Overheat Detection
HOW ARE “THERMOSWITCHES” WIRED TO EACH OTHER.
In Parallel
(#2, slide 4) (pg. 642 figure 18-3)
WHAT DOES “EUTECTIC” MEAN?
Low melting point (#3, slide 8) (pg. 645)
WHICH CONTINUOUS LOOP FIRE DETECTION SYSTEM HAS TWO INTERNAL CONDUCTORS?… AND, … WHICH HAS JUST ONE?
Kidde has two (#3, slide 14)
Fenwell has one (#3, slide 11)
(AF pg. 900-901) (pg. 645)
WHAT IS A CLASS “B” FIRE? … WHAT IS A CLASS “C” FIRE?
B- Flammable liquids (#6, slide 18) (#1, slide 29)
C-Electrical fires (#6, slide 18) (#1, slide 29) (pg.639)
WHAT DETERMINES THE FIRE ZONE ON AN ENGINE
Volume of airflow, smoothness of airflow (#1, slide 22) (pg. 640)
A fire detection system that initiates a fire warning when there is an excessive rate of temperature rise in the monitored compartment is the _____________ (thermo-couple or thermo-switch) system.
Thermo-couple
Pg. 899
WHAT TWO FIRE DETECTION SYSTEM USE BUILT IN “HEATERS” TO TEST THE FIRE WARNING SYSTEM.
Lindberg (#4, slide 6)
Rate-of-rise-temperature-rise (#2, slide 19) (AF pg.900)
Describe the single-conductor continuous loop system and how it works.
Contains ceramic beads with a single conductor through the middle of those beads. There is a eutectic salt with a low melting point whose resistance drops when there is heat applied. Therefor, a signal is sent to the flight deck.
Pg. 900
Carbon Monoxide is usually detected by chemical crystals that change their ___________ (color or electrical resistance) when they are exposed to CO.
Color
Pg. 903
NAME 6 THINGS THAT HAPPEN WHEN YOU PULL THE FIRE HANDLE.
Close engine fuel shut off valve
Trips the generator field relay after a short delay
Closes engine bleed valve
Closes wing and engine anti-ice valves
Closes hydraulic supply shut-off valves
Turn off hydraulic pump low press warning lights
(#6, slide 42) (pg. 650)
The fire detection system that can operate properly when their is either an open or a short circuit in either of the two loops is the _______________ (single terminal or two-terminal) thermo-switch system.
Two-Terminal
Pg. 898
Current flows in a fire warning thermocouple circuit because of the voltage produced by the difference in the ______________ between the junctions.
Temperature
Pg. 899
Describe the two-conductor continuous loop fire detection system and how it works.
A system with two thermistor type conductors whose resistance drops with a rise in temperature. One conductor is grounded to the outer tube and the other is connected to the control unit that measures the total resistance of the sensing loop.
Pg. 901
Some of the air in the ionization-type smoke detector is ionized by a tiny piece of __________ material.
Radioactive material
Pg. 904
THE THREE REQUIRNMENTS FOR A FIRE ARE?
Fuel
Oxygen
Heat Source
Pg. 895
How does a thermo-switch type spot detector system work?
When a fire occurs in the area where there is a detector, the detector is heated and strips on which the contacts are mounted distort and close the contacts. After, a signal is sent to the flight deck.
Pg. 897
What is a thermocouple?
A loop made up of two different types of wire. A small amount of voltage is produced between the two wires causing a difference in voltage. This voltage difference causes current to flow.
Pg. 898
The two conductor continuous loop fire detector ______________ (does or does not) detect a general overheat condition as well as a local hot spot.
Does
Pg. 901
The light that actuates a visual smoke detector ___________ (is or is not) visible by the pilot.
Is not
Pg. 904
Tell me each fire extinguishing class:
Class A -
Class B -
Class C -
Class D -
Class A - Wood, Paper
Class B - Fuel, Oil
Class C - Electrical
Class D - Metallic
What are three different requirments for a fire detection system?
1. System must not give false warnings.
2. Must give rapid indication of a fire
3. Be able to indicate that the flames have been extinguished.
4. must be able to sound a warning
5. Must be able to continue indicating if there is a fire.
6. Be able to be tested from the cockpit.
7. Detectors can not be in a position to be damaged by engine fluids.
8. Must be lightweight
9. Circuitry must operate directly from the electrical system.
Continued on page. 896
What are the two wires in a thermocouple sensor made out of?
Iron
Constantan
Pg. 899
A pneumatic fire detection system ___________ (does or does not) warn of a general overheat condition as well as a fire.
Does
Pg. 901
A fire that involves solid combustibles such as paper and upholstery is a class ___________ fire.
A
Pg. 895
What are the three on board fire extinguishing agents?
Carbon Dioxide
Liquid Nitrogen
Halon