Fuel System

Question 1

Two types of fuel system

Answer 1

1. Gravity-feed system
2. Fuel-Pump System

Question 2

Gravity-feed system

Answer 2

Utilizes the force of gravity to transfer fuel.

Ex. on high-wing airplanes, the fuel tanks are installed in the wings.

Question 3

Fuel-pump system

Answer 3

Main pump system is engine driven; auxiliary pump (electrical, used for startup).

Question 4

Avgas 80

Answer 4

• Color Red
• Has a Very low lead content
• Only suitable for low compression engines

Question 5

Avgas 100 color

Answer 5

• Color Green
• High lead content
• Used on high compression engines

Question 6

Avgas 100LL color

Answer 6

• Color Blue
• Contains a Low lead content

Question 7

Jet A1 color

Answer 7

Colorless or straw.

Question 8

Automobile gas (MOGAS)

Answer 8

Use of automobile gas to the aircraft like for Example: Petron Blaze 100 octane.

Supplemental Type Certificate (STC) issued by the Federal Aviation Administration for approval of any modification.

Question 9

If proper grade fuel type is not available…

Answer 9

Use the next higher grade as a substitute.

Question 10

MOGAS advantages

Answer 10

Cheaper than AVGAS.

Question 11

MOGAS disadvantage

Answer 11

• It tends to cause vapor locks in pipelines at high temperature and altitudes
• Carbureted engines using this fuel are more susceptible to carburetor icing
• It has low lead content which can lead to pre-ignition and detonation.

Question 12

Fuel Related Problems

Answer 12

• PRE-IGNITION
• DETONATION
• FUEL CONTAMINATION DUE TO CONDENSATION.

Question 13

Pre-ignition

Answer 13

Ignition of the fuel/air mixture ahead of the spark provided by the spark plugs

Question 14

Pre-ignition cause

Answer 14

• Premature burning is usually caused by a residual hot spot in the combustion chamber, often created by a small carbon deposit on a spark plug.
• Using a lower than prescribed octane rating.

Question 15

Detonation

Answer 15

Uncontrolled/ Instantaneous explosive ignition of the fuel/air mixture in the combustion chamber.

Question 16

Detonation cause

Answer 16

• Use of a lower fuel grade than that specified by the aircraft manufacturer.
• Operation of the engine with extremely high manifold pressures in conjunction with low rpm.
• Operation of the engine at high power settings with an excessively lean mixture.
• Maintaining extended ground operations or steep climbs in which cylinder cooling is reduced.

Question 17

FUEL CONTAMINATION DUE TO CONDENSATION

Answer 17

• Empty space inside fuel tanks contains moisture that condenses when the outside air temperature cools.

Solution: * Refilling the fuel tanks to full levels at the end of each day.