What Heavy jet will SWA buy?

[waveflyer]

GL, you're an idiot and from one troll to another- you're a troll.

Jim,
Do you think you could jump seat on us a lot more so this pilot group can get it?

Also, how do you make the "STEEP DESCENT AFTER XXXXX" message go away?

That one confuses me almost every flight

 

[General Lee]

GL, you're an idiot and from one troll to another- you're a troll.

Jim,
Do you think you could jump seat on us a lot more so this pilot group can get it?

Also, how do you make the "STEEP DESCENT AFTER XXXXX" message go away?

That one confuses me almost every flight

An idiot? At least I can use VNAV in Europe. You can do whatever you want in West Texas, but when your FMS says "drag required", you may want to take it's advice or reprogram it. Good luck! How are the auto throttles working out for you guys too? Happy 4th!


Bye Bye---General Lee

 

[SWA Bubba]

If you're talking SWA, I've jump seated in the cockpit enough to know the inability to maintain VNAV path is self induced. When the FMS says "drag required" you have to increase drag. The SWA rule against speedbreaks with any flaps makes that hard to do unless you want to start throwing your landing gear out.

Not exactly. (And I read your later post on the subject as well)

Sorry, Jim, but the inability to maintain VNAV path almost always has nothing to do with drag. It's more to do with the VNAV software we use, and not keeping up with it, or failing to program it properly (incl. descent forecast). However, it happens fairly often even with proper programming. And 98% of the time, inability to maintain VNAV path occurs during 'idle descent' from altitude, and not while in 'geometric descent' in the terminal area, so flaps are not a player here. In 'idle descent,' it will revert to VNAV speed, and you will generally get high on path when it attempts to capture the desired speed first.

If, however, you capture VNAV path in 'geometric descent,' the speed range opens, and vertical path is maintained automatically without regard to airspeed (short of overspeeding the aircraft). The "drag required" message may appear if you're above desired speed, but you will stay on the path; you'll just be fast.

Some observations on your stated 737 theory/techniques, Jim:

-- "Drag required" messages leading to losing VNAV path occur during 'idle descent' from altitude, so using flaps is inappropriate in this regime in the first place. Speedbrakes may be used, or better yet, simply increase the descent speed in FMS or with 'Speed intervention' to regain the path without leaving VNAV or shaking the plane.

-- "Drag required" messages during 'geometric descent' with a captured speed range indicate excessive speed, not an impending departure from the vertical path. Speed brakes may be used if you have to slow down (assigned speed, etc.). However, if somewhat higher speed is not a problem, don't worry about it; you've already paid for that energy, you might as well use it rather than bleeding it off with speedbrakes.

-- using flaps and speedbrakes together puts more stress on the airframe, and causes a pretty good buffeting for your passengers. If you understand the relationship between speed and vertical path during the two types of VNAV descents, than you should be able to avoid using speedbrakes the overwhelming majority of the time, and give your passengers a smoother ride.

-- blindly following "instructions" from your FMS scratch pad (i.e. pulling the speedbrake handle just because the "drag required" message appears) is probably not a good idea in the first place. Understanding the system and how it works goes a long way to making your life easier, and your flight smoother.

At any rate, Jim, I'll grant you that a fair number of our guys don't necessarily use the best techniques with VNAV. I suspect that this stems from being taught from day one to fly the plane one way, and then when SWA finally got around to embracing VNAV, the training these older guys got consisted mainly of assigned self-study. When they're out there, they often revert to the way they "used to do it." But having said that, your response of merely throwing out drag in response to a FMS message isn't always the best idea either.

Bubba

 

[SWA Bubba]

An idiot? At least I can use VNAV in Europe. You can do whatever you want in West Texas, but when your FMS says "drag required", you may want to take it's advice or reprogram it. Good luck! How are the auto throttles working out for you guys too? Happy 4th!


Bye Bye---General Lee

Seriously?

Do all you guys automatically yank on the idiot stick as soon as a "drag required" message pops up?

Bubba

 

[General Lee]

Seriously?

Do all you guys automatically yank on the idiot stick as soon as a "drag required" message pops up?

Bubba

Not always, you can always use other means, like FLCH or increase your speed and descent rate in the CRZ or DES page and still hit a point on speed and altitude, but what I'm saying is that the VNAV is giving you a major hint, and to disregard it is ridiculous. Throwing out a little drag via the spoilers is probably a bit easier, and you don't have to punch in a bunch of numbers.

So, do all of you guys taxi at V1?



Bye Bye---General Lee

 

[scoreboardII]

The other common mistake I've seen SWA pilots do when trying to change speed to stay in VNAV Path is to do so by using speed intervention and then wonder why it goes to VNAV Speed mode. Unless you are in the approach phase within the FMS logic, you need to change the speed within the FMS and not set a manually selected speed. Any other time speed intervention automatically takes it out of VNAV Path.
.

I'm not going to disagree with your other points as we have more than enough Tyrannosaurus Rex pilots trying to make the stuff work. Very amusing mostly...

However, your point above is counter intuitive and against common strategies to make the system work.

We know it goes into VNAV SPD when you select intervention, it's supposed to. That does not mean it's off VNAV profile. If a higher speed is selected, it descends to lowest altitude available, and speeds up, and continues until returned to VNAV un-interventioned.

However, entering a change into the FMC descent speed will cause the system, at least our version (which may be one step above Fred Flinstones version) to hiccup, puke, and probably leave you with a VNAV disconnect.

Additionally, intervention allows you to return to expected speeds as that is the VNAV profile the FMC is referencing. Changing the descent speeds manually buys you zero flexibility end game if they descend you at a higher speed. If they descend you at a slower speed, your comment has some merit, but that is usually not the case and if inside the geometric/idle descent point, you're screwed either way.

Or, I'm wrong, and you need to show me the reference

 

[waveflyer]

Or....
You're flying with a guy who needs to be at 261kts on every descent regardless of SA and will even decline requests to go faster with the "unable" (imagine my surprise when this real cool cat did that- and then smugly said to us - 'they know they're not supposed to be going that fast'
Assume.

So I 'accidentally' get a little high and pretend to fumble a bit-
"Oh, dang it- look what I did- one day I'll get this thing figured out"
Everyone laughs and we come down at a more elegant and cooperative 280-300.

Seriously though, I may hire some of you as flight instructors. If you're really airline pilots, I'll pay your rate to jumpseat with us and give me some good tips and explain how Swa pilots are messing it up.

GL , are you a cfi?

In any case, Bubba chimed in with the appropriate response I'm too ornery to give
Well said-
Maybe, when jumpseating, you might not know exactly how each plane is configured, since Boeing offers dozens of levels of vnav
If you want to critique SWA for dumbing down airplanes...well- that would be big news.
If you want to critique that there are more than a few still trying to fly it like -200, that's even BIGGER news- please tell us who fly with these guys every day ALL about it from your vast jumpseating experience.
Sorry Jim, you've always been a good guy on here - even with me trolling on the always personal acquisition front- which is pretty classless- but I have to give you a hard time for those posts.
You've got to admit, it's sweepingly funny in the context of now 8,000 pilots

 

[waveflyer]

you've already paid for that energy, you might as well use it rather than bleeding it off with speedbrakes.

Bubba

Best thing bubba said-
It is painful seeing some guy pull on the plane shaker just bc vnav path limped up a few knots- especially when we aren't at assigned speeds- just altitudes.
Painful, but happening less and less-

One thing Jim does have correct is that it has and will take a few years for ALL of us to get the memo on changes-
Good thing we haven't changed much in 40 years
:-/

 

[BILL LUMBERG]

All this fire from the boys who just got auto throttles and VNAV!

I'm sure the 37 community thanks you for making sure they still have to turn on pitot heat manually. (Let's be honest, the NG was just appeasing SWA)

 

[redflyer65]

O'Good Lord. Southwest flies 3 thousand 500 flights everyday and you guys are acting like we can't fly? Odds are, we put in more flights and flight hours than most of you guys combined.

And Bill, we've been using VNAV and throttles now for 4 years, but you keep acting like we 'just turned them on'.