Blackout at high altitude

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Hobart Escin

Re: Blackout at high altitude

Post by Hobart Escin »

http://a2asimulations.com/forum/viewtop ... 15&t=40848

Slew mode might've been involved in the above tragedy... :roll:

james1967a1
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Re: Blackout at high altitude

Post by james1967a1 »

I'm a little confused, as I was flying the Cherokee last week and I thought for sure I ran across blackout. I was flying Montana to Wyoming at 11,000 feet. The autopilot was on. I was away for a bit, and came back and noticed I was at 17,000. The VC view was pulsing in and out and then the screen went black. I thought something was wrong with my computer. I turned off the autopilot and set up a descent. But in reality with the autopilot on, I'd be done for. At lower altitudes, everything went back to normal, and I landed in Casper Wyoming.
Jim

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Wiqvist
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Re: Blackout at high altitude

Post by Wiqvist »

I have offered me self to do a test fly, and I defenetly died and have never seen so much red in the hangar.

I tested this before and went to 14500 and stayed there for some time and nothing at all did happen. Now I tested it again and this time went higher and higher. At 17500 the view started to pulse in and out and at 17 700 everything became black and after some time the Aircraft crashed in the middle of the air. When I then checked her in the hangar and I was amazed that there were so much red around the aircraft and everything in the engine is red.

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Great Ozzie
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Re: Blackout at high altitude

Post by Great Ozzie »

Wiqvist wrote: I tested this before and went to 14500 and stayed there for some time and nothing at all did happen. Now I tested it again and this time went higher and higher. At 17500 the view started to pulse in and out
I had performed a similar test some time ago Wiqvist, with similar results.

I was at 14,500 for an hour or so? (don't have my notes) and then I think 15.5 for a half hour. Shortly after climbing above 16,000' was when I got the 'pulsing'.

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taildraggin68
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Re: Blackout at high altitude

Post by taildraggin68 »

Tested from Sea Level, rapid ascent to a little over 18,000 MSL before "pulsing" started. Rapid descent, but pulsing did not stop until around 8,000 MSL. No blackout, which I was kind of expecting at that altitude....
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Made it back down safe though :D

Next test will be the Cherokee, Cessna was just first one loaded up :roll:

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Jacques
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Re: Blackout at high altitude

Post by Jacques »

I just tried a search and came up empty, but I think I remember just seeing a patch note that mentioned moving the hypoxic altitude from 14500' to 16500'. I'm not sure if that applies to all Accusim core aircraft, but I assume it does.

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taildraggin68
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Re: Blackout at high altitude

Post by taildraggin68 »

All I could get was 17000 MSL before pulsing began, also hard to get any altitude gains without stalling :D in clean configuration.
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pilotgod
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Re: Blackout at high altitude

Post by pilotgod »

I had the great fortune of being able to get my high altitude endorsement via the FAA's high altitude chamber in Oklahoma City. The program involves two demonstrations that have you going into the chamber and doing some normal tasks like copying sentences, doing a connect the dot puzzle, etc. They take the chamber up to 15,000 feet and have you remove the mask, then keep doing the tasks. It took about 5 minutes before they felt I was at a point where the mask needed to come back on. I didn't ever feel like I was slowing down, or having any other issues, but the video showed that I was getting slower and sloppier. The next (and last) demonstration was the chamber at 28,000 feet or almost the same elevation as the summit of Everest. From the time I took my mask off until I passed out was about 40 seconds. I don't remember that either. What I do remember is the awesome feeling of the 100% oxygen being forced into my lungs. Best...high...ever!!! :shock:

The experience gave me a very healthy respect for hypoxia and showed me that at least for myself, I can not physically detect a slow onset hypoxia. Now, any flight I do where I will be above 10,000 feet I bring along a Pulse/Ox meter. I've also learned that the nasal canulas are only good for me up to about 18,000 feet. I rode along in a Turbo 210 and the pilot took it up to FL220 just to see how the plane flew. I wasn't noticeably hypoxic, but I did develop a moderate headache and the SkyOx was on full.
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Dogsbody55
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Re: Blackout at high altitude

Post by Dogsbody55 »

The highest I've had the Cherokee is about 12,000ft, and I found that control starts to get mushy at those heights, so didn't bother to try for a higher altitude. I might have a try, just to see what happens, but in the real world, I don't believe you'd go much higher than 10,000ft, both from a safety viewpoint (hypoxia) and from a performance viewpoint. If you look at Mr Taildraggin's shots, you'll see just how hard it is top maintain such heights. Check the attitude and airspeed indicators, and you'll see what I mean.


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DC3
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Re: Blackout at high altitude

Post by DC3 »

I recently flew at 13,500 ft at 104 mph (90kts) ias. If you live in California and fly around the Sierra Nevada mountains it would not be uncommon to be over 10,000 ft in altitude. In the r/w oxygen would have been mandated for that altitude. In the FSX world I did not suffer any ill effects having not come close to 14,500, or 16,500 ft and of course I didn't use any oxygen :lol: . The highest I ever flew when flying Archers was 8,500 ft. That was a thrill at the time. :)

CookerCook
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Re: Blackout at high altitude

Post by CookerCook »

This happened to me at 17000 ft. How do I stop it though? I based the ceiling height on wikipedia which is 18,100 ft. Is there like a pressurization thingamajig that i can press or something to prevent this? (Sorry I am new to this Aircraft and it's uses
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AKar
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Re: Blackout at high altitude

Post by AKar »

That kind of ceiling for an aircraft is essentially a measure of how high you can get it in certain circumstances. In case of unpressurized light singles, it is not intended to represent a practical operating altitude.

If an unpressurized aircraft is flown much above 10000 ft for extended periods of time (check your applicable ruling!) some portable oxygen solutions exist in reality. Personally I'm not a fan of those and find them rather dubious to various degrees, but that's just me. I think you can find some 'cheats' and even some mods that simulate having onboard oxygen to some degree from these forums.

Flying at high altitudes in unpressurized airplanes without a very practical reason to do so is something that I've never seen happening in reality.

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Lewis - A2A
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Re: Blackout at high altitude

Post by Lewis - A2A »

Yes, you dont want to be flying the little cherokee all that high at all, as well as blacking out from lack of oxygen you're also not getting any performance benefits climbing to heights of 10k or above.

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CookerCook
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Re: Blackout at high altitude

Post by CookerCook »

Lewis - A2A wrote: 29 May 2020, 08:31 Yes, you dont want to be flying the little cherokee all that high at all, as well as blacking out from lack of oxygen you're also not getting any performance benefits climbing to heights of 10k or above.

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Lewis
Lewis, Sir, if I may ask. Is it okay if I keep the A2A Cessna 182 at a peak of 13-14000 feet without pressurization?
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Lewis - A2A
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Re: Blackout at high altitude

Post by Lewis - A2A »

Personally I'd be flying well under that in a standard GA aircraft, 10k can be called high. So 13-14 you are well beyond that for a standard engine GA without oxygen.

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