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Guest s_L_Y_F_a

A/T mode confusion in TOGA 744

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Guest s_L_Y_F_a

you are getting it wrong.TOGA (Take-off/Go-around) is also an AP mode for pitch and bank. If you press the TOGA button, the TOGA mode for pitch AND bank gets automatically activated.If you select heading hold in the PMDG menu this means that the AP will maintain current heading while being in TOGA mode. So if you are departing from a runway with a runway heading of 251 then the AP will hold this heading until you either select LNAV or HDG SEL by pressing the HDG SEL knob on the MCP.The alternative for TOGA bank mode is to hold ground track(selectable in the PDMG menu). This is useful during X-wind takeoffs if you do not want to be blown away from the runway centerline right after takeoff.

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Guest BAW1085

>you are getting it wrong.TOGA (Take-off/Go-around) is also an>AP mode for pitch and bank. If you press the TOGA button, the>TOGA mode for pitch AND bank gets automatically activated.>If you select heading hold in the PMDG menu this means that>the AP will maintain current heading while being in TOGA mode.>So if you are departing from a runway with a runway heading of>251 then the AP will hold this heading until you either select>LNAV or HDG SEL by pressing the HDG SEL knob on the MCP.>>The alternative for TOGA bank mode is to hold ground>track(selectable in the PDMG menu). This is useful during>X-wind takeoffs if you do not want to be blown away from the>runway centerline right after takeoff.This is exactly what I have said in my post..???The problem I'm finding is that the aircraft is not doing this.Try it yourself.Set up for a normal TO with TOGA activated and VNAV/LNAV disconnected. Set an altitude in the MCP then TO. See what happens.

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David-Yes- I think you are missing something. If you allow the airplane speed to decay and the airplane to depart- that is generally considered bad piloting. ;-)Where did you collect this information (1-4 as you listed above?)There are a number of customer options that can be configured in the airplane to determine what happens at various points in the process. The one you describe is not familiar- so I'm doubting we used it.I have duplicated as you describe, and the only way I can succeed in getting speed to "just decay" is to leave the speed bug set down around V2. Even doing this, once the airplane levels at the MCP ALT the A/T changes to SPD mode and bumps the speed bug.I'll point Dr. Vaos at this thread, since he's the one "code responsible" in the area- and possibly he can walk you through the data points.Disclaimer: He's traveling and exceedingly busy- so you may not get an answer.


Robert S. Randazzo coolcap.gif

PLEASE NOTE THAT PMDG HAS DEPARTED AVSIM

You can find us at:  http://forum.pmdg.com

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Guest BAW1085

My understanding is that when the TOGA is pushed for T/O (prior to 50 kts) without VNAV/LNAV armed the following events occur:1. The thrust levers advance to the selected T/O thrust (THR REF) and the vertical mode will be TO/GA.2. At 65 kts the autothrottle annunciates HOLD3. At 400' the autothrottle again indicates THR REF4. At the selected altitude, the vertical mode changes to ALT but the A/T remains in THR REF and the aircraft accelerates up to the flap placard speed or VMO as applicable.5. Having previously selected heading hold in PMDG options for TOGA the aircraft should hold the HDG SEL heading.I find that the Aircraft does not accelerate to a placard speed, the speed just decays when reaching the MCP altitude. Thereafter the heading is not maintained either and the aircraft simply departs.Am I missing something here ?Informed comments welcome....David MilesAirbus

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Guest D17S

Did you see that when the AT was used without Vnav for takeoff . . . : (?)As the MCP altitude capture event initiated, the AFS would shift Thrust/Pitch modes from TOGA/TOGA to SPD/ALT. This is good. However, If the MCP had not yet been re-set to a higher airspeed from the initial V2(+X) setting (or Previously Selected Airspeed -PSA-), and the pilot had already accelerated the airplane beyond the initial MCP setting of the PSA+25 during the post-acceleration altitude climb, the MCP airspeed would auto-reset from the PSA to only the "PSA" +25 knots . . . even if the airplane was already at a faster airspeed! As this occurs, the AFS will command the airplane to slow down (via its "SPD" thrust mode), to PSA+25. Or: If the MCP airspeed had been manually reset by the pilot to a new higher airspeed, the MCP would reset to this new MCP airspeed, +10 knots.Really keeps a pilot on his toes, but neither AFS function seemed right.

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Guest BAW1085

Hi RobertThanks for the reply, after a more rigourous test I discovered the following.Set up.1. VNAV/LNAV disconnected2. Flaps 203. VR 162ktsMax thrust then TOGA before 50ktsAircraft works as advertised, rotate pos rate Gear and all the good things happen ie Mode annuciations etc. approaching MCP Altitude flaps still at 20, ignoring schedule. Speed bug bumped upto 197kts Placard speed for Flaps 20 ?. Speed and ALT mode annuciated A/C maintans 197kts but does not capture MCP Altitude. At no time is the AP activated or any speed interventions made eg FLCH etc..Questions....1. Should TOGA capture an MCP altitude ? I was led to believe it does.2. I realise that TOGA sets a commanded pitch attitude on GA but does it do this for TO ?I realise this is a very quiet corner of the operating envelope and one not used in normal operaions. but I guess this is the way you get to learn more than you'll ever need to know. and just to add frankly I'm constantly amazed at the fidelity of this Add on and wonder whether or not you might not go down the route of PS1.RegardsDavid MilesAirbus

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Guest D17S

Just to join the conversation: TOGA will guide to a pitch attitude only until you are airborne. Then it will provide flight guidance to a "speed on pitch" climb at the MCP airspeed. THRust remains REFerenced to takeoff power. You, el Cap-i-tan, control speed with the pitch of the airplane. Thrust is just locked at TO power. I expect you had your MCP set to 197-25, or 172kts as your initial V2 climb speed. Without Vnav in the picture, that initial MCP airspeed hop is based on the initial MCP setting. If you really want to stay with this MCP airspeed, recognize that thrust just pulled back (big time) and you are now going to be using pitch to maintain your climb to the MCP altitude. Now thrust is controlling speed and you are now controlling altitude with pitch. Note that you and thrust just swapped jobs.You were probably going faster than the 197 when thrust shifted to "SPD", so watch out. You are probably going to slow down. Thrust is now controlling speed and you now have to use pitch to climb. You will be manually pitching up to maintain the climb while thrust is automatically backing off to capture a slower airspeed. Like I said above, this is a bad combination and definitely not the place I want thrust to be slowing me down . . . especially when I now need to pitch up to maintain a climb . . . and I

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>TOGA will guide to a pitch attitude only until you are>airborne.I wish I could exactly understand what this sentence means.Thanks.

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That means the fixed pitch-up attitude that you see on the PFD on the ground prior to lift off, don


/Tord Hoppe, Sweden

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Tord-TOGA commands 8deg nose up pitch for takeoff. At 11 degrees you will drag the tail of the airplane and cause the airplane to be out of service for at least a few days while extensive structure integrity checks are carried out.(When the company payroll-deducts the costs of this procedure- it has a deflating effect on one's earnings for the rest of your career... ;-) )Dirk-(Don't forget to sign your posts!)What that sentence means is:TOGA is commanding the pitch angle to which you should rotate during takeoff. Once you have left the ground and the tail is clear of the strike hazard zone, TOGA pitch provides you with the correct pitch angle to maintain speed.Steven's post above is a good description of what is going on- and you can also find information on this with TRC Lesson 2: page 2-11/12....


Robert S. Randazzo coolcap.gif

PLEASE NOTE THAT PMDG HAS DEPARTED AVSIM

You can find us at:  http://forum.pmdg.com

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>That means the fixed pitch-up attitude that you see on the>PFD on the ground prior to lift off, don

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>Tord->>TOGA commands 8deg nose up pitch for takeoff. At 11 degrees>you will drag the tail of the airplane and cause the airplane>to be out of service for at least a few days while extensive>structure integrity checks are carried out.>>(When the company payroll-deducts the costs of this procedure->it has a deflating effect on one's earnings for the rest of>your career... ;-) )>>>Dirk->>(Don't forget to sign your posts!)>>What that sentence means is:>>TOGA is commanding the pitch angle to which you should rotate>during takeoff. Once you have left the ground and the tail is>clear of the strike hazard zone, TOGA pitch provides you with>the correct pitch angle to maintain speed.>>Steven's post above is a good description of what is going on->and you can also find information on this with TRC Lesson 2:>page 2-11/12....>>Thanks for the comments. I got it now.Dirk.

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It is all getting more clear and structured in TRC4 I'm reading thgrough now. What a relief, thanks.

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Robert do airlines actually payroll deduct for tailstrikes? If so how much ( on average ) is it? Now I don't feel so bad about paying to fix dents in the car! Thanks, Joe Colao


Joe Colao

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