Flying at 17,000ft

bing2385

Anyone ever experienced flying at 17,000ft in an unpressurised aircraft?
What was it like?
How long were you at that height for?
How long were you on oxygen for?

Were there any problems?
What should we watch out for?

ronnie3585

I was up to 16,000ft in a C172R with a friend of mine who's also a PPL and medical doctor too. He was P1 and me P2 as he has far more experience than me.

The biggest danger in climbing above 10-12,000ft in an unpressurised cabin is Hypoxia. Both of us are non-smokers and very fit so thankfully it never became an issue for us. We were very active in looking out for the symptoms and every 1,000ft above FL100 we asked each other a set of questions to make sure we were in good shape mentally. However, it is a very real danger at this height so at the first sign of any of it's symptoms it's time to descend, fast.

It took ages to get up there. Off the top of my head the published service ceiling for the 172R is about 14,000ft, however this figure is not the level at which the aircraft will stop climbing, it is when Vx and Vy are the same. The aircraft will continue to climb above this level however the performance isn't great, depending on the weight of the aircraft your looking at about 250fpm. When we reached FL160 we didn't stay there long primarily due to the cold. Even with the cabin heat on it got uncomfortably cold.

One extremely important requirement for flying this high in a SEP is good engine management. Accurate leaning is a must. Obviously this is required on the climb to get the engine producing full power however it must not be forgotten on the decent. Being that high with such a long decent means that it is very easy to over cool the engine.

If you are thinking about doing this my strong advise is that unless you are very experienced at doing this kind of thing, do it P2 with someone who is very experienced. I'm not talking about an airline pilot with 10,000hrs in a B737, but someone who has lots of experience flying light aircraft and doing long climbs and descents in them. I'm not trying to scare you off, it's a great experience, but it's not something to be undertaken without proper planning.

fireplace1982

Regardless of having a second guy beside you...do not fly to 17,000ft unpressurized, it would be pure stupid to do so, anything over 10,000ft and you are physiologically less safe to operate regardless of aircraft performance and the amount of engines, i have previous experience at this...dont do it. Why would you want to anyway?

FlutterinBantam

Roger- that's a bit of good advice there.

Flyer1

I've been to FL140 in an unpressurised aircraft, but that was only dropping meatbombs ( ie those mad parachutist types ).

ronnie, do you mind me asking why FL160 in a 172 ? Or was it just one of those random " I wonder " moments.

As for the OP's original question. You could do, but not for long periods of time, as stated hypoxia etc. all can have an effect. Physical fitness has a big thing to do with it too.

pclancy

Meatbombs lol.

FestivalFox

Meatbombs!!!

When will you "flying" types realize that most of the fun to be had is outside of the plane!

If sitting in a cockpit is flying...... then sitting in a boat would be swimming.:P

Mr Benevolent

Both of us are non-smokers

Ironically, being a smoker would have increased your tolerance to the high altitude environment. A smoker's body adapts to the carbon monoxide intake over time.

You both took a serious risk going up to 16,000 without oxygen for any period of time. Not only is personal anoxia diffcult to detect without hyperbaric training, the P1 could have had less tolerance then you and done something stupid. Him being a doctor is irrelevant to the whole thing.

Finally there's the issue of having unnoticed anoxia in an aircraft at the edge of its performance envelope. There are lots and lots of cases of pilots doing very strange things at altitude, and that's why the FAA and EASA limit non-pressurised aircraft (and pilots) to 14,000ft. You took a big, but (to both of you) seemingly innocuous risk, and I'd suggest that you take a few lessons away with you. 1) Stay within the aircraft's performance envelope. 2) Stay within the human performance envelope.

To the OP: 17,000 without oyxgen is very, very dangerous.

PS: Apologies if I sound preachy, but these are very subtle dangers - the equivalent of drinking just a couple of pints and going driving down country lanes at night.

FestivalFox

What exactly are the rules? I thought that planes were restricted to 14k without oxygen. I was jumping in Spain 2 weeks ago. They brought us up to 16k 5 times on one of the days. Granted it didn't take long to get to 16k, the beech 99 we were using had a pair of PT6A-34 engines under her wings.

Mr Benevolent

What exactly are the rules?

For crew it's constant demand oxygen above 14,000ft. Most high altitude unpressurised aircraft pilots will go on oxygen at about 10,000 as it makes a big difference to their vision, especially at night.

It's all to do with exposure times. 5 minutes at 14,000 won't do any harm. 10 minutes at 16,000 can induce mild euphoria. 10 minutes at 18,000 can cause hallucinations. 20-30 minutes at 18,000 will cause unconsciousness.

The problem with the regulations is that personal anoxia symptoms are completely different from one person to the next and can't be predicted except in a hypobaric chamber. Interestingly, hypobaric tests are not administered to airline pilots, only the military. Sensible enough, but it'd be useful for everyone to know what anoxia feels like.

There was a good article in Flyer a year or so ago about skywriting. Brian Lecomber went up to 16,000 feet in a Pitts to write for a Japanese company. After he got down again he looked up at his handiwork. It was a mess. The anoxia made it look like he'd been doing it drunk.

robinph

Was up at 15,000 myself once. Then I decided I didn't like it so jumped out.

The really scary bit was that the plane landed before I did though.

bing2385

dont worry lads - oxygen will be supplied! i wouldnt even think about going up that height without!

The reason is that we have some aerial survey work to do, and just wonder if anyone has been up that height before, or what signs to watch out for etc etc.

As im only the navigator/camera operator, i dont have as much to worry about, but this will be the first time ive been above 10000ft in an unpressurized aircraft. So im just wondering if im 'plane' stupid to let work send me up there, or if its safe enough.

I just dont know how we will breath oxygen and communicate at the same time?

chickenhawk

I've flown at 12-13,000ft for long periods (due to weather) and it gave me and a friend (in another plane beside me) headaches and didn't feel 100% for a while after.

Another friend of mine has a video of himself going up to 18,000ft. Took him ages and he passed out when he got there. Woke up at 10,000ft. He admits it was stupid and he was 18 at the time so fit enough.

Wouldn't advise it without oxygen.

Cessna_Pilot

chickenhawk wrote: »

Another friend of mine has a video of himself going up to 18,000ft. Took him ages and he passed out when he got there. Woke up at 10,000ft. He admits it was stupid and he was 18 at the time so fit enough.

QUOTE]

Stupid is not the word. He deserves to have his licence revoked for that kind of carry on.

chickenhawk

Ha bit late now. He works for a pretty successful airline.

And no it wasn't me.

fireplace1982

I would love to fly with the type of guy who videos himself flying without Oxygen at 18,000 feet...thrupenny bit.

ronnie3585

Flyer1 wrote: »

ronnie, do you mind me asking why FL160 in a 172 ? Or was it just one of those random " I wonder " moments.

Yea, plan was to go to FL140. At 140 she still had a very good rate of climb so we kept going really to look at the performance of the aircraft. Once we reached FL140 we didn't hang around and started the descent.

Like yourself I had been meatbombing up to FL140 in an unpressurised 206 with a PT6 though, wanted to see how a SEP would handle it. Was surprised how good the performance was.

I was 19 at the time of the flight and a lot less cautious than I am now. I wouldn't choose to fly that high again without oxygen however it was a great learning experience. A lot of VFR PPLs are afraid to fly at anything above 3,000ft. It gave me the knowledge to start traveling at higher altitudes. If I get the weather its great to travel at FL80 or 90. There is a great saving to be had in fuel and time, not to mention the extra time and range should the donkey quit.