Hi AllI've just started to get to grips with Just Flight's (PSS) Boeing 757 Professional.However, I'm having some real problems performing a standard takeoff in the 757-200 RR.I set the MCP up for a V2 of 137kts an altitude of 3500, A/T and FD engaged. I advance the throttles to 70% N1 then engage EPR. The takeoff all starts off OK with the correct EADI annunciators being displayed. However, it's at V2 where the problems start. Once airborne, the A/C accelerates like a balistic missile, continuing all the way up to approx 220kts at about 4000ft/min. The nosepitches up violently and I have to push the yoke all the way forward just to keep the angle < 20deg. If I release the pressure, it pitches up > 40deg. At about 1000ft I engage CMD C. This has no effect on VS or AoA.The A/C continues to climb past the set altitude of 3500ft (sounding an "Altitude" cockpit warning), eventually levelling out at about 4500ft. At this point, it starts to decelerate, levels off, then begins a slow descent back down to 3500ft. Eventually, levelling out at 137ktswith some semblance of normality returning.I've practised and practised this procedure, but each time, the 'exact' same thing happens.I'm obviously missing something here; I'm not questioning the software. I've read numerous tutorials and actual takeoff procedures, but there's just no way that I can maintain a climbout of V2 + 10kts at an angle of 15deg !!! Any help or advice much appreciated.RegardsGary

The main things that come to mind are..A. What is your Gross Take Off Weight? (GTOW)B. What Derate/Assumed Tempreture are you using in the FMC?C. What Thrust reduction altitude have you set in the FMC?

Hello Gary,The 757 is a very powerful aircraft and the PSS version simulates that caracteristic. I have a couple of 757 WAR dvds and it's not unusual to see a take-off climb pitch of 20 degrees.First of all, the PSS A/P requires you to put V2+15 on the MCP and not V2 such as in PMDG aircraft. Also, as far as I know you must engage EPR with a right click for it to work properly.The questions in the above post are very important, if you're flying light then derate your thrust, either manually or by selecting TO1 or TO2 on the thrust mode panel situated just above the flap indicator. I suggest doing the latter to get familiar with the thrust rates.You also have to enter the thrust reduction height with your flap setting which is in the Takeoff Ref page of the FMC.Now, you can either arm the VNAV which will engage once you hit the A/P button and go to climb thrust at the thrust reduction height or you can press the climb thrust button yourself. I have seen this done in real life, again in one of my WAR dvds so don't worry about it being realistic or not.I would have recommended reading the manual but I know it isn't very clear on this, so, if you have any further questions or this isn't clear enough do ask.Once you get the grips with this add-on it's very pleasant to fly.Happy landings

Hello Gary,The 757 is a very powerful aircraft and the PSS version simulates that caracteristic. I have a couple of 757 WAR dvds and it's not unusual to see a take-off climb pitch of 20 degrees.First of all, the PSS A/P requires you to put V2+15 on the MCP and not V2 such as in PMDG aircraft. Also, as far as I know you must engage EPR with a right click for it to work properly.The questions in the above post are very important, if you're flying light then derate your thrust, either manually or by selecting TO1 or TO2 on the thrust mode panel situated just above the flap indicator. I suggest doing the latter to get familiar with the thrust rates.You also have to enter the thrust reduction height with your flap setting which is in the Takeoff Ref page of the FMC.Now, you can either arm the VNAV which will engage once you hit the A/P button and go to climb thrust at the thrust reduction height or you can press the climb thrust button yourself. I have seen this done in real life, again in one of my WAR dvds so don't worry about it being realistic or not.I would have recommended reading the manual but I know it isn't very clear on this, so, if you have any further questions or this isn't clear enough do ask.Once you get the grips with this add-on it's very pleasant to fly.Happy landings

Very nice and thoughtful reply. :( Mitch

Many thanks, guys for some really useful information.Having read your replies and doing a lot more research through this and the PSS forum, I had more success last night. Rob, using your questions as a pointer, I derated the takeoff by setting in the FMC an assumed temperature of 60deg (a value acquired through a PSS thread). GTOW was approx 190,000Lbs and thrust reduction altitude set to 1000ft, 5deg flaps.This gave me a far more controlled takeoff. I could confortably hold a nose up pitch of 15deg. IAS during the initial part of the climb was a lot lower, but still reached approx180kts - is this what I should expect to see ? At approx 2500ft, the rate of climb started to reduce. On the MCP, thrust control changedfrom EPR to SPD, with the A/C gradually levelling off to the desired, 3500ft with an IAS of 217kts - again, is this what I should expect to see ? I must confess that I am still in the dark regarding the derating of the takeoff and don'tfully understand the principles; the PSS tutorial flight makes no mention of it. I've read other tutorials and takeoff instructions on the 757, but they all seem to gloss overderated takeoffs and at best, just mention the switch settings on the thrust mode panelwithout giving an overview as to their operation.Would either of you have any suggested reading material that could form the basis ofa "derated takeoffs for dummies" guide ?Onur, the PSS FMC guide states that TAKEOFF REF page has two pages and that thereshould be a THRUST

Yup, you're right on the missing Thrust Limit page, although stated in the manual it doesn't exist in the FMC, well at least I haven't been able to find it! You have to set your thrust rates via the Thrust mode panel just above the flap indicator.I wish I could guide you to any reading material on derated take-off but I can't as I'm not aware of any. I have the PSS 757 since about a year now and I've learned setting the thrust rates by experience and trial and error.I wouldn't worry about the speed reaching 180, just control your airspeed with your pitch and like I said before, a 757 eats 15 degrees nose-up pitch for breakfast. If you're speed is increasing just pitch up more. If you're still not satisfied than derate your thrust a bit higher. After a few take-offs you'll master it.Try arming VNAV before take-off and see where that get's you. Also, setting the altitude to 3500 won't help as it's kinda of low, set it to a higher altitude and observe the thrust mode changes.Finally, don't except a smooth climbout thrust wise as in the PMDG 737, this one is more brutal if you see what I mean.

Hi Gary,Glad things are working a little better for you. The best tool out there for calculating derates/assumed temps is TOPCAT http://www.topcatsim.com/ unfortunately data for the 757 is not currently available but I would still recommend downloading the manual and having a read to gain some knowledge on how derates work.I just did a search on the Avsim Library and found a tool for the 757 do a search for Universal Take Off Performance Information Application (UTOPIA) 1.2 utopia12.zipReal world crew use onboard laptops to calculate performance data nowadays, a number of variables are used to calculate the optimum assumed temperature to use in the FMC, some of these variables include Airport elevation, atmospheric conditions, aircraft gross weight, optimum flap setting and obstacle clearance. Software like Topcat & Utopia do all the hard work for you.As a side note entering the wrong Assumed temperature when the aircraft is heavy or near it's max take off weight could be disastrous. There have been a number of real world accidents due to this. The most recent incident was a Emirates A340 departing out of Melbourne, the crew entered the wrong Take off weight into the laptop causing the aircraft to 'think' it was a lot lighter then it really was and therefore giving a wrong assumed/flex temperature that was 'way' too high (both pilots missed the error). The crew luckily managed to scrape the aircraft of the runway causing heavy damage and then returned to Melbourne. http://en.wikipedia.org/wiki/Emirates_Flight_407Regards

Very nice and thoughtful reply. :( Mitch

Thanks, Mitch! :(

I just did a search on the Avsim Library and found a tool for the 757 do a search for Universal Take Off Performance Information Application (UTOPIA) 1.2 utopia12.zip

Will 2nd this as this is what I use for most if not all my Derate Info.

OK, I'm gonna try to break this issue of derated takeoff into pieces for you.First, a de-rated takeoff is one when you don't use the full thrust the engines can provide you. Why? Sometimes the takeoff conditions don't require the full thrust. Conditions why the full thrust is not necessary include: Low aircraft weight, low ambient temperature, low airport elevation, no (or low) obstacles around, no-slope or down-sloping runway. A de-rated takeoff then, it is one when you takeoff at a thrust setting lower than maximum, since it is not needed, to increase engine (and its components) service life. That is the primary reason to do a de-rated takeoff. A de-rated takeoff is not the same as a FLEX takeoff. The main difference between them is in the event of an engine failure; if you have an engine failure doing a de-rated takeoff, YOU CANNOT ADVANCE THE THROTTLES TO MAX THRUST; if you lose an engine doing a FLEX takeoff, you CAN advance the throttles to max thrust. But that's a story for another day.As far as your takeoff problems go, as many others suggested, try to de-rate even further if the aircraft outperfoms. Correct aircraft takeoff configuration is the next one:Flight directors on; no other mode engaged! The FD's will provide you with pitch and roll instructions for initial climb-out. Set V2 in the speed window (no +15 knots addition, the FD does it by itself). Heading window in runway heading (or initial turn heading, FD instructs you to maintain the heading you had when the wheels left the runway). Initial (cleared) or final FL altitude in the altitude window.Arm the autothrottle, and with the takeoff thrust mode selected (Full Takeoff, De-rated 1 or De-rated 2), accelerate to 1.4 EPR (or 60% N1) and once the engine is stabilised, push the EPR button and be vigilant for the engine instruments going to takeoff setting. Rotate at Vr and pitch up to the flight director indication, it will provide you a pitch attitude that will maintain V2+15 KIAS. Select gear up once positive rate of climb is established. At 400ft above ground level, select LNAV; then at 1000ft select VNAV, and if desired, select autopilot center command. You can fly the airplane manually or engage the autopilot to fly the departure. Retract the flaps per schedule (showed on the speed tape or the speed bugs in the airspeed indicator, depending on the type of instrumentation you are equipped with).There's your 757 (and 767) takeoff!Try that and give us feedback of how it goes.Best regards.

Very nicely explained, Ed.Just for the record, I also remember reading somewhere that de-reated thrust isn't used on wet runways. Or maybe that was only on Airbus aircraft...? :(

Hi GuysThought that I'd give you a quick update.After taking your advice, takeoffs are now sooo much better. Setting the MCP speed to V2 + 15made a big difference. The FMC calculated V2 as 147kts, hence, MCP speed was set to 162kts. Tomy surprise, with a nose pitch of 15deg, the A/C climbed at 162-ish kts !!!I tried different derating settings and the one that (for me) worked the best was the assumed temperature of 60deg. One other small improvement was changing the PFD from singleto split cue FD. I now find the FD inputs far easier to follow.I intend to have a go with Utopia tonight and see how takeoffs are using the derating settings that it produces.Just out of interest, I stumbled across an excellent site for real-world 757 info that may or may not be aware of:http://biggles-software.com/main/index.htmI've acquired some really useful stuff from it.Once again, many thanks for your time and patience.RegardsGary

Good news! :( Thanks for posting that link, looks very informative. :( Happy landings!