Depends. Just because your climbing at 2000 fpm to your last 1000 ft to go doesn't mean George isn't already starting the level off.
Ok, I'll eat the crow I deserve, or how I learned to love the Bus.
- Thread starter nimslow
- Start date
Depends. Just because your climbing at 2000 fpm to your last 1000 ft to go doesn't mean George isn't already starting the level off.
Cherokee_Cruiser
Bronteroc
I use VS quite a bit on the Bus. Works perfectly. And as mentioned, don't mess with stuff near ALT*
Last edited:
Cherokee_Cruiser
Bronteroc
I understand leaving managed descent, by ya'll know it gives a +/- 20 knot window each side. And the STAR says transition to 280 kts. You set 280 on descent page and are managed descending. Every here and there the speed lags on the bottom magenta line on the speed scale, 20 knots below 280, now you're coming down at 260 kts.
Frequently, I'll just pull speed 280 and then managed descent. Sorcery!
Frequently, I'll just pull speed 280 and then managed descent. Sorcery!
wheelsup
Well-Known Member
I'm too lazy to care. Some would call that bad form. Me? I call it technique. You go a little faster, a little slower, just take the average. It'll work out.I understand leaving managed descent, by ya'll know it gives a +/- 20 knot window each side. And the STAR says transition to 280 kts. You set 280 on descent page and are managed descending. Every here and there the speed lags on the bottom magenta line on the speed scale, 20 knots below 280, now you're coming down at 260 kts.
Frequently, I'll just pull speed 280 and then managed descent. Sorcery!
The most common error, apart from going into V/S to 'smooth out' a climb/descent is being in V/S and constantly tweaking the setting as ALT* engages at a moment you didn't expect.
Personally, if I was an instructor (which I'm not), I'd probably just cover up the MCP and teach my students to reach for the correct control and then set the autopilot while watching the FMA. The MCP is what you want, the FMA is what you're getting.
Cherokee_Cruiser
Bronteroc
What do you call it passing a fix that says AT 280kts while the plane is doing 260?
I usually don't care how people fly and as FO of course I'm not raising alarm bells for things outside of safety of flight. But crossing a fix 20 knots below published restricted airspeed, IMO, is bad form.
That's a gotcha. One shouldn't be tweaking it near ALT* , the time to do that is before and then leave it and let it capture.
Another fine example of when using open descent or managed descent will leave you high is on the Williamsport3 arrival into EWR. Cross SLT at FL310. Typically scenario is we're on a transcon at FL370 and tailwinds of 50-100 knots at that point. If you put SLT at 310 in the box, and set 310 on the FCP, it almost always puts the TOD arrow at exactly 18-19 miles, which is literally a 3 to 1 rule. It doesn't work if you try to start down at the arrow with tailwinds being what they are (strong). The Vdev ball goes low quickly and the power is of course slow to come off. Soon it hits idle, and it's diving down at top of the 20 knot scale in order to chase the ball. It finally ALT* at a fairly high point and starts to level the nose/reduce descent rate. With managed descent and even open descent, Starting down at the TOd arrow which is 18-19 miles away from SLT, I've seen guys cross it at FL314-318. Again, probably not a big deal to ATC considering the plane is leveling and their radar sweep isn't fast enough and they'll probably not notice. You are after all leveling at Fl310. Case like this personally I dial in VS down about 26-28 miles out instead of 18-19, and a rate of about 2200-2500 fpm works great. Ends up crossing SLT at level altitude.
The other technique/finese thing is resetting the vertical dev after crossing a much higher altitude restriction. So same arrival, level at FL310, the Vdev ball continues to go down for HAYED at FL180. But you still have quite some room before you really have to start down. If you don't reset it (re-input crossing altitude at later fix, or swap flaps full to flaps 3 and back to full on Perf page), the Vertical dev doesn't recalculate itself. Managed descent at this point will initially start a dive down until the ball comes in, them it starts to shallow it down to ~500/600fpm. Again, not that big a deal. But it's a finesse thing IMO and just better form/more efficient. If you come down 50 miles sooner because the Vdev wasn't reset, then not that big a deal. If I was CA I wouldn't bug the FO about it. But if I'm flying the leg, I'll do stuff like the above. No CA has complained yet
I'm not sure I understand. Your in Open or Managed Descent. Maybe your descending at 3-4000 fpm and you decide that you'd not like to capture at that descent rate so you'd like to go maybe 1500 rpm. For whatever reason(don't want the engines spooling up too quickly, maybe you ACTUALLY follow the AIM guidance on the last 1000 feet or so cause that's actually a thing, or some other quirky reason). And for the last thousand feet or so you descend at 1500 fpm. What's the issue?
Or are you saying that people are WAITING till ALT* (capture) THEN they are reaching up and dialing a vertical speed? Because that would be pointless since the autopilot is raising the nose to actually level off at the Pre Selected Altitude. And at the perfect rate to reach 0 VS at the Pre-Selected Altitude.
Or are they actually in the process of spinning the VS Knob when the airplane goes into Alt* in which case, I don't think anything would happen unless you pulled the Vertical Speed Knob again. Admittedly I'm not sure on this one. If it ALT* Captures, and you are still spinning the VS Knob but you don't pull it, does that mess up the ALT* Capture?
Last edited:
Nick
Well-Known Member
This is a scenario where it seems to me, FPA is the simplest option. Dial it in and stick the whatever color little thing right on SLT.
Good to know. I had only heard of entering any (current or new) cost index.
The error is generally thinking "maybe I'll intervene" and not realizing that it's gone into ALT* because of the rate.
High risk. Pyrrhic reward. I've just seen it far too much and hate writing ASAPs over entirely preventable shizzle.
Dexter
Hop off there, Blonde Ambition Tour
roundout
VNAV monitor
Bus level: expert
My instructor descried the MCP as "your hot neighbor" and the FMA as "your wife": "This is what you want, this is what you've got" or something like that.
Dexter
Hop off there, Blonde Ambition Tour
My instructor descried the MCP as "your hot neighbor" and the FMA as "your wife": "This is what you want, this is what you've got" or something like that.
Cheers to that
Attachments
Toobdrvr
Estrellas Asesino
Or reset the cruise alt in the prog page. Watch the speed though (likes to slow down). Pro tip: entering any single digit in LSK 1L will set the cruise alt to whatever is in the FCU! No idea why...
Toobdrvr
Estrellas Asesino
Meh. I find it entertaining watching it go "VS, ALT*, VS, ALT*,..." Other guy's saying "what's wrong with this stupid airplane!"
Almost as good as when he's trying to push the alt knob though the glareshield, trying to get "CLB".................in heading mode!
WompWompWaaaaa!!!
Soul Brotha'
Off to go do Black guy stuff
You can also re-enter the temp on the Perf page for it to recalculate. If anyone can tell me why the plane wants to scream down after leveling off and capturing the first altitude when descending on multiple altitudes. It thinks it's high and the hockey stick never readjusts.
jtrain609
Antisocial Monster
There is at least one place you need to do this.
On the CASTA out of LAX, which has since been replaced, you'd be climbing out of LAX at 6,000 FPM to the same place in space that traffic on the SADDE is descending to at a rate lower than this, but sometimes still relatively quickly.
If one or both aircraft don't reduce their rate of climb/descent, you both get an RA as the descending aircraft is leveling at 10,000 and the climbing aircraft is going to 9,000.
I was teaching guys to switch into VS and roll it down to 1,000 FPM around 7,000, since you'd transition from FLCH to VS before you went into ASEL (ALT* on the bus). The training department was teaching guys to keep it in FLCH (OP CLB on the bus) and override the thrust levers to produce a 1,000 FPM climb. The second technique wouldn't really translate very well on the bus, since it'd put you into mixed automation modes.
Last edited:
Nark
Macho Superpilot
Happens all the time in Houston. Chicago, the climb and level off at 5000 doesn't normally do that.
Your new routes out of LAX are generally trans cons, and they depart (generallly) south and west towards Catalina (2/3 of the time were being vectored as soon as we check on with Dep) . You're nearly at 10,000 before crossing LAX towards Dagget.
Yes!
My "retractable dog leash" has gotten real long, so I generally let them run around until they get tired or almost walk down a dangerous, un-saveable path and then, ***ZIP***