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cloudboy
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Significance Of 10,000 Ft

Tue May 20, 2008 9:02 pm

Is there any significance to 10,000 ft? This is the altitude at which seatbacks are supposed to be upright, electronics put away, etc.

I was just wondering if this altitude was choosen for a particular reason, i.e. studies show this to be the level below which most incidents occur, if there is some kind of ATC reaon, or perhaps a range reason. Or was this altitude choosen simply because it is a nice, round number?
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Boston92
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 9:08 pm



Quoting Cloudboy (Thread starter):
Is there any significance to 10,000 ft? This is the altitude at which seatbacks are supposed to be upright, electronics put away, etc.

I may be totally incorrect, but I was under the impression that you could recline your seat once off the ground. I always have.

Also, you put away your electronic devices when the captain rings the "double ding" prior to landing. The F/A;s don't ask for you seats to be upright, tray tables up, headrests down until the captain asks the F/A's to prepare for landing.
 
deltabobo
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 9:09 pm

10,000 FT is the upper limit of sterile cockpit rule, the 250 or below speed limit, and other stuff, but the reason why, I have no clues. I don't question the FARs, just abide by them!  Smile
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KELPkid
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 10:40 pm

10,000 feet is generally considered to be the altitude at which pressurization is no longer required, and in the US, it is kind of unofficially the transition between "high" altitude and "low" altitude. It's assumed, I guess, that most Cessnas and Pipers will be found at 10,000 feet and below  Smile (although they will cruise higher, and I've done it  Wink ). This is why we have the 250 knots below 10,000 feet rule here in the 'states.

10,000' MSL is the top of most class B airspace in the US...
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IAHFLYR
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 10:46 pm



Quoting Cloudboy (Thread starter):
Or was this altitude choosen simply because it is a nice, round number?

That would be my guess.....other than the previously mentioned sterile flight deck but that should not impact the passenger cabin! Great topic.

Quoting Deltabobo (Reply 2):
I don't question the FARs, just abide by them!

What FAR is this listed in?
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KELPkid
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:18 pm



Quoting IAHFLYR (Reply 4):
What FAR is this listed in?

http://www.flightsimaviation.com/data/FARS/part_119-7.html

If it's in the op specs, it's just as good as an FAR  Wink
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IAHFLYR
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:25 pm



Quoting KELPkid (Reply 5):
If it's in the op specs, it's just as good as an FAR

Almost, except it doesn't take an act of God to get an ops spec changed to fit a particular operator, only an act of FAA God's!  point 
Any views shared are strictly my own and do not a represent those of any former employer.
 
KELPkid
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:30 pm



Quoting IAHFLYR (Reply 6):
Almost, except it doesn't take an act of God to get an ops spec changed to fit a particular operator, only an act of FAA God's!

True, but if you bust an item in your carrier's ops manual, the Feds will come after you just as if you busted an FAR  Smile
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IAHFLYR
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:35 pm



Quoting KELPkid (Reply 7):
True, but if you bust an item in your carrier's ops manual, the Feds will come after you just as if you busted an FAR

Oh I won't disagree except that you might not get caught initially at least!  Smile

My point is I have not found the specific CFR (FAR) that addresses the 10,000' restrictions mentioned in the thread other than the 250 KIAS non sense. Not to mean it isn't in the CFR's but I've not found it.
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miamiair
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:40 pm



Quoting Boston92 (Reply 1):
may be totally incorrect, but I was under the impression that you could recline your seat once off the ground. I always have.

Also, you put away your electronic devices when the captain rings the "double ding" prior to landing. The F/A;s don't ask for you seats to be upright, tray tables up, headrests down until the captain asks the F/A's to prepare for landing.

The seat backs fwd and the trays up is in the case of an emergency egress. So you are correct.
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Jetlagged
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:40 pm

Quoting Boston92 (Reply 1):
I may be totally incorrect, but I was under the impression that you could recline your seat once off the ground. I always have.

You must be the person who always gets the seat in front of mine.  

Quoting Boston92 (Reply 1):
Also, you put away your electronic devices when the captain rings the "double ding" prior to landing. The F/A;s don't ask for you seats to be upright, tray tables up, headrests down until the captain asks the F/A's to prepare for landing.

There won't be much difference in time between passing 10,000 ft and preparing the cabin for landing. On most airlines I've flown with recently the two go together, which is a pain when you miss the last five minutes of the movie.

[Edited 2008-05-20 16:41:03]
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bond007
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RE: Significance Of 10,000 Ft

Tue May 20, 2008 11:53 pm

Quoting IAHFLYR (Reply 8):
My point is I have not found the specific CFR (FAR) that addresses the 10,000' restrictions mentioned in the thread other than the 250 KIAS non sense. Not to mean it isn't in the CFR's but I've not found it.

Correct, AFAIK, Part 121 does mention those things, but only in respect to all or some of the following phases of flight... "landing, takeoff, or movement on the surface". As long as everything is complete prior to landing, then then you are OK by the FARs.

As already mentioned, most of final preparation is done below 10,000ft - usually 20 mins or less before landing.


Jimbo

[Edited 2008-05-20 16:54:54]
I'd rather be on the ground wishing I was in the air, than in the air wishing I was on the ground!
 
Boston92
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 12:05 am



Quoting Jetlagged (Reply 10):
You must be the person who always gets the seat in front of mine.

Actually, I usually only recline if I am in F, and I always prefer the last row in F for exactly that purpose. Believe me, I am the person (6'3") who shoves my knee as far as I can in the seat when someone tries to recline on me. Believe me again, that my foreward knee pressure almost always beats the backwards movement  Wink
 
Boston92
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 12:10 am



Quoting Jetlagged (Reply 10):
On most airlines I've flown with recently the two go together, which is a pain when you miss the last five minutes of the movie.

I can only speak from experience with United, but they seem to do the "double ding" about 20-30 minutes prior to touchdown, and the formal "prepare for landing" occurs 5-15 minutes prior to touchdown (depending on aircraft).
 
IAHFLYR
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 12:28 am



Quoting Jetlagged (Reply 10):
You must be the person who always gets the seat in front of mine.

lol...nah, that is me, gear up, climb power, seat back.....just a little and never to crowd the person in the row behind.

Quoting Boston92 (Reply 13):
I can only speak from experience with United, but they seem to do the "double ding" about 20-30 minutes prior to touchdown, and the formal "prepare for landing" occurs 5-15 minutes prior to touchdown (depending on aircraft).

And I only from experience with CO, right at or very near to beginning the decent below 10,000' MSL....and that can be very close to the airport such as at DFW or ATL as you turn downwind at 11,000' MSL to places where you're much lower farther out and straight-in!
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Boston92
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 5:51 am



Quoting IAHFLYR (Reply 14):

I have been on flights that have leveled at 10,000 feet and remained their for 20 minutes. It all depends on the two people up front as to when they want you to put away the E-devices, and seats upright. Hell, I have been on flights where the seatbelt sign popped on about 200 AGL.
 
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NWOrientDC10
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 7:31 pm



Quoting KELPkid (Reply 3):
10,000 feet is generally considered to be the altitude at which pressurization is no longer required, and in the US, it is kind of unofficially the transition between "high" altitude and "low" altitude.

Isn't the air pressure above ten thousand feet low enough to cause unconsciousness if an aircraft cabin is depressurized? Also, aren't oxygen masks deployed above ten thousand feet (but not below) if depressurization occurs?

Good Day  Smile

Russell
Things aren't always as they seem
 
KELPkid
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 7:38 pm



Quoting NWOrientDC10 (Reply 16):
Isn't the air pressure above ten thousand feet low enough to cause unconsciousness if an aircraft cabin is depressurized? Also, aren't oxygen masks deployed above ten thousand feet (but not below) if depressurization occurs?

Good Day

Russell

I sure hope not, I have hiked a 12,000' mountain pass before...  Wink

FYI-

The FAA allows unpressurized aircraft to cruise unfettered between 10,000 and 12,499 feet (no Oxygen requirements for anybody). Above 12,500 feet and below 14,000 feet, you are allowed to be up there without oxygen for 30 minutes. At or above 14,000', supplemental oxygen is required for crew, and above 15,000', supplemental oxygen must be provided for passengers (but the law doesn't say that the passengers must use it... Big grin ).

Anyone know the field elevation at Quito, Ecuador? I'm sure that the local inhabitants don't go around with oxygen masks on  Smile

Likewise for Leadville, CO, although it's not nearly as high as Quito...
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Mir
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 9:02 pm



Quoting Boston92 (Reply 1):
I may be totally incorrect, but I was under the impression that you could recline your seat once off the ground. I always have.

I tend to wait until the FAs are up and moving around before reclining my seat.

Quoting KELPkid (Reply 3):
although they will cruise higher, and I've done it

It is quite fun.  biggrin 

Quoting NWOrientDC10 (Reply 16):
Isn't the air pressure above ten thousand feet low enough to cause unconsciousness if an aircraft cabin is depressurized?

Nope. You can last for quite a while above 10,000ft. In fact, judging by this, you can last at least 5 minutes at 22,000ft following an explosive decompression: http://en.wikipedia.org/wiki/Time_of_Useful_Consciousness

-Mir
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Viscount724
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RE: Significance Of 10,000 Ft

Wed May 21, 2008 11:06 pm



Quoting KELPkid (Reply 17):
Anyone know the field elevation at Quito, Ecuador? I'm sure that the local inhabitants don't go around with oxygen masks on

Quito is 9,228 ft. La Paz, Bolivia is significantly higher at 13,325 ft.
 
mpdpilot
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RE: Significance Of 10,000 Ft

Thu May 22, 2008 4:43 am



Quoting IAHFLYR (Reply 8):
My point is I have not found the specific CFR (FAR) that addresses the 10,000' restrictions mentioned in the thread other than the 250 KIAS non sense. Not to mean it isn't in the CFR's but I've not found it.

I don't have the FAR in front of me but I have taken a number of practice ATP tests and they all mention that there needs to be a sterile cockpit below 10,000' unless you are cruising below 10,000'. I would imagine that if it is in the ATP test then it is a FAR.

Wait I take the FAR part back, FAA written tests are a little messed up in that area.
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bond007
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RE: Significance Of 10,000 Ft

Thu May 22, 2008 2:05 pm



Quoting MPDPilot (Reply 20):
I don't have the FAR in front of me but I have taken a number of practice ATP tests and they all mention that there needs to be a sterile cockpit below 10,000' unless you are cruising below 10,000'. I would imagine that if it is in the ATP test then it is a FAR.

That still doesn't address what should happen in the cabin though, which was the orginal question.

Quoting KELPkid (Reply 17):
Anyone know the field elevation at Quito, Ecuador? I'm sure that the local inhabitants don't go around with oxygen masks on

No, but they've lived there for years. You will certainly feel the effects of oxygen deprivation when you initially go there, until you have been fully acclimatized.

IMO there is much more of an effect over 10,000ft than some might think. I used to do a lot of GA flying around 11,000ft with no oxygen (over the top of ORD class B!!), and this was actually specifically to teach folks the effects of low oxygen levels. Of course, one of the classic effects, is that you feel pretty good ... making you tend to forget the reason why.

Now, getting up to 11,000ft in a Beech Sundowner was no easy or quick task ... although getting back down was fun  Smile


Jimbo
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miamiair
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RE: Significance Of 10,000 Ft

Thu May 22, 2008 2:11 pm



Quoting Viscount724 (Reply 19):
Quito is 9,228 ft. La Paz, Bolivia is significantly higher at 13,325 ft.

Bangda, China (ZUBD) is in the Tibetan Highlands at an elevation of 14,219 feet msl and has a single, 18,045-foot-long runway. When the ambient temperature is 75 degrees Fahrenheit, density altitude is 18,300 feet. (A portable oxygen bottle is needed to conduct the preflight inspection.)
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