Aircraft Emergency, Fire, and Fuel Safety PDF

Breakdown W1 7 W2 7 W3 10 W4 10 W5 8 W6...

Breakdown W1 7 W2 7 W3 10 W4 10 W5 8 W6 8 Week 1: Fuel Types, Production and Characteristics Two types -​ AVGAS (Gasoline) -​ Jet Fuel (kerosene type) -​ All are distilled from crude oil and made out of hydrocarbons -​ Gone through a distillation process -​ Heavier that burn off later becomes kerosene, diesel fuel, furnace oil -​ Baffles are used in fuel tanks and other systems to direct the flow of liquids and gases AVGAS -​ Used for reciprocating (piston engines) -​ Very volatile and extremely flammable with a low flash point Turbine -​ Higher flash point, less flammable -​ Higher volatility and higher flammability Volatility -​ the tendency of a liquid to turn into a vapour -​ low volatility vaporizes slowly; which can cause hard engine starting, slow warm up and poor acceleration Vaporization -​ Ambient Pressure Decreases -​ Ambient Temperature Increases This becomes a problem as the fuel too volatile will cause detonation and vapour lock AVGAS is blended to the limit the tendency to vaporize, especially at high altitudes Bending of the fuel is also to ensure smooth performance range Reid vapour pressure tester -​ used to measure volatility of fuel, AVGAS has vapor pressure 5.5 lbs per PSI and 7.0psi at 100F Problems with AVGAS -​ Vapour Lock -​ Carburetor Icing -​ Detonation Vapour Lock -​ Condition which avgas vaporizes in the fuel line or other components between the fuel tank and the carburetor -​ Caused by: excessively hot fuel, low pressure, excessive turbulence -​ Liquid fuel vaporizes and blocks the flow to the carburetor 3 main causes -​ Low atmospheric pressure -​ High fuel temperature -​ Excessive fuel turbulence Fuel vaporizes too slowly -​ which can cause engine starting, slow warm up and poor acceleration High altitude -​ Higher altitude, lower atmospheric pressure -​ Low pressure lowers boiling point of the fuel causing vapour bubbles to form High Fuel Temperature -​ Heat from the engine can cause boiling of the fuel in the lines Fuel Turbulence -​ Sloshing of the fuel in fuel tanks will mix air into fuel Stopping Vapour lock -​ Keep fuel lines away from source of heat, sharp bends and steep rises -​ Keep boost pumps under pressure -​ Vapour eliminates may be installed in some system ahead of the metering device Carburetor Icing -​ When fuel vaporizes it extracts heat from its surroundings -​ More volatile the fuel the more rapid the heat extraction -​ Vaporization of fuel occurs mostly in the venture throat or throttle valve of the carburetor -​ The rapid drop in temperature as the field vaporizes may freeze the moisture of the incoming air -​ Carburetor icing is around 30ºF to 40ºF (-1.1°C to 4.4°C) OAT (outside air temperature) Detonation -​ Is a rapid uncontrolled explosion of fuel due to high pressure and temperature -​ Burns smoothly on top of piston of engine -​ Is heard as a engine knock or ping  -​ Can be reduced increasing the octane rating of fuel Octane rating -​ Higher octane rating more compression the fuel/air mix can withstand without detonating -​ Rating of anti-detonation or anti-knock qualities -​ Tetraethyl lead is added increase the octane rating Main grade of Avgas -​ 80/87 identifies as 80, RED -​ 82UL (unleaded), PURPLE (Newest) -​ 100/130, identifies as 100, GREEN  -​ 100LL, Blue Fuel mixture Lean/rich -​ Amount of fuel vs air mix -​ Too lean = more air in mixture -​ Too rich = more fuel -​ Lean mixture will burn hotter than a rich mixture -​ Lower the octane rating is for the lean mixture setting Numbers -​ 80/87 -​ First number indicates the lean mixture rating -​ Second number indicates the rich mixture rating -​ 80/87 is in low compression engines -​ 100/130 is in higher compression engines -​ 100LL stands for Low lead, means that the tetraethyl lead is reduced Flash Point -​ Of a volatile liquid is lowest temperature at which it can vaporize -​ Flammable fuels have a flash point 38 °C -​ AVGAS flashpoint -27°C -​ Jet A flashpoint 38°C -​ Jet A-1 flashpoint 38°C -​ Jet B flashpoint