A few questions: Blue and white rotating rings

[asdro 13]

Hello

 

can you answer please theese questions?

 

1) What are the blue and white rotaing rngs on the EHSI for?

 

2) Does the 777 start engine with packs on? Also with dual engine start?

 

3) what do the blue arrows next to airports on the EHSI mean?

 

4) I saw in a video that the DING DONG messages like "CABIN READY" are announced. Are there more messages like "NO MOBILE".

 

Do the pilots cancel the messages or will they go after a certain time?

 

5) What do the white boxes on the upper EICAS mean next to the EICAS Caution messages. Some of the messages have some don`t have a white box at the beginning.

 

Thanks for help.

[davidz 26]

1) The blue and white rings are part of the off-path descent system. You hit "OFF PATH DES" on the VNAV DES page. They give you an idea of your energy state relative to your target fix/altitude. Inside the inner ring, you have no hope of making it (unless you do some S-turns). Between the two rings, you will need a degree of speedbrake to make it. Outside the outer ring, you will make it with a clean aircraft. They don't actually rotate - it just looks like that because the rings are expanding/contracting.

 

2) Packs are automagically managed for the start - you turn the switch to "START" and a system will turn off the packs for you.

 

3) Blue arrows indicate alternate airports that are off-scale (e.g. if you are in Europe and set YSSY and KJFK in the alternates page, you will get an arrow pointing to each of Sydney and New York)

 

4) The CABIN READY message disappears after a certain amount of time. This is triggered by the cabin crew (or through certain actions/logic in the sim)

 

5) A white box next to an EICAS Caution indicates that there is an associated electronic non-normal checklist.

 

For example, if you get [] ENG FAIL L (for which there are no memory items), once the aircraft's flight path is stabilized, you hit ECL and it will bring up the checklist for an engine failure.

[machine2035 176]

Hello

 

can you answer please theese questions?

 

1) What are the blue and white rotaing rngs on the EHSI for?

 

2) Does the 777 start engine with packs on? Also with dual engine start?

 

3) what do the blue arrows next to airports on the EHSI mean?

 

4) I saw in a video that the DING DONG messages like "CABIN READY" are announced. Are there more messages like "NO MOBILE".

 

Do the pilots cancel the messages or will they go after a certain time?

 

5) What do the white boxes on the upper EICAS mean next to the EICAS Caution messages. Some of the messages have some don`t have a white box at the beginning.

 

Thanks for help.

Hi,

 

First of all please sign your full name per this thread.

 

Now while most your questions can be found by simple search, since I am such a nice human being, and I need some wrist exercise, I will answer your questions.

 

1) They are from the OFFPATH DES page. The two circles provide the direct-to distance from the aircraft to the computed top-of-descent point at the current altitude for a full speed brake idle AND clean (no flap, gear, speedbrake etc.) descent.

 

2) I believe the APU is able to provide enough air to start two engines at once, however due to size of the GE90, SOP's usually dicate to start 1 at a time to reduce the chance of 2 hung starts.

 

3) If you are referring to blue arrows pointing towards airport, they are set up on the ALTN page and point towards the airports with a distance to such said airports

 

4) The CABIN READY message, along with messages like PASSENGER SIGNS are white on the EICAS. White messages will not dissapear with a press of CNL button on the DCP.

 

5) I am not sure what you are referring to in this question so cannot answer.

 

Hope this helps, but next time remember to search first

[asdro 13]

thank you.

 

But concerning my first question...I still did not get it.

[machine2035 176]

thank you.

 

But concerning my first question...I still did not get it.

Okay, say there is an active 3000ft altitude constraint.

 

One range ring indicates where your latest chance of descending using no drag devices is.

 

The other range ring indicates where your latest chance of descending using drag devices is.

[asdro 13]

ok. I see.

 

But is not the green banana enough for that? It helps me also to reach a certain waypoint constraint. I can adjust my sinkrate with it.

[Fabo 213]

No this is a bit different. The green banana will tell you where will you end your descend if you continue at present rate, The rings give you the last place to start your descent if you want to make the restriction.

[asdro 13]

nice. to know.

So it calculates the kinetic energy to start descend on the right time when you want to reach a certain altitude at a certain point.

[3-2-1-Now 126]

It's a bit more complex than that - it considers the drag of the aircraft, and the vertical speed it can sustain at IDLE during the descent, works the flight path backwards, and determines the closest you can get to that waypoint, also taking into consideration winds.

 

There are two profiles - clean (no speedbrakes/flaps/gear) and with speedbrakes fully extended.

 

If you are at 25000 ft descending to 20000 ft the rings will be much smaler than if you were descending from 35000 ft to 10000 ft.

 

Best regards,

Robin.

[Don t moderate me this way 882]

Bonus question:

 

What about a speed restriction in the upcoming constraint? Is deceleration taken into account as well?