" Goodbye, Ruby Tuesday ".......nice version Franco ! :(

" Goodbye, Ruby Tuesday ".......nice version Franco ! :(

:( :(

About the rate of descent i talk about my experience: 250KIAS with IDLE thrust without using speedbrakes make me maintain maximum 1200/1300ft/min and honestly i don't know if it is realistic, i think it could be a quite less than real b738...I hope you'll help me to solve the problem...:-)

This morning i had the opportunity to ask to Ryanair pilot the maximum rate during the descent, mantaining 250kias on idle without using speedbrake, and the answer to my question was around 1800ft/min. I'm able to mantain max 1200ft/min...:-(

This morning i had the opportunity to ask to Ryanair pilot the maximum rate during the descent, mantaining 250kias on idle without using speedbrake, and the answer to my question was around 1800ft/min. I'm able to mantain max 1200ft/min...:-(

Yep, and add about 500fpm for the speedbrake, or 2300fpm.

some descent tips from real world BBJ opsBefore Descent (AIRBAG)• A-TIS• I-nstall the Approach• R-adio’s -- Tune and ID• B-rief the Approach• A-pproach Checklist• G-o Around Procedures (How will the airplane fly it? HDG SEL, etc.)Planned Descent Point• Timing -- Approx. 10 seconds for every 100’ of altitude to lose• Distance -- Divide HAT by 300’. This is the distance to start descent from the end of the runway.Enroute Descent Path Planning• Build a waypoint 40 NM track distance from the landing runway with240/10000 inserted for Speed/Altitude. - AND/OR - Use the fix page andput a 40 NM circle around the runway (or FAF) and plan to cross thecircle at 240/10000 for a straight-in arrival.• When planning an enroute descent to radar vectors to final it can bedifficult to determine how far out you will be vectored and how soon you should begin your descent. Request a descent at a distance that will allow a constant 1500 fpm descent. To determine this descent point:• Load the expected approach using the FMS DEP/ARR page• Load the FAF or OM point/altitude on the descent page at 3R.• You can monitor the V/S as you approach this point. When the V/Sapproaches 1500 request descent. Even if the descent is not grantedimmediately, you will have a very good target descent rate when ATCpermits the descent. This technique provides a constant descent thatmirrors our constant climb to cruise profile.Descent Profile• 3.5:1 (Miles : Altitude)• For every 50 Kts of wind +/- 2 Miles• Losing 10 KIAS Takes 1 NM10,000’ check during descent (10,000’ AGL for higher fieldelevations) (FLAAPS)• F-uel Pumps (Ctr Tank management per alternate operating procedures)• L-anding Lights -- EXTENDED/ON (consider 18,000’ in high-trafficareas)• A-irspeed -- decelerate to 250• A-PU -- On/as desired/WX considerations• P-ressurization -- set for landing field elevation• S-eatbelt (double ding by going on/off/wait 1 sec/on)Most jets can do atleast 1500ft per minute clean at 250 below 10,000ft. Even the over powered and clean G5/550 can do it.

Edited February 16, 201214 yr by G550flyer

Thanks for all great and interesting info posted in this thread! I found the stuff about the CI value of particular interest and that it will in fact affect your descent profile, I always thought using different CI values only affected your speed and thus your fuel burn...not VNAV's ability to keep the calculated descent profile correctly.Looking forward to try this on next flight :(

As real as it gets: for the NGX, CI: 10 to 30http://www.boeing.com/commercial/aeromagazine/articles/qtr_4_07/article_05_3.htmlBert Van Bulck

Very interesting, thanks for the link!

I always thought using different CI values only affected your speed and thus your fuel burn...not VNAV's ability to keep the calculated descent profile correctly.

That's what I thought, too. And I fly the thing. The highest I've used was 60. It would do it, but if you had to slow for turbulence, you could end up high.

If I am online, which is 99.9% of the time....I don't use VNAV anyways....and just hope the ATC knows what they are doing. If I am online with no ATC....I always start my TOD 10miles back...just to make sure....also ya...I always check my speed into my descent, and make sure it is not to zippy and my CI is always never above 30. Doing just the above...I always (99%) of the time can make my restrictions even into KLAX, which in my opinion, have some of the toughest...as in like....5 or 6 in a star alone....

Just so you know, most ATC would expect you to use VNAV... after all, in RW, there is ATC and they still use VNAV! ATC aren't there to manage your descent and most frequently you will hear clearance such as "When ready, descend (level)" or in the US, "Descend via the STAR". The VNAV is designed to give you an optimum profile and help you meet all of the restrictions... but of course, only if you feed it with all of the required data (descent winds help) - rubbish in, rubbish out.

Just so you know, most ATC would expect you to use VNAV... after all, in RW, there is ATC and they still use VNAV! ATC aren't there to manage your descent and most frequently you will hear clearance such as "When ready, descend (level)" or in the US, "Descend via the STAR". The VNAV is designed to give you an optimum profile and help you meet all of the restrictions... but of course, only if you feed it with all of the required data (descent winds help) - rubbish in, rubbish out.

Maybe we are misunderstanding each other. I have not encountered one ATC yet, that has allowed me to just be in His airspace, and let the FMC just VNAV me all auto.That is what I meant.Not the use of it, but the general, set and forget use of it.

Depending on the traffic area, Real world, I rarely get the chance to descend via the arrival. Normally we have to tell ATC that we are looking for lower. Along the way you are given crossing restrictions. Though VNAV would be most efficient, ATC will usually conflict with the VNAV profile. In this situation I can give myself a vertical direct to a waypoint altitude(honeywell), and the box(FMS) will recalculate the profile from my altitude at the time i select it. This is nice, but i will have to constantly do this each time im given a restriction. I like it because it gives me an idea of whats required to meet the restriction. At this point i instantly know if i cant make the restriction based on the descent profile it calculates. I can also see the vvi required on the prog page. I can notify ATC earlier if i cant comply and it saves on the mental/public math.

Ok, we're talking about the descent planning, but the question is: Is not 1200ft/min quite less as vertical speed considering that the real B738 can maintain about 1800ft/min with the same configuraton, is it?!

That's what I thought, too. And I fly the thing. The highest I've used was 60. It would do it, but if you had to slow for turbulence, you could end up high.

Well...a comfort in some regard when not even a real NG driver like yourself was aware of this :(

Well...a comfort in some regard when not even a real NG driver like yourself was aware of this :(

My point was it's not as much of an issue in the real plane. It seems more often than not that I end up adding power during the descent in VNAV.VNAV, LVL CHG, V/S. . . it doesn't matter - they can all achieve the same descent rates. One doesn't magically make the same plane descend at a higher rate.