sciing
in service - 1 year
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Posts: 2,503 
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Post by sciing on Oct 13, 2018 8:17:25 GMT 1
Does anybody have old flight data from the A345 times? I wonder if the A350 is faster because it can fly higher (less drag). Looking on the flight profile the A359ULR go to FL35 right after the start. If you look on other ULR flights for example DOH-AKL by a 77L, they seem to be limited to FL31 at the start. The maximum altitude of an aircraft is limited by the lift of the wings in comparision to the weight as you need higher speeds not to stall and maximum speed is limited by the overspeed limit—>coffin corner  corner |
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Post by fanairbus on Oct 13, 2018 9:53:30 GMT 1
Sorry, I'm confused! So 4 pilots? If so, what is the maximum flight length allowed for just 2 crew?
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Post by Jkkw on Oct 13, 2018 12:35:28 GMT 1
Sorry, I'm confused! So 4 pilots? If so, what is the maximum flight length allowed for just 2 crew? I believe in Australia (and maybe the US) pilots are only allowed to fly 8 hours if there are no relief crews. Looking at the following document stipulating Singaporean flight crew limitations, 2 member crews have an allowed flight duty period (which spans from the time a member of flight crew has to report for a flight until the conclusion of a flight) of between 9 and 13 hours (for flights with a flying time of over 7 hours). This can be extended to 15 hours with the addition of a third member of crew and up to 18 hours with a 4th member of crew . See page 260 for more details. The following document also has a section for ULR ops which covers flights from Singapore to LAX and NYC (see from page 240 onwards). Of course these are just the minimum legal requirements and internal airline policy/crew agreements may specify stricter requirements www.caas.gov.sg/docs/default-source/pdf/air_operator_certificate_requirements_issue_3_revision_32b0f3dfbb3903666590f0ff000087c682.pdfDoes anybody have old flight data from the A345 times? I wonder if the A350 is faster because it can fly higher (less drag). corner The following trip report for SQ21 shows an initial cruising altitude of FL320, ascending to FL350 by the time it flew over Japan, and FL370 by Alaska. I believe the A350 is also faster by design with a cruise speed of 0.85 compared to a cruise speed of 0.83 of the A345. www.airliners.net/forum/viewtopic.php?t=977121 |
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philidor
in service - 6 years
Posts: 8,950
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Post by philidor on Oct 14, 2018 10:49:35 GMT 1
Does anybody have old flight data from the A345 times? I wonder if the A350 is faster because it can fly higher (less drag). Wing loading and flight altitude do matter, but there are other factors, such as the speed the aircraft has been optimised for (by design), and the power settings. On a very long flight, pilots refrain for overspeeding, to save fuel. |
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Post by kevin5345179 on Oct 15, 2018 2:06:17 GMT 1
Sorry, I'm confused! So 4 pilots? If so, what is the maximum flight length allowed for just 2 crew? I think this not only depends on airline but also regulator policies as well as take off time IIRC, Swiss pilots flown 10 hr without additional crew and this is because they take off in "regular" morning .... However, I don't think they can do only 2 pilots for 10 hr if they take off at night |
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Post by kevin5345179 on Oct 15, 2018 2:10:43 GMT 1
Does anybody have old flight data from the A345 times? I wonder if the A350 is faster because it can fly higher (less drag). Looking on the flight profile the A359ULR go to FL35 right after the start. If you look on other ULR flights for example DOH-AKL by a 77L, they seem to be limited to FL31 at the start. The maximum altitude of an aircraft is limited by the lift of the wings in comparision to the weight as you need higher speeds not to stall and maximum speed is limited by the overspeed limit—>coffin corner corner I think altitude may be smaller factor as the optimal cruise speed is related to aircraft shape the other big factor is the speed during oceanic crossing is set by ATC ---> which limits how fast you can go anyways ...... for 77L to do long flight FL310 is actually pretty good already as most of time I see is around FL280 |
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