Slow slats retraction

[scandinavian13 5,192]

1 minute ago, kevinh said:

I don't think anyone else has suggested anything like that, Kyle. People are just trying to figure out the reason why things have happened as they have.

"I'm pretty sure that the slat retraction from 1 to UP doesn't take nearly 2 minutes IRL, does it?"

Seems to be pretty clearly questioning the simulation, to me at least.

[Budbud 227]

Ok thanks for rectification. 

However, there is something not clear to me.

FCOM says: If any flap position is non-normal or if flap control is in secondary mode, all flap
positions are displayed.

And also: If any flap group fails to move to the commanded position, the FCUs switch to secondary mode for the related group driving the flap group through electric motors.

But is there a way to identify on the expanded display which flap group is in secondary mode since it seems that the FCU can swith either group at a time and not necessarily all at once?

[Robert3512 21]

10 minutes ago, scandinavian13 said:

"I'm pretty sure that the slat retraction from 1 to UP doesn't take nearly 2 minutes IRL, does it?"

Seems to be pretty clearly questioning the simulation, to me at least.

It was a very crude stab at humor, that unfortunately didn't catch on. 

[kevinh 409]

12 minutes ago, scandinavian13 said:

"I'm pretty sure that the slat retraction from 1 to UP doesn't take nearly 2 minutes IRL, does it?"

Seems to be pretty clearly questioning the simulation, to me at least.

But all the replies show an understanding of what has happened. That's what I meant.

For what it's worth, I've just tried this myself in the 747v3. Even with engine 4 shutdown, hyd pressure with flap retraction doesn't even twitch from 3000 psi, so there would be no reason for the flaps to go into secondary mode. In reality the hydraulic load of flap and gear operation causes hyd pressure from engine 1&4 pumps to drop significantly, often causing the demand pumps to run. Looks to me like something isn't right with the hydraulic pressure simulation (hyd quantity does react to gear operation as it should do).

The OP reports normal TE flap operation, so there is no obvious reason why the LE flaps switched to secondary mode. It didn't do that in my case.

If people weren't questioning the simulation, I am now.

Edited February 23, 2018 by kevinh

[Robert3512 21]

Now, I would like to note that I do have service based failures on, but either it didn't register on the PMDG > FAILURES page, the EICAS page (unlikely) or my simulation just hiccuped. I did happen to have a HYD PRESS SYS 4 light that came on momentarily, then extinguished. Unfortunately, I wasn't looking at the HYD page, so I couldn't tell you what caused it, and honestly the memories are a tad fuzzy now. But then again, as pointed out be quite a few folks, the LE slats run on bleed air, and the hydraulic systems shouldn't affect it, as it didn't affect the TE flaps, which is normal. 

[Budbud 227]

Then in this case, if everything is configured correctly on the aircraft and there is no failure active, maybe we need in search to another direction:

Robert, do you use a custom panel state? And Fsuipc?

If you use a custom panel state I would advise you try to reproduce the issue but with the default panel state loaded at the start of the sim.

If it still occurs with the default panel state, then you may try to temporarily move the fsuipc.ini out of the module folder and rebuild a profile to see if it fixes the issue.

 

[Robert3512 21]

2 minutes ago, Budbud said:

Then in this case, if everything is configured correctly on the aircraft and there is no failure active, maybe we need in search to another direction:

Robert, do you use a custom panel state? And Fsuipc?

If you use a custom panel state I would advise you try to reproduce the issue but with the default panel state loaded at the start of the sim.

If it still occurs with the default panel state, then you may try to temporarily move the fsuipc.ini out of the module folder and rebuild a profile to see if it fixes the issue.

 

I've never bothered with panel states, but I do use FSUIPC. I'll poke around and see what I can do.

[Budbud 227]

1 minute ago, Robert3512 said:

I've never bothered with panel states

Sorry, I should have also added not only custom panels but also the other panels that the default one. 

Which panel do you use to load the aircraft with? If not the default one with engines running, then you should try with this one first before going to the fsuipc thing.

For some reasons, the long, short turn over and cold and dark panel states provided also get corrupted and that trigger a wide range of strange behaviours to some users.

[Robert3512 21]

7 minutes ago, Budbud said:

Sorry, I should have also added not only custom panels but also the other panels that the default one. 

Which panel do you use to load the aircraft with? If not the default one with engines running, then you should try with this one first before going to the fsuipc thing.

For some reasons, the long, short turn over and cold and dark panel states provided also get corrupted and that trigger a wide range of strange behaviours to some users.

I just load the aircraft in its default state every time. The two or three times I tried to load a panel state it absolutely destroyed my simulator. I figured a couple more minutes of flicking switches and pushing buttons isn't worth a potential CTD.

[berts 97]

14 hours ago, Robert3512 said:

https://imgur.com/a/i3gLg

So, I was retracting flaps and slats from 10 to UP, and I'm pretty sure that the slat retraction from 1 to UP doesn't take nearly 2 minutes IRL, does it? The flaps retracted on schedule. I have no failures in the PMDG > FAILURES section active.

What you are seeing in https://imgur.com/a/i3gLg is actually normal behaviour with a FLAPS PRIMARY message.  Your flap sequencing is operating in Secondary Mode with your Flap Lever UP (shown by the Expanded Flap indications on the Primary EICAS display). 

Normally the three Flap Control Units (FCU's) operate the Trailing Edge Flaps hydraulically and the LE Flaps pneumatically (incidentally, they are not LE Slats!).  However, if any Flap group fails to move to the commanded position the FCU's will automatically switch to Secondary Mode and drive the symmetrical Flap groups on both wings using electric motors.  It takes approx 4 minutes for the TE Flaps to move from UP to Flaps5 and approx another 2 minutes for them to move from Flaps5 to Flaps30 (this explains your nearly 2 minutes from Flap1 to UP).

You will need to allow extra time and distance with this condition during the initial Climb and cleanup as well as for the approach; paying particular attention to speed control during the Flap operation.

Bertie Goddard

[Samany69 41]

Hello . might be a repeat of the same answers yet i will let you have some info
according to AMM ATA Chapter 27-Flight Control :

High Lift System EICAS Messages:
The EICAS caution message FLAPS PRIMARY is displayed when one or more flap groups enter primary electric mode due to a disagree.
The EICAS caution message FLAPS DRIVE is displayed when one or more flap groups fail to move in primary electric mode due to a disagree or a shutdown.
The EICAS status message TE FLAPS appears when hydraulic TE flap operation has failed, or when there is a flap asymmetry.
The EICAS status message LE SINGLE Drive is displayed when there is a single Leading
Edge Drive Mode Failure. The status message LE MULT DRIVE is displayed when there
are multiple Leading Edge Drive Mode failures on one or more Drive units. A mode is
either Primary Pneumatic or Primary Electric operation.
The EICAS status message FLAP SYS MONITOR is displayed when there is a failure of a LE flap power drive unit limit switch, TE flap position RVDT transmitter, or flap lever RVDT.
The EICAS status message FLAP CONTROL L, FLAP CONTROL C, or FLAP CONTROL R is displayed when there is a failure of the corresponding flap control unit. The EICAS caution message FLAPS CONTROL is displayed when there is a failure of all three flap control units, or if the ALTN FLAPS ARM switch is pressed to the ARM position.
NOTE: With the hydraulic pressure reduced, the EICAS message FLAPS PRIMARY will
be displayed. The EICAS can display the message FLAPS DRIVE.
NOTE: The EICAS messages FLAPS PRIMARY and FLAPS DRIVE can be displayed.
Hydraulic system No. 1 pressurizes the inboard flaps.Hydraulic system No. 4
pressurizes the outboard flaps.
NOTE: When only one hydraulic system is pressurized, you cannot use the EICAS
messages to verify the flaps extend hydraulically. You must do a visual check
to make sure the flaps extend.
The primary electrical system controls the LE and TE flaps through the flap control lever. A "FLAPS PRIMARY" caution message will be shown on the EICAS to show that the primary electrical system is in control.
The primary electrical system controls the LE and TE flaps through the flap control lever. A "FLAPS PRIMARY" caution message will be shown on the EICAS to show that the primary electrical system is in control.
Additional lift is provided during takeoff and landing by 28 leading edge (LE) flaps operating with the trailing edge (TE) flaps. Extension of the wing flaps changes wing camber to produce the desired lift.
The 11 outboard and midwing flaps in each wing are variable camber flaps with the camber being changed as the flaps are extended. The remaining three flaps in each wing are Krueger flaps.
Primary pneumatic power to position all LE flaps is provided by pneumatic motors. Electric motors provide power to position LE flaps in alternate or primary electrical operations.
The EICAS caution message FLAPS PRIMARY is displayed when one or more flap groups enter primary electric mode due to a disagree.
The flap control lever starts the primary operation of the leading edge devices. Usually pneumatic motors operate the LE flaps. If the flaps do not operate in the pneumatic mode, the electric motors will then automatically operate the flaps. Change to the electric mode will cause the EICAS caution display "FLAPS PRIMARY" to come into view. As the result, more time is necessary to operate the flaps because of the slower electrical extension or retraction.

Regards.

Edited February 23, 2018 by Samany69
Minor Dictations.

[berts 97]

2 hours ago, Samany69 said:

NOTE: With the hydraulic pressure reduced, the EICAS message FLAPS PRIMARY will be displayed. The EICAS can display the message FLAPS DRIVE.

Sorry, but this is not strictly correct. 

The FLAPS PRIMARY message will display if a Trailing Edge Flap group is being driven in the secondary mode due to a LACK of hydraulic system pressure and not simply for a reduced pressure.  Under normal operating conditions the relevant Demand Pump will usually kick in as soon as a drop in hydraulic system pressure is detected e.g. when extending and retracting the Flaps normally or after an Engine/EDP failure.  If this wasn't the case the FLAPS PRIMARY Caution message would appear every time the system pressure reduced. 

The FLAPS DRIVE Caution message is displayed when a drive failure of either the Trailing or Leading Edge Flaps is detected or if a Trailing Edge Flap asymmetry condition exists which cannot be corrected by use of the electric motors. Incidentally, if a Trailing Edge asymmetry is detected the primary operation is shut down immediately for the asymmetric group and the the FCU's do not use the secondary mode.  It can also take up to 50 seconds for the Flap system to detect a Leading Edge Flap group failure but any asymmetry this delay might cause is controllable

Some of the other things you mention are not quite correct either; for example:-

2 hours ago, Samany69 said:

NOTE: When only one hydraulic system is pressurized, you cannot use the EICAS messages to verify the flaps extend hydraulically. You must do a visual check to make sure the flaps extend ......  etc etc.

Carrying out a visual check might be OK as a mechanic on the ground, but it is not recognised as standard practice for the pilots.on a B744 in flight.  The EICAS system is very reliable and in the case of the Flap indications etc it can be relied on to give the pilots the correct information they need to determine whether or not the Flaps are operating correctly. Any one of the FCU's is capable of performing any or all of the basic functions: i.e. Primary and Secondary control as well as annunciations and indications.  There is also an Alternate mode which is selected manually and bypasses the FCU's; so there is a great deal of redundancy built into the Flap system. 

I accept there might be one or two occasions when a pilot will want to visually check the Flaps in flight, say after suffering external damage, but this is obviously a command decision on the day.  But even then crews are trained to carry out the appropriate QRH for the EICAS messages and any other indications they have presented to them in the cockpit first. 

Bertie

[Samany69 41]

4 hours ago, berts said:

Sorry, but this is not strictly correct

Dear Friend. It is fine that you don't accept it . I don't mind it at all . you are not standing against my words. your actually standing actually against what boeing company has Said about their own airplane in the official documents.

I have the documents. I'm an aircraft maintenance Engineer and just brought you the info directly from the Maintenance manual , Chapter 27 - Flight Control . Go Ahead my friend, Please tell Boeing that they are giving wrong info in their official FAA Approved Maintenance Manual Documents to the Operators.  

Regards.

[Samany69 41]

5 hours ago, berts said:

It can also take up to 50 seconds for the Flap system to detect a Leading Edge Flap group failure but any asymmetry this delay might cause is controllable

and where is the Reference or the document which you are taking this info from ?? ... I am looking straightly at the Original document and can't find anything about 50 seconds of Fault or Disagree Detection ! and hey , In flight , 50 seconds of delay in an approach procedure could lead the plane to somewhere really bad .... Fortunately Boeing is not doing anything wrong haahaa .... Trust me my friend. I wont give out info in this Forum until they are official or 100% correct , otherwise i will Straightly mention that what I have said is according to my own experience or is just my opinion . yet as you see I just said according to the maintenance manual . so i'm not going to change your mind about what I have said . neither Boeing company does convince the operators that something in the airplane works this or that way. this is a fact to be honest. 

 

Have a Good day.

Regards.

[rsrandazzo 6,353]

Gents,

Another important consideration for you all to ponder:  Some 747-400s (mostly UAL airplanes) have 4 pneumatically driven hydraulic demand pumps.  (Called ADPs.)  instead of the standard 2 ADP and 2 EDP configuration.  In this case, if the load on the bleed system is extremely high and there is a deficit in production, you **could** conceivably trigger a flaps primary condition because the leading edge devices use pneumatic pressure as their normal motive power.  (I would have to go back and sniff around some schematics to see if you would get it in the situation Robert created...  Please forgive me for not doing so tonight...)

And to those of you who immediately suspected a problem in the hydraulic system, remember that this would give you a problem on the trailing edge, not the leading edge.  Not exactly germane to this discussion- but worth pointing out since a number of you immediately went for hydraulics as the source of motive power for the LEDs.

Also- points to everyone for the engagement in the discussion.  I love when someone stumbles into something non-normal that shows off the depth of the simulation value.  Most users don't touch even 10% of the simulation value in this product- and if I constantly pointed things out- you guys would grow bored of my constant lectures. 

 

To EVERYONE:  When you get EICAS messages- make sure you read them.  Then go to the QRH and look at the trouble shooting process.  You will learn some REALLY interesting things about your airplane!