737NGX will not climb or achieve FMC settings

[freded 3]

B737-800NG will not exceed 200 KIAS or climb to altitude set in FMC during initial stages of Tutorial 1 flight from EGKK to EHAM.

 

FMC & MCP setup as per Tutorial 1...

Both F/Ds: 'ON'

AP CMD A: 'ON'

A/T: 'ARM'

LNAV: 'ON'

VNAV: 'ON'

N1 'ON'

 

 

Tried turningg A/T off and advancing throttles to full: Speed does not increase above about 208 Knots.

 

Tried using LVL CHG to increase altitude to height-setting in FMC for present leg: A/C climbs but as soon as VNAV is turned on, climb ceases.

 

Now approaching DAGGA where speed should be 257 KIAS and height FL101 (according to FMC), but speed is 200 and alt 6500.

 

Checked that Gear and Flaps are retracted and that Speed Brakes are 'Down'.

 

What is wrong?

 

I have tried this flight three times now with same or similar problems.

 

Mark

[Spin737 102]

What's the TAT say? Could be a weather issue.

 

How about a screen cap?

[fencer 16]

Isn't your plane overloaded ? A screen capture would definitely help.

 

Bruno

[tazisdylan 2]

Are you getting the flaps up indicators on the tape and setting flaps-up speed after T/O? Is your IAS speed set accordingly?

 

Is anything disengaging after T/O either through human error or a conflict of key bindings? Using FSUIPC?

 

By speedbrakes 'down' I hope you mean disarmed.

 

As suggested, a screenie would probably help.

[Guest BeaverDriver]

Well, it won't be weather (the 737 can easily overcome any temperature/density altitude issues you'll find on this planet unless you are horribly over gross) and if you can get it in the air, it should climb. It sounds to me like something is interfering with your thrust levers, pulling the power back on you. I know you pushed the thrust levers up, but what are your N1's actually saying during the climb? Did you somehow build a speed/altitude restriction into your programmed flight path? As the others have said, a screen shot or 3 would really help.

[freded 3]

Thanks, lads.

 

I'll answer your comments:-

 

Spin737: Not weather. I selected scattered clouds, no wind & no precip, as suggested in Tutorial 1.

 

fencer: Aircraft is not overloaded: Fuel 1/3; Pax Full; Cargo 2 x 1500 lbs - all as instructed in Tutorial 1.

 

tazisdylan: Flaps are UP according to gauge and lever-position. IAS set to 250 and AT set.

Yes, I use FSUIPC but no previous problema attributable to this.

Speedbrakes are disarmed.

 

BeaverDriver: After I pushed the thrust levers up, I checked and N1 was well over 90%.

FMC was set up according to Tutorial 1 and agreed with the images shown at each stage. No other speed restrictions were added, apart from those included in the mTutorial.

 

I'll send a screen shot or two if the same errors occur next time I fly the NGX.

 

Mark

[pete_auau 1,153]

whats was your tat reading?

[freded 3]

TAT, as in Total Air Temp?

 

Didn't know it was shown on panel...

 

Probably quite low - the flight is out of Gatwick in May.

 

Mark

[Jeffrey L. Whitaker 0]

Mark,

 

They are asking about TAT because a high TAT can interfere with the climb performance. Consequently, if you are using FSINN and have not selected "Disable Weather by Default", your climb issue may well be the result of higher than expected TAT. Next time you are on climbout, have a look in the upper left corner of the upper display unit. Check your TAT.

 

JW

[pete_auau 1,153]

yea it shown on top left hand side of your right hand side pfd if its very high you will have trouble climbing to your assigned altitude

[scandinavian13 5,192]

Well, it won't be weather (the 737 can easily overcome any temperature/density altitude issues you'll find on this planet unless you are horribly over gross

[Emphasis Mine]

 

That's all well and good, but certain programs that adjust the weather do not do so in an on-this-planet like fashion. FSINN, as an example, has a weather bug that increases temperature as altitude increases. So, while weather might not be a normal assumption on a real aircraft exhibiting these behaviors, it is in the sim for the above reason.

[Guest BeaverDriver]

Fair enough, but bugs notwithstanding, it's not at all unusual to see temperature inversions that can be quite significant in real life. It would take an extremely wild swing of temperatures to cause a 737 to not be able to climb pretty much normally. These airplanes are built to overcome pretty much anything that can be thrown at them, and in the 737 class, it's highly unusual to even have to step climb as you do in the 747 when loaded. The power to weight ratio is just too great. Now, if you are getting a temperature of +50C or higher at 10,000 ft, then maybe you have an issue (and I'd be telling the developer he either fixes a bug of that colossal a magnitude or you'll spread the word that this program should be avoided at all costs), and certainly if you do get very high rises in temperatures your climb rate will suffer, but no way down low should you see what the OP is seeing due to weather. I'm quite certain that you can see 737's, A320's, 747's, etc., etc. taking off at all the tropical airports those planes routinely go into at any time of the day or night and in extremely hot weather. In fact, in the tropics it's unusual NOT to have a pretty good inversion early in the morning and late in the evening (more often the former). If they can do it there, then surely you can get out of Gatwick and climb to cruising altitude at the weights the OP is at without having the 737 even breathing hard, even with unusually high temperatures and a hefty inversion. Something else is going on there, but it ain't weather, again, unless FSINN is really horribly out to lunch, but with temps that you again wouldn't find on this planet. If that IS the case, you can't blame it on the airplane, although I don't think anyone necessarily is at this point.

[scandinavian13 5,192]

Glenn,

 

Definitely. Most of the time, when people bring up the weather issue, it's brought up in defense of the plane. It's also normally associated with not being able to reach a reasonable cruise level, not so much speed and low alts as is the case here.

 

I forget how the tutorial is written in terms of settings, but the flight is supposed to be flown with the values pounds, right? If so, and the plane is configured to expect KG values, it will assume that it's very much over weight and act oddly. Same goes for the inverse.

[Spin737 102]

in the 737 class, it's highly unusual to even have to step climb as you do in the 747 when loaded. The power to weight ratio is just too great.

I had to step a few days ago coming out of KPHX to KSEA. Too heavy for our filed FL380, so we stopped at FL360 for a bit. Happens on the Hawaii flights, too, quite often.

 

It's not every flight, but it's not highly unusual, either.

[Guest BeaverDriver]

What are you flying (not doubting you - just interested)? I know my friend who flies 757's has had to step out of Guyana before but I guess he doesn't do it all that often. But that's a 75, not one of the heavies. But for a 737 I would be surprised to hear it happens very frequently, but I'm not a 73 captain :smile:.

 

That all said, my point though was that there's no way temperature (if they are even close to realistic) would cause the 737 to perform like that down that low in Britain. I'm wondering if maybe a door got left open or something like that. Not likely though. I've done that before and it was 10K before I started to get the aural warning and it didn't take me all that long to get there. Sounds like it might be a gremlin of some kind.