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-   -   HORIZON! (https://www.pprune.org/north-america/546264-horizon.html)

AF330 25th Aug 2014 08:57

HORIZON!
 
Hi everyone,
I just had this silly question:
I just learnt that pitch was where the aircraft was pointing and the Horizon.
But the Horizon is just a line that separates earth and sky.
But how can you go bellow the horizon line during a descent?
Has the plane a different horizon than the earth one?

Please explain!
Thanks a lot,
AF330

Radix 25th Aug 2014 09:50

HORIZON!
 
............

alldaysushi 25th Aug 2014 12:25

The Horizon is frame of reference only for the aircraft you are in.
If you take the longitudinal axis of the aircraft, ( nose to tail ),
Extend it, you will show a descent if below the horizon,or a climb if above.

In larger equipment, the aircraft may be straight and level while showing the aircraft a few degrees above the horizon line, in different configurations.

Safe journey...Sushi

Amadis of Gaul 25th Aug 2014 13:02

Meanwhile, in other threads he's asking about Alpha floor, autothrust et al...

AF330 25th Aug 2014 14:07

Thanks to everyone,

"The Horizon is frame of reference only for the aircraft you are in."
Ok, so it is basically only a line which tells you if you are going up or down. In the blue part, you are climbing, and in the brown part, you are going towards the ground, so descending.

Wikipedia: "The horizon (or skyline) is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not."


So the horizon, of a plane is not at all related to this one! Because, if it shows that we are below Horizon, it would mean that we are on ground level!
The pitch is calculated with the "artificial" horizon, not the "wikipedia's" one, am I right?

Thanks,
AF330

PS: "Meanwhile, in other threads he's asking about Alpha floor, autothrust et al..." Ok, Amadis of Gaul... I didn't really get your post... Still, thanks for posting this!

glendalegoon 25th Aug 2014 18:47

the horizon does not tell you if you are climbing or descending. you would need the altimeter or VSI or IVSI to tell you if you are climbing or descending.

you live in San Francisco. are you taking flying lessons anywhere?

and you should get your terms straight

natural horizon

artificial horizon

.

and just think of PITCH ATTITUDE REFERENCE instead of horizon and you might figure it out better. You never reach the horizon (natural) even if you went towards it fo rhours

Amadis of Gaul 26th Aug 2014 20:11

I applaud your desire to learn, especially since you're venturing far beyond any thirteen-year-old I know, but I remain puzzled on why you confine your questions to the North American forum, since Airbuses (Airbi?) fly all over the world. It also seems to me you're attempting some marathon running prior to learning to crawl. If you're still learning what pitch is, perhaps getting into advanced flight control functions might be a bit premature?

AF330 27th Aug 2014 10:08

Yes, you are right. Absouletely right. I just understood the FPA/PITCH/AoA stuff!
This forum was the most active and some members were asking these types of question, so i posted my question too!

Please understand!
Kind regards,
AF330

PS: You tell me to ckeck the FCOM (smart cockpit) but I promiss that, each time I have a doubt, I always check there first! But, I don't know why, i always have questions after having read it!

Zaphod Beblebrox 29th Aug 2014 17:17

I be flying to the edge of the earth... The maps all say "Here by dragons" and when we has flown to the edge we will hit a wall, like in that there Jim Carrey movie "The Truman show". Or maybe we-just flies off the earth and heads out into space. Arrr, I be pondering on it for sure. Me an Capn Jack Sparrow, be consulting with our charts and crazy compass.

All we knows is that you can't get to the edge of the world unless you start out lost to begin with.


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