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787WannabePilot

Some advice for descent and slowing down...

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Approximately how far how do you decide to "dial in" your speed to start slowing down through the "flap phases" ?

 

Seems I run into issues when dialing the speed down, that the AP kicks in VNAV Speed (instead of path), forcing the plane to slow down by leveling off, causing me to come in a bit high in the flight path.

 

Or is the only way to combat this is to use the speedbrakes? (Which I have been doing.. but trying to find a more gradual way of slowing down).

 

Thanks.

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The speedbrakes are on the plane to be used.

 

Since it is all a function of distance, altitude and speed you have to juggle around with these a little bit.

 

What I usually do is to anticipate any speed and altitude constraints to plan the descent and use the speedbrakes when necessary. So if I need to be slow at a certain point but have no intermediate altitude constraint in the way, I just switch to FLCH to expedite the descent and then slow down, once the airplane levels off. At idle thrust you can bleed of some altitude quickly at the expense of more speed and thus less distance to waypoint remaining.

 

If approach procedures force you along a very narrowly defined descent corridor, you will have to use what ever is at your disposal, including the speedbrakes. What you can also do is to slow down before you start the descent, which can ultimately throw your fuel figures off a bit, as you won't be descending on idle thrust most of the time.

 

Once you are slow enough you can also use the flaps for added drag. But people on the ground will thank you if you don't. Unless they are aviation nuts. ;)

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It took practice. I have found that if I wait until within five to ten miles of the final approach course, I am able to start dialing in a Flaps-1 speed like 210 without pitch going from PATH to SPD. If you're not dropping like a rock it does not take far to slow down to flap speeds, I seldom have problems getting to Flaps-15 where gear down will end any concerns for slowing down.

 

Also, dropping your gear early is a perfectly good technique if you find yourself high and fast. Just don't be too fast and blow the gear doors off. That ###### off the chief pilot.

 

Some approaches, like the slam-dunk into KSFO or dropping into KONT, simply require practice.

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It's hard to slow down while descending without pitching up. I generally start to decelerate when I level off prior to intercepting the localiser. That way there is no conflict with VNAV and speedbrake use can usually be avoided. It can be a bit more challenging to do when ATC is giving you speed restrictions on the approach.

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In addition to other suggestions, start extending flaps when slow enough to do so w/out damaging flaps (below placard speed for a given flap setting), not when your (slowing) speed requires you to do so. 

 

Also remember that you can use partial speed brake.

 

Mike


 

 


Some approaches, like the slam-dunk into KSFO or dropping into KONT, simply require practice.

 

Hi, Dan,

 

I know this is a RW practice at SFO, but does it ever happen in the sim?  Is there an RNAV approach that will do this?

 

Thanks,

Mike

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I know this is a RW practice at SFO, but does it ever happen in the sim?  Is there an RNAV approach that will do this?

 

It's more the STAR than the approach. I can't think of any approach in the United States that would use an aggressive descent. Approaches are designed to be very stable. A slam dunk would not be stable. Granted, there are some with steeper glidepaths/slopes, but any time people talk "slam dunk" they're referring to STARs (or ATC instructions that approximate STARs), as far as I'm aware.

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Proper performance calculation and entering accurate data in the "DES FORECAST" page of the CDU is key for a stable and on-path descent or approach. Especially in bad weather conditions! 

PMDG has great uplink features for that so the only thing you have to do is request and load the data and cross-check it with your OFP. Done.  

 

And even if you get off the desired path for whatever reasons, there's nothing you can't solve with some good 'ol drag (speedbrakes, flaps, gear extension...retractable landing lights...on the MD-80 at least :P )

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Proper performance calculation and entering accurate data in the "DES FORECAST" page of the CDU is key for a stable and on-path descent or approach. Especially in bad weather conditions! 
PMDG has great uplink features for that so the only thing you have to do is request and load the data and cross-check it with your OFP. Done.  

 

Those definitely help.

 

Love the new profile pic, btw.

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Those definitely help.

 

Love the new profile pic, btw.

 

Thanks. I just love old stuff...especially the piston engine DC's.

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In addition to other suggestions, start extending flaps when slow enough to do so w/out damaging flaps (below placard speed for a given flap setting), not when your (slowing) speed requires you to do so. 

 

Also remember that you can use partial speed brake.

 

Mike

 

 

 

 

Hi, Dan,

 

I know this is a RW practice at SFO, but does it ever happen in the sim?  Is there an RNAV approach that will do this?

 

Thanks,

Mike

For two days now, I've been unable to QUOTE in AVSIM... it's a pain in the ***.

Sorry about the last post.... Tom made me do it.

 

Anyway... the charted arrival (not approach, thank you Kyle for being ever so vigilant) is Ziggy into Ontario CA KONT. You stay high over the San Bernardino mountains then drop directly into the FAF for the West approaches.

 

Uncharted but practiced most every day by SFO approach is the Golden Gate arrival landing 28R.. you stay above 10000 until abeam SFO then drop to 6000 before turning base. Lots of fun. The high arrival is to give clearance to O

akland traffic departing West below you.

 

 

EDIT: Well, now Tom tricked me... first time I posted it was just the quote. Second time, without quoting, I get both quote and text I've added. Interesting.

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thank you Kyle for being ever so vigilant

 

Welcome - figured I'd clarify since I saw what you were getting at.

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Here are some tips from Ken Pascoe's website - (RW 777 Driver w/ Virgin Australia)

 

http://www.infinidim.org/managing-the-mass-b777

 

I have the day off on Friday, I plan on trying Flaps 5/ Flaps 5 speed down the glideslope (3 degree) approach to see if I can handle it. [i usually fly my landings manually from 5,000 feet down]  Right now I'm at more of a flaps 20 and  gear down the glide slope level.  One of the things he points out is, quoting loosely, a profile like this (Flap 5, Flap 5 speed) any distraction could foul up the approach.

 

Richard

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