Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
2a353 Volume 3 CH 1
USAF Tactical Aircraft Maintenance CDC Questions 2016
| Question | Answer |
|---|---|
| How is Oxygen separated from other gases in the air? | By compressing and cooling the air |
| Why must aviators breathing oxygen be "bone dry"? | To ensure operation of oxygen system components. Oxygen with a high moisture content would freeze at high altitudes, causing the oxygen system to be inoperative. |
| List some of the warning signs of hypoxia | Blurred vision, slight shortness of breath, a vague week feeling, light dizziness |
| What is the maximum pressure at which low pressure gaseous oxygen cylinders are charged? | 450 psi m |
| What color are low pressure gaseous oxygen cylinders painted? | yellow |
| How are oxygen tubes color-coded? | With bands of green and white cellulose tape |
| What two types of connections are used in low pressure oxygen systems? | pipe-thread and flared tube connections |
| What component reduces system pressure in a high pressure gaseous oxygen system? | a pressure reducer valve |
| What construction methods prevent high pressure gaseous oxygen cylinders from shattering? | heat treated alloy wrapped with steel wire |
| What are the two main types of oxygen regulators? | the continuous flow and pressure demand type |
| Whats a disadvantage of the continuous flow regulator as compared to other types? | wastes oxygen |
| The MD-1 oxygen regulator can be used with what types of oxygen systems? | with high or low pressure gaseous or LOX systems |
| In an emergency the pressure demand regulator can supply oxygen to what altitude? | 50,000 feet |
| What should system pressure be during an operational check of a regulator? | near normal operating pressure |
| Explain hoe the molecular sieve bed operates | Nitrogen in the air is absorbed in one bed of molecular sieve while oxygen passes through the bed. When the molecular sieve becomes saturated, the concentrator vents the nitrogen overboard |
| What happens if the MSOGS concentrator fails? | It will turn on an oxygen caution light in the cockpit and automatically switch to the backup oxygen supply |
| Whats the temperature of liquid oxygen? | -297 degrees F |
| Why should liquid oxygen never be sealed, capped, or trapped in a container without a relief valve? | It will rupture the container |
| What factors are used to determine convertor size? | The number of crew, mission duration, and the type of oxygen regulation equipment used |
| Whats the probable cause if frost appears on the outside of a LOX container? | Vacuum loss |
| How are pressure control valves controlled? | Spring-loaded bellows |
| Whats the primary purpose of the pressure closing valve? | To maintain a constant head pressure on top of the liquid oxygen in the storage container |
| Whats the normal position of the pressure opening valve? | Closed |
| Why is it important to ensure there is no moisture in the fill, buildup, and vent valve? | It may freeze in the vent position |
| In what position should you manually place the buildup/vent valve during a filling operation? | VENT position |
| How are the check valves in quick disconnects operated? | Automatically |
| What are the two modes of operation in the supply sequence of the liquid oxygen system? | The economy mode and demand mode |
| What Technical Order covers the requirements for LOX systems inspection? | -6 technical manual for the specific aircraft |
| What is the purpose of a bleed air system? | To operate or control pneumatic systems or components |
| What are three sources of bleed air used for system operations on jet aircraft? | Aircraft engines; ground air cart; and gas turbine compressors, gas turbine units, to Auxillary power units |
| What equipment provides bleed air when the aircraft is on the ground with the engine shutdown? | A ground air cart |
| List the components of a bleed air system | Check valves, shutoff valve, wing isolation or body crossover valves, flow control valves, pressure regulating valves, bleed air ducting, and the necessary controls |
| What is the purpose of a ground-air-connection check valve? | Prevent the escape of bleed air from the system |
| What material is usually used for high pressure/high temperature ducting? | Stainless Steel |
| What action should you take to ensure a good airtight seal when installing a V-Band clamp? | Tap around the circumference of the clamp as its tightened |
| Why should you install the bottom bolts on a bolted flange duct first? | This forms a cradle and holds the gasket in place while you install the remaining bolts |
| Besides stainless steel, what other materials can be used in the construction of medium-pressure/medium-temperature ducting? | Titanium to aluminum alloy |
| What type of lubricant can be used on beaded duct sleeves to aid in installation? | Water only |
| Where in the Aircraft is molded fiberglass ducting used for distributing conditioned air? | Cabin Area |
| Whats the purpose of gaskets? | To make an airtight seal with most types of flange connections |
| What devices are installed in bleed air systems to compensate for thermal expansion of ducting? | Expansion joints(bellows), thermal compensators, universal joints, loops, horseshoe bends, and offsets |
| Whats the most important reason for insulating ducts? | To prevent heat damage to structural members, electrical wiring, and combustible material, as well as hydraulic, oxygen, and fuel lines |
| What type of insulating material is fireproof? | Fiberglass fabric blankets |
| What is the purpose of the rubber accordion boot wrapped around the duct between the sections of the insulation? | This boot allows for differences in expansion rates of the duct and insulation |
| Whats used to lace the studs together in a metal foil blanket? | Wire |
| What are the most common types of duct damage? | Scratch, minor dent, major dent,and gouge |
| Define gouge | A defect wherein the surface of the material is cut or removed sufficiently to cause the duct wall thickness to be reduced |
| Which bleed air duct system is subjected to the highest pressure/temperature? | High pressure/high temperature |
| What should you do anytime you locate a non permissible leak in the high-pressure/high temperature section of the bleed air system? | Inspect the aircraft structure in the immediate area of the leak for heat danage |
| What is air conditioning? | The simultaneous control of temperature, humidity, and air distribution within a space |
| Does heat always move to cold or does cold always move to heat? | Heat always moves to cold |
| While the aircraft is in flight, what controls the flow of ram air to the PHE? | Moveable ram air inlet and/or exit doors that modulate in flight |
| During low airspeeds or ground operation what induces cooling airflow to the PHE when there is not enough ram air to cool the PHE? | Ejectors |
| What consists of a centrifugal air compressor and an expansion turbine, and is often known as the pack? | Air cycle machine (ACM) |
| Why would some of the outlet air from the PHE need to bypass the air cycle machine? | If cabin temperature controls call for warmer air |
| What component provides an additional stage of cooling after the bleed air has left the PHE and, if required, the air cycle machine? | Secondary Heat Exchanger |
| What is the primary purpose of the refrigeration bypass valve? | To prevent water from freezing in the water separator |
| What component uses centrifugal force to remove moisture in the air that is caused by rapid cooling? | The water separator |
| What two forms of energy are essentially interchangeable? | Pressure and temperature |
| What happens to heat the engines bleed air as it passes through the PHE? | Some of the heat is transferred to ram air |
| What happens to the pressure of the engine bleed air as it passes through the PHE? | Almost no change |
| What happens to the air as it enters the compressor of the air cycle machine? | The pressure increases and, therefore, the temperature increases |
| What results in a very large decrease to the air cycle machine? | As the air expands across the turbine, the pressure decreases greatly. The pressure decrease, coupled with the energy extracted to drive the compressor, results in a very large decrease in temperature. |
| What are the two methods of cooling used in typical bootstrap system? | 1). By transferring heat to the ram air, or 2). removing most of the heat by expanding it and converting it into work to drive the compressor |
| The refrigeration bypass valve opens so that warm air can mix with the air in the water separator if the water separators outlet air temperature falls below what temperature? | 38 degrees F |
| Explain the difference between preconditioned air and conditioned air | Once the air has cycled through the entire system with the exception of the water separator, it is called preconditioned air. Preconditioned bleed air becomes conditioned air when it has made its way through the water separator |
| What percentage of the earths air is nitrogen? | 78% |
| List the three pressurization ranges | Unpressurized range, isobaric range, and differential range |
| What is isobaric range? | 8,000 to 21,000 feet above sea level |
| Where does the differential range extend? | From where the isobaric range stops to the maximum altitude of the aircraft |
| What component opens and closes to control the amount of air leaving the aircrafts pressurized area? | Outflow valve |
| What is the approximate atmospheric pressure at sea level? | 14.7 psi |
| The aneroid is fully expanded and the metering valve is closed at what specific altitude? | 8,000 feet |
| What two pressures are applied to the differential diaphragm? | Control and atmospheric pressure |
| What section of the pressure regulator protects the crew from too fast a rise in cabin pressure? | The rate control section |
| In addition to a regulator, two outflow valves, and a pneumatic relay, what other component is a part of the dual-differential regulator? | Dump Valve |
| What component operates as a safety valve if the regulator fails? | Outflow valve |
| Why are two outflow valves used on aircraft with large crew areas? | Because of the large volume of air to be relieved |
| How can the dump valve be operated in case of electrical failure? | Manually |
| What are the three features of the pressure controller? | Isobaric, firrential, and rate controls |
| How is isobaric control maintained? | Adjusting spring tension |
| What types of pressure act on the differential controllers diaphragm? | Control head and atmospheric |
| How is the rate control orifice size adjusted? | Rate control knob |
| During a dive, what prevents damage cause by reverse flow of atmospheric air? | The ball check valve |
| Describe the purpose of the manual control valve? | It is used to manually set and regulate the control pressure if the automatic cabin pressure pressure controller fails |
| What happens if the pressure regulator test handle remains in the TEST position? | The aircraft will pressurize on the ground |
| Where are the fire detectors normally placed on aircraft? | On conventional aircraft they are placed in the engine and baggage compartments. On jet aircraft they are placed on the engine section, nacelle, or tail cone |
| How are the thermal switches connected? | In parallel with each other, and in series with the warning light |
| What re the two types of thermos witches? | FENWAL switch and Iron Fireman switch |
| How do the FENWAL and Iron Fireman detector switches operate? | The inside of the switch has a low coefficient of expansion, while the shell has a high coefficient of expansion. When they are heated, they will expand and contact will be made. |
| What causes a thermocouple fire detector system to activate? | A rapid rate of temperature increase beyond normal engine warm-up |
| What are the three circuits in the thermocouple fire warning system? | The detector, alarm, and test circuit |
| How are the thermocouples connected inn respect to each other? | In series |
| What does a photoelectric detector cell consist of? | A glass envelope, which is coated on the inside with infrared-sensitive lead sulfide |
| The amplifier of a photoelectric fire detection system is sensitive to what frequencies? | Between 7 and 60 hz |
| How can you distinguish the fire warning light from the overheat light in the photoelectric fire detection system? | The overheat light flashes and the fire warning is steady |
| What are fire detector sensing loops made of? | A center conductor embedded in a semiconducting compound enclosed within a tube |
| How do liquid agents extinguish fire? | By excluding oxygen from the fire area |
| How will an insufficient nitrogen charge effect agent discharge? | The cylinder won't have enough pressure to discharge properly |
| What shape are aircraft fire extinguisher containers? | Spherical |
| What prevents leakage between the bonnet assembly and container during discharge? | A rubber O-ring packing |
| How are squibs fired? | Applying 28 VDC to the squib |
| What is incorporated in some two-shot systems to delay electrical current to the bonnet assemblies? | Time delay relay |
| What does a flashing re light in a fire emergency control handle indicate? | An overheat |
| What steps should be taken to remove liquid fire extinguishing agents if moisture or high temperature was present? | 1).Purge the area and surface with clean, dry air 2). Clean the affected areas with cleaning solution and rinse with water 3). Drain excess water and dry the area with cloths, or air pressure no greater than 10 psi |
Created by:
wcarrel11
Popular Military sets