DGCA Technical General: Fire & Smoke Protection Questions
86 exam-style Fire & Smoke Protection questions for the DGCA Technical Generalpaper (CPL & ATPL). The first 12 are free below with answers and explanations — sign up free to practise all of them with progress tracking.
- Q1
Without added oxygen the time of useful consciousness at 25,000 ft is approximately:
- Atwenty seconds.
- Beighty seconds.
- Cthree minutes.
- Dsix minutes.
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Correct answer: C. three minutes.
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- Q2
The principle of operation of firewire is
- APositive coefficient of impedance, negative coefficient of inductance
- B Positive coefficient of resistance, negative coefficient of capacitance
- CPositive coefficient of inductance, negative coefficient of impedance
- DPositive coefficient of capacitance, negative coefficient of resistance
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Correct answer: D. Positive coefficient of capacitance, negative coefficient of resistance
The continuous fire-detection element works because its temperature-sensitive filling has a positive coefficient of capacitance and a negative coefficient of resistance: as the element heats up its capacitance rises and its electrical resistance falls, and either change can be sensed by the control unit to trigger the warning.
- Q3
What type of fire extinguisher would be used on a propane fire?
- A Foam
- B Water
- C Dry powder
- DSand
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Correct answer: A. Foam
Propane burns as a flammable-fuel fire in the same class as liquid fuels, and foam extinguishes it by blanketing the burning area, excluding oxygen and preventing re-ignition; water is ineffective and can spread the fire.
- Q4
In which of the following areas would an overheat/fire warning be provided.
- AFuel tank
- B Cabin
- C Tyres
- D Wheel/Undercarriage bay
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Correct answer: D. Wheel/Undercarriage bay
The wheel bays are provided with overheat or fire warning because hot brakes, hydraulic fluid and tyres retracted into a confined bay create a real fire risk. Fuel tanks and tyres themselves have no fire loops, and the cabin is protected by smoke detection and crew vigilance instead.
- Q5
388.On receipt of left engine fire warning the sequence will be 3. PULL No. 1 FIRE HANDLE 1. IF AFTER 30 SECONDS FIRE WARNING REMAINS ILLUMINATED ROTATE No. 1 FIRE HANDLE RIGHT TO ITS MECHANICAL LIMIT AND HOLD FOR AT LEAST 1 SECOND. THIS WILL DISCHARGE THE RIGHT BOTTLE INTO THE LEFT ENGINE. 6. LAND AS SOON AS POSSIBLE 5. CLOSE LEFT THRUST LEVER 4. LEFT ENGINE HP OR ENGINE START LEVER CLOSE 2. NUMBER 1 ENGINE FIRE HANDLE ROTATE LEFT TO MECHANICAL LIMIT AND HOLD FOR AT LEAST 1 SECOND. THIS WILL DISCHARGE THE LEFT BOTTLE INTO THE LEFT ENGINE
- A5,4,3,2,1,6
- B2,4,6,3,1,5
- C6,5,4,3,1,2
- DIf after 30 seconds fire warning remains Illuminated rotate no. 1 fire handle right to its fire bottle mechanical hold for at least 1 second this will disc the right bottle into the left engine
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Correct answer: A. 5,4,3,2,1,6
The engine fire drill follows a strict order: first contain the engine by closing the throttle and shutting off the fuel, then pull the fire handle to isolate fuel, hydraulics and bleed air and arm the extinguishers, and discharge the first bottle. Only if the fire warning is still illuminated after 30 seconds is the handle rotated to its mechanical limit to discharge the second bottle into the same engine.
- Q6
With out added oxygen the time of useful consciousness at 40,000 ft is approximately:
- Atwenty seconds.
- Bthree minutes.
- Ceighty seconds.
- Dsix minutes.
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Correct answer: A. twenty seconds.
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- Q7
On what principle do smoke detectors work?
- A Resistance and capacitance
- B Ionisation and impedance
- COptical and ionization
- D Inductance and light diffraction
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Correct answer: C. Optical and ionization
Aircraft smoke detectors work on two complementary principles: optical detectors sense light scattered or obscured by smoke particles, while ionisation detectors sense the change in ionisation current caused by combustion products. Combining both improves reliability and reduces false warnings.
- Q8
When is an engine overheat firewire system activated
- AWhen an overheat is detected all along the length of both firewire loops
- B When an overheat affects one detector loop at a point anywhere along its length
- C When an overheat is detected all along the length of one firewire loop
- D When an overheat affects both detector loops at a point anywhere along their length.
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Correct answer: D. When an overheat affects both detector loops at a point anywhere along their length.
To guard against spurious warnings, a dual-loop overheat detection system requires both firewire loops to sense the overheat at the same point before a warning is given. A single loop reacting at any point is treated as a possible fault rather than a real overheat.
- Q9
The maximum altitude without oxygen at which flying efficiency is not seriously impaired is:
- A10,000 ft.
- B17,500 ft
- C25,000 ft.
- D30,000 ft.
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Correct answer: A. 10,000 ft.
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- Q10
An ion detector detects
- A Smoke and fire
- B Smoke
- COverheat
- D Light
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Correct answer: B. Smoke
An ionisation detector responds to the change in ion current caused by the products of combustion entering its chamber, and is used to detect smoke. It is not a general overheat or flame sensor.
- Q11
In a pressure demand oxygen system:
- Aeach member of the crew has a regulator.
- Beach member of the crew has a continuous oxygen supply.
- Coxygen is supplied with a continuous pressure flow.
- Doxygen demand will cause the pressure to rise.
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Correct answer: A. each member of the crew has a regulator.
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- Q12
The type of smoke detection system fitted to aircraft is
- A Optical and ionization
- BChemical
- C Electrical
- D Magnetic
Show answer
Correct answer: A. Optical and ionization
The smoke detection systems fitted to aircraft are of the optical and ionisation types, optical units sensing light scattered by smoke and ionisation units sensing changes caused by combustion products, giving reliable early warning.
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