The 600 and 700 fly beautifully in all phases of flight.

 

But the 800 is a beast that doesn't want to slow down. Above FL100 I can set about 280 knot speed and get a good descent rate. But when I need to limit my speed to 250 or below, I just can't keep her slowed down enough to get a good descent rate. Any tips? Do you slow down to around 200-220 and set flaps 1? Do you go with the airbrakes a lot?

 

Thanks

 

David Simpson

I'm sure others will help you better, but yes use flaps to slow you down. The speed brakes don't work that great on the 737, but will help to slow you down. use your gear to create more drag as well, and you can always hold straight and level with idle engines to bleed the speed a lot then you can use higher flaps settings to help with decent steeper.

 

Evan

Descending on time and staying on the descent profile will greatly help with speed, I never had to break out the gear or flaps early when on profile. When using vertical speed I don't go past ~1,300-1,400 fpm at the most (I usually use 1,100-1,200 when I'm below 10K feet) and at those rates the spoilers work alright.

Descending on time and staying on the descent profile will greatly help with speed, I never had to break out the gear or flaps early when on profile. When using vertical speed I don't go past ~1,300-1,400 fpm at the most (I usually use 1,100-1,200 when I'm below 10K feet) and at those rates the spoilers work alright.

 

You must be descending when you want then. Rather than at stages as requested by atc. It's hard to stay on profile when you get different level clearances and vectors. I Just find I can't set 250 knots and a level change to a lower level while getting 1000 fpm descent rate. Only airplane I've ever had a problem with.

Yeah I know the 800 can be a pain to slow down at times. I usually plan to level off before atc assign my next altitude so I can bleed off allot of that airspeed, once at a stable speed I will put down 1-2 degrees of flaps and then wait for atc to issue me a new altitude.

I set 280 knots descent before top of descent, once descent has started and i have gone down about 3000ft i change desncent speed to 310 knots.

 

The aircraft will nose over and achieve lower altitudes quicker but then the descent will be shallow.

 

I find doing it this way i hardly ever need the spoilers.

 

 

Any tips? Do you slow down to around 200-220 and set flaps 1? Do you go with the airbrakes a lot?

 

Thanks

 

David Simpson

 

Your having fun now!

Slowing to 200-220 with flaps 1 or even 5 works well and sometimes is the only option to loose a fair amount of altitude at lower speeds in the shortest distance. It’s just a fact of life at certain airports, Las Vegas for one, that ATC loves to keep you high and fast as long as they can. Try to get down first with the speed brake and no flaps. If you’re still high and fast, go to flaps 1 or 5 and 200-220 KIAS with or without speed brake. I wouldn't go past flaps 5 with speed brakes up. It makes lots of noise and more airframe vibration. You do what you have to do as long as you keep safety and passenger comfort in mind and at the same time, staying within aircraft limitations in the AFM!

You must be descending when you want then. Rather than at stages as requested by atc. It's hard to stay on profile when you get different level clearances and vectors. I Just find I can't set 250 knots and a level change to a lower level while getting 1000 fpm descent rate. Only airplane I've ever had a problem with.

 

In the US I almost always get a "descend at pilots discretion" for top of descent and if they are getting late then I send in a request so I can start my initial descent which is almost always granted, plus the profile does take restrictions into account but if ATC waves them thence I use FLCH and set the speed to 250 and gradually slow down with full spoilers which is not always needed.

 

Vectors don't bother my descent and can help to reduce speed plus I'm starting to see that ATC is using continuous descent more and more as it is more efficient.

David, as you kindly gave me an answer in another post, can I suggest that you put your speed restrictions in the FMC waypoints, i.e lower than 240/10000. That way, as she descends to your approach altitude, she will decelerate as per the VNAV and speed restrictions. That's what I use. I'm assuming that you will have input your V_ref for your last flap position?

Also, try using a lower cost index. 35 seems to work perfectly for me. I only need the use of speedbrakes if I have a tailwind, and even then not very much. Also helps to add a few levels of wind to your descent forecast page.

I remember about a month back when I was talking to a Pilot who flies the 737 for KLM and he was telling me about one time when he was flying near London and ATC told a BA aircraft nearby to descend to FL120 and reduce speed to 250, and the BA Pilot replied "I can even descend or reduce speed, not both at the same time so which one would you like?" :P

I remember about a month back when I was talking to a Pilot who flies the 737 for KLM and he was telling me about one time when he was flying near London and ATC told a BA aircraft nearby to descend to FL120 and reduce speed to 250, and the BA Pilot replied "I can even descend or reduce speed, not both at the same time so which one would you like?" :P

 

 

The meaning from ATC was: Descend to FL120 and just before reaching that level reduce speed to 250. And yes you can reduce speed and descend on the same time. It's a matter of descend rate.

Hi,

 

Are you sure you don't have the problem that the engine N1 is too high because of some throttle (joystik) problem? This has been reported by a couple of people.

 

Best Regards,

Bert Van Bulck

try using a lower cost index.

 

This is what tamed the 800 for me. I use a CI of 25 everywhere now and haven't had a speed issue since..Flying properly is another matter altogether

 

Give it plenty of time, and don't start the decent too late or too fast

What i normally do is when decending after 20.000ft keep my speed around 270 knots i start to pull back abit on the VS and use the speedbrakes to counter this..... after 10000FT speed to 250 240 knots i start to drop the flaps to about 5 then so on this helps me.. The real Bird is very hard to slow down and PMDG have really caught the realism very well