106 - AIRFRAME / PROPULSION / FUEL FUNDAMENTALS

.1 Discuss the corrosion prone areas of the P-3.

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.  

 

.2 Discuss the purpose of the Aircraft Automatic Flight Control System:

The AFCS is designed to maintain the aircraft on any selected heading while keeping it stabilized in pitch, roll and yaw attitude. The aircraft can be made to climb, descend, or make coordinated turns by means of the pitch and turn controls.

.3 State the type and model of the P-3C engine.

The P-3 is powered by four T56-A-14 turboprop engines.  

.4 Discuss the purpose of the constant speed propeller.

The purpose of a constant speed propeller is to maintain a pre-selected 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 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-percent rpm.  

.5 Discuss the P-3 aircraft fueling methods:

The P-3 aircraft is designed to be fueled by two methods: Center-point pressure fueling and overwing gravity feed. The normal fueling for the P-3 aircraft will be accomplished with the center-point pressure system, which is designed to accept 600 gallons of fuel per minute from two fuel trucks pumping simultaneously or from one truck at 300 gallons per minute (gpm). The pressure fueling connectors and control panel are located on the lower surface of the starboard wing immediately outboard of the fuselage and just forward of the flaps. Fueling with the APU running is considered normal fueling, NOT HOT REFUELING.  

.6 Discuss the type construction used by the P-3 aircraft?

The P-3 aircraft is of 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.

.7 Describe the type of landing gear used 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 in the event of a hydraulic failure, gravity, assisted by air loads and a bungee spring, extends the gear.