Mailinglist Archive: opensuse (3337 mails)

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Re: [SLE] Warning to Americans!
  • From: Peter B Van Campen <pbvanca1@xxxxxxx>
  • Date: Sat, 29 Apr 2006 19:50:18 -0500
  • Message-id: <DAC3A918-FED9-472A-AAD7-89F5F3A9A293@xxxxxxx>

On Apr 29, 2006, at 5:23 PM, James Knott wrote:

Anders Johansson wrote:
On Saturday 29 April 2006 14:44, James Knott wrote:
Anders Johansson wrote:
My favourite is the Canadian incident, where they ordered the amount of
fuel in kilos but received it in pounds, so they went flying with half a
Incidentally, planes often fly with less than full tanks. They carry
only enough to reach their destination, plus a margin for safety. To
always fly with full tanks would simply waste fuel and money.

Is this relevant? What are you saying? Are you suggesting they glided to save
money on fuel?

No, I'm saying planes often fly with less than a full tank, when it's
not needed to fly to the destination. If a plane takes of with a full
tank of fuel, when only half a tank is sufficient, then they're carrying
all that fuel at great expense and may also decrease available payload.
Don't forget, fuel consumption depends on weight, so if they carried
far more fuel than they needed, they'd burn significanly more fuel to
carry it. In that Gimli Glider incident, they goofed in calculating how
much fuel they needed.


The airlines pay lots of money for apps that check fuel price and availability many times a day at each of their destinations. The app then crunches away and makes recommendations as to quantity and location for each plane to fuel. These calculations can really get a big system to crunch away! The FAA requires all commercial flights to carry at least enough fuel to fly to their destination, then to an alternate dest 45 minutes further, then an additional 45 minutes flying time more. In the US aviation GASOLINE is sold and used by the US Gallon; Jet-A fuel is sold and used by the POUND. No expantion/ contraction issues that way.

I have friend that was a long-haul trans pacific 747-400 captain. Fun fact: the 747-400 has fuel tanks in the horizontal stabilizer (tail) that hold 10,000 pounds of Jet-A. Modern jets have computerizd fuel systems that talk to the 're-fueler' system; it tells the refueler how much fuel to deliver and it sorts it out into the many onboard tanks as determined by the Flight Eng or Co-Pilot. What amazes me about these fuel-starvation incidents is that the personel don't see them coming in time to make a 'powered' landing!


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