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Olympic260

Quick Preflight at FAOR

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G-CIVX preflight from cold and dark to ready for push at FAOR. PMDG B744v3 BETA
 
Getting ready for the return flight to LHR
 

 

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Why are the Yaw Damper switches still showing INOP? :smile:

 

John H Watson

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No hydraulics?

 

 

Oddly, Ryan, the INOP lights will go out on the YD switches just with full IRU alignment during preflight. Same on the 767. My training instructor thought that hydraulics were required, too, but during a practical session on the real aircraft, I showed him otherwise :P

 

I haven't been able to persuade a pilot to turn the hydraulics off an on in-flight yet, so the logic remains a mystery (I've been trying to find the logic for the lights for over 10 years). I was hoping one of Mr Randazzo's Boeing contacts would be able to solve the mystery.

 

I have a few theories:

The INOP lights only come on if the aircraft is in the air and you lose hydraulics (the YD system only starts operating the hydraulic actuators in the air... It has a "fade-in" mode. On landing, it has a fade out mode)....  OR

The system has to see hydraulics on, then off to display an INOP... OR

The system is smart enough to know that hydraulics have been switched OFF and realises that the system itself is not faulty (It does receive pressure information from hydraulic system pressure switches)....and doesn't trigger the INOP lights at any time (due to hydraulics loss).

 

There may be some strange sequence of events which trigger the EICAS messages and the INOP lights (although not necessarily at the same time).

 

Regards

John H Watson

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John,

 

(How the heck are YOU?!  Long time no see!  :hi: )

 

Interesting.  This isn't my system so I'm going to pass back your observation to the developer responsible...

 

I've honestly never looked up at the switches at any point in time when i would have noticed they were illuminated...  Interesting how the pilot's mind tunes out a set of dusty switches we never touch anyway.

 

As for turning the hydraulics off in flight- have you considered offering the pilots free food?  We pilots do quite a bit for free food, you know.

 

I've added that to our sim agenda.  We'll give it a go and see what comes of it.  Next best thing to doing it on a line airplane, I suppose.  :P

 

Of your three theories:  I'm leaning toward the air/ground input playing a role just sitting here pondering it.

 

The other two options would seem to be quite different than the rather straightforward logic used on so many other systems that WILL register a failure even if the hydraulics are switched off intentionally...  If they had succeeded in making the system self aware enough to suppress- i bet we would see that same logic applied to many other locations on the airplane. 

 

It seems they didn't get around to doing that routinely until the 777...

 

Okay- i'll dig around and see what we come up with.  My favorite former flight test engineer spent an hour on skype today discussing something esoteric- i'm sure he will be happy to hear from me again today. 

 

Be well, John...  Good to see you about!

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The other two options would seem to be quite different than the rather straightforward logic used on so many other systems that WILL register a failure even if the hydraulics are switched off intentionally... If they had succeeded in making the system self aware enough to suppress- i bet we would see that same logic applied to many other locations on the airplane.

 

Hi, Robert, long time no see indeed. :hi:

 

I couldn't resist... your new sim looks amazing.

 

I did think that some of my options were a bit dodgy :Tounge: Usually it's Status and CMC messages which have the most "screening" (to avoid niusance messages).

 

... Currently looking for other possible causes of the EE CLNG SUP FAN Status message (in another thread somewhere). The Boeing Fault Isolation Manual says there are a number of electrical bus faults which can produce this message:

 

Util Bus 1 (3 phase fan power)

AC1 (powers Util Bus)

AC3???

AC4???

DC Bus 1 (controls the fan power relays)

 

I've spent two days looking at wiring diagrams and still can't figure it out. Glad I didn't come across this defect in the real world :Tounge: It didn't help that my training manuals showed a faulty diagram.

 

It's interesting to note that the EE CLNG SUP FAN Status message should not appear (even if it has died) if :

1) Equip Cooling is in Override (the fan is not supposed to run in this mode anyway)

2) The "cleaning mode" is activated for 25 seconds every 10th descent (as above).

3) The fwd/aft cargo fire switches are activated (as above)

 

An interesting mental exercise in semi-retirement :fool:

 

Cheers

John H Watson

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Most of the videos I see have the panel option enabled for the vor/adf tuner below the clock, but I have never seen that in real life. Does any carrier have that option? Interesting I never knew it existed. Great video I can't wait to see this released and get my hands on it when I can afford the P3D version later next year. - David Lee

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vor/adf tuner

 

I had to stop and think about that one..., ah then I connected the dots.  RMI Radio Magnetic Indicator,  very handy instrument for a number of routine IFR tasks. Been around awhile.

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I had to stop and think about that one..., ah then I connected the dots.  RMI Radio Magnetic Indicator,  very handy instrument for a number of routine IFR tasks. Been around awhile.

I have never seen that on a 747 - David Lee

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Most of the videos I see have the panel option enabled for the vor/adf tuner below the clock, but I have never seen that in real life.

 

 

It's perhaps because it's hidden by control columns and pilots' knees :Tounge:  I've seen a few with this option (BA, Thai, Korean, ... ).  There is actually an option for one on each side (captain's and F/O's). I think some of Thai's 744's had this dual RMI option. The pointers on the instrument also come in different colours.

 

I guess some of the old folks still know how to use them :wink: Normally, the Right IRU controls the compass card on the Captain's RMI. This is good for crosschecking the instruments.

 

Cheers

John H Watson

P.S. Here's a picture of an unpowered one (sorry, can't remember which airline I was working on at the time)

 

ChronoRMI.JPG

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Not standard fit necessarily, just an option. Virgin jumbos don't have them (pretty sure anyway)

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