Erics Stealthy Skyhawk Flashcards
What is a negative effect of pressurising aircraft?
How can we increase the safe life?
It has EFFECTS on the FATIGUE LIFE of an aircraft;
With each PRESSURISATION CYCLE the a/c will initially STRETCH placing SKIN under TENSION and FASTENERS under SHEAR stress, followed by DEPRESSURISATION back to NORMAL;
INCREASE its life by LIMITING the cruise ALTITUDE, flying WITHIN the ENVELOPE, AVOIDING TURBULENT AIR and HEAVY LANDINGS to REDUCE SKIN TENSILE STRESS
What are the structural members of the semi monocoque fuselage?
Describe each one?
LONGERONS: LONGITUDINAL structural members;
BULKHEADS: SOLID structures 90° to the LONGERONS;
SKIN: Takes SOME of LOAD, rest is TRANSFERRED to LONGERONS, STRINGERS, FORMERS and BULKHEADS
FORMERS: Similar to BULKHEADS but HOLLOW to MAINTAIN FUSELAGE SHAPE
STRINGERS: LIGHTWEIGHT versions of LONGERONS to take SOME LOAD and TRANSFER rest to FORMERS, some BUILT INTO SKIN
What are the advantages of semi monocoque skins?
STREAMLINE and COMPLEX FUSELAGE SHAPES;
COLLECTIVE COMPONENTS make up the STRENGTH so if there is DAMAGE to 1 COMPONENT it will NOT COMPLETELY COLLAPSE
What the advantage of a non metallic construction material?
When a structure is metal what precautions are used to counter this disadvantage?
ABSENCE of CORROSION;
REGULAR WASHING;
HANGARING aircraft if in IDLE for a LONG TIME;
AVOID DAMAGING PAINTED SURFACES;
Treating INTERNAL STRUCTURES with MOISTURE EXCLUDING COMPOUNDS
What contaminant is most hazardous to metals?
What does it do?
MERCURY;
DRAMATIC and INSTANT REACTION which will lead DESTRUCTION of STRUCTURAL INTEGRITY of aircraft structure
What is corrosion?
How is it removed?
What aircraft components are affected by it?
LOSS of METAL from a SURFACE by CHEMICAL or ELECTROCHEMICAL REACTION; Usually EASILY REMOVED by MECHANICAL ACTION; ANY METAL; CONTROL CABLES; SKIN/STRUCTURAL MEMBERS; ENGINE COMPONENTS; PROPELLERS; ELECTRICAL SYTEMS
Can engines tolerate water?
Most can TOLERATE DISSOLVED WATER;
FREE WATER/LARGE SLUGS can cause ENGINE DAMAGE and FAILURE;
FREE WATER will FREEZE and could BLOCK FILTERS and IMPEDE FLOW;
Can facilitate CORROSION and MICROBIAL;
WATER DENSER than FUEL so COLLECTS at BOTTOM of TANK so must be DRAINED
What are the 4 types of gas turbine fuels?
TURBO FUEL A (AVTUR 40);
TURBO FUEL A-1 (AVTUR 50);
TURBO FUEL B (AVTAG or WIDE CUT)
TURBO FUEL 5
What are the main characteristics of jet A fuel?
CIVIL AVIATION KEROSENE;
Essentially NO GASOLINE BLEND;
PRIMARY fuel for COMMERCIAL and GENERAL AVIATION in US;
Generally NO MILITARY USE
What are the main characteristics of jet A-1?
LOW TEMPERATURE with LOWER FREEZING POINT than JET A;
Most COMMON FUEL in NZ;
Used MOST by INTERNATIONAL AIRLINES
What are the main characteristics of jet B?
30% KEROSENE 70% GASOLINE WIDE CUT FUEL;
VERY LOW FREEZING POINT and LOW FLASH POINT;
PRIMARY in MILITARY similar to JP-4
What are the main characteristics turbo fuel 5?
HIGH FLASH POINT MILITARY fuel;
Used in NAVAL AIRCRAFT CARRIERS
What are jet fuels comprised of?
What are the characteristics of it?
What is the colour of it?
LIQUID HYDROCARBONS similar to kerosene;
MIXES FREELY with OXYGEN at COMBUSTION FLOW RATES and COLD TEMPERATURES;
OXIDES which are FORMED in COMBUSTION are GASES which keeps SOLID PARTICLES MINIMUM to avoid EROSION;
NOT COLOUR coded, have NATURAL STRAW COLOUR
What does mixing gasoline in jet fuels do at altitude?
It may become TOO VISCOUS
What are the identification for jet A, A-1, and B?
JET A: BLACK LABEL, 1 BLACK STRIPE, JET A in WHITE;
JET A-1: BLACK LABEL, 2 GREY STRIPES, JET A-1 in WHITE;
JET B: BLACK LABEL, 3 YELLOW STRIPES, JET B in WHITE
What are jet fuel identifiers?
TYPE NUMBERS and have NO RELATION to the FUELS PERFORMANCE in the aircraft ENGINE
What are the different types of fuel tanks?
Describe each one?
RIGID TYPE: METAL tanks usually made of ALUMINIUM ALLOY with WELDED JOINTS sometimes COVERED with a SHOCK RESISTANT RUBBER COATING that is SELF SEALING;
BLADDER TYPE: THIN FABRIC impregnated with NEOPRENE/similar that is IMPERVIOUS to FUEL may also be SELF SEALING;
INTEGRAL TYPE: USED in LARGE AIRCRAFT to REDUCE WEIGHT, structure SEALED in CONSTRUCTION, includes BAFFLES to PREVENT SURGING during ALTITUDE CHANGE, PRESSURISED to provide POSITIVE HEAD to system PUMP, VENTING SYSTEM to PREVENT CAVITATION
What are the 7 features of all fuel systems?
Describe each one?
FILLER CAP: Used for an ENTRY to ADD FUEL, keeps out CONTAMINANTS;
EXPANSION SPACE: ADDITIONAL SPACE for fuel to EXPAND to when the tanks are FULL and the fuels HEATS UP
VENTS: Allows air to FLOW IN and OUT when it EXPANDS/USED UP to PREVENT CAVITATION and EXPANSION STRESSES;
BAFFLES: PREVENT FUEL SURGING with ALTITUDE CHANGE and INCREASES STRENGTH;
SUMPS and DRAINS: The LOWEST point of every tank, allows IMPURITIES to ACCUMULATE in such a way that SAMPLES can be COLLECTED, INSPECTED, and TOTALLY DRAINED from this point
FUEL QUANTITY DETECTOR:
STRAINERS and FILTERS:
What is the purpose of sumps and drains?
How does it work?
Allows SAMPLES to be COLLECTED, INSPECTED and and TOTALLY DRAINED OFF;
DRAIN VALVE has POPPET, which, when DECOMPRESSED allows FUEL to flow OUT and when RELEASED, SEALS again
What is the main purpose of sampling fuel?
What other precautions are there to avoid this?
Why may this be more important in AVTUR or AVGAS?
To REMOVE any WATER DEPOSITS;
REFUELLING at the END of DAY to PREVENT CONDENSATION processes, including STANDPIPE into DESIGN
AVTUR is MORE HYDROSCOPIC than AVGAS
What are the types of fuel quantity indicators?
SIGHT GLASS;
FLOAT type;
ELECTRIC type;
ELECTRONIC type
How does the sight glass indicator work?
A CLEAR GLASS or PLASTIC TUBE is OPEN to the fuel TANK that FILLS with fuel to the SAME LEVEL as the fuel in the tank;
CALIBRATED in GALLONS or FRACTIONS of a tank
How does the float type indicator work?
Utilises a FLOAT with an INDICATING ROD attached to it. As the float MOVES up and down WITH the FUEL LEVEL in the tank, the portion of the ROD that EXTENDS through the fuel cap INDICATES the QUANTITY of fuel in the tank
How does the electric type indicator work?
Operates with DIRECT CURRENT and use VARIABLE RESISTANCE in a circuit to drive a RATIOMETER-TYPE indicator through the MOVEMENT of a FLOAT in the tank which moves a CONNECTING ARM to the WIPER on a variable resistor in the tank;
CHANGES to the CURRENT flowing through the RESISTOR change the current of one of the COILS in the indicator;
This ALTERS the MAGNETIC FIELD which indicates the quantity
How does the electronic type indicator work?
Utilises a BRIDGE CIRCUIT which measures the CAPACITANCE of the tank units through fixed CAPACITORS that measure the DIELECTRIC CONSTANT (amount of fuel/air between the plates) then the CIRCUIT DRIVES INDICATOR
A REFERENCE CAPACITOR is used to account for differences in TEMPERATURE
What is a drip gauge used to measure?
The amount of fuel in a tank
What is the functions of an auxiliary pump?
Provides FUEL for STARTING at the REQUIRED PRESSURE to the CARBURETTOR or to the FUEL METERING UNIT of FUEL INJECTION system;
Supplies FUEL if the ENGINE DRIVEN (MECHANICAL) PUMP FAILS ie REDUNDANCY;
PURGES the FUEL LINES of any VAPOUR to REDUCE possibility of VAPOUR LOCK;
CROSS FEEDING;
FUEL JETTISON
What are the types of auxiliary pumps?
How are they powered?
VANE type;
CENTRIFUGAL type;
ELECTRICALLY DRIVEN
What are the features of a auxiliary pump?
PRESSURE RELIEF VALVE;
BYPASS VALVE;
Often SUBMERSIBLE type allowing them to be INSTALLED IN FUEL TANK
What is the purpose of a cross feed system?
What is the keyword?
FLEXIBILITY;
To be able to DRAW FUEL from ANY TANK to ANY ENGINE;
If one ENGINE FAILS the FUEL from that ENGINES TANK can be SUPPLIED to OTHER ENGINES;
Used to CORRECT IMBALANCE of FUEL/WEIGHT between wings as a result of UNEQUAL FUEL BURN due to DIFFERENT ENGINE TBO AGES, HEATERS using ONLY 1 SIDE, FUEL LEAKS or SINGLE ENGINE TRAINING OPERATIONS
What is vapour lock?
What is an example?
FUEL VAPORISES in HIGH POINT of in FEED LINES of FUEL SYSTEM PREVENTS LIQUID FLOW passed the point;
CAUSED by EXCESSIVE HEAT or LOW PRESSURE or COMBINATION;
When SHUTTING DOWN, there is NO AIRFLOW or active COOLING SYSTEM as WATER is LOCKED in causing TEMPERATURE to INCREASE and HEAT FUEL LINES;
HOT START with BOOST PUMP OFF
What are the effects of vapour lock?
What can be done when vapour lock is experienced on ground?
ENGINE will suffer from FUEL STARVATION; BOOST PUMP ON; MAGS OFF; FULL THROTTLE and MIXTURE RICH; WIND ENGINE for a FEW SECONDS; CHECK EXTERNALLY for FUEL FLOW to CARB; DRAIN; LEAVE ENGINE to SIT for 10 MINUTES; NORMAL HOT START
What are the advantages of hydraulic systems over mechanical systems?
LIGHT for POWER OUTPUT;
MECHANICAL ADVANTAGE through DIFFERENT SIZE PISTONS;
EASE of INSTALLATION;
SIMPLIFICATION of INSPECTION;
MINIMUM MAINTENANCE requirements due to LESS MOVING parts;
CHEAPER due to LESS MAINTENANCE costs;
TRANSFER FORCE long DISTANCES;
Can use FLEXIBLE PIPES to TRANSFER PRESSURE
Almost 100% EFFICIENT
What is the function of a hydraulic system accumulator?
DAMPEN PRESSURE SURGES in the hydraulic system CAUSED by ACTUATION of a unit and the EFFORT of the PUMP to MAINTAIN PRESSURE at a PRESET level;
AID or SUPPLEMENT the POWER PUMP when SEVERAL units are OPERATING at ONCE by SUPPLYING extra power from its ACCUMULATED or STORED power;
STORE POWER for the LIMITED OPERATION of a hydraulic unit when the PUMP is NOT OPERATING;
SUPPLY FLUID under PRESSURE to COMPENSATE for small internal or external (not desired) LEAKS that would CAUSE the system to CYCLE CONTINUOUSLY by action of the PRESSURE SWITCHES continually KICKING IN
What is the principle of operation of a hydraulic accumulator?
2 CHAMBERS, 1 with AIR/NITROGEN and one with HYDRAULIC FLUID divided by DIAPHRAGM, BLADDER or PISTON;
COMPRESSED AIR/NITROGEN CHAMBER is CHARGED to LEVEL LOWER than OPERATING PRESSURE (Accumulator preload);
Once the HYDRAULIC FLUID PRESSURE EXCEEDS the accumulator PRELOAD the air/nitrogen will COMPRESS and the RESISTANCE will act as a SPRING to provide RESERVE HYDRAULIC PRESSURE;
The charged accumulator may also SUPPLY fluid PRESSURE to actuate a component(s) briefly in case of PUMP FAILURE
How can you tell in an accumulator has a leak?
When system is OFF the PRESSURE GAUGE NOT reading PRELOAD PRESSURE;
When SHUTTING DOWN, the PRESSURE will IMMEDIATELY drop, it should BE GRADUAL as ACCUMULATOR provides PRESSURE
What checks can be done on an accumulator during the preflight?
CHECKING for LEAKS;
CHECKING PRESSURE GAUGE itself
What is the purpose of a pressure regulator?
Where are they positioned?
What do they do to a constant delivery type pump?
MANAGE the OUTPUT of the PUMP to MAINTAIN PRESSURE;
PERMITS PUMP to TURN WITHOUT RESISTANCE when pressure is NORMAL;
Located so that PUMP OUTPUT can get INTO PRESSURE CIRCUIT ONLY passing through REGULATOR;
Turns it to a VARIABLE DELIVERY TYPE PUMP
What is the purpose of a pressure relief valve?
How can they be operated?
BACKS UP the PRESSURE REGULATOR;
LIMITS the PRESSURE EXERTED on a CONFINED FLUID;
PREVENTS RUPTURE or FAILURE of components under excessive PRESSURE and HIGH TEMPERATURE;
MANUAL, ELECTRIC, MECHANICAL, HYDRAULIC or a COMBINATION
What are the types of valves?
Briefly describe each one?
RELIEF: SAFETY valves that are usually SPRING LOADED which will OPEN if PRESSURE EXCEEDS PREDETERMINED LEVEL;
CHECK: NON-RETURN valves, fitted to PREVENT REVERSE FLOW within the system usually through the use of a BALL and SPRING which TRAP PRESSURE in the lines BETWEEN the VALVE and ACTUATOR to generally HOLD the ACTUATOR at selected POSITION, this acts to COUNTER any UPSTREAM LEAKS;
BYPASS: A valve which provides an ALTERNATIVE PATH around a component if it is NOT REQUIRED or the PRESSURE becomes TOO LARGE;
SELECTOR: A VALVE is used to CONTROL the DIRECTION of movement of the pressurised FLUID to the SELECTED ACTUATING FUNCTION;
Can be ROTATING PLUG, POPPET TYPE or an OPEN CENTRE ROTATING PLUG;
SEQUENCING: VALVES that cause FUNCTIONS to operate in a CERTAIN ORDER. Most commonly known through the WHEEL well DOORS and the LANDING GEAR;
SHUTTLE: A VALVE that allows FLOW from an OUTLET port FROM either of 2 INLET ports while BLOCKING FLOW to the OTHER if original PRESSURE DROPS below a certain THRESHOLD
What is the purpose of an actuator?
What are the types?
CONVERTS HYDRAULIC PRESSURE into MECHANICAL MOVEMENT to do USEFUL WORK;
LINEAR actuator/JACK; SINGLE, DOUBLE, TANDEM, 3 PORT DOUBLE, SERVO;
ROTARY actuator/HYDRAULIC MOTOR: PISTON, VANE, RACK+PINION
What are the ideal characteristics of hydraulic fluids?
LOW VISCOSITY;
CHEMICAL STABILITY;
HIGH FLASH POINT;
HIGH FIRE POINT
What are the different types of fluid?
What are their colours?
Vegetable based: BLUE
Mineral based: RED
Synthetic: LIGHT PURPLE