer, flaps, wing-tip speed brakes, wheels, and tow link. Each indicator in the integrated position indicator displays three positions (except nosewheel and flap position indicators). Each of the display functions is controlled by individual solenoids.

201.2.1 Briefly discuss how the control stick and rudder pedals operate the primary flight control surfaces.

The flight control surface consist of a stab stabilizer, a rudder, and upper wing surface spoilers called flaperons. The control stick and rudder pedals are linked directly to their corresponding surface actuators by a system of pushrods, bellcranks, and cables.

201.5 What special safety precautions apply to the:

(a) Ejection Seat - Due to the explosive nature of the four installed Martin Baker MK GRUEA-7 ejection seats caution must be adhered to whenever working around or sitting in the ejection seat. Each seat has it’s own set of safety pins installed at various explosives initiation points. The safety pins are checked for installation prior to entering the cockpit every time. With an ejection sequence time of 1.20 sec for all seats to be ejected out of the aircraft, the ejection seats need the utmost respect and caution.

(b) Canopy Jettison System - The canopy jettison system is another explosives system on the EA-6B aircraft, which if not given proper respect may damage machinery, injure, or kill personnel. Prior to entering the cockpit the canopy jettison pins shall be checked to ensure they are installed. The system is safety pinned at the initiation points in the forward and aft cockpits at the jettison handles. The handles are pinned and unpinned by aircrew members prior to launch and again after landing.

(c) Canopy Normal System - The canopy normal system, is the system, which allows for opening and closing of both the forward and aft canopies. Nitrogen is the primary force in opening and closing the canopies and operates a canopy actuator to accomplish this. The canopy handles are pinned immediately after opening and prior to entrance into the cockpit.

LOX - LOX (liquid oxygen) is by its very nature a hazardous material and should be handled only by qualified personnel. LOX presents a hazard by being a fire accelerator and is very unstable with petroleum based products. LOX has an expansion rate of 862 to 1 and if expansion is not controlled, can turn a LOX converter into a bomb. LOX presents a hazard in that proper personal protective equipment must be utilized to prevent frostbite and the handlers clothes from becoming saturated with oxygen.