Cessna, I think it's hilarious that you took this picture with a cellphone! haha! I KNEW the turn your cell phone off thing was just bogus! (just messing around).
Actually, believe it or not, they can screw up some of our systems. Sometimes we can hear it in our headsets if the person is sitting near the receiver for the radios. But also cellphones will drive our radar altimeters crazy, and if they start having fits on the ground, it starts generating caution messages for the spoilers, etc. Gets messy. But on flights with long taxi times we'll make a PA with a timeframe for takeoff and let the pax know they can use their cell phones and we'll give them a 10 minute warning before takeoff to shut them back down (partially to make sure we don't get any more caution messages)
On a more serious note though, how do you guys factor in the wait times for the amount of fuel you take for the flight? (ie. how do you know how much fuel to give yourself for the taxi portion of your flight? is it just best guess based on an estimate you get from somewhere or what? I know more or less how you guys calculate fuel for flight to destination, approach, then alternate airport, etc. but what about the taxiing?)
Yeah, without going into the boring details, here's the various categories of our required fuel:
Reserve + burnoff + contingency + alternate = Min fuel for takeoff + taxi + extra = Min fuel at the gate
Reserve = the standard 0:45 IFR fuel per the FARs (we never get this low)
burnoff = the amount of fuel we should burn from the time we takeoff to the time we land
contingency = added fuel due to weather deviations, holding, traffic congestion (we don't always carry cont. fuel, just usually flying into any major airports that usually have traffic delays, or if there is weather enroute)
alternate = fuel to fly to our IFR alternate airport if we have one (if the weather is perfect, then we don't have an alternate, so we don't have any fuel for it either)
Min fuel for t/o = the absolute minimum fuel we have to have when we push the thrust levers up to takeoff
taxi = Fuel for taxi out (I'll get to more of this in a moment)
extra = Extra fuel for tankering purposes (buy the cheap gas in cities where we get a good deal on it so we don't pay high prices at the other cities
Taxi fuel will vary wildly with each airport we depart out of and times of day due to traffic. On a normal day leaving a smaller city (LEX, GSO, BUF, etc) we will have 300 lbs of taxi fuel. Moderate sized cities (CVG, MSP, ATL, BOS, etc.) usually have 480 lbs of fuel. The larger airports are where the taxi fuel varies. JFK at 10am might have a taxi fuel of 600 lbs, and at 6:30pm might have 1300 lbs. Our dispatchers are the ones who work up all of these numbers. Obviously there are defaults in the system that automatically recommend fuel loads, but they can change it with the click of a button. Then, as a crew, we can also add more fuel on if we wish. We obviously cannot go below the min for takeoff without working it out with our dispatcher first.
Hope this helps. Let me know if you guys have any other Qs