737 Assumed Temperature Chart
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Join Date: Jan 2002
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737 Assumed Temperature Chart
Hello,. .Would anyone happen to have a 737-300 Assumed temperature chart for reduced thrust takeoffs that they could email me? My address is [email protected]. .. .Thanks,. .Brad
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"Assumed temperature" is a method, or procedure, applied to a normal maximum thrust RTOW chart, when appropriate, to obtain a safe level of reduced thrust for the present takeoff. . .. .In essence, the (chart entry) OAT is presumed to be higher than the actual OAT to take advantage of a weight margin below the maximum for the day. The procedure is conservative as the aircraft's performance will reflect the actual OAT, not the presumed higher value. The end result is that the operator gains a small cumulative maintenance (cost) benefit associated with lower exhaust temperatures for the takeoff.
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To what chart are you referring?. .. .If you want to be able to calculate the assumed temperature, you would need the OAT, QNH and A/C gross weight. Therefore, there is not normally a 'chart' as such, because the assumed temperature calculation is based on actual conditions, in conjunction with the airfield data.. .. .Most airlines produce their own performance manual containing all the data needed to calculate this, given the above parameters.. .. .Can you be more specific about what chart you are after?
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John may disagree with this, but there are those who will say that you can enter the regular charts in the Flight Planning and Performance manual, not with ambient conditions to find RTOW, but with ATOW to find equivalent limiting ambient conditions, and thus an assumed temperature.. .. .Of course, the Flight PLanning and Performance Manual is only of academic interest as its data is so limited. With an enormous amount of time available, you might be able to have a stab at calculating the necessary figures for a take-off, but I wouldn't like to do it often! You'd need lots of data about obstacles too.. .. .Practically, individual charts for each runway (and often, various configurations of bleed, anti-ice, and runway conditions, braking actions etc) will be produced for the operator, by companies such as Flygprestanda, Jeppesen, et al. These charts incorporate a means of finding assumed temperatures for thrust reduction. So, there will not be a '737-300 Assumed temperature chart for reduced thrust takeoffs' per se as requested above.. .. .Hope this is helpful.
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NorthernSky,. .. .No problems there ... the practical dictates prevent other than a computerised interative analysis .. or else the conventional RTOW chart fudges.. .. .It is noteworthy that most operators/NAA impose some conservative level of fudge factor.. .. .I like Wal Stack's philosophy in the early QF reduced thrust days of the 707 ... a thousand feet pad of concrete was a reasonable thing ...
