FUEL – Air – DGCA Question Bank For Politics

#1. A fuel grade which is used in typical aircraft engines is:

D.T.D. 585/100

D.E.R.D. 2479

AVGAS 100

D.E.R.D. 2484

#2. The "anti-knock" value of a fuel is its:

Degree of resistance to pre-ignition.

Resistance to adiabatic combustion.

Ability to oppose burning.

Resistance to detonation.

#3. The differences between AVGAS 100 and AVGAS 100LL are:

Colour - Same, Anti-knock value - Same

Colour - Same, Anti-knock value - Different

Colour - Different, Anti-knock value - Same

Colour - Different, Anti-knock value - Different

#4. The Octane rating of a fuel is determined by comparison with mixtures of:

Methane and orthodentine.

Heptane and iso octane.

Methane and iso octance.

Heptane and orthodentine.

#5. In the internal combustion engine, detonation occurs due to:

The use of too high an R.P.M. with too little manifold pressure.

The use of the wrong grade of oil.

The cylinder temperatures and pressures being too low.

Excessive combustion temperatures and pressures.

#6. The calorific value of a fuel is the:

Kinetic energy contained within it.

Heat energy in the fuel.

Heat energy required to raise the temperature of the fuel to its boiling point.

Heat energy required to raise the temperature of the fuel to its boiling point from absolute zero.

#7. The octane rating of a particular grade of fuel is given as 100/130, this indicates that:

It will act as both 100 octane and 130 octane fuel at take off power settings.

With a rich mixture it will act as 100 octanes, and with a weak mixture it will act as 130 octanes.

Its "anti-knock" qualities are identical to iso-octane.

With a weak mixture it will act as 100 octane, and with a rich mixture it will act as a 130 octane fuel.

#8. Tetra ethyl lead is added to some aviation fuel to:

Decrease its octane rating.

Decrease the risk of detonation.

Increase its calorific value.

Increase its specific gravity.

#9. If the vent pipe of an aircraft's fuel tank becomes blocked, it will cause:

The pressure in the tank to fall when fuel is used.

The pressure in the tank to rise when fuel is used.

The evaporation rate of the fuel to decrease as fuel is used from the tank.

The fuel pressure at the carburettor to rise.

#10. If the specific gravity of a fuel is known to be 0.7, 100 Imperial Gallons of it will weigh:

700 Ib

70 Ib

7000 Ib

7,100 Ib

#11. Detonation is liable to occur in the cylinders:

With an over rich mixture at idle power.

With a weak mixture and high cylinder head temperature.

With a rich mixture at high power settings.

At very low engine speed.

#12. Pre-ignition refers to the condition when:

A rich mixture is ignited by the spark plug.

The spark plug ignites the mixture too early.

The mixture is ignited by abnormal conditions within the cylinder before the normal ignition point.

The mixture burns in the inlet manifold.

#13. An exhaust gas temperature gauge is powered by:

12v DC

115v AC

28v DC

A thermocouple which generates its own voltage.

#14. "Flame Rate" is the term used to describe the speed at which:

The mixture burns within the cylinder.

The combustion pressure rises within the cylinder.

Peroxide forms within the cylinder.

Fulminates form with the cylinder.

#15. The colour of 100 / 130 grade low lead fuel is:

Green.

Blue.

Red.

Straw yellow.

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