Goinv From United Kingdom, joined Jan 2005, 262 posts, RR: 2 Posted (7 years 2 months 3 weeks 5 days 13 hours ago) and read 12546 times:
Hi,
Just upgraded from PMDG B737-700 to B737-800. I find that the 800 series is difficult to slow down. As soon as I get descent clearance I pull the throttles back to idle and usually do a "Level Change" to get the steepest descent at the desired speed.
However, I find that I am now arriving at the airport way too high and having to use speed brakes. I know spped brakes are used in real life - but not on every flight.
How do other PMDG B737-800 series pilots descend?
Your hints / tips are greatly appreciated.
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Gunsontheroof From United States of America, joined Jan 2006, 3462 posts, RR: 11 Reply 2, posted (7 years 2 months 3 weeks 5 days 12 hours ago) and read 12557 times:
I've got the same problem...I usually just ask for a lower cruising altitude and start decending a ways before the T/D. The hot approaches were fun for awhile though...
Qantas744ER From United States of America, joined Jun 2005, 1252 posts, RR: 4 Reply 3, posted (7 years 2 months 3 weeks 5 days 11 hours ago) and read 12545 times:
Hey, I fly the PMDG 747-400, and often the the same problem happens to me because VNAV makes a very tight descent so what you need to do is press on the Hold button in the FMC and put the name of one of the Waypoints about 25Nm to 30Nm away from your destination. Then you can keep on descending with speedbrakes and dont need to worry of coming in to fast and too high so with the holding pattern you have as much time as you want to reach your desired speed and altitude then just press exit hold on the hold page and your plane will return onto the desired course.
Goinv From United Kingdom, joined Jan 2005, 262 posts, RR: 2 Reply 4, posted (7 years 2 months 3 weeks 5 days 10 hours ago) and read 12542 times:
Quoting Qantas744ER (Reply 3): so what you need to do is press on the Hold button in the FMC and put the name of one of the Waypoints about 25Nm to 30Nm away from your destination.
Good idea about the hold - but try telling this to the MSFS ATC
Be who you are, The world was made to measure for your smile. So Smile.
Qantas744ER From United States of America, joined Jun 2005, 1252 posts, RR: 4 Reply 5, posted (7 years 2 months 3 weeks 5 days 3 hours ago) and read 12505 times:
Quoting Goinv (Reply 4): Good idea about the hold - but try telling this to the MSFS ATC
LOL! I dont even talk to those idiots anymore
I fly on VATSIM and its just great
Goinv From United Kingdom, joined Jan 2005, 262 posts, RR: 2 Reply 6, posted (7 years 2 months 3 weeks 5 days 1 hour ago) and read 12495 times:
Just done another flight. Before descent I was cruising at M.078 which equated to 245knots IAS.
This time, when MSFS told be to descend, I maintained the IAS (245 Knots) and used the LVL CHG to get the steepest descent for the speed. I managed to get to the desired level for the ILS at the destination airport some 7 miles before intercepting the ILS. There was a pretty strong headwind so I don't know if this helped.
Normally I would maintain Mach Number (rather than IAS) until the Indicated Airspeed reached 300Knots, then hold 300 Knots until 10000 feet, then hold 250 knots until the ILS.
I'll see what happens on subsequent flights.
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CDreier From United States of America, joined Feb 2006, 65 posts, RR: 0 Reply 7, posted (7 years 2 months 3 weeks 4 days 7 hours ago) and read 12461 times:
Just a thought. Holding 250k to the ILS is way too fast. You should be slowed to perhaps 180 intercepting the localizer, and then down to 160-165 upon interception of the glideslope. Then you reduce as you proceed down the slope to your target landing speed, usually somewhere in the 140-150k range. Atleast that's how it's done in real life, and it works like a charm on my PMDG 737-800.
Gerry From Australia, joined Jul 1999, 241 posts, RR: 1 Reply 8, posted (7 years 2 months 3 weeks 3 days 10 hours ago) and read 12424 times:
Yes, the PMDG series does require a lot of drag in the descent and sometimes not even long deployment of the speed brakes may be enough. Just start the descent using say 1800 fpm on the VS some 10 - 15 Nm before the T/D point. 250 kts is way too fast to intercept an ILS. By the way the LDS 767 does not suffer from this being well behaved in the descent at all times with no speed brakes necessary on the way down.
Mir From United States of America, joined Jan 2004, 19700 posts, RR: 56 Reply 9, posted (7 years 2 months 3 weeks 3 days 8 hours ago) and read 12417 times:
I use VNAV for the descents, and it works pretty well for me. Sometimes I'll need to use speedbrakes if there's a tailwind, but usually not.
-Mir
7 billion, one nation, imagination...it's a beautiful day
SevenHeavy From United Kingdom, joined Mar 2004, 1126 posts, RR: 10 Reply 10, posted (7 years 2 months 3 weeks 14 hours ago) and read 12345 times:
It is also worth reducing airspeed a little before commencing descent. At cruise try slowing to around M0.72 or so before descending. I always control my descent myself rather than let the VNAV take care of it. The generally accepted rule is 3 miles for every thousand feet of altitude.
For example from FL330 you should be in a position to commence descent at 99 miles out.
This is a fair representation of real world handling - the B737NG is notoriously slippery and requires carefull descent planning.
Goinv From United Kingdom, joined Jan 2005, 262 posts, RR: 2 Reply 12, posted (7 years 2 months 2 weeks 6 days 15 hours ago) and read 12292 times:
Quoting Goinv (Reply 6): Normally I would maintain Mach Number (rather than IAS) until the Indicated Airspeed reached 300Knots, then hold 300 Knots until 10000 feet, then hold 250 knots until the ILS.
Just to clarify my orginal post, to be more accurate it should have read
"then hold 250 knots until the ILS intercept altitude" - hopefully this will be a few miles before you intercept the ILS and then I begin a steady decrease in speed until I intercept the ILS (as many pointed out - about 180knts).
Sorry for be misleading - well done to those who spotted it.
Just thought I was driving for WN that's all.
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