Over-speed after take-off

[ZKOKQ 984]

Thanks Rob.About to do a departure out of Dubai, so will try it. Thanks for your help. BTW, I agree with your comment regarding Topcat. I am really missing using it, so hopefully soon.

 

Edit Thanks Olli

[VLJ510 16]

Thanks Rob.About to do a departure out of Dubai, so will try it. Thanks for your help. BTW, I agree with your comment regarding Topcat. I am really missing using it, so hopefully soon.

 

Edit Thanks Olli

 

Temps @ DBX are already 63c.  Just kidding.

[FLEX1978 373]

Temps @ DBX are already 63c.  Just kidding.

Haha, that's a very good point, it is 40c in Dubai this morning if you are using real weather! I am on my way to Doha tonight, not looking forward to it!

[donkey20048 19]

So in my scenario I hope you can all help

 

I am doing a manual takeoff so not using lnav or Vnav and just using toga thrust. Once airborne how do I keep the speed minimised as obviously ap is off so I can manually steer the airplane.

 

Thnaks

[ZKOKQ 984]

Too hot for me. I am use to a cold climate. Glad I can go to Dubai without working up a sweat

[FLEX1978 373]

So in my scenario I hope you can all help

I am doing a manual takeoff so not using lnav or Vnav and just using toga thrust. Once airborne how do I keep the speed minimised as obviously ap is off so I can manually steer the airplane.

Thnaks

If you insist on using TOGA your only option is to use pitch to control speed. In reality at light weights you would not use TOGA unless absolutely necessary, even if the runway is contaminated you can still use a derate.

[Lukas_Mathijsen 41]

Aye the chaps covered it. If aircraft is light seriously derate the engines!!! Try it.. Put in no load with light fuel, take off with no derate and you will quickly find yourself at FL*rediculous* and too fast for the flaps!

[davidz 26]

You don't need TOPCAT or Utopia to work out your assumed temp. All the data you need is in the FCOM (under Vol 1, Performance Dispatch). I think James White did a tutorial on this in this forum a few weeks ago. I'll also be doing a video tutorial soon.

[FLEX1978 373]

David, the FCOM doesn't give you runway specific data, they are just balanced v speeds hence why we are all waiting for TOPCAT.

[Lukas_Mathijsen 41]

Aurasim also is developing a take-off/landing performance calculator for the 772LR (like they did for the majestic q400).

[ZKOKQ 984]

Rob, I tried your method  departing Dubai, it was spot on. it was the info I was after, as most of my take offs previously would have a real pilot in jail. So, thanks to you and Oliver.

[FishermanIvan 110]

One other thing to keep in mind, is that airliners are routinely cleared through the 250 knot "speed limit" if traffic allows it. CYEG where I live isn't massively busy and I see 737NGs climb out unrestricted all the time.

 

Makes speed management in the 777 a little easier when you can go to 320 knots pretty much right away.

[BilboBaggins 82]

Derate your engines if light. I'm talking serious derates like TO-2 with a 65C assumed temp. These engines are incredibly powerful and it will do that in the real thing too - you can't pitch fast enough to stop the acceleration just after liftoff at full thrust without risking a tailstrike.

Funny this is exactly what I was doing, especially with the assumed temp - set that higher and you'll go rocketing off into space.

 

The manual has good detail on this, thank you, Ryan.

 

[oscayala 0]

where's your throttle after to-ga switch pressed? 

Thanks. I advance manually the throttles until I get around 50% of N2 (as I do successfully with the NGX)  and suppose the auto throttle sets the position for the correct speed. Of course my previous setting has the restriction for max 250 knots below 10000 feet.

[davidz 26]

David, the FCOM doesn't give you runway specific data, they are just balanced v speeds hence why we are all waiting for TOPCAT.

 

Of course it doesn't. However, you can work out your limit weights for each of the conditions (take-off field, climb, obstacle and tire speed) for a given runway distance, ambient temperature and elevation... or run it backwards and find the limit temperature for each condition and use the lowest temperature as the assumed temperature.

 

You do realise that the exact same process is used with the FPPM (the FPPM just has more data and more detailed data in the form of graphs), the same process is used to generate runway analysis tables and the same process is used by computer tools like TOPCAT?