fuels midterms Flashcards
can enter the airplane wing from either the uplifted fuel or through the fuel vent systems.
contamination
three basic types of fuel contamination are:
water, particulate, and microbial growth
JET FUEL’S COMPOSITION ALLOWS WATER TO BE EASILY ABSORBED. WATER CAN BE INTRODUCED IN VARIOUS WAYS INCLUDING THROUGH HUMIDITY IN THE AIR. WATER PRESENT IN THE FUEL IS EITHER SUSPENDED OR IS PRESENT AS A LIQUID. THE DEGREE OF SUSPENSION IS AFFECTED IN PART BY TEMPERATURE.
water contamination
CERTAIN BACTERIA AND FUNGI THRIVE IN WATER WHERE IT INTERFACES WITH JET FUEL. THESE MICROORGANISMS FEED OFF ALKANES AND ADDITIVES IN THE FUEL. THE BYPRODUCT OF THESE ORGANISMS IS A SLUDGE-LIKE SUBSTANCE THAT CAN CAUSE CORROSION ON STEEL AND ALUMINUM SURFACES AND ATTACK RUBBER FUEL SYSTEM COMPONENTS. IT CAN ALSO FOUL FILTERS AND SYSTEM INSTRUMENTATION.
microbial growth
ONE WAY TO CONTROL MICROBIAL GROWTH
ELIMINATING WATER FROM THE FUEL SYSTEM
can be introduced in many different ways. From dirt and sand getting in open ports to degradation of fuel system lines, these are constantly being introduced to fuel systems.
particulates
how to protect open fuel lines
covering all open lines during maintenance, fuel sampling, top off tanks, good housekeeping
CAN HELP REDUCE PROBLEMS WITH MICROBIAL GROWTH AND FREEZING ASSOCIATED WITH WATER IN THE SYSTEM. IT CAN ALSO HELP IDENTIFY IF PARTICULATE CONTAMINATION IS PRESENT
fuel sampling
JET FUEL HAS A TENDENCY TO ABSORB MOISTURE FROM THE ATMOSPHERE. WITH LESS AIR IN THE FUEL CELLS AREAS, THE RATE OF ABSORPTION WILL BE SIGNIFICANTLY LOWERED.
top off tanks
CAN REDUCE CONTAMINATION OF THE FUEL SYSTEM. FUEL STORAGE AND DISPENSING EQUIPMENT SHOULD BE KEPT CLEAN AT ALL TIMES.
good housekeeping
requirements and properties of lubricants
- Keep surfaces separate under all loads, temperatures and speeds, thus minimizing friction and wear.
- Act as a cooling fluid removing the heat produced by friction or from external sources
- Remain adequately stable in order to guarantee constant behavior over the forecasted useful life
- Protect surfaces from the attack of aggressive products formed during operation.
- Show cleaning capability and dirt holding capacity in order to remove residue and debris that may be form during operation.
The main properties of lubricants, which are usually indicated in the technical characteristics of the product, are:
viscosity
viscosity index
pour point
flash point
describes the flow behavior of a fluid. The viscosity of lubricating oils diminishes as temperature rises and consequently is measured at a given temperature (e.g. 40°C).
viscosity
determines the thickness of the layer of oil between metallic surfaces in reciprocal movement.
viscosity
The most widely used unit of measurement of viscosity
centistokes (cSt)