Fly however you want to fly, its totally up to you. If you don't like my advice then don't take it.

He doesn't need your advice since he flies this aircraft for a living.

I would show more deference to someone at his experience level, we certainly need such guys around on this forum.

And that FORCAST page is not a make/break I find to be a rather significant point, a constructive debate is beneficial to many here whether you approve of it or not.

That seems a bit excessive doesn't it? CI's between 15 and 45 are the norm

 

It's only excessive in the terms that it burns more fuel than the bean counters

would like.. :|

If you use a high CI, it will account for the change in speeds, and the results

*should* pan out just as well as the low CI.

I've done flights with the CI all over the map, and never had any problems,

even on short routes.

That said, I tend to use fairly low CI's these days, just to mimic the usual

bean counter induced stingyness on fuel burn.

I've been running the Southwest routes pretty low lately. 20-36 depending..

But I still prefer 40-45 with my 600 BBJ..

Anyway, I don't agree with blaming a high CI on not being able to slow down

for the approach.. It's not the CI per say.. It's other issues. Or I think anyway.

Fly however you want to fly, its totally up to you. If you don't like my advice then don't take it.

 

I simply offered the guy an answer to his question. Without asking for a debate.

 

V/S- The simmers favourite choice.

 

I lurk here as a source for good questions mostly. I hope to get on the instructing side some time down the road, so it's good to hear different ideas and then crack the books or the logbook for answers.

He doesn't need your advice since he flies this aircraft for a living.

I would show more deference to someone at his experience level, we certainly need such guys around on this forum.

And that FORCAST page is not a make/break I find to be a rather significant point, a constructive debate is beneficial to many here whether you approve of it or not.

No need for deference. I just like to throw in some RW experience and I hope it's helpful. I learned something a few weeks ago from some simmer on this forum, so what comes around, goes around.

Drop the anchor (the landing gear) for increased drag. Its far more efficient at helping the plane slow down than the speed brakes. AFAIK speed brakes are never used while the flaps are extended.

Drop the anchor (the landing gear) for increased drag. Its far more efficient at helping the plane slow down than the speed brakes. AFAIK speed brakes are never used while the flaps are extended.

Not more than 10 degrees with speedbrakes per Boeing. Some companies do prohibit flaps and speedbrakes.

I have also struggled to slow the -800 down when preparing for an approach and particularly when throwing the boards out.

 

I'm new to the 737 but have previously flown the 744 on PS1 and then PMDG for almost 15 years so I know how to plan a descent and get it down on profile.

 

I agree with the other posters who said the -800 is a slippery beast! Got myself into a bit of trouble on approach to LPMA/FNC last night when I couldn't get the damned thing to slow down like I wanted. I like to switch from VNAV to V/S below 10k and I was descending at 500fpm and she still took her time to bleed off the speed.

 

It's going to be a nice challenge to get my descents sorted!

Fly however you want to fly, its totally up to you. If you don't like my advice then don't take it.

 

I simply offered the guy an answer to his question. Without asking for a debate.

 

V/S- The simmers favourite choice.

 

Spin 737 is a real 737 pilot so whatever infos he deploys those are diamonds for us.

 

Told that, I use a C.I. of 90 because I like to go fast even if I know that in the reality the C.I. is usually between 10 and 30.

 

In the reality the FORECAST is properly filled I know but within NGX it is not so important in fact it doesn't, never , affect my descents and I use the speed brakes only every now and then when I judge it is required therefore a debate IMO is not a bad thing, above all in a hi-fi flight simulation forum ^_^

 

p.s. I do not trust very much the wind in FSX so the FORECAST to me sounds more as an optional feature.

If you play with the FORECAST page on ground, with a route planned, and watching the TD, you will see great differences in T/D point filling the forecast pages. Obviously, there must be head/tail wind and/or ice conditions to see big differences, but, if you try strong winds and put the AI on for almost all the descent, you will see the T/D moving of miles away from its original position. This TD movement reflect to a different descent angle, so a different aircraft decelleration tendency.

It is something that is simulated in the NGX, if you have AI on and you've not forecasted it, you will overshoot your speed and speedbrakes must be mantained for long time to mantain speed.

Same for winds, fsx default winds are not so good, but with external programs you will see a difference.

I have REX E but how can you be sure that a forecasted wind ( inserted into the FMC when on ground ) can be the same of the one you will face hundreds of miles away ?

I have REX E but how can you be sure that a forecasted wind ( inserted into the FMC when on ground ) can be the same of the one you will face hundreds of miles away ?

You cant. That is why it is called a forcast not a fact. By entering the best information you have, you get the best plan available. As you get more and better information, you update and refine your plan.

 

Also consider getting AS2012. REX E has prettier pictures then AS2012, but its weather engine doesn't compare.

6 years later I have a question regarding this and the question still stands despite all the advice here about C.I. and TOD.

I was just forced into doing a 1080º spiral by the PMDG 738 in P3D because apparently, at thrusts idle (39% N1), speed brakes full, 1400fpm, that yields 250 knots and impossible to go slower.

Then on the approach at 160kts* about to capture glide I had 25º flaps and even then my nose-up was 10º in level flight.

Is gravity in P3D set to that of Jupiter or something?

 

*Would have liked slower but alas the 738 wouldn't allow

 

EDIT: I would have deleted this but I've just read a few other pieces online about how apparently this is just how the 738 is, and that 1200fpm yields 250kts at idle, particularly winglet versions. https://aviation.stackexchange.com/questions/1265/is-the-descent-performance-of-the-pmdg-737-800-accurate

Guess I'll adjust my ATC program to give me a quicker TOD!

9 minutes ago, JKawai said:

at thrusts idle (39% N1)

What was your altitude? 39% N1 seems a bit high to me for idle thrust at low altitude. Did you check the thrust levers were fully retarded?

There is a limitation in the sim where the thrust levers are fully retarded only below FL300. Above that even pressing F1 doesn't bring the levers fully back.

So if you retard the levers above FL300 and doesn't press F1 or move the levers forth and back to bring them to full idle once passed below FL300, you will have an above idle thrust remaining.

Just now, Budbud said:

What was your altitude? 39% N1 seems a bit high to me for idle thrust at low altitude. Did you check the thrust levers were fully retarded?

There is a limitation in the sim where the thrust levers are only fully retarded below FL300. Above that even pressing F1 doesn't bring the levers fully back.

So if you retard the levers above FL300 and doesn't press F1 or move the levers forth and back to bring them to full idle, you will have an above idle thrust remaining.

Thanks very much for this - It was FL260 onward. Thrust levers definitely fully retarded. I've read somewhere though that at this sort of altitude 40% idle is about right? I'll have a fiddle next time and see if I can get it lower, I wonder if it's worth me calibrating my Saitek to have 'headroom' at the idle end?

Just tried FL350 and idle was 50%...

Skip to 0:23 in this video I did demonstrating PF3 being ridiculous and you'll see I'm doing 260kts at flight idle with spoilers up, not even descending. Just utterly ridiculous and out of control. 39% is idle apparently (on the ground 20% is idle). 39% should never yield 260kts spoilers up level flight anyway.