Unit Specific 106
106.1 Discuss the corrosion prone areas of the P-3 aircraft.
Corrosion on P-3 aircraft has been found to exist principally along the seams of 7075-T6 aluminum alloy structures, in box beam skin centroid areas and around cadmium plated steel fasteners. Other corrosion prone areas of the aircraft are located on unpainted surfaces of actuating mechanisms, painted surfaces that are chipped or peeled, skin seams, lap joints and areas where dirt and grime can collect. Rub strips, access doors, cowling areas and crevices are corrosion prone due to their affinity for accumulating moisture and cleaning compound residues.
106.2 Discuss the purpose of the Aircraft Automatic Flight Control system.
Automatic flight control and stabilization systems ease the pilots workload and provide aircraft stability at all speeds. The information now flows directly to a flight control computer rather than to an indicator. This action lessens the time required to start a control movement to nearly zero (increased stability). The system also provides command controls by which the computer can control the aircraft in early any desired flight condition. Some automatic flight control systems are capable of flying the aircraft to radio navigation aids, correcting for wind, and making pilot-unaided landings.
106.3 State the type and model of the P-3C engine.
Four T56-A-14 turboprop engines power the P-3. Each engine provides 4,600 SHP (maximum rated) for takeoff.
106.4 Discuss the purpose of the constant speed propeller.
Constant-speed propellers were eventually designed to maintain a preselected rpm automatically. Suppose the aircraft is heading into a gradual climb. The constant-speed propeller maintains the selected rpm automatically by turning the propeller blades to a lower angle. That is, the propeller takes a smaller bite of air when the load on the engine is increased. Now, should the aircraft assume a nose-down attitude, the propeller blades move automatically to a higher blade angle; hence, the propeller takes a larger bite of air. In other words, increase the load on the engine and the propeller takes a smaller bite of air. Decrease the engine load and the propeller takes a larger bite of air. This function will keep the turboprop engine at 100% rpm.
On constant-speed propellers, the blade angle must be adjusted to provide the most efficient angle of attack at all engine and aircraft speeds. The most efficient angle of attack is very small; it varies from 1 to 4 degrees positive angle. The actual blade angle necessary to maintain this small angle of attack varies with the forward speed of the aircraft. With constantly increasing aircraft speeds and high-altitude operations, it is necessary to have a wide range of blade angle settings. This range of settings must adapt the propeller to conditions encountered in takeoff, climb, and cruising.
106.5 Discuss the P-3 aircraft fueling methods.
Center-Point Pressure Fueling
The normal fueling method.
Designed to accept 600 gallons of fuel per minute from two fuel trucks pumping simultaneously.
Can be fueled at a rate of approximately 300 gpm by one truck.
2. Overwing Gravity Feed
The center section and fuselage tank do not incorporate a gravity filler well.
106.6 Discuss the type of construction used by the P-3 aircraft.
The P-3 is all metal construction. The primary construction of the wing consists of a box beam comprising two main spars with upper and lower surfaces of integrally stiffened skins. Ribs are provided at frequent intervals to stabilize the structure and maintain contour. The fuselage is of semimonocoque construction consisting of skins, stringers, longerons, and bulkheads or frames.
106.7 Describe the type of landing gear utilized on the P-3 aircraft.
The landing gear is a fully retractable tricycle type gear consisting of two main gears and a nose gear. Each gear extends down and aft so that inb the event of a hydraulic failure, gravity, assisted by airflow loads and a bungee spring, extends the gear.