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joolsd

Over thrust again at EGJJ

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I'm not sure why I end up over thristing into red brick area from this airport. It is ethier something I am habitually not doing right, but I can't think what it is? Or is it a A/T realisim setting in the menu options I am not doing? Or am I triggering something with my throttle? I certainly thought my take off though. For example tonight I used Flaps 15 as it is a short runway at EGJJ I used TO2, FLAPS 15 accelleraation hight 3000f. However all that is being ingnored. I did not arm Lnav or Vnav as it was the ORTAC 2A from EGJJ. I had flew up to 2000 then heading direct to ALD. I have noticed this before from the same departure, and have to dis-engage the A/T to get the speed back. Is it something to do with my follow through with throttles, when hitting toga? It doesn't always happen and I can't always re-produce this problem? Julian.

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Is it something to do with my follow through with throttles, when hitting toga?

 

If you're not arming VNAV and hitting TOGA, then your AT mode is probably still in N1 when this is happening. This means that the AT is simply giving you the full rated thrust (at whatever limiter you selected - TO/TO1/TO2 plus whatever assumed temp), with no limits on speed. The reason for this is that the climb profile for a departure is very much a pitch for speed maneuver. When you pitch over to stop at an altitude and the AT is still in N1, you're not bleeding off extra speed by climbing and your speed, naturally, increases.

 

You should always pay attention to your FMA at the top of your PFD.

 

 

 


It doesn't always happen and I can't always re-produce this problem?

 

This usually means you're doing something differently.

 

Unless you're familiar with running the AP in different modes by selecting them manually, then you should be flying your departure in VNAV. Otherwise, you're going to run into the problems you're seeing because you're not limiting the AP/AT behavior by simply hitting TOGA with no armed mode.

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If you're not arming VNAV and hitting TOGA, then your AT mode is probably still in N1 when this is happening. This means that the AT is simply giving you the full rated thrust (at whatever limiter you selected - TO/TO1/TO2 plus whatever assumed temp), with no limits on speed. The reason for this is that the climb profile for a departure is very much a pitch for speed maneuver. When you pitch over to stop at an altitude and the AT is still in N1, you're not bleeding off extra speed by climbing and your speed, naturally, increases.

 

You should always pay attention to your FMA at the top of your PFD.

 

 

 

 

This usually means you're doing something differently.

 

Unless you're familiar with running the AP in different modes by selecting them manually, then you should be flying your departure in VNAV. Otherwise, you're going to run into the problems you're seeing because you're not limiting the AP/AT behavior by simply hitting TOGA with no armed mode.

 

 

It might explain why this happens at this airport. I must try it again.

 

I don't always use VNAV and I have notices the AT work.

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is flaps 15 the best option for a short runway and your weight? I think flaps 5 would be the best mix of enough flaps to generate lift and not as much drag as flaps 15

 

I can spit out numbers on the great TOPCAT takeoff calculator if you give me your weights - David Lee

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is flaps 15 the best option for a short runway and your weight? I think flaps 5 would be the best mix of enough flaps to generate lift and not as much drag as flaps 15

 

I can spit out numbers on the great TOPCAT takeoff calculator if you give me your weights - David Lee

Yes I got the figures from Topcat... I think as Ryan said its a matter of modes. Its easy to forget things, so simple departures can produce oversights. I was wondering if I should use N1 or just VNAV, for a simple 'point the heading bug' and go departure? I have tried flaps 5 at EGJJ, but flaps 5, gives you very little runway to abort. The OAT is also very warn. I will try and get my take off performace for that flight if it is of interest? I am only on my iphone now.

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You can use VNAV as a pitch mode even if you plan to use HDG SEL as roll mode. Actually you can select a wide range of configuration: 

LNAV with LVL CH or VNAV or V/S (not recommended for initial clb though)

And VNAV with LNAV or HDG SEL

 

LNAV and VNAV don't have to be used together at all times.

 

For departure, if you expect some heavy workload due to traffic or ATC with some speed or altitude restrictions and you are not familiar with the selection of modes during the initial climb, then arming VNAV on ground is advised. It will managed for you the speed and altitude restrictions.

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I was wondering if I should use N1 or just VNAV, for a simple 'point the heading bug' and go departure?

 

LNAV and VNAV are independent. They're best used together, but even on a vectored departure (heading bug and go departure), it's probably best to use VNAV. Remember that N1 is a "dumb" mode. Its instruction is literally "set throttle on limits and keep it there." That is it. No further instruction or limit is provided. N1 doesn't know about the 250 restriction. It doesn't know about the airframe limits. It doesn't know what altitude you're leveling off at. It doesn't even care that you have a route programmed in there. Max throttle. Go until told to do something else.

 

Since it doesn't seem you're too familiar with the modes, then you should probably just use VNAV. Once you're more familiar and quick on your feet (and want to add what I'd consider unnecessary complication), then you can use other modes. Some airlines use other methods, like bugging the flap speeds in FL CH as you accelerate (VNAV does this automatically) and climb. This is better with two crew members, so if you have FS2Crew, then it might work for you if you're comfortable with the extra commands.

 

Don't over think it  :wink:

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LNAV and VNAV are independent. They're best used together, but even on a vectored departure (heading bug and go departure), it's probably best to use VNAV. Remember that N1 is a "dumb" mode. Its instruction is literally "set throttle on limits and keep it there." That is it. No further instruction or limit is provided. N1 doesn't know about the 250 restriction. It doesn't know about the airframe limits. It doesn't know what altitude you're leveling off at. It doesn't even care that you have a route programmed in there. Max throttle. Go until told to do something else.

 

Since it doesn't seem you're too familiar with the modes, then you should probably just use VNAV. Once you're more familiar and quick on your feet (and want to add what I'd consider unnecessary complication), then you can use other modes. Some airlines use other methods, like bugging the flap speeds in FL CH as you accelerate (VNAV does this automatically) and climb. This is better with two crew members, so if you have FS2Crew, then it might work for you if you're comfortable with the extra commands.

 

Don't over think it  :wink:

 

I do use VNAV and LNAV with most departures, I hardly ever use N1(kind of forgotten what it does almost) , but occationally FLCH in flight for getting down to a certain FL, when on decent or in climb. I have never used it for a simple departure yet.

 

If VNAV is armed will it do anything if CMDA is off but the A/T is on? Or does it only offer guidence in the PFD? I alway thought CMDA had to be on for those modes to work?

 

When I did my sim session, we did a lot of clicking on the MCP but the CMD A wasn't on alot of the time. I think it was more for reference than anything.

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I usely engage VNAV only once the aircraft is on stabilized climb at 250kt. I ask the FO to select LVL CH after I have asked him to set "Flaps up speed" because I mostly use the NAPD2 and it is to me the easiest way to proceed. If I armed VNAV on ground, it would command 250kt once cleaned above the reduction/acceleration height instead of flaps up speed which I don't want.

When I select LVL CH, it commands N1 and switches to ALT HLD / SPD if I reach the altitude set in the MCP.

I arm VNAV on ground only if I use NAPD1 or no NAPD and/or if there is a lot of traffic and ATC in which I could expect earlier level off or need more attention around and in which case I might forget about the modes.

 

VNAV doesn't need the A/P to be on.

If VNAV is armed and the A/T are on, even if the AP is off, the trust will be commanded according to the phase of the flight (if you are in climb, then N1) and the FD will provide guidance to follow the flight path.

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I do use VNAV and LNAV with most departures, I hardly ever use N1(kind of forgotten what it does almost) , but occationally FLCH in flight for getting down to a certain FL, when on decent or in climb. I have never used it for a simple departure yet.

 

If VNAV is armed will it do anything if CMDA is off but the A/T is on? Or does it only offer guidence in the PFD? I alway thought CMDA had to be on for those modes to work?

 

When I did my sim session, we did a lot of clicking on the MCP but the CMD A wasn't on alot of the time. I think it was more for reference than anything.

 

The F/D drives the autopilot. The F/D, of course, is driven by the active mode as selected/armed by the MCP.

 

Again - don't over think it  :wink:

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VNAV doesn't need the A/P to be on.

If VNAV is armed and the A/T are on, even if the AP is off, the trust will be commanded according to the phase of the flight (if you are in climb, then N1) and the FD will provide guidance to follow the flight path.

 

 

OK when I try this dep again I think I will arm VNAV and have FD on.

 

The F/D drives the autopilot. The F/D, of course, is driven by the active mode as selected/armed by the MCP.

 

Again - don't over think it  :wink:

 

 Sunday PMDG drivers. :wink:

 

I notice other pilots do differnt things, some arm L and V Nav some don't, with different techneques.

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I notice other pilots do differnt things, some arm L and V Nav some don't, with different techneques.

 

Right, but they come equipped with the knowledge of how to properly use those techniques. If you're confused by why you're overspeeding after hitting TOGA and leveling off at an altitude, you are not equipped with this knowledge yet.

 

We're here to give you that knowledge (which, honestly, is the reason I spent so much time explaining these concepts not once, but twice in this thread), but you also have to realize that, when knowledge is being delivered and someone says to not overthink it, they're generally speaking from a position where they recognize you're unnecessarily letting your assumptions get in the way of learning valid knowledge.

 

I know a lot of people don't understand, or point at the underlying learning theories behind what we're discussing here, but they're extremely important. Think of it this way: it can actually be easier to teach real world private pilot students who have not flown in Flight Sim, because they have not picked up bad habits that cloud (or even sometimes block) picking up the new/correct knowledge. Granted, in most cases, teaching simmers to fly in the real world is a lot easier, but training them out of the habit of staring at the gauges during primary training is actually a very real issue. This is the case here: you've picked up the assumption of how the system works from somewhere, and it's not correct. Your comment that you "hardly ever use N1" only further drove this point home for me. You're using N1 every time you hit TOGA (watch the FMA next time right after you hit TOGA, and again when THR HOLD drops). The only difference is that with VNAV armed, VNAV ends up taking over and adding limits to the N1 operation, but you're still in N1 as a thrust mode.

 

So, in response to a few of your comments, I noted that you're overthinking it. Trust us that we're providing you reasonable information. If you prefer not to trust us, at least give us the benefit of the doubt until you can test and verify for yourself, but don't combat the information immediately with more assumptions without first verifying. Chances are, if we knew of limitations to what we're telling you, we would've mentioned them. In this case, you incorrectly assumed selected MCP modes wouldn't work without the AP active. I countered that this wasn't true, explained why, and reminded you to not overthink it, again, on the concept that you're letting false assumptions inhibit learning the correct knowledge.

 

 

 

TL;DR: If someone notes that an assumption is incorrect and explains why, let the knowledge sink in and try to verify it before discounting it, or combating it with more assumptions.

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Right, but they come equipped with the knowledge of how to properly use those techniques. If you're confused by why you're overspeeding after hitting TOGA and leveling off at an altitude, you are not equipped with this knowledge yet.

 

We're here to give you that knowledge (which, honestly, is the reason I spent so much time explaining these concepts not once, but twice in this thread), but you also have to realize that, when knowledge is being delivered and someone says to not overthink it, they're generally speaking from a position where they recognize you're unnecessarily letting your assumptions get in the way of learning valid knowledge.

 

I know a lot of people don't understand, or point at the underlying learning theories behind what we're discussing here, but they're extremely important. Think of it this way: it can actually be easier to teach real world private pilot students who have not flown in Flight Sim, because they have not picked up bad habits that cloud (or even sometimes block) picking up the new/correct knowledge. Granted, in most cases, teaching simmers to fly in the real world is a lot easier, but training them out of the habit of staring at the gauges during primary training is actually a very real issue. This is the case here: you've picked up the assumption of how the system works from somewhere, and it's not correct. Your comment that you "hardly ever use N1" only further drove this point home for me. You're using N1 every time you hit TOGA (watch the FMA next time right after you hit TOGA, and again when THR HOLD drops). The only difference is that with VNAV armed, VNAV ends up taking over and adding limits to the N1 operation, but you're still in N1 as a thrust mode.

 

So, in response to a few of your comments, I noted that you're overthinking it. Trust us that we're providing you reasonable information. If you prefer not to trust us, at least give us the benefit of the doubt until you can test and verify for yourself, but don't combat the information immediately with more assumptions without first verifying. Chances are, if we knew of limitations to what we're telling you, we would've mentioned them. In this case, you incorrectly assumed selected MCP modes wouldn't work without the AP active. I countered that this wasn't true, explained why, and reminded you to not overthink it, again, on the concept that you're letting false assumptions inhibit learning the correct knowledge.

 

 

 

TL;DR: If someone notes that an assumption is incorrect and explains why, let the knowledge sink in and try to verify it before discounting it, or combating it with more assumptions.

 

 

Of course I apreciate your helps, Iam not ignoring what you have said.  One of the pit falls of flight siim  that it can be very insular. Sometime you have to experiment, or make mistakes.

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Since joining BAV I've done EGKK-EGJJ and the return a few time (very sadly since Friday I can no longer use the NG, A319..lets not go there)

 

May I suggest this wa to you. (Its very easy to do if using FS2Crew Reboot, this is a SOP 3 Ryanair SOP, but you will get the idea.)

 

You arm LNAV but not VNAV.

 

You manage speed and flaps. You climb at V2+ 

At the right height you call "bug up"/ you set Flaps up speed and clean up the  flaps.

When you happy to go from there you arm VNAV. Then your speed will go upto 250 under 10k.

 

This way speed never runs away from you and LNAV is your friend. 

 

The other thing I do is e.g EGKK to EGJJ the SID has a 4000ft restriction, I always set the ALT to that, until am cleared to climb if you want to use LNAV/VNAV that will help.

 

 As you might know only climbing to 4000ft/6000ft is common around London. 

 

This way controlling speed yourself is the best option.

 

You are the pilot in control make sure the aircraft does just what you want. Its your Job. The learning is fun.

 

On a side note TOPCAT give Flaps15 for EGJJ as its so short. Nothing wrong with that.

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Since joining BAV I've done EGKK-EGJJ and the return a few time (very sadly since Friday I can no longer use the NG, A319..lets not go there)

 

May I suggest this wa to you. (Its very easy to do if using FS2Crew Reboot, this is a SOP 3 Ryanair SOP, but you will get the idea.)

 

You arm LNAV but not VNAV.

 

You manage speed and flaps. You climb at V2+ 

At the right height you call "bug up"/ you set Flaps up speed and clean up the  flaps.

When you happy to go from there you arm VNAV. Then your speed will go upto 250 under 10k.

 

This way speed never runs away from you and LNAV is your friend. 

 

The other thing I do is e.g EGKK to EGJJ the SID has a 4000ft restriction, I always set the ALT to that, until am cleared to climb if you want to use LNAV/VNAV that will help.

 

 As you might know only climbing to 4000ft/6000ft is common around London. 

 

This way controlling speed yourself is the best option.

 

You are the pilot in control make sure the aircraft does just what you want. Its your Job. The learning is fun.

 

On a side note TOPCAT give Flaps15 for EGJJ as its so short. Nothing wrong with that.

 

Since joining BAV I've done EGKK-EGJJ and the return a few time (very sadly since Friday I can no longer use the NG, A319..lets not go there)

 

 

BA seem to be putting the lid on the 737, all seems to be airbus.

 

You manage speed and flaps. You climb at V2+ 

At the right height you call "bug up"/ you set Flaps up speed and clean up the  flaps.

When you happy to go from there you arm VNAV. Then your speed will go upto 250 under 10k.

 

This way speed never runs away from you and LNAV is your friend. 

 

The other thing I do is e.g EGKK to EGJJ the SID has a 4000ft restriction, I always set the ALT to that, until am cleared to climb if you want to use LNAV/VNAV that will help.

 

 

Well I will definantly arm VNAV and LNAV FD on, as the other guys mentions. This should make the speed restrictions work for sure.

When I have done EGKK to EGJJ I fly the SAM4M or 5J, and that lets you up to 4000f or above by MID. I have been only arming LNAV on that route, I am not sure why this didn't overspeed. I pretty sure I didn't arm VNAV. Anyway lets not assume anything.

 

On a side note TOPCAT give Flaps15 for EGJJ as its so short. Nothing wrong with that.

 

 

The runway is just too short even for flaps 10, you end up just getting the wheels over the fence.

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