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colang

Is it normal?

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I tried yesterday some local training flight, following a tutorial written for 737 NG.In the first step there ia s flight without using FMC, manually contolling autopilot.So I started cold and dark, switched up APU, generator, electrical, engines, generators, electrical, bleed, and all things until had an overhead with all alarm lights off, except for yaw damper.I DON'T initialized IRS.Started flight at KTNT with IRS in ATT mode, v1 and vr inserted manually, autothrottle armed with speed set to 250.Acivated TO/GA mode, rotated at 126, taken off, retracted gear and... AAAAGGHHH!!!After few seconds, I presume at the moment in which Autothrottle switched from N1 to Speed mode, the plane started climb almost vertically until stall speed, then started pitching up and down and rotating on itself until overspeed crash (maybe the FSX way to interpret the spin?).Autopilot was still unactivated so the instintive press on disengage bar to try a manual recovery didn'tmake any effect, and autothrottle disengaged itself.Can it be a normal behaviour of the real plane? (I had some difficult to believe in reality an incorrect setting can kill 150 people without any alarm and any recovery chance).It seems me something software related.I already deinstalled and reinstalled 737NGX plus SP1, so next step could be a ticket to request a new complete installer.Before this, can someone confirm it's not normal behaviour or only my mistake?

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Why don´t you take your time to learn and fly the included Tutorial written by Ryan.Very hard for to us to know everything you did wrong. But I´m sure you did!First of all you´ll have to trim the ac and also use derated T/O and climbif very light. If you don´t do that, you could have a unbalanced rocket in your hands./ Leffe

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Yes, I agree with you, I already completed (and repeated until understood what I'm doing) the London-Amsterdam tutorial.Also I completed other flights starting with default (pre-takeoff) setup and all went OK, all systems working correct from takeoff to landing.I just started experimenting different situations.Takeoff was with trim manually set to 4.0, fuel 1/3, payload half passengers. FMC used to calculate CoG and trim, takeoff derated at 22000 lbs, climb2 selected.One try with fmc, one try with vspeeds manually set. I also believe I did something wrong but... the results are too much "unreal".

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You would only go to 250 above 10,000 feet.
Huh? Wow I must be flying wrong all these years. I am always at 250 knots already when reaching 10,000. Since when is flying 250 knots below 10,000 a bad idea?

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It's not, you accelarate to your minimum clean speed or higher at whatever acceleration height you programmed during preflight, normally 1000ft above thrust reduction depending on NDAP1 or 2Not sure about the US but in many places around the world ATC have no problem with you requesting a high speed climb and zooming away at 320+ kts below 10000 Regards

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the rule is : not passing 250kts below 10000ft, if you get a clearence you can go faster, like anything else, if you get clearence to.

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Colang, sign the post with a full name as per forum rules.OT: Are you using ASE? I had a similar thing happen to me, and I know fairly well how to operate NG.

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The law is 250 under 10K.
Yes but you can exceed it on request, I have flown jumpseat many times out of Heathrow and seen it done. Anyway, thread drift...Btw colang, do you have wake turbulence switched on?

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FMC is probably changing it to 240/10000 cause that gives you some leeway not to exceed the 250 knot limit on the way down. But in the US it's 250 knots or less under 10,000 (Not 240).I was doing 350 knots below 10,000 last night on descent into KORD. ATC got distracted and forgot to tell me to descend from STYLE at 12,000 to pick up ILS 22R at 3,000 and by the time he realized the error it was way too late. But rather than vector me around he just says, best rate to to 3,000 and I said Ok you got it! Captured the LOC at about 260 kts and by time I got to the outter marker was down to VREF. Not often you get to do that, but was FUN! Devil.gif

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Huh? Wow I must be flying wrong all these years. I am always at 250 knots already when reaching 10,000. Since when is flying 250 knots below 10,000 a bad idea?
I believe with the MD11 (and MD80), you set the speed to 250, but with the 737 it's set it to V2.

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I believe with the MD11 (and MD80), you set the speed to 250, but with the 737 it's set it to V2
After I start climbing from 5,000 I already have 250 dialed in on the MCP manually.

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FMC is probably changing it to 240/10000 cause that gives you some leeway not to exceed the 250 knot limit on the way down. But in the US it's 250 knots or less under 10,000 (Not 240).I was doing 350 knots below 10,000 last night on descent into KORD. ATC got distracted and forgot to tell me to descend from STYLE at 12,000 to pick up the ILS 22R at 3,000 and by the time he realized the error it was way too late. But rather than vector me around he just says, best rate to to 3,000 and I said Ok you got it! Captured the LOC at about 260 kts and by time I got to the outter marker was down to VREF. Not often you get to do that, but was FUN! Devil.gif
How on Earth did you manage to decel from 260 at loc capture to Vref at the LOM? Must´ve been a hair-raising approach. I´d have thrown a couple of barrel rolls to help manage deceleration hehe

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How on Earth did you manage to decel from 260 at loc capture to Vref at the LOM?
I was level at 3000 when I captured the LOC and had speed brakes deployed, then at 250 knots gear finally came down, and then as the speed rapidly was bleeding off I kept adding flaps.At 250 knots with Landing Gear down, Speed Brakes and Flaps 2, you can slow down in a hurry if in level flight.

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Colang, sign the post with a full name as per forum rules.OT: Are you using ASE? I had a similar thing happen to me, and I know fairly well how to operate NG.
Oh, I'm sorry, I added now in my signature.No, I don't have ASE, meteo was the standard FSX Fair Weather theme, and yes, turbulence is switched on but i think it cannot be the problem as the effect was really different.At the moment in which Autothrottle automatically switch mode from N1 to Speed or Level Change, it disengaged and plane put nose up almost vertically, like it would have commands locked at full range; no way to manually control the plane, all commands seems not have effect (and it exclude for me a temporary joystick spike).Only unusual thing I did was take off with IRS not fully aligned, in ATT mode (and consequently yaw damper off); beside this, the plane was correctly trimmed, flaps 5, and... whatever speed you want select in autopilot (v2+x or 240 or 250) it never had the chance to be activated as well as the autopilot.I exclude at 99% any hydraulic or pneumatic failure as before start I checked the "Service all" and "Clear all" in the failures section in FMC.Unless a 737 due to IRS misconfiguration can suddenly go vertical up to stall with locked commands, and kill 150 people without any advice message or sound to the pilot, i think I have a software problem.If you takeoff with this configuration does the plane become crazy in the same way?If yes we found a bug , if no I have to reinstall.Thanks for any ideas.Claudio Colangeli

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Yes but you can exceed it on request, I have flown jumpseat many times out of Heathrow and seen it done. Anyway, thread drift...Btw colang, do you have wake turbulence switched on?
Very often in Italy you can hear if there are restrcions on speed or not declared by Dep/App controllers, they inform Pilot on restricions quickly. Usaully is ' az1228 radar contact procced as cleared no restrictions on speed' Anyway pilots can ask to controller at anytime but If it doesn't sais you have to respect standar procedures, so 250kts under 10.000ft.Cheers,Francesco
Oh, I'm sorry, I added now in my signature.No, I don't have ASE, meteo was the standard FSX Fair Weather theme, and yes, turbulence is switched on but i think it cannot be the problem as the effect was really different.At the moment in which Autothrottle automatically switch mode from N1 to Speed or Level Change, it disengaged and plane put nose up almost vertically, like it would have commands locked at full range; no way to manually control the plane, all commands seems not have effect (and it exclude for me a temporary joystick spike).Only unusual thing I did was take off with IRS not fully aligned, in ATT mode (and consequently yaw damper off); beside this, the plane was correctly trimmed, flaps 5, and... whatever speed you want select in autopilot (v2+x or 240 or 250) it never had the chance to be activated as well as the autopilot.I exclude at 99% any hydraulic or pneumatic failure as before start I checked the "Service all" and "Clear all" in the failures section in FMC.Unless a 737 due to IRS misconfiguration can suddenly go vertical up to stall with locked commands, and kill 150 people without any advice message or sound to the pilot, i think I have a software problem.If you takeoff with this configuration does the plane become crazy in the same way?If yes we found a bug , if no I have to reinstall.Thanks for any ideas.Claudio Colangeli
Ciao Claudio... sei nuovo del Forum?Francesco( Rocca di Papa -ROMA- )

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Very often in Italy you can hear if there are restrcions on speed or not declared by Dep/App controllers, they inform Pilot on restricions quickly. Usaully is ' az1228 radar contact procced as cleared no restrictions on speed' Anyway pilots can ask to controller at anytime but If it doesn't sais you have to respect standar procedures, so 250kts under 10.000ft.Cheers,FrancescoCiao Claudio... sei nuovo del Forum?Francesco( Rocca di Papa -ROMA- )
Yes, almost new in forum;Replayed in private to avoid OT.

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Noone will never take off with ONE IRS in ATT, you did with both... Yes, it is not part of the problem now, and you can still fly like an old plane using radios, but it is not supposed to take off with both or only one on ATT.Both must be on NAV.Apart of that, does your flight controls work correctly?

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The controls worked correctly during ground roll, rotation and initial climb.Apparently, at the moment of autothrottle mode switch from N1 to Speed, it disengaged and controls stopped working, like they were locked in full back position without any more effect on both pitch and roll.Studying a bit about IRS I found ATT mode is used only in case of some failure, and reading what you wrote I understand it's a mode not to be used in normal operation.So maybe I explored a "not to do in this way" zone of the software.I also read in this case the pilot should manually insert the heading in irs but i didn't find a way to do it, so maybe it's a non simulated feature, or a minor bug, or maybe both.

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I would simply say that FSX went crazy hence the weird behaviour of the plane.

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I think there should be a sticky for this:Don't touch the SPEED button.Sheesh.

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Just for curiosity, I tried to recreate the situation from scratch and see if the problem was repetable.Started form free flight, loaded 737NGX and KTNT airport, loaded cold and dark and performed startup without align IRS.The behaviour was the same.Opened a ticket to support attaching saved situation before takoff.If they can recreate the problem we have a little bug (maybe not so important, as the situation should never happen in real or simulated flight), if they can't I have a software problem and will try to reinstall.

I think there should be a sticky for this:Don't touch the SPEED button.Sheesh.
OH NOOOOO!!I pressed some button without labels and it automatically switched the sign in front of passengers from "No Panic" to "OK Panic" and all people started beat the lady in the front row to calm her.

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After this thread I tried the autopilot after take off with both IRS in ATT, the plane goes crazy, if autopilot will be not disengaged immediately it will perform movements that also a UFO cannot do! and after few time it cannot be recovered also if AP will be disconnected.

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The law is 250 under 10K.
That's not a universal rule - at least in Sweden that doesn't apply. If you are flying IFR in class C airspace (in Sweden only class C and G are used) there is no such speed restriction unless explicitly stated in the SID and STAR for the airport. If you are flying VFR the 250 below 10,000 is indeed valid in class C airspace.

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Sounds to me like this is another case of trying to engage the autopilot before the gear is up and locked... try and hand fly the airplane through accel height at least.. (It really is fun to actually fly the plane, rather than watch the computer fly the computer, thats flying the computer)... just follow the flight director through accel height, wait for CLB thrust, pitch down, trim off the pressure, engage CMD A+B and bring the flaps up slowly... have never had any erratic AP behavior, so I doubt its a bug.

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