Deceleration help needed

[scandinavian13 5,192]

Yeah, I'm looking for those tuts now that Arjen mentioned them.

Edited my above to include the link to the vid.

[ZachLW 37]

Here are the videos Zach, this is exactly what I meant:http://forum.avsim.n...edbrakes-video/http://forum.avsim.n.../page__hl__vnav

Edited my above to include the link to the vid.

Thanks guys.

[selby 0]

Perhaps another video is in order from Mr Colwill.... PleeeeeaseJoel Fraseer

[pcubine 143]

What is your idle thrust below FL150 in a clean configuration (no flaps, no gears)?If it is near to 40% of N1 you are experiencing the idle thrust bug that will be fixed on the SP1b.If it is normal (around 34%) you have to check wheater and cost index. Fill the des forecast page and use a cost index between 20-40.A trick: fill the des forecast page with a tail wind a bit higher than what is present, it will change your TOD a bit, reducing the descent ramp.In the first case, you will solve by using the keyboard G key to rise/lower gear.

AndreaThe N1 on descent is in the 43-45% range from cruise to around 10000 ASL. So I must have the idle thrust bug and need to wait on SP1b. On most descents I give up on VNAV and switch to VS and disconnect the AT but N1 still remains in the 43-45% range even when manual throtlle is used. The 800 continues to pick up speed on a 1200-1300 FPM descent so I must start the descent about 200 mile from the destination airport and drop the FPM to 500-700 at about 14000 feet so I can be at 210 knots at 10000 feet. A hell of a way to conduct a flight. SP1b can't come soon enough for me.Michael Cubine

[davierosoft 13]

People with the bug normally ad normal idle (34-35%) from cruise until 15000ft, then "a jump" to 39-40% .You, with 45% of N1, have a strange value, a value that cannot be related to the bug, is your controller set to idle? What about AT override settings in FMC?

[Guest]

I have to say I posted about this earlier in time, I feel I have the same issue.Maybe it works like that and I am doing something wrong but each flight I have to use the air brakes multiple times and for a very prolonged time each usage.I have flown a bit as passenger in the reality but I have never seen a massive usage of air brakes as required in NGX.

[Spin737 102]

Like Andrea said, this all sounds like the high N1 problem that many are experiencing. Fix that and it should clear up most of the problems.

[pcubine 143]

People with the bug normally ad normal idle (34-35%) from cruise until 15000ft, then "a jump" to 39-40% .You, with 45% of N1, have a strange value, a value that cannot be related to the bug, is your controller set to idle? What about AT override settings in FMC?

AndreaI can't get at anything concerning the NGX right now because I am doing a EHAM-KSEA in the MD-11 in full screen mode. I assume by controller you mean the joystick manual throtlle and where is the AT override settings in the FMC?Thank youMichael Cubine

[davierosoft 13]

The controller is your joystick, don't use it for gear extension/retraction, set the throttle to idle when descending and to mid/max position during climb and cruise.The setting is in the PMDG options, I don't remember exacty the page.

[Paul_Smith 92]

I think it is worth stating that the message "Drag Required" does not mean the pilot must use speed brakes, it only means that the pilot should think about speed brakes. If you have entered a reasonable forcast, your descent plan includes a 'decel' point ahead, and you are not too far off profile, then extra drag might not be needed. Even the dreaded "DES PATH UNACHIEVEABLE" is not as fatal as some would have you believe. It is simply a warning that indicates that the current plan can not be acheived unless something changes. You as pilot must decide what, if anything, to change, or if the plan you already have will cope.

[scandinavian13 5,192]

Exactly. Well said Paul.

[davierosoft 13]

I think it is worth stating that the message "Drag Required" does not mean the pilot must use speed brakes, it only means that the pilot should think about speed brakes. If you have entered a reasonable forcast, your descent plan includes a 'decel' point ahead, and you are not too far off profile, then extra drag might not be needed. Even the dreaded "DES PATH UNACHIEVEABLE" is not as fatal as some would have you believe. It is simply a warning that indicates that the current plan can not be acheived unless something changes. You as pilot must decide what, if anything, to change, or if the plan you already have will cope.

If the aircraft continues to accelerate over the drag required (>15 kts) you will have overspeed disconnection of the VNAV, so, in order to continue to use it the thing that must change is to slow down, the ways are 2, disconnect, slow down, then resume descent, or use the speedbrakes, or a third solution tat is a combination of the two.Finally an holding can help, but it is an expensive solution, not what the FMC is made for (save time and fuel).If FMC tells you that des. path is unachievable it means that, with the aircraft performance stored in the FMC, the path cannot be reached, to do it you must force an overspeed, you must do something (like an holding), it is not possible to simply push the column and use the speed brakes...When FMC alerts that something is required, maybe you need to accomplish what it says... but, you can see the speed tape and speed trend to see if speed is going to increase or if it is simply momentarily or almost costant.So... monitoring...

[hmslion 1]

What is your idle thrust below FL150 in a clean configuration (no flaps, no gears)?If it is near to 40% of N1 you are experiencing the idle thrust bug that will be fixed on the SP1b.If it is normal (around 34%) you have to check wheater and cost index. Fill the des forecast page and use a cost index between 20-40.A trick: fill the des forecast page with a tail wind a bit higher than what is present, it will change your TOD a bit, reducing the descent ramp.In the first case, you will solve by using the keyboard G key to rise/lower gear.

This may be it - my idle thrust is about 40% N1...

[pcubine 143]

I just tried a KATL-KTPA flight. I changed the AT override from NEVER to ARM and HOLD. It made no diffference that I could see. TD was about 140 miles from KTPA. The NGX stared down at 1700 FPM and at a target speed of 258 kts and an N1 of 43.8% and maintained that down to 10000 ASL. I took Paul Smith's advice about DRAG REQUIRED and didn't deploy the speedbrakes even though the CDU said drag was required. When I arrived at 11000 ASL at 285 kts I figured it was time to do something - maybe a hold to reduce speed below 250 kts so I could go below 10000 and continue on to KTPA and land. I well just use VS and see if SP1b makes any difference.Michael Cubine

[Spin737 102]

When I arrived at 11000 ASL at 285 kts I figured it was time to do something - maybe a hold to reduce speed below 250 kts so I could go below 10000 and continue on to KTPA and land. I well just use VS and see if SP1b makes any difference.Michael Cubine

Michael,11,000 at 285 sounds normal. The jet will start to slow and level as it approaches 10,000. Look for the doughnuts on the Map display and it will show you where the FMC thinks it's going to slow. The jet will start to slow, but it probably won't get a very good descent rate with the high N1%.