jgoggi

Any news on HOLD mode bug at takeoff?

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Hi, just out of curiosity, how is the fixing of the increasing thrust during HOLD mode at takeoff going? Did you manage to find out what it is caused by? I suppose you have been working on it for more than 4 months, now, it must really be a tough issue.

Thanks.

 

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7 minutes ago, jgoggi said:

Hi, just out of curiosity, how is the fixing of the increasing thrust during HOLD mode at takeoff going? Did you manage to find out what it is caused by? I suppose you have been working on it for more than 4 months, now, it must really be a tough issue.

Thanks.

 

Since the NGX had just released and the recent 744 update was just a minor fix, it probably wasn't included since attention was all on the NGX. I reckon the next big updates for the 744 (possibly in line for the 748 release) might include it. 

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Oh not again.... come on James, they are working on it and it is not a high-priority fix. Hell, it is probably within the allowable margin of sensor error on the real aircraft.

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Oh, great. Here we go again. I don't know how many times everyone has to tell you, PMDG included, that if it was an easy fix, it would have already been fixed. The fact that it still hasn't been fixed yet is likely because it isn't an easy fix. Pestering them again and again isn't going to make it get solved any faster, and I think Kyle asked you to knock it off. Really, the only person who is fixated on the EICAS screen on take-off for whatever reason is you. Like I've said before, although it has been acknowledged that the issue is there, I have never personally noticed it unless I was going back through my videos actively looking for it. On take-off, I have more pressing matters to worry about than a minor thrust increase.

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11 minutes ago, jgoggi said:

Hi, just out of curiosity, how is the fixing of the increasing thrust during HOLD mode at takeoff going? Did you manage to find out what it is caused by? I suppose you have been working on it for more than 4 months, now, it must really be a tough issue.

Thanks.

 

James, please enlighten me...

I assume you've already submitted a ticket to the PMDG Support Staff regarding this, correct? If that is the case, why do you keep making new topics regarding this, when the PMDG team is already aware of this issue and are working on it. 

I'm terribly sorry, but quite frankly I fail to understand your logic behind these posts? You have (of course) every right to do so - I simply don't understand what you hope to accomplish...

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Please, could the question be directed only to PMDG? Thanks. Since the only known fact is that they are working on it, I was just curious if they are still facing problems with the issue and trying to fix it or if it has already been solved and will be included in a next update. Once again, please, refrain from replying unless you are from PMDG and know what is being done with it. I will skip reading any reply that is not from PMDG. If they reply, I will say thank you, if they don't, ok, it was just a curiosity, since I did not think it was such a hard issue that after almost 5 months a solution was not found yet. Thank you!

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Just now, jgoggi said:

Please, could the question be directed only to PMDG? Thanks. Since the only known fact is that they are working on it, I was just curious if they are still facing problems with the issue and trying to fix it or if it has already been solved and will be included in a next update. 

1. If you only want PMDG to respond, reply to your support ticket in their system. Not on the forum...

2. If they have not yet fixed it, then, ergo, they must still be working on it, ergo, they have nothing to report.... but perhaps Kyle will be along shortly to indulge you.

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2 minutes ago, jgoggi said:

Please, could the question be directed only to PMDG? Thanks. Since the only known fact is that they are working on it, I was just curious if they are still facing problems with the issue and trying to fix it or if it has already been solved and will be included in a next update. Once again, please, refrain from replying unless you are from PMDG and know what is being done with it. Thank you!

James we are not going through this every time there is an update. PMDG are not going to come on these forums after every update and give you specifically an update on when it will be done. I thought we were being reasonable about this, I thought you had accepted the fact that it was getting worked on. It doesn't take a genius to realise that if it wasn't included in the latest fix, it isn't ready yet. And please, stop shutting everyone down who replies and demanding only a response from PMDG. You've been given a response countless times and it's still the same, just because you're a customer doesn't mean you have the right to demand a response from PMDG. If you want an official response, submit another support ticket.

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Quite strange though...

Mighty PMDG and some pesky bug during hold mode on TOGA, when O see those numbers N1 exceed the set max I get agitated.

Aarghh not again... come onnnnnm

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42 minutes ago, jgoggi said:

Please, could the question be directed only to PMDG? Thanks.

No. As has been stated the last time you said this, you're posting this in a public forum, where anybody can respond. If you only want PMDG to respond, you need to submit a support ticket. Ignore everyone else if you wish, but you still have to follow the rules here.

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The thrust increasing is a natural effect seen on every jet aircraft i have flown.

The throttle hold mode(note its NOT thrust hold) is a mode whereby the autothrottle sets the limit thrust(Thrust ref)...on reaching HOLD(65-80 kts airframe dependent) speed the autothrust no longer can modify engine thrust. Ie it sets the thrust then depowers the servos to the thrust levers to ensure an autothrottle issue cannot reduce thrust.

It isnt an active system ie continually keeping the thrust the same like the Airbus system which continually maintains the desired EPR or N1.

As the aircraft with thrust set accelerates and the autothrottle in hold and no ability to adjust thrust accelerates ram effect will increase engine rpm ie N1 and can change EPR.

Here is an extract from our 787 manual...the 747/777/767/757 are all identical in application of Throttle Hold mode.

Quote...

The PM should verify that takeoff thrust has been set and the throttle hold mode (HOLD) is engaged. Once HOLD annunciates, the autothrottle cannot change thrust lever position, but thrust levers can be positioned manually. The HOLD mode remains engaged until VNAV engagement or another thrust mode is selected. 
Note: Takeoff into headwind of 20 knots or greater may result in HOLD before the autothrottle can make final thrust adjustments. 

The HOLD mode protects against thrust lever movement if a system fault occurs. Lack of the HOLD annunciation means the protective feature may not be active. If HOLD annunciation does not appear, no crew action is required unless a subsequent system fault causes unwanted thrust lever movement. As with any autothrottle malfunction, the autothrottle should then be disconnected and desired thrust set manually.

 

The engines spinning up due to Ram effect occurs on EVERY engine on every jet out there. As you can see its not a THRUST HOLD function but THROTTLE HOLD designed to not hold a set thrust setting but depower the autothrottle servos and stop a malfunction reducing thrust catastrophically.

 

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PS and a video in HD of the 747 which clearlybshows the drift away from the Thr Ref setting during the take off roll. Its in HD and if you screenshot the Vid yiu can zoom in and see thst after Thr Hold engages the EPR and rpm change.

Enjoy...

 

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4 hours ago, Captain Kevin said:

Oh, great. Here we go again. I don't know how many times everyone has to tell you, PMDG included, that if it was an easy fix, it would have already been fixed. The fact that it still hasn't been fixed yet is likely because it isn't an easy fix. Pestering them again and again isn't going to make it get solved any faster, and I think Kyle asked you to knock it off. Really, the only person who is fixated on the EICAS screen on take-off for whatever reason is you. Like I've said before, although it has been acknowledged that the issue is there, I have never personally noticed it unless I was going back through my videos actively looking for it. On take-off, I have more pressing matters to worry about than a minor thrust increase.

You have made your point in several topics, no need to go all over it again it seems to me you like your own sound in this forum. Give it a break please.

Mo Dez

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54 minutes ago, DEHowie said:

PS and a video in HD of the 747 which clearly shows the drift away from the Thr Ref setting during the take off roll.

Doesn't seem to me like you say. Look at min. 3:00: N1 after HOLD engagement is about 90.1 and at lift off it even decreases to 89.9, anyway remains we can say constant between 89.9 and 90.1. You can see many real life videos on Youtube and you can realize that after HOLD engagement N1 remains more or less constant. Now go and see what our 747 does....

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1 hour ago, EGLL said:

it seems to me you like your own sound in this forum.

WEL, no, not really, considering it's a little difficult to hear text on a forum. In any event, I'm not entirely too clear on what his point in bringing this issue up again was when it was established some time ago by Kyle that it was not an easy fix. Incidentally, I wasn't even the first one to respond to this.

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Im telling you how it is in the real world. 

You need to get it that it is NOT a THRUST HOLD function on the Boeing like it is on an Airbus.

On a 320 and 330 which have a N1 or EPR hold function which is continually active and constant EPR you will see up to a 2% increase in N1 simply caused by ram effect on an EPR monitored aircraft. Now this is on a plane which IS maintaining a thrust setting.

The Boeing is NOT it is simply holding the thrust levers in whatever position they where in when the Throttle hold speed was passed. Hence there will be an increase in thrust due to RAM effect as the aircraft accelerates after it has passed the Throttle Hold speed. If your departing in strong headwinds you WILL need to set take off thrust by hand frequently after throttle hold has engaged as the aircraft will pass that airspeed at very low groundspeed.

Now whether P3D or Pmdg's logic is completely accurate is a different discussion with regard to the amount of spool up.

However the concept that the model is not accurate because thrust values increasing after throttle hold engages is NOT correct.

It is expected and does happen in the real world and a bug it isnt.

It is only prevalent between Throttle Hold and 400' AGL when Thrust Ref re-engages with Vnav.

Very observant mate but the Boeing autothrottle system has some weird "features" like Throttle hold, its numerous Vnav modes many which are counter intuitive and have traps awaiting every corner.

Converting from Airbus to Boeing for me is an eye rolling experience..lol..Airbus autothrust..its on or off easy. Boeing autothrust...its on then off but not really off then its back on..mostly..but if you move the thrust levers its on and off until you really need it then its definitely off and the toga button works most of the time except when you really need it.

Any wonder the NTSB ripped them apart...

 

 

 

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19 minutes ago, Captain Kevin said:

WEL, no, not really, considering it's a little difficult to hear text on a forum. In any event, I'm not entirely too clear on what his point in bringing this issue up again was when it was established some time ago by Kyle that it was not an easy fix. Incidentally, I wasn't even the first one to respond to this.

:biggrin: Yes Kevin, but he is a PMDG customer and he is entitled to ask as many times he wants to.
If he doesn't get a message, from the forum member is no point keep repeating he is not going to listen to any one.

All the best

Mo Dez

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8 minutes ago, DEHowie said:

However the concept that the model is not accurate because thrust values increasing after throttle hold engages is NOT correct.

It is expected and does happen in the real world and a bug it isnt.

 

Darren, I appreciate your effort to get a logic explanation, but please, let's not discuss whether it's a bug or not, it has widely been aknowledged that it IS a bug, no doubt. No real life 747-400 (and not even the Aerowinx PSX, that is another very faithful copy of a real life 747-400) has that behaviour of constantly increasing N1 between 80 knots and 400 ft...

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James, as a peanut-gallery observer, I gather Darren is an actual 747 pilot, and bases his answers on his experience with an actual aircraft. May I politely inquire whether you are arguing from the same position, i.e. you fly 747, and notice discrepancies; or are you just detail-oriented flightsim enthusiast as many of us are? Darren, also, please correct me if I am wrong in my assumption. 

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7 hours ago, EGLL said:

:biggrin: Yes Kevin, but he is a PMDG customer and he is entitled to ask as many times he wants to.
If he doesn't get a message, from the forum member is no point keep repeating he is not going to listen to any one.

Asking is one thing, but being a paying customer doesn't give anybody the right to be disrespectful, either. The last few posts he made regarding the matter made it seem like it was either an easy fix or PMDG was somehow being the bad guy by intentionally withholding the fix, in which neither is the case. At one point, he even expected that this issue should be treated with the highest priority and everybody should just drop whatever else they're doing. That I have a problem with, especially seeing that there were people out there that had issues where they actually weren't able to fly the plane. As far as I'm concerned, those issues are the ones that need to be dealt with first.

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9 hours ago, jgoggi said:

No real life 747-400

Unless you have experience, how can you say that? I will take the word from someone like Darren who is clearly qualified on this equipment and is experienced, over enthusiasts who spend hours analysing Youtube videos. Why not just give it a rest until PMDG give a firm position on the matter. Quite frankly, you're starting to make yourself look silly.

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1 hour ago, Captain Kevin said:

Asking is one thing, but being a paying customer doesn't give anybody the right to be disrespectful, either. The last few posts he made regarding the matter made it seem like it was either an easy fix or PMDG was somehow being the bad guy by intentionally withholding the fix, in which neither is the case. At one point, he even expected that this issue should be treated with the highest priority and everybody should just drop whatever else they're doing. That I have a problem with, especially seeing that there were people out there that had issues where they actually weren't able to fly the plane. As far as I'm concerned, those issues are the ones that need to be dealt with first.

I for one find the autobrake issue with 777 a much more noticable, yet I am fine waiting for the fix.

 

It's software. It will be riddled with bugs. And that's OK. Whoever claims software has no bugs, clearly has no idea what they're talking about :-). That, too, is OK.

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9 minutes ago, icemarkom said:

I for one find the autobrake issue with 777 a much more noticable, yet I am fine waiting for the fix.

Exactly.

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How about PMDG gives James the source code for the autothrottle system and lets him solve the problem if it's such a quick and easy fix.

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