Randy, I told you my english was not very good.In the first and last items, in which you said I was not correct, I wanted to say exactly what you said. :) (I always thought my english teachers were not good enough for me to write in the AVSIM forum LOL :() In the first item, when I said that the plane follows the descent rate, that descent rate is calculated to keep SPEED, as you said (and as I wanted to say ;)). In the last one, I really wanted to say the same thing you did: in SPD mode, you would never need to deploy speed brakes nor the thrust system would need to increase thrust to maintain speed.In the second one, I admit I was incorrect.

I think I am finding that if I lower or reduce the FMC generated ALT/SPD restrictions that are developed from filling in the PERF INIT screen and I insert such modifications, working backwards from the last waypoint in the flightplan before landing, to around 12,000', this generates "DECEL" (deceleration) indicators on the Nav Display for selected waypoints that are very helpful in controlling my speed on the way down in such a manner that overspeed is quite difficult.With regard to spoilers, we learned during our UNITED sim time at AVSIM-Denver that there's no shame in throwing out the barn doors. Sometimes, it's just got to be done for various reasons. I feel a lot better now about using them !Jonathan

If you read the Pprune forums (http://www.pprune.org/forumssearch "VNAV" on the tech log forum), you see that the real 737NG pilots have also problems with the descent speed.So the Pmdg 737 seems to simulate things very well.Some examples from Pprune:"Howdy all.... Just started polling around 737 Ng series [700/800] and having never flown jets before am having a little trouble on descents. Tell me folks what do you think is the best profile or method to descend these things???I've heard and been shown a few methods..ie starting descent early so that it will hold the profile in VNAV Path, using Speed in leiu of path etc, etc. It appears with a bit of a tailwind the Aircraft wont hold VNAV Path and tends to go into ' overspeed disconnect' fairly early on descent. Any thoughts, profiles from experience, FMC manipulations, methods or calculations that may help the process would be appreciated""I certainly do not know all the answers, however,Nothing you put in the FMC will make any difference. On the descent page there is provision for anti-ice on and off levels but as the VOL 2 states it does not affect the a/c performance.Most jet jockeys that have been around for a while will tell you that having "gates" on your descent is the way to go. I.E. an ALT at a given distance. It is simple mental gymnastics that provide a simple back up to what the FMC is doing. NEVER EVER have total blind faith in the FMC! The FMC always flies a 3 degree profile in path and will generally hit profile limits pretty close to the mark. You have probably found that the heavier the a/c the more difficult it is to hold speed when descending in path. Some pilots swear by speed at all times and forget about the path (as long as they are above or below any limiting steps). I always put 500 feet below a AT or BELOW step on a STAR. This will account for any speed or path excursions that you have to fix at short notice, ATC restrictions etc.Dont be affraid to use the airbrake at the higher levels if the speed starts to get away from you. Disregard the "he man" B.S. some testosterone heads carry on with about using the airbrake. It is there for a reason. I have found that overspeed disconnect is generally only a problem at higher levels. I never descend early for no other reason than economy, although that can be argued against as the saving is minimal. I rarely have disconnect problems any more due to a bit of experimentation, and as I said they all started at higher levels (above 30,000 feet).""Most guys here use the DES NOW prompt and start down a bit earlier than normal to keep the speed from running away, especially at the higher levels (>35K). I only put in descent tailwinds above say 30 kts but normally anticipate going to FLCH around ten grand.Program in a sensible descent speed(I don't know what CI you use, we're around twenty), we leave the Mach No and change the IAS to 280 kts. SOP is 250kts below 10k also so we leave that in at the planning stage.If you program say 315 kts it limits the margin to increase speed to gain the path if you end up getting high.I'm not that keen on getting above 300 kts now as we can't use the speedbrake there, so unexpected turbulence at >300kts is more of a consideration now.The speed brake isn't ideal but often it's the only sensible option, it's there so use it if you need to.Keep the track miles updated and use 3 x height plus tailwinds/ Anti ice and a few miles in proportion to speed.This may be a conservative approach to descent planning but it serves me well and keeps the stress levels down.""Monitor the FMC using the following:Press the Metres button - use the readout to give the track miles required to touchdown. It gives you a little over 3 x FL at height (which allows for the greater speed) and closer to 3 x Ht as you get closer to mother earth.Less than 250kts requires exactly 3 x Ht for a constant descent approach. Works every time (sensible correction for wind). "If you get a VNAV overspeed disconnect, going to Lvl Chg and increasing speed is not always a good option.Speedbrakes are fitted in this aircraft to be used if required. All speedbrakes are uncomfortable for God's sake.Getting high in the latter stages of an approach in this aircraft is most definately the wrong place to be.Practice the fast and high approach procedures any day at BCN when Rwy 07 in use!!!!!!!!!!""I use descend now at about 20 nm to run to the descent point.I also put a QNH of about 8 hPa higher than the ATIS. This has the speed sitting at about 7-8 knots below bug (in path). This gives you the option of going to speed or lvl chg to increase the ROD (it will accelerate to pickup that 7-8 knots thus increasing ROD).I have found that this works really well and I only very rarely have an overspeed disconnect.many guys use speed rather than path and forget to monitor the vertical restrictions on STARS, and get embarrased at the last minute....""I program the VNAV descent page for .79/300kts. I display the VNAV descent page and keep an eye on 4R, which displays V/S required to make what's displayed in 3R.Simple technique. Comfortable, elegant and in control. When the V/S required reads 2000'/min....I ask ATC for descent clearance. This is generally 20-40 miles from top of descent point T/D, depending on winds. No wind results in a V/B vertical bearing of approximately 2.7 degrees. Result is a part-throttle descent. No brainer.It can be tough to slow down and get down in an NG. I find the speedbrakes to be ineffective in all phases of flight and generally ARM them before descent and rarely use them until landing. The best way to slow down, get down is to level off. Much more effective than speedbrakes. Just go V/S = 0, then when lyour within 10 kts of your speed, hit level change. Elegant and effective.I'll only use VNAV for climbs, approaches or complex SIDS. Keeping an eye on 4R gives you performance that's as good as VNAV without the extra degree of separtion caused by automation. You actually feel like your in charge and not the computer."Interesting, isn't it?Guy

Yes, it is. A little bit OT. but.. I have been a long time reader on the Pprune forum, and to some extent, they are discussing the very same issues as here on our forum, and with the same solutions! Sometimes I have to look in the header to see which forum I am in...:-) You may also pick up some good tips from the "testosterone jockeys" over there, but mostly the topics that concern us are already well covered in our forum.This also tells me that the PMDG NG is extremely well modelled!