Vaportrail
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Rex and Fast Cargo you are both correct.
The pilots do have the enter zero fuel weight and total fuel into the flight management system when they are pre-flighting. The FMS is what is used to plot the course from point to point and the auto-pilot/auto-throttle systems use as guide points for vectoring. The FMS will calculate fuel burned over the route based on throttle input as well as pilot input for wind velocity/direction. It does not look at the fuel quantity system to figure actual fuel used, but is rather a guide for the pilots if they need to make corrections or change routes in flight. The fuel quantity indication system will keep track of fuel burned and is accurate enough the pilots rely on it. So at way-point such and such a pilot might see FMS calculates thirty minutes fuel left(hypothetical). He then checks the "gauge" and hopefully they agree. If not the "gauge" is correct and he adjusts accordingly.
ZFW and Total fuel calculations are used for maximizing take-off power based on PAX/Cargo weight, field pressure, temperature and run-way length. Saving fuel is saving money so while you may be capable of producing 25,000 lbs thrust per engine, you won't use that much depending on your take-off config. So pilot input of fuel quantities are very important and on all the aircraft I've experience with, the systems aren't integrated to do this for them.
Most all fuel quantity systems are capacitance type. Measuring tank density rather than level. Fuel quantity indication can be MEL'd so long as the tank is "sticked" at each station. However, only one wing is capable of being deferred and it's a hot item. Usually they don't pass thru a MTX base without being fixed. And yes the fuelers and airplane have to agree otherwise the system needs troubleshot, deferred, fixed whatever. The flow meters are on the engines and are used for starting references as well as power calculations. The fuel meter system doesn't care that E1 flow meter says it's burning 2,000 lbs per hour while E2 says 900(just an example...). Fuel metering just sees that 10lbs were removed from that tank and reports it.
While I haven't worked every plane out there, this is pretty standard on Boeing, Airbus, Embrear, Canadair Regional Jets-all transport category aircraft, and a large variety in technological skills.
I personally believe someone stole this plane. Either for the plane, cargo, or passengers. No matter what happened, I don't think it ends well for the passengers.
Mark
The pilots do have the enter zero fuel weight and total fuel into the flight management system when they are pre-flighting. The FMS is what is used to plot the course from point to point and the auto-pilot/auto-throttle systems use as guide points for vectoring. The FMS will calculate fuel burned over the route based on throttle input as well as pilot input for wind velocity/direction. It does not look at the fuel quantity system to figure actual fuel used, but is rather a guide for the pilots if they need to make corrections or change routes in flight. The fuel quantity indication system will keep track of fuel burned and is accurate enough the pilots rely on it. So at way-point such and such a pilot might see FMS calculates thirty minutes fuel left(hypothetical). He then checks the "gauge" and hopefully they agree. If not the "gauge" is correct and he adjusts accordingly.
ZFW and Total fuel calculations are used for maximizing take-off power based on PAX/Cargo weight, field pressure, temperature and run-way length. Saving fuel is saving money so while you may be capable of producing 25,000 lbs thrust per engine, you won't use that much depending on your take-off config. So pilot input of fuel quantities are very important and on all the aircraft I've experience with, the systems aren't integrated to do this for them.
Most all fuel quantity systems are capacitance type. Measuring tank density rather than level. Fuel quantity indication can be MEL'd so long as the tank is "sticked" at each station. However, only one wing is capable of being deferred and it's a hot item. Usually they don't pass thru a MTX base without being fixed. And yes the fuelers and airplane have to agree otherwise the system needs troubleshot, deferred, fixed whatever. The flow meters are on the engines and are used for starting references as well as power calculations. The fuel meter system doesn't care that E1 flow meter says it's burning 2,000 lbs per hour while E2 says 900(just an example...). Fuel metering just sees that 10lbs were removed from that tank and reports it.
While I haven't worked every plane out there, this is pretty standard on Boeing, Airbus, Embrear, Canadair Regional Jets-all transport category aircraft, and a large variety in technological skills.
I personally believe someone stole this plane. Either for the plane, cargo, or passengers. No matter what happened, I don't think it ends well for the passengers.
Mark
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