Hi all,I have a question about the climb/descent rate. What is the maximum rate of climb/descent for passenger conveniance during Vnav or a Lvl Chg?Best Regards,Alex

VNAV and LVL CH do not adhear to pax comfort ;) This is where you, the pilot, steps in with your skill to make the transition smoother. If you want smooth, then first use V/S then engage another pitch mode..... [h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

Hi Alex,Vertical speed doesn't directly affect passenger comfort. This is a misunderstanding many people here are making. You can be climbing at 45.000 ft / minute (theoretically) and still be perfectly comfortable experiencing 1 G. There are two things that will affect comfort however. These are body pitch angle (attitude) and acceleration forces. With seat belts off, you may climb with around 7.5 degrees nose up. Just use the vertical speed you get at that attitude.Regarding accelerations: As long as you make a smooth level off and a smooth transition from level flight to climb and then from climb to level flight, you won't have a problem.Regards,Mark

Interesting question. Following another thread I have an intense commnunication with several NG pilots regarding that (4 via Email, one I know myself).The interesting thing is you get 5 slightly different answers, also regarding what is done in practice. Having said that, there is no "the NG is flown like this" answer possible. Often heard is "depends on weight".As had been mentioned, anything that involves changes in climb/descend rate affects passenger comfort. Example : The speed change from 250 to 280 using LVL CHG or VNAV would involve some noticeable discomfort, because this implies bigger rate changes. The 1G remark above is of course relevant, but from a certain fpm range only theoretical. The practical consensus I got goes similar like that :"Consider a climb rate of 3000 fpm (plus something) to be practically relevant, much more is avoided or might be not possible for that weight. Depending on weight, we use CLB, CLB-1 or CLB-2 to get this. I can't quickly give you exact max. climb rates, but these are practically irrelevant because that would mean empty plane and full climb thrust, which rarely happens".Or this, for the -800" I suppose it could climb more steeply than 3000 fpm, but these are just figures that are reasonably normal.Then, of course if we fly at lower weights, we would be using CLB-2.Theoretically I suppose you could do about 4000 ft/min if empty at full thrust and 250kts. But that doesn`t happen very often in real life"Also regarding the question "what modes you use when" you get no consistent answer. But there's e.g. a tendency for the climb to use V/S mode below 10000 ft and LVL CHG above 10000 ft.Disclaimer : Please consider any mentioned values above to be practical ranges and not performance table validated values. Of course this depends on weight, altitude, etc.Disclaimer 2 : English is not my native language, so is likely to contain misunderstandable wording. Before pilots mentioned get blamed for their answer, please ask back first regarding potential misunderstandings. Example : Question - Why did the pilots mention climb rates and not pitch attitudes ? Answer - Because I asked for climb rates.;)Mike

It's a very good point that there is no single way to fly this aircraft. Not to say there are not things that all NG pilots MUST follow like flaps retraction prior to VNAV engagement etc. Some pilots will not use VNAV (other than SWA who never use VNAV) for descents while others will most always use it. It sure is much better at DESCents with U10.5 than prior UXXXX updates. Flight is dynamic and so should the pilot. Happy flying.............................[h4]Best Wishes,Randy J. Smithhttp://img.villagephotos.com/p/2003-5/196432/winglets_lg.jpg

Thnx everybody for your answers.Alex :-wave