Here is some info on Alternate flap extention:

 

Flap/Slat control EICAS:

Flap and Slats both in Alternate mode (normal plus standby mode inop)

flap lever input normally is to the FSEU’s. If they (2x) are broken you have to

use alternate flap extension.(electrical)

max flaps 20/slat 1.

Load relief for flaps is not available and not required for slats.

 

You do not get a green Flap indication once the desired flap setting has been

reached. The indications stay white because the flap lever is bypassed (the system does not know what your target position is.

Manually stop flap movement once target position has been reached.

 

 

I remember timing flaps 5 to flaps 20 extention once in secondary (flap) mode.

It took about 2.5 minutes.

Flaps 0 to 5 took even longer!

 

EDIT:

If your question is about the flaps not starting to move (in alternate mode) untill the flap lever is moved to 20, that should not be, no.

Might be an FSX limitation though.

Since the flap lever is bypassed it does not matter where it is.

I might be misinterpreting this, but my understanding was that the flight control laws relate only to the function of the flight computers which take pilot input and translate into physical movement of the flight controls. In your case, provided all computers stayed online, the law shouldn't change because despite the fact that the computers have less toys to play with, they are still functioning correctly. If one were to be taken offline, then a change in law would be expected. I'm just guessing here, not an expert by any means.

Normal Law involves complex gain scheduling based on airspeed, Mach number, CG, and other key parameters to provide consistent level 1 handling qualities across the envelope. With a minimum set of surfaces and reduced actuation capabilities on those remaining surfaces, that handling quality couldn't possibly be achieved. The availability and dependability of those sensory inputs affect your control law as well.

 

What I don't understand is how, with that many surfaces lost, and possibly loss of probe heating as well, PMDG 777 can still support Normal Law. Some more details beyond the FCOM would be very enlightening for all of us.

 

 

if I would have studied something proper

:lol: Don't know about being a pilot in Europe, but in my land being an airliner pilot is synonymous with steady high cash flow and high social status. Being among the best academic student/engineer usually lands you in...well, not really jail, but a very modest pay and uneventful life. I know, I've been there.

 

You are totally right about how high fidelity simulation such as PMDG has enabled many people to broaden their horizon. A reminder for myself, just don't treat it as a Boeing engineering simulator!  :blink:

 

 

 

I did not quite understand your question about alternate flap extention.

Sorry. I set the fuel to zero so that the APU couldn't possibly power the ADPs, or the electrical network. Then I flipped the Alternate flap PBA guard open, press it to engage Alternate flaps, and turned the little rotary switch behind to 'EXT'. No indication on EICAS, no idea what the flaps are doing. So I moved the lever to flaps 5. Indication appears on EICAS but still there's no movement for a looooong time...Previously I have been able to deploy flaps but that's when APU is on. I suspect there's a bug here that allows APU to bypass overhead panel ADP switches and power the Center system directly. With the Center system powered by RAT+ADPs, the flaps will deploy at close to normal rate, with normal lever control. But when the APU is very dead due to fuel starvation, the Center system is on RAT only and the electrical Alternate flap simply doesn't work for some reason. 

 

 

 

I remember timing flaps 5 to flaps 20 extention once in secondary (flap) mode.
It took about 2.5 minutes.
Flaps 0 to 5 took even longer!

Or perhaps I just didn't have enough altitude to wait for things to happen! :lol: Seriously, though, if Alternate flaps is indeed as slow as your recollection shows, then it's pretty useless in a dual engine flame out scenario. The crew then has to time flap deployment accurately to place the aircraft in just the right configuration, at the right speed, over a suitable landing field. Raises eyebrow I guess. Don't know how the Gimli 767 crew handled the situation. Perhaps some windmilling helped, through the EDPs.

:lol:

Or perhaps I just didn't have enough altitude to wait for things to happen! :lol: Seriously, though, if Alternate flaps is indeed as slow as your recollection shows, then it's pretty useless in a dual engine flame out scenario. The crew then has to time flap deployment accurately to place the aircraft in just the right configuration, at the right speed, over a suitable landing field. Raises eyebrow I guess. Don't know how the Gimli 767 crew handled the situation. Perhaps some windmilling helped, through the EDPs.

Alternate flaps is not there for engine failures.

It is there in case the normal or secondary flap mode dont work.

 

If you have a dual engine failure when high, you would want to get the windmilling start going (with 270kt or more).

No quick flap extention required at that speed.

 

If you have a dual engine failure when low, it depends, but you can allways just keep the speed you have. I mean you are flying right now, so at that speed you will keep flying.

Having engines or not does not change that.

No need for rapid flap extention here either.

 

Anyway, rather than trying to make things fail by setting fuel to 0, or shutting down engines, why dont you just activate the FLAP/SLAT control 1 and/or 2 fail in the CDU and see what happens then? I mean this should be as in real life as the scenario is programmed by PMDG.

 

 

I mean this should be as in real life as the scenario is programmed by PMDG.

Yeah, I'll see what happens in that scenario. Actually, where is this list of 'official' programmed system faults from PMDG? Do you mean those that you can activate via the CDU? At least in NGX that's pretty limited. Again, I should enjoy flying the normal airplane, instead of using it as a 'what if' machine. The simulation is really not built for that purpose.

 

Also, as a real-life pilot, what is your opinion about retaining MCP for airspeed/altitude/heading bug setting? I mean, the autoflight system may be out, but for pure manual flying the ability to set those targets is still quite important for safety, right?

 

 

So let’s start by stating this is by no means a challenge to PMDG's authenticity, since I have no idea how a real 777 will respond either.

 

So the point of posting this thread was to...?

 

Based on several of your points making an inference that something is modeled incorrectly, either come out and say it, or don't say it at all.

 

I'm not saying you're wrong, or that it's wrong to point out something that seems to be a discrepancy, but own up to it.  Call someone out for something that's wrong and stand behind that accusation, or don't say anything.

 

 

 

Another odd thing is that the MCP seems to be of a lower priority than FO’s displays, which is counter-intuitive…Setting airspeed/altitude/heading targets should be quite an essential and basic safety feature especially in a high workload scenario. Does this reflect the real thing?

 

To be honest, one of the biggest simisms out there is this idea that the AP should still be active and fully in control during non-normal operations - from missed approaches to emergencies.

 

Why would I cut power to one side's when I could just cut the MCP, because in a situation that bad, you're probably not going to have the AP on anyway?  Sure, the targets are nice, but many pilots are going to have come up the ranks in aircraft that didn't even have autopilots, much less more advanced bugging features.  Claiming otherwise is joining the ranks of those who, after the Asiana crash, claimed that the plane crashed because the glideslope was out...

 

Nice? Sure.

Necessary? No.

 

I'd rather my FO be able to see his/her own indications to back me up than fully isolate him/her just so I can have my MCP.

I flew again with fuel quantity set to zero. This time there's no ADP, but flight control stayed in Normal Mode. "Flight Control" message was shown to indicate that some surfaces are unavailable. I guess the boeing control law and flight control architecture are simply very different.

 

Also, you mentioned Pitot Heat lost. Reading QRH dual eng fail checklist it does suggest that this message will appear as a result of loss of both engines. If all probe heating is off, then air data input to FCEs cannot possibly be trusted for control law computation. How is Normal Law still sustained?

FLIGHT CONTROLS QRH pages state that there is a degrade in the flight control capability. Seems the FBW mode in this case is not affected as it is an actuator problem, not a FBW problem.

Based on several of your points making an inference that something is modeled incorrectly

I think actually that point still has still to be addressed. It's a valid, and interesting question at that.

 

Best regards,

Robin.

 

 

I think actually that point still has still to be addressed. It's a valid, and interesting question at that.

 

Note I also said "I'm not saying you're wrong, or that it's wrong to point out something that seems to be a discrepancy, but own up to it.  Call someone out for something that's wrong and stand behind that accusation, or don't say anything."

 

He dismissed his own statement as "no means a challenge to PMDG's authenticity, since I have no idea how a real 777 will respond either."

 

As such, I have no reason to take it seriously.

 

I just took issue with what seemed to be a lack of commitment.  Either stand behind what you say or don't say it.  This "I'll make some huge post about things that seem inaccurate, but I'll dismiss them before even posting most of it" is just pointless.

 

Do I pay attention to what you're going to write or not?  That's the only issue I had with it.

Yeah, I'll see what happens in that scenario. Actually, where is this list of 'official' programmed system faults from PMDG? Do you mean those that you can activate via the CDU? At least in NGX that's pretty limited. Again, I should enjoy flying the normal airplane, instead of using it as a 'what if' machine. The simulation is really not built for that purpose.

 

Also, as a real-life pilot, what is your opinion about retaining MCP for airspeed/altitude/heading bug setting? I mean, the autoflight system may be out, but for pure manual flying the ability to set those targets is still quite important for safety, right?

Yes, I mean the list from the CDU, but you can find an overview in the manual (starts on page 101) with everything that is simulated and that work like in real life (I assume)

 

And yes, even though the AFDS is out you stoll want to set heading/speed in the MCP.

First because it helps, second because having them anywhete else is distracting and annoying and last, once the Primary flight control modes again and you engage the AP it will not do something strange.

 

In real life with a dual engine failure, after you have done the checklist item "Primary Flight Computers - "Disconnect then Auto, the AFDS is usually available again.

Even with both engines still failed!

So the point of posting this thread was to...?

 

Based on several of your points making an inference that something is modeled incorrectly, either come out and say it, or don't say it at all.

 

I'm not saying you're wrong, or that it's wrong to point out something that seems to be a discrepancy, but own up to it.  Call someone out for something that's wrong and stand behind that accusation, or don't

Hi Kyle.

 

I cant look in the OPs head of course, but I had the feeling he was just messing about and seeing what the sim would do in this particular case and trying to get info if this is realistic behavior or not

I think he also agreed the simulation fidelity has to end somewhere.

 

You are defending PMDG here....or feel PMDG is attacked.....but I did not have that feeling.

 

I did say the whole excersise was a bit too much and even unrealistic, but I did not have the feeling he was out to cal PMDG anything.

"Call someone out for something that's wrong and stand behind that accusation" that might be a bit harsh on him.

 

Anyway, we have evolved to trying the failures that ARE simulated correctly (and I am realy impressed by how many of those are on the list) so we can put the dual engine failure with nothing restarting and no APU to bed now :-)

 

 

You are defending PMDG here....or feel PMDG is attacked.....but I did not have that feeling.

 

Nope.  Not at all.  Note that I said "I'm not saying you're wrong, or that it's wrong to point out something that seems to be a discrepancy, but own up to it.  Call someone out for something that's wrong and stand behind that accusation, or don't say anything."

 

That's all I'm getting at.

 

It's a motivation thing.  If you want someone to look at something, say it.  Based on that line that I highlighted, I'm not really sure if this post was meant to have someone take a look or what...

 

As usual - not trying to be mean - I'm just trying to make a point: if you want someone to invest time in your issue, show them that you're invested in your issue.

I tested the hydraulics - I don't see any transfer of fluid from one system to the other.

 

The way it is stated in the manual, makes it appear that fluid transfer should be evident pretty quickly, otherwise for the time it takes to pressurize the hydraulics before start, any fluid transfer would be insignificant and not worthy of metion.

 

I left each individual system running for over 5 minutes each - far longer than it takes to pressurize the entire system during start-up - based on the manual I'd expect to see something.

 

Best regards,

Robin.

otherwise for the time it takes to pressurize the hydraulics before start, any fluid transfer would be insignificant and not worthy of metion.

 

...or the fact that over time, this could become significant.  Things aren't written in manuals just because they affect the one flight, or the flight immediately following.

 

Like overstressing the flaps:

Yeah, sure you might not break them off and plummet to your death, but the damage has been done, and it might affect something later.

OK - I'm going to leave it running for the next couple of hours. It must be significant enough to mention in the manual and have a specific procedure.

 

Best regards,

Robin.

 

 

OK - I'm going to leave it running for the next couple of hours. It must be significant enough to mention in the manual and have a specific procedure.

 

Cool - update here with the results.  I'm not saying you're wrong - I just wanted to point out an alternate explanation.