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Ocean altitude limit?

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Starman

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If I understand it correctly, there is an altitude limit for GA aircraft operating visual over the continental US, but is there an altitude limit out over intercontinental ocean? You know, like to keep from getting smashed across the front of some airliner or Learjet.
 

TFF

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The jets are at 30000-40000 ft. There are international agreements over the ocean; about the same rules as the FAA.
 

orion

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The reduced separation limits have pretty much delegated general aviation to below 29,000 feet. I believe these limits are international although other countries may impose further limits. GA can go higher however any plane wishing to do so must have the proper equipment. About a year ago I was told that installation, calibration and certification of that equipment can run upwards of one mil. $.
 

Starman

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Thanks, 29,000 sounds like more than enough to me, about the same as Everest, so no oxygen needed :ponder: Oxygen is recommended? above 10,000 feet, but it seems most people in good health (hikers) should be able to go to 20,000 with no trouble.
 

rtfm

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Thanks, 29,000 sounds like more than enough to me, about the same as Everest, so no oxygen needed :ponder: Oxygen is recommended? above 10,000 feet, but it seems most people in good health (hikers) should be able to go to 20,000 with no trouble.
Hi,
I wouldn't bank on it. Guys I fly with have gone to 9k ft and definitely felt that O2 was required. Depends on your history, your health etc. Forget 20k ft w/o O2 - it isn't realistic.

Regards,
Duncan
 

Jman

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I've flown over 12,000 feet msl while flying at just 50ft AGL with no O2. Not only did the helicopter fly like crap but the effects on my coordination and timing were significant. I would not consider going above that for any length of time without O2. I could easily see myself, or anyone for that matter, just drifting off to sleep and waking up with not a drop of gas in the tanks. Oh so easy to do with the nice steady drone of the engine sounding in your ears. Scary thought. Not worth the risk.
 

Will Aldridge

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The regs state that you can fly at 12500 msl for as long as you like without oxygen (but not necessarily a good idea). You can go up to 14500 (I think) for 30 min without oxygen then you either have to come back down or start using it. Above 14,500 you need it no matter what.
 

Jman

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Since we are on the subject here is Part 91 Subsection 211 (Supplemental Oxygen).

§ 91.211 Supplemental oxygen.

(a) General. No person may operate a civil aircraft of U.S. registry—

(1) At cabin pressure altitudes above 12,500 feet (MSL) up to and including 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen for that part of the flight at those altitudes that is of more than 30 minutes duration;

(2) At cabin pressure altitudes above 14,000 feet (MSL) unless the required minimum flight crew is provided with and uses supplemental oxygen during the entire flight time at those altitudes; and

(3) At cabin pressure altitudes above 15,000 feet (MSL) unless each occupant of the aircraft is provided with supplemental oxygen.

(b) Pressurized cabin aircraft. (1) No person may operate a civil aircraft of U.S. registry with a pressurized cabin—

(i) At flight altitudes above flight level 250 unless at least a 10-minute supply of supplemental oxygen, in addition to any oxygen required to satisfy paragraph (a) of this section, is available for each occupant of the aircraft for use in the event that a descent is necessitated by loss of cabin pressurization; and

(ii) At flight altitudes above flight level 350 unless one pilot at the controls of the airplane is wearing and using an oxygen mask that is secured and sealed and that either supplies oxygen at all times or automatically supplies oxygen whenever the cabin pressure altitude of the airplane exceeds 14,000 feet (MSL), except that the one pilot need not wear and use an oxygen mask while at or below flight level 410 if there are two pilots at the controls and each pilot has a quick-donning type of oxygen mask that can be placed on the face with one hand from the ready position within 5 seconds, supplying oxygen and properly secured and sealed.

(2) Notwithstanding paragraph (b)(1)(ii) of this section, if for any reason at any time it is necessary for one pilot to leave the controls of the aircraft when operating at flight altitudes above flight level 350, the remaining pilot at the controls shall put on and use an oxygen mask until the other pilot has returned to that crewmember's station.
 

TFF

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If your using a naturally aspirated engine your not going to fly much over 10K anyway. Took a Grumman Traveler to 10K and it would barely fly. A Cirrus R22 does great at 10K, but it has 140 Hp more and a more efficient airframe.
 

Starman

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If your using a naturally aspirated engine your not going to fly much over 10K anyway. Took a Grumman Traveler to 10K and it would barely fly. A Cirrus R22 does great at 10K, but it has 140 Hp more and a more efficient airframe.
How about a naturally aspirated 400 hp Corvette engine in a 2 seat sailplane? I can put a turbo on it later anyway, but probably wouldn't need it.

Concerning the comments about altitude, I've camped and hiked up near 10,000 ft before and it didn't seem to be a problem, and hikers regularly go above 10,000 around here. I was thinking that maybe the stronger breathing and aerobic exercise helps keep you oxygenated, but I was sleeping and sitting around at 10,000 and no stumbling around, maybe that's because of the Jedi way of breathing I use. My wife started getting altitude headaches at 7,000 ft.

I've read that breathing oxygen dries your sinuses. How bad is that, and are there ways of fixing it, like humidifiers?
 

Topaz

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...Concerning the comments about altitude, I've camped and hiked up near 10,000 ft before and it didn't seem to be a problem, and hikers regularly go above 10,000 around here. I was thinking that maybe the stronger breathing and aerobic exercise helps keep you oxygenated, but I was sleeping and sitting around at 10,000 and no stumbling around, maybe that's because of the Jedi way of breathing I use. My wife started getting altitude headaches at 7,000 ft.
Don't mess with hypoxia. It'll be on you before you know it's happening, and you're usually the worst judge of your own capabilities, or the degradation thereof. Hiking and camping don't task your fine motor skills and judgement to the degree that flying does. The two activities are not comparable in terms of hypoxia.
 

Dana

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Concerning the comments about altitude, I've camped and hiked up near 10,000 ft before and it didn't seem to be a problem, and hikers regularly go above 10,000 around here. I was thinking that maybe the stronger breathing and aerobic exercise helps keep you oxygenated...
No, it's that you have more time to acclimate to the higher altitude as you climb, unlike in an airplane when you get to that altitude relatively quickly.

-Dana

Things should be made as simple as possible, but not any simpler.-- Albert Einstein
 

Dan Thomas

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The complexity of flying demands a brain that gets plenty of fuel. Hiking at 12k would be somewhat simpler than operating an airplane at that altitude. Night vision begins to deteriorate above 5000 msl. Eyeballs are particularly susceptible to oxygen deprivation.
Effects  of  Hypoxia

Dan
 

Robby

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Wasn't Paine Stewart's Lear where the crew succumbed to hypoxia and went in a few years ago.
At least hypoxia was suspected, the aircraft couldn't be contacted via radio and if I remember correctly, a military aircraft's pilot could see the crew inside but was unable to contact them visually.
One piece of speculation was a leak in the pressurization system.

Hypoxia is quicker than you think, little warning ( fingernails and lips ) and once you
doze off ......................................................

Sorry but just not worth the risk.
Besides, there's nothing up there to look at anyway :ban:
 

Topaz

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Wasn't Paine Stewart's Lear where the crew succumbed to hypoxia and went in a few years ago.
At least hypoxia was suspected, the aircraft couldn't be contacted via radio and if I remember correctly, a military aircraft's pilot could see the crew inside but was unable to contact them visually.
One piece of speculation was a leak in the pressurization system.

Hypoxia is quicker than you think, little warning ( fingernails and lips ) and once you
doze off ......................................................

Sorry but just not worth the risk.
Yep. AvWeek reported that the NTSB wrote the accident off to a faulty cabin pressurization valve, and possibly a fault in the pressurization warning system. Apparently the leak started almost immediately, and the crew and passengers passed out before they knew anything was wrong - it just sneaked up on them. They'd had the aircraft set up for the climb to altitude, and it it just kept climbing until it either ran out of ceiling or the autopilot set up the cruise (I don't recall), and then it was just a ghost plane full of dead people, flying on-course until it ran out of fuel. The F-16s chasing it couldn't do a thing, and IIRC, they said the cockpit windows were all frosted over from the inside.
 

Lucrum

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The reduced separation limits have pretty much delegated general aviation to below 29,000 feet. I believe these limits are international although other countries may impose further limits...
RVSM, it's not world wide but covers much of the globe including the N.A.T tracks across the Atlantic and a chunk of the Pacific.
http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/rvsm/

Thanks, 29,000 sounds like more than enough to me, about the same as Everest, so no oxygen needed :ponder: Oxygen is recommended? ...
You'll want O2 above 14,500 if not sooner. Supplemental O2 systems aren't all that expensive anyway. If you can afford a plane you can afford the O2.
 

Lucrum

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Yep. AvWeek reported that the NTSB wrote the accident off to a faulty cabin pressurization valve, and possibly a fault in the pressurization warning system. Apparently the leak started almost immediately, and the crew and passengers passed out before they knew anything was wrong - it just sneaked up on them...
I may be wrong but I was thinking the crew was suspected of NOT turning on an O2 valve during the preflight as well. A valve located externally.
 

Starman

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I'm hoping for a 3000 mile range so around how much oxygen would you need to carry for a single person for say 24 hours? I want to be able to fly across the Pacific and also into the South Pacific because I like snorkeling. I think it would be good to fly some at low altitude anyway or all the way if the weather is good down low, wave skimming in ground effect.

Also I've heard that oxygen dries your sinuses and wonder if that can make things too uncomfortable on a long trip or is that not a serious issue? It seems saline nasal spray will take care of it anyway.
 
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