Passenger signs

[cavaricooper]

Hardy-

When AUTO is selected for the Seat Belts/ No Smoking signs, they extinguish at 10000 and light up at 10000.... should there not be a corresponding seat belt chime with deactivation/activation?  If so, I do not hear one.  If not, allest gut.

Best- C



Edit HH: Started new thread

[Hardy Heinlin]

Ref. page 106: It's 10000 ft cabin altitude.

The logic includes gear and flap positions.


|-|ardy

[cavaricooper]

Hardy- yes, but the question is about the chime.... should it chime or not (I do not hear one in AUTO, but do when I manually select)....?  I thought it was supposed to chime to get the passenger's attention as well as serve as a positive indicator on the flight deck?

Best- C

[Hardy Heinlin]

The AUTO mode does not involve any condition referring to 10000 feet aircraft altitude.

What do you expect at 10000 ft? There is no event there.


Page 106:

"AUTO: FASTEN SEATBELTS and RETURN TO SEATS signs illuminate when gear down, or flap lever out of up, or cabin altitude above 10000 feet. FASTEN SEATBELTS signs illuminate and RETURN TO SEATS signs extinguish when passenger oxygen deployed."

I hear the chime accordingly. See bold font.


|-|ardy

[cavaricooper]

Ok- therein lies my confusion. I was under the (apparently incorrect) assumption that selecting AUTO for signs resulted in the signs going off in the climb (at 10000) and on in the descent (10000).  Your explanation of the AUTO function is vastly different- hence my question- disregard.

Best- C

PS- I just checked the FCOM 1.30.3 and I still think there is more to this, sorry..... There is a clear reference to airplane altitude and configuration- NOT cabin altitude.

[Hardy Heinlin]

You still don't hear the chime? I do.

Set gear up, and play with the flap lever between UP and 1. There's always a chime.

[cavaricooper]

I do not when in Auto and passing 10000. I DO WHEN I MANUALLY SELECT BELTS....

Is there some audio setting I ought to check?

C

[Hardy Heinlin]

As I said above, there is no event at 10000 ft.


Set gear up, and play with the flap lever between UP and 1. There's always a chime.


See also passenger signs on Instructor > Analysis > Misc

[cavaricooper]

Hardy-

Respectfully, FCOM 1.40.4

Cabin Signs

The cabin signs are controlled by selectors on the aisle stand. The signs illuminate when the following conditions are satisfied:

FASTEN SEAT BELTS signs (AUTO selected):
• landing gear not up and locked or
• flap lever not up, or
• airplane altitude below 10,300 feet, or
• cabin altitude above 10,000 feet, or
• passenger oxygen on

NO SMOKING signs (AUTO selected):
• landing gear not up and locked, or
• cabin altitude above 10,000 feet, or
• passenger oxygen on.

In Seat Belts AUTO, with gear and flap up the lights would extinguish passing 10,300 (WITH A CHIME) nicht? I am still confused..... sorry!  Perhaps JHW or one of our RW pilots can clear this up.... I do not mean to be argumentative... just would like some clarity on this issue.

Best- C

[Hardy Heinlin]

OK, that 10300 thing might be company specific or even a general update. This condition is not included in PSX. I'll consider adding it.

But you asked if the chime works. I say it works (with ref. to page 106). Just try what I wrote above.


|-|

[cavaricooper]

Hardy, danke!

The quote was from a bog stock Boeing FCOM... I appreciate your consideration.  To clarify- yes, I do hear the chime with flap - but, to add to this conundrum, I believe that to be incorrect as well.... Based on the quoted criteria, it would not extinguish until a/c above 10300.....

Ducking for cover now

C

[Hardy Heinlin]

FASTEN SEAT BELTS signs (AUTO selected):
• landing gear not up and locked or
• flap lever not up, or
• airplane altitude below 10,300 feet, or
• cabin altitude above 10,000 feet, or
• passenger oxygen on

[cavaricooper]

Exactly, any ONE criteria would NOT extinguish the lights (and thereby activate the chime)..... Thus for normal ops... Gear and flap up, AND THEN when passing 10300 lights extinguish.... Or come on in descent....

C

[Hardy Heinlin]

Yes, but in the current PSX version the 10300 condition is not included. You can evaluate your quoted logic only when PSX has got this condition.

To check if your chime is linked with the signs, you need to check the signs on Analysis > Misc and then listen when they change.

By the way, the chime sound comes from outside the flight deck; on the freighter the chime is louder because the entry is open.

[Hardy Heinlin]

A question for the engineers:

Does anybody know which device feeds the aircraft altitude data into the pax sign logic? As ICU L or R are already involved to provide cabin altitude data to the MAWEA (for pax signs), maybe the cabin pressure control system also provides the aircraft altitude data? Or maybe it's the captain's selected ADC? Whatever it is, there's also the question if it's pressure altitude or QNH altitude.


|-|



For now I'll take the QNH altitude of the captain's selected ADC ... until somebody knows more about it :-)



P.S.: I bet there is a hysterisis instead of this single 10300 value. Maybe 10200/10300, or 10300/10400. Otherwise, if you happen to be flying level at 10300, you may get some random flip-flops.

[Britjet]

BA - in AUTO - the chime sounds as the aircraft passes 10,000ft altitude in the climb. It also sounds every time that the seat belt signs are switched ON or OFF. I don't know if it sounds similarly in the descent - we always would have switched it to ON long before then anyway, but I guess it would..

If selected to AUTO the NO SMOKING signs will chime as the gear comes up - (although always selected to ON, these days).

You can hear the chime in the flight deck.

Peter

[cavaricooper]

To follow up with our engineers as well.... Since smoking on aircraft hasn't been permitted for a long time now (except for certain captains known to pull a certain CB at TOC ) I thought there had been a revision on most 744s to ignore that particular switch position, leaving the signs always on?

JHW and others, could you please comment?  This would remove the extraneous chime at flap retraction, without necessitating moving that switch/knob to on.  I accept that on airframes without that particular modification the switch would always be ON.

BTW, since EICAS inhibit only occurs with BOTH switches ON.... Would the modification (if acknowledged to be existent) need a corresponding EICAS logic programming change?

Best- C

[Avi]

Hi Hardy,

At first you did have this aircraft altitude (10,300 ft) condition in the code but then we received a new chart (from 2006) for the passenger signs where this condition removed so you removed it too from PSX.
However, I have a chart from 2011 where this condition does exist so it is looks like it is an airline specific.

Cheers,

[Hardy Heinlin]

BA - in AUTO - the chime sounds as the aircraft passes 10,000ft altitude in the climb.

Is it exactly 10000 or is this number symbolically meant, Peter? :-)

I can't prove it, but I'm sure there is a hysterisis, maybe even by 300 ft rather than 100 as I suggested above, because, otherwise, flicker may be caused not only in level flight with turbulence, but also by TL/QNH transitions in states where the TL is at FL100.

10300 is a strange value, isn't it? I think it has to do with the hysterisis.

New theory:

- When seatbelts off, "below 10000" will turn them on
- When seatbelts on, "above 10300" will turn them off

See, even the slightest mini modification is not entirely trivial :-)


Cheers,

|-|ardy


Hi Avi, messages crossed ... :-) Thanks for the reminder! To avoid another option item, I think it's best to implement this 10300 feature on all models.

[Britjet]

My manual says "airplane altitude below 10,300ft" they are on when selected to Auto. Mo more.

Peter