Speedbrake Deployment & Bounce Landing

[Guest wee_davie_2612]

Hey all,The 737 autoland system has a wind speed/gust control system inbulit and so when flying a full auto land the speed should be set to Vref+5 only.In other words autolands don't have wind correction added to the Vref speed.Also I done another test flight in the 700 and it bounced/skipped on landing and this time I have many pictures to prove it. I also performed the same test in the 600 and it landed without a skip (I have pictures of that aswell incase of naysayers who suggest those with problems aren't "doing it right" - call me pessimistic!)Details of the 700 flight:ZFW 120454lbs (Max ZFW 120500lbs)Take off gross 8546lbsLanding gross 127.6 (Max landing 128000lbs)Flaps 30 (Vref30=133) Wind none[a href=http://www.ibsw08346pwp.pwp.blueyonder.co.uk/700slideshow/Cache Page.htm]Results[/a] in a slideshow, last slide displays loadmanager. The slides will play in a continuous loop after being started.I'll be performing more tests later and will report back.CheersDavid

[crvm 0]

Well some of us "naysayers" happen to fly the real NG (Brad Marsh) so I think they have some weight don't you think Dave? I have flown this bird since day one of it's development so I believe I qualify upon it's handing. It's true that the A/T takes into account the extra **gusts** with the VREF set to + 5. Do you have flaps 40 here Dave? No one doubts that you are indeed bouncing but the question is why you and some others ARE and others like ME are not, we do not have two sims here (as long as we are both using the 800-900 and 600-700 updates). So why not show us the exact same frame by fram of what your cockpit looks like during the same time frame? I think this would be much more helpful to the discussion.Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

[crvm 0]

Let's also keep some things in perspective here regarding bouncing. It happens in real life too. And I believe that some of the real reasons it happens is also why we see it in the sim. Number one reason I believe this happens is for excess speed upon T/D. The plane in your pictures seems to want to spring back right into the air. If your speed was indeed falling (The speed should be right AT or deceling below REF) upon T/D with idle throttles @ 30 RA, speedbrakes out at contact of main gear with ground should in help keep the aircraft firmly upon the ground but only if the speed is indeed correct. Now everyone does things differently, there is no way for us to know how one performs a flight and landing unless one provides detailed information for us to review. It is a fadct some bounce so the next logical step would be to provide all relevent data to show why. This way we can deal with only facts and if there is perhaps something a bit off then it can be shown and most important replicated each and everytime.Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

[Guest wee_davie_2612]

>> Well some of us "naysayers" happen to fly the real NG (Brad>Marsh) so I think they have some weight don't you think Dave?>I have flown this bird since day one of it's development so I>believe I qualify upon it's handing.I'm talking about the naysayers who dismiss out of hand the fact that some guys are having these problems and simply put it down to pilot error. I'm not doubting the real world pilots, it's the self announced experts that have nothing good to say bar "your doing something wrong" instead of trying to help figure out the reason behind it. If they don't have anything constructive to say they should keep their "superior" comments to themselves and let us plebs try and get down to fixing it.B!tch over!> Do you have flaps 40 here Dave? No, 30

[Sartanius 399]

Randy,I posted the specifics for a flight tonight in my other post here in the PMDG forum titled, "Which Vref To Choose?". Please look there and see how I had the aircraft configured.Thanks!DougDell 8250 (3.06GHz/533FSB)1GB Rambus RAM120MB ATA 100 (7200 RPM)ATI Radeon 9700 Pro (Catalyst 4.5)Audigy 2 Sound (latest drivers)MS Force Feedback 2WindowsXP Pro (SP1)DirectX 9.0b

[Guest wee_davie_2612]

P.s. Replyed before I seen the second post:>Number one reason I believe this happens is for excess speed>upon T/D. The plane in your pictures seems to want to spring>back right into the air. If your speed was indeed falling (The>speed should be right AT or deceling below REF) upon T/D with>idle throttles @ 30 RA, speedbrakes out at contact of main>gear with ground should in help keep the aircraft firmly upon>the ground but only if the speed is indeed correct. The engines were winding down, shame pics can't include sound :-)I switched to the outside view just as the 'RETARD' came up on the PFD annunciator so am unsure about the actual speed. Speed was perfect at Vref30+5 all the way down - I monitored the approach to the last minute when I switched to take photos. I can say with 99% certainty that it wasn't going too fast. Just as I write that I've had a though but I'll get back to it later (it's 0500 here).Also note in the pics that the brakes and spoilers don't deploy on the first touchdown (kudos programmers!)>> Now everyone does things differently, there is no way for us>to know how one performs a flight and landing unless one>provides detailed information for us to review. It is a fadct>some bounce so the next logical step would be to provide all>relevent data to show why.As I said before, write me a list of the details you need and I'll get them to you.David

[crvm 0]

Thanks David, I will do another fight tonight. I tend to think we somehow have excess speed here. Can you do me a favor and leave the MCP spd to VREF without the correction and tell me if you still have the bounce? I will try it myself...Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

[Kosta 122]

This is all very interesting what you write, I've been trying all morning today to get to the bottom of this, doing small takeoff-turn-land flights up to 4000ft around LOWS. So far I've tested 700, 800 and 900 models, and on all 3 models, speedbrake DID NOT deploy automatically (nor did throttle idled itself in the throttle quadrant upon flare). And aircraft bounced after that. Bounces are slightly different, depending if I set VREF or VREF+5, also angle of attack prior to landing is different. I still have to use F1 to be kinda 80% sure that SB will deploy (also sometimes it doesn't).Considering my joystick, MSFF2, it's calibrated correctly, since the idle throttle yields around 20.3% N1.Any ideas? My machine could handle FRAPS movie, so Randy, if you'd like, I can record the whole flight and then you can see for yourself what I may be doing wrong or if there's some other error...I wish that we once and for all get this to WORK.

[Guest wee_davie_2612]

Hey all,I forgot to mention: I am not having any problems with speedbrakes and/or auto throttles. The test route I flew was basically a circuit of the airport that was flown on autopilot from 1000ft to touchdown. I'll post the route if you guys want so that we are singing from the same song sheet.I had the though that I posted on another thread that perhaps the problem at high gross landing weights is that the autothrottles don't have enough time to bring the throttles all the way back to idle through the flare due to the higher thrust settings required to hold the approach speed at the higher weights.i.e. at max landing weight perhaps you need 80% N1 to hold the approach speed (just for talking sake) and at a lower weight you only need 60% N1.Now if the auto thrust system pulls back the throttles at the same time (altitude AGL) and at the same rate then it is obvious that the 80% setting is going to take longer to pull to idle than the 60%.Now, if the 60% hits idle power as the mains touchdown then it is obvious going by the previous statement that there will be 20% power left on in the higher thrust situation upon touch down.This small thrust setting could be enough to cause a skip.What do you guys think?I'll do some flights later at Vref without the +5 and at a lower landing weight. I'll also get some screens of a bounced landing from the cockpit so that you can see the thrust settings etceteraHave a good one,David

[Kosta 122]

David,I think bouncy landing is only due to too heavy or too fast vertical approach, because if you do it manually, and set the aircraft nicely on the runway, it will not bounce.But I think you might have something on this one...Say, situation you are talking about, is it without A/P, with one A/P or two A/P (full auto-landing)?

[Guest wee_davie_2612]

Full Auto KostaDavid

[Guest jacaru]

Why dont we all do the same 737 (800 ie), circuit & approach on a neutral weather condition, no wind, standard landing weight. Some of us are making a mistake somewhere and only you guys which got it right can help us.I will do this approach:PMDG 737 800 (latest patches & model update)LEMD 33 ILS CAT III approachFull Autoland, flaps 40

[Kosta 122]

OK, I'm doing the flight you suggested.Procedure:- start up FS, select Air Europa 800 model, LEMD 36L, daytime, clear weather, fuel - 10900 pounds, L-R wing- engine startup procedure (Battery, APU, switches etc...), ENG GEN both on, APU BLEED OFF- FMC setup - LEMD->LEMD, INIT - GW=135.5, FUEL=10.8, RESERVES=5, COST=50, CRZ ALT=4000, EXEC, N1 LIMIT, TAKEOFF - FLAPS=1, DEP/ARR - DEP=36L (not selecing a SID), ARR=18L, ACTIVATE, EXEC, back to TAKEOFF REF page for V1,VR,V2- MCP - set 4000ft, speed to 150, HDG to 020, FD on, A/T on, set FLAPS 1, brake release- throttle idle - reading 20.4, N1 to 60%, TOGA, takeoff- gear up, A/P after 500ft, turning to HDG 020 and 4000ft, MCP spd to 210, flaps up- holding course until ready for the turn for the ILS of 18L- radios to 109.30, course 183, VREF set 137KT, flaps 40- speed 180, flaps 2- turning for ILS intercept- engaging VOR/LOC- setting 3000ft and LVL CHG, speed 167KT, flaps 5 (1700 AGL)- ILS intercepted, engaging APP (SINGLE CH appears)- slowing down to 147KT, flaps 25, gear out- one thousand- setting VREF 137KT +5 = 142KT in MCP, flaps 40, engaging A/P 2- PFD says G/S, and FLARE below in white, speed stable at 142KT, arming speedbrakes and setting brakes to 2- while flaring, pulled the throttle back to 0 on the joystick, observed the throttle window - throttle did NOT set back to idle while in the flare, but was too late to push F1- S/B did not deploy- bounced once or twiceSo, if ANYONE else gets this right, I'd appreciate your help a lot!

[crvm 0]

- while flaring, pulled the throttle back to 0 on the joystick, observed the throttle window - throttle did NOT set back to idle while in the flare, but was too late to push F1 Maybe I did not understand your post but are you saying you already did this or are going to? I would not touch any controls in the A/L whatsoever. Leave the throttle where it is, the FMS will cut it at FLARE on it's on so IF you do touch it after this you might indeed have a problem because ANY throttle will inhibit the S/B just like the RW.Best Wishes,[h4]Randy J. Smith[/h4][h3]P M D G's 747-400[/h3][h4]coming to a runway near you[/h4][/font color]Caution! Not a real pilot, but do play one on TV ;-)AMD 64 3200+ | ASUS KV8 DELUXE | GFORCE 5700 ULTRA @535/1000 | Maxtor 6Y080M0 SATA 80 GIG | 512 DDR 400 | Windows Xp Pro | Windows Xp Pro 64 |

[Kosta 122]

I just did the flight.OK, I'll do now absolutely the same flight, and I'll do following- after engaging the autopilot after takeoff, I'll set the joystick throttle to 0 and leave it be until the bird landed.Be right back...