MD-11 system depth preview: Electrical trouble!

[Slick Willy 2]

In the event of that many failed Generators, would starting APU have been part of that checklist too? This AC looks brilliant! Just trying to pass time w/ the Queen in FSX until MD11 release.WillyOuch! no autopilot and having to go thru all of that. Does this bird diconnect from auto real smooth?

[chiswick72 145]

You also get to hear the sound of the ADG when deployed! :)Armen L Cholakianhttp://www.precisionmanuals.com/priv/img/forum/sig_pmdg.jpg

[DLP084 5]

>>>does the PMDG MD11 simulate a realistic ECON speed>>(including>>>the wind factor)?>>>>Holger,>>yes ECON speed calculation as well as all wind entry>>possibilities are modeled.>>>>Regards,>>Markus>>>Thank you Markus!>>Just to be sure. I dont talk about the wind entries in the>fmc. I talk about a dynamic ECON SPD, which increases with>higher headwind components. Currently I only know the>Lenonardo Maddog, which simulate this correctly.>>>Thanks,>Holger Hi Holger, I don't find any reference in the manual of the leonardo maddog regarding a dynamic ECON SPD. I tried to enter some winds at the legs page, but the ACT ECON CRZ speed stayed where it was. The only thing that changes it directly is the cost index (+ changing acft we

[Holgi 1]

Hi Jan-Paul,this is not influenced by the fmc directly. You have to monitore your PFD. Watch the MACH Nr. with headwinds and then with tailwinds. When the headwind component increases then also the MACH increases. This is more influenced by the actual wind conditions which you can see on the ND or on the progress page (747).This is especially interesting when you cross the atlantic ocean with 100kts headwind for example.Friendly regards,Holger

[emvaos 13]

I beg to differ. The wind effect is not simulated anywhere correctly. Abruptly, in a gizmo fashion for simmers that are not really familiar with cost index equations yes. Correctly no... Sorry to break the illusion.As far as the MD11 FMS goes, the ECON speed model has been validated by over 100 prediction vs. measurement data in the real sim. Hope this makes you happy :)Best,Vangelis ===================================== E M V Precision Manuals Development Group www.precisionmanuals.com=====================================

[Guest iflyc77]

Wow...:-eek

[mburkhard 23]

>In the event of that many failed Generators, would starting>APU have been part of that checklist too?Yes, but it's not that simple. Starting the APU at high level after more than two hours inflight is not recommended in this situation due to heavy battery drainage. And it's not guaranteed that the APU will start above FL250, so you wouldn't want to drain all your battery trying to get the APU started.>Ouch! no autopilot and having to go thru all of that. Does>this bird diconnect from auto real smooth?What do you mean by that? If you disconnect AP in a no wind situation then airplane's pitch and bank would just stay where it was with AP.Regards,Markus

[3-2-1-Now 126]

Hi,I don't quite see the logic here:>> Starting the APU at high level after more than two hours inflight >> is not recommended in this situation due to heavy battery drainage.Getting a couple of gens online has to be better than emergency power any day of the week! ;) >> And it's not guaranteed that the APU will start above FL250So get to FL250, start the APU, get #2 back up, and climb again, using the APU gens for electrical power!Best regards,Robin.

[Los Pilotos 39]

>Hi,>>I don't quite see the logic here:>>>> Starting the APU at high level after more than two hours>inflight >>> is not recommended in this situation due to heavy battery>drainage.>>Getting a couple of gens online has to be better than>emergency power any day of the week! ;)But what if it doesn't start? Then you've just wasted a huge amount of battery power and then you have an even bigger problem as the battery normally only last for about 30 mins and you may have to rush to get on the ground instead. In this case I will rather stay with what I know I've got than what I may get or could lose.>>> And it's not guaranteed that the APU will start above>FL250>>So get to FL250, start the APU, get #2 back up, and climb>again, using the APU gens for electrical power!Why would you even consider climbing back up? In case I've lost all my main generates it would be an emergency with the associated mayday call and diversion to nearest suitable airfield. Also depending on the apu you may not be able to load it although you can (maybe) start it.Rene

[3-2-1-Now 126]

Let's break this down:You've got 2/3s available thrust that you had before the loss of #2. You might need to start a drift-down procedure.You say you only get 30 mins battery. OK - so you're mid-Atlantic, and 4 hours flight time from the nearest airport. You're going to worry about a 30 minute battery being depleted to get the APU running?>> Why would you even consider climbing back up?Simple - fuel efficiency. I'd need to descend to get the APU running. Once the APU is running, I can get the APU gens online to power the systems, get the fuel pumps running again and can get #2 restarted. The point of 30 mins battery becomes moot once it's powering the systems.I do see your point about the APU failing to start, but if it did, you're stuffed anyway. Once the APU is powering the systems, you're most of the way there.The above are just the core reasons why I'd want the APU started. I'd also be wanting to know why I lost all 3 gens.From the MD-82:LOSS OF BOTH GENSThis emergency condition is indicated by:

[Qavion 19]

Interesting... Do you still get MCP displays after a 3 generator failure on an MD11?If the A/P isn't working, what's the point of powering the MCP? Course selection?ThanksCheers.Q> (non MD11 guy) :(

[Guest rellehenk]

When you pull the ADG and switch on ADG ELEC, the battery is being charged and the right and left emergency busses are powered. So we have unlimited emergency power. Fuel pump of engine number 2 is powered by the right emergency bus. After switching on the ADG ELEC and ignition override, the engine will run again. No need to start the driftdown procedure, because the MD11 is able to maintain the altitude for a while until it reaches its driftdown N-1 speed.You can consider to start the APU, but indeed, there is a large performance decrease. Max operating altitude with APU running is FL300.

[mburkhard 23]

>Max operating altitude with APU running is FL300.No, if the APU is running you may use it up to the service ceiling which is FL430.It's just not guaranteed that it will start above FL250-FL300. The higher the ambient temperature the higher are chances for a successful start at altitude.Regards,Markus

[3-2-1-Now 126]

Nice!!Best regards,Robin.

[Guest rellehenk]

No, my FCOM says max operating altitude is FL300, max starting altitude FL250. Maybe there is a difference between MD11-operaters, but at my company we can only use the APU below FL300Regards