Fuel Systems

Question 1

Regulations 14 CFR 23.2000 to 14 CFR 23.2010

Answer 1

Applicability

Question 2

14 CFR 23.2430

Answer 2

fuel systems

Question 3

14 CFR 23.2605, 23.2610,23.2615

Answer 3

Instrument placards and installation

Question 4

purpose of fuel systems

Answer 4

deliver an even flow from storage unit by means of constant pressure

Question 5

control unit

Answer 5

carburetor, fuel injection or turbine fuel control

Question 6

requirements

Answer 6

must be reliable, Must be able to use all usable fuel, fuel systems must be independent of one another

Question 7

volatility

Answer 7

the tendency (rate) of a liquid to vaporize under given conditions

Question 8

how do you measure volatility

Answer 8

a Reid vapor pressure “bath’ /”bomb”

Question 9

aviation fuels are limited to what PSI

Answer 9

7 psi

Question 10

too high Volatility

Answer 10

can cause vapor lock in the lines
can bring about carb icing

Question 11

too low volatility

Answer 11

hard starts
slow warming
poor acceleration

Question 12

vapor pressure

Answer 12

pressure above liquid that keeps liquid from evaporating

Question 13

what determines volatility

Answer 13

vapor pressure

Question 14

boiling point

Answer 14

the temp at which the vapor pressure of the liquid equals the pressure surrounding the liquid and the liquid changes into vapor

Question 15

detonation

Answer 15

uncontrolled burning of the fuel in the combustion chamber
- occurs before spark event
- causes extremely high combustion chamber pressure
- Severe engine damage

Question 16

compression ratio

Answer 16

ratio of volume between piston and cylinder head before and after compression stroke

Question 17

higher compression ratios =

Answer 17

higher octane fuel

Question 18

gasoline

Answer 18

A blend of hydrocarbon compounds that have a wide range of boiling points and vapor pressures

Question 19

Iso-octane

Answer 19

A flammable, colorless hydrocarbon liquid used as a component of aviation gasoline
- Used as the datum for anti-detonation characteristics comparison

Question 20

Heptane

Answer 20

A flammable, colorless hydrocarbon liquid used as a component of aviation gasoline.

Question 21

Octane ratings

Answer 21

Is a standard measure of the performance of a motor or aviation fuel
- The higher the octane number, the more compression the fuel can withstand before detonating

Question 22

100 octane gasoline

Answer 22

is a blend of hydrocarbons tha have the same anti-detonation characteristics as pure iso-octane

Question 23

92 octane gasoline

Answer 23

is a blend of hydrocarbons that have the same anti-carbon characteristics as 92% iso-octane & 8% heptane

Question 24

115 octane (performance number) gasoline

Answer 24

is a blend of hydrocarbons that exceed the detonation characteristics of pure iso-octane

Question 25

115/145 octane

Answer 25

- dual number octance rating - low number - octane of fuel at lean cruise - High number - octane of fuel at rich takeoff

Question 26

Tetra-ethyl lead (TEL)

Answer 26

- Knock inhibitor - Octane boost - Corrosive - Not used in quantities in excess of 6ml per gal

Question 27

AVGAS

Answer 27

-Non-aromatic -Aromatic fuels cause deteriration of rubber parts - 100 fps flame front - 6.8 RVP - Contains TEL

Question 28

Jet fuel

Answer 28

Jet Fuel - Jet A and Jet A-1 - Kerosene based - Refined to international standards - Equivalent to JP 8

Question 29

JET B

Answer 29

- Kerosene and Naphtha - Cold weather operations - Dangerous to handle

Question 30

Fuel color codes

Answer 30

- 80-87 = red - 91-96(100LL) = blue - 100-130 = green - 115 - 145 = purple - Jet fuel is clear or straw

Question 31

Fuel Systems - Contamination Water

Answer 31

- Most Common - 30 ppm max - Entrained : separates out over time - Suspeneded : does not seperate out - Primarily jet fuel - Freezes at altitude- blocks filters

Question 32

rust or scale

Answer 32

from sitting on the ramp

Question 33

metal

Answer 33

Component wear

Question 34

Dirt or silicon

Answer 34

Crud

Question 35

Sediment, particulates, crud sizes

Answer 35

- 1 Micron - 1/1,000,000 meter - 1/25,400 inch - 40 microns = invisible to naked eye - 100 microns = human hair - Filter/ strainers can filter down to 10 microns

Question 36

when avgas fuels are mixed

Answer 36

color turns clear

Question 37

when jet A and avgas are mixed

Answer 37

Turbine TEL forms deposits on turbine blades

Question 38

Reciprocators

Answer 38

Just a little Jet A (0.5%) in the avgas lowers the anti-knock characteristics to dangerous levels

Question 39

Microbial Growth

Answer 39

- Microorganisms feed on hydrocarbons - Upon their death - Falls to bottom of tank creates a green/black scum - Causes corrosion of tank - Scum can break loose, plug fuel screens and filter

Question 40

Solution for microbial growth

Answer 40

Use anti microbial / anti freeze additive - Prist (trade name) - Includes antifreeze and biocide components - Refiners often add it to fuel supplies

Question 41

internal tanks

Answer 41

Separate tank located inside the airframe structure - Subtypes - Rigid (metal) - Bladder (flex ballon)

Question 42

Internal (rigid) tanks

Answer 42

- Advantages - Can be removed, repaired, replaced - Disadvantages - Heavy, must be supported, less volume

Question 43

Bladder (flex balloon)

Answer 43

- Advantages - Fill volume more efficiently - Disadvantages - More easily damaged, deteriorate over time

Question 44

Intergral

Answer 44

AKA wet wing - Tank is part of the wing structure - Advantages - Efficient use of volume , low weight - Disadvantages - Maintenance prone to leakage

Question 45

External tanks

Answer 45

- Added on to airframe structure - Removable wing tip tanks - most common - Belly tanks, pylon tanks - Rare in civilian aircraft