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Guest _Christopher_

757 Derated Takeoff

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I have seen a LOT of mention recently in posts mentioning the 757 and derated takeoff being selected.My issue is this:On the T7, I can actually choose between 3 levels of derated takeoff -- full thrust, -5% derate or -15% derate (I hope I got those numbers right).I cannot find this page on the 757 FMC and the manual does not mention this page.I know that just entering an assumed tempurature cannot effectively derate the thrust because that still gives you a fixed thrust for the current tempurature -- so my question is this:"How do you derate the thrust in stages to choose a low power takeoff on the PSS 757, since the procedure is obviously different from the B777?"Thanks, Chris

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Okay I must be losing my mind. Now I am looking at page 8 of the FMC manual for the 757 and one of the steps is to go to the Thrust Limitation Page. I know for a fact that I must be doing something wrong, because everyone else here is talking about how they are derating their takeoff. Did I have a bad install?

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Hey,Instead of pressing a button to reduce takeoff thrust, you enter in an assumed temperature which is higher than the actual outside temperature. Thats why I have been asking for charts based on runway length and aircraft weight to find assumed temperatures.

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Hey Chris, Try the "1" or "2" buttons on the TRP (right side of the cockpit) below the MCP, above the gear handle. I'm almost certain that TO-1 is 5% derate and TO-2 is 15% for the 75. You can actually combine this with an assumed temp for more derate and get D-TO 1 or D-TO 2. Now you can help me too...Do you know how to pre-select reduced climb thrust on the ground? I'm guessing that by selecting a set derated take off (1 or 2) that also arms CLB 1 or CLB2. I've been trying to figure this out since I got the bird since I know it is possible just look at that other company's 767. Anyway, hops this helps.-adam

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>Hey Chris,> Try the "1" or "2" buttons on the TRP (right side of the>cockpit) below the MCP, above the gear handle. I'm almost>certain that TO-1 is 5% derate and TO-2 is 15% for the 75. You>can actually combine this with an assumed temp for more derate>and get D-TO 1 or D-TO 2. Now you can help me too...Do you>know how to pre-select reduced climb thrust on the ground? I'm>guessing that by selecting a set derated take off (1 or 2)>that also arms CLB 1 or CLB2. I've been trying to figure this>out since I got the bird since I know it is possible just look>at that other company's 767. Anyway, hops this helps.>-adam>Thank you -- I'l look for and try that when i get home from work in the morning. I was just confused as to all the other posts around here where everyone was apparently pre-selecting their derated T/O in the FMC instead of using the panel. I did find the operations of this panel on page 42 of the PSS 757 Panel manual.Chris

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Chris, One more thing. I found that if the preset derate (1 or 2) is selected, it will override the assumed temperature EPR unless the assumed temperature gives a more restrictive EPR. It makes sense really. I'm certain this is how it is supposed to function in the real A/C. Also, selecting TO 1 or TO 2 definately preselects CLB 1 or CLB 2, respectively. It seems redundant to have both selected but I think this is for the sole purpose of having a low TO EPR for takeoff with assumed temperature and at the same time preselecting a derated climb. I have yet to find a condition where I could go without derated climb power and still have comfortable (virtual) passengers. It is the rocketplane, after all. Of course, I haven't tried the EGE GYPSUM3 from 23 yet. :)-adam

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Thank you for the reply, Adam.LOL. Aye you should try some departures from KEGE . . . :-)I just got home from work, so going in now to take a look at her again with the settings I took notes on at work from another manual.Chris

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Okay, so an update:I did as advised here in the thread and i am STILL doing something wrong. I know it has to be me, as I am the only one reporting this issue, so help me out, guys. What am I doing wrong?See the screenshot for the steps I took:http://puebloaviation.org/images/troublesh..._AT_Issue_1.jpgI am following the PSS manual, and according to the manual AND you guys I **thought** I was following the right steps, but she refuses to derate. What step(s) am I missing?A/T seems to kick and and work great during VNAV and FLCH operations, so it's just the T/O derate i am having troubles finding what I am doing wrong with.

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Instead of right clicking thr AT-Arm button press the EPR-Butten just above the SPD hold butten for Take off and it runs up your engines just untill the derated EPR Setting! ;)Good Luck, Patrick

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I was ACTUALLY about to post on that -- I just landed for a flight from KABQ to KCOS and in the process of fiddling with the mouse I accidently right clicked too low -- on the EPR button -- annnnnd . . . had derated takeoff. LOL.In fact I am kind of embarrassed as i have no idea where i got the right click the A/T thing other than maybe I was confusing the T7 manual with the 757 manual. But she sure climbed out smooth with this setting. Not a KEGE departure LOL. On this flight I had a nice, smooth, 2000 FPM climbout to altitude.And so I started re-looking through the manuals and found on page 25 and 26 in the tutorial right where it says to use the EPR button. I must have grabbed my T7 manual or something when i was looking before.I believe this is why they do not allow pilots to fly while suffering sleep deprivation . . . .Chris

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Chris,You appear to be confused over the use of TO thrust and CLB thrust. I'd suggest you try the tutorial.

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No, actually I was referring to TO thrust and the TO/GA mode, but I figured it out, Dean :-) Many thanks.Chris

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Chris,The key thing to remember is that CLB CLB1 CLB2 are climb thrust modes and are used in conjunction with either FLCH, VNAV or V/S.

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I know that. But the same buttons are used to select the derated TO TO1 and TO2 modes. That's what we were referring to here ;-) Also, when you choose TO, TO1 or TO2 the setting carries over to CLB, CLB1 and CLB2. The procedure was already there in my head. The main point of this thread turned out to be just a click spot I was misunderstanding the location of in the VC, which was frustrating me until I found out I was just one button off. Got my answer thanks to the great replies above. :-)Chris<> To correct spelling.

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