The text book lies ...

[Gertrude the Wombat]

... when it says that the bottom thousand feet are the worst from the POV of pressure changes affecting the ears.

OK, so I'm nearly all better from a bit of a cold, right, and as far as I could tell it never got anywhere near the ears anyway, right, and the text book says that the bottom thousand feet are the worst.

So, if I flew a circuit with an instructor (being one day out of currency) and had absolutely no detectable effects in the ears whatsoever (as I expected from the cold being nearly all gone and not having affected the ears anyway) I'd be OK going a bit higher on the subsequent solo, right? (Point being that if I was going to have a problem it would be whilst there was an instructor in the aircraft to sort it out.)

Wrong.

The book lies.

I had no symptoms whatsoever on the check circuit, and then my ears blocked up on the descent from the solo trip.

I learned about flying from that. I should have scrubbed the trip and waited a few more days.

[GT]

I think what the 'book' meant was that on a rapid descent from high altitude any discomfort is more likely to be felt as you enter the lower few thousands of feet of the atmosphere. Then again, I could be wrong.

GT.

[scubawasp]

The text book is correct.

The air is more dense at sea level and half as dense at 18000ft. So in real terms, as you descend the pressure difference between your ear drum increases. As you get nearer sea level the pressure difference is greater as you don't have to descend as far to achieve the same amount of pressure change.

[Circuit Basher]

GtW - (non-medically trained comments follow!) from personal experience (mostly as commercial pax), I would estimate that from top of descent @ cabin altitude of 8 - 10k ft, I have to keep the eustacean tubes clear the whole way down. If I get a pressure imbalance 'locked in' which I fail to clear within a minute or so, then it gets progressively more difficult to clear. The point at which I am finding the ears most prone to pressure imbalance is when I estimate cabin alt is between 5k ft and 2k ft. Generally speaking, it is very rare for me to have any problems clearing my ears from 2k ft down.

[High Wing Drifter]

ft/mb = 96 * Temp(Kelvin) / Pressure. So the higher you go the more vertical distance you need to travel to feel the same pressure differential as felt at lower altitudes. So descending 5000' from 5k to SL would be much more noticable than descending 5000' from 15K.

[FlyingForFun]

Have only flown with a bad cold once - as pax on a commercial flight. No problem at all throughout the flight. No problem at all as we started descending, other than the usual need to clear the tubes out. Once we got down to, I'd guess (from looking out the window) 5000' my ears started to feel slightly uncomfortable, but manageable. On final, I found the pain getting worse and worse to the point that I was close to shouting at the pilot that he had to go back up, my ears were going to explode if we went any lower. Ears continued to be painful for the next four or five hours afer landing.

Just my personal experience, of course, but it seems to agree with the textbooks.

FFF
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[rodan]

The book IS correct. From personal experience descending from about FL60 a few years ago in a Bulldog. I had a cold starting that I didn't know about, (symptoms appeared the next day), and had a piercing pain start in my sinuses as we passed 2000' descending to circuit height. So painful, in fact, that I was unable to concentrate on flying, and my instructor took over. He was concerned enough that he declared an emergency and had an ambulance meet us on landing, after a very gentle descent.

I certainly wouldn't risk flying with a cold now.

[foxmoth]

Agree the book is right - the first flight was not a problem because you only came down 1,000', if on the second flight you had landed at aa airfield only 1,000' below the max you had climbed to you would probably STILL have been OK, it is the TOTAL height that you descended through that made the difference and the last bit would have had the most effect for reasons described above (and in the text books):hmm:

[Gertrude the Wombat]

the last bit would have had the most effect for reasons described above Oh, I understand the physics all right, but this is not what happened to me in terms of symptoms. The ears blocked up coming down from 5000' to 3000', and proceeded to get no worse from there to the ground. (Just as well, really.) (What was I doing at 5000' anyway? - well, just experiencing the novelty of an aircraft that could actually get that high without taking the whole hour about it.)

[foxmoth]

In that case I think you were very lucky because usually it WILL get worse the more you descend, and climbing above the height you had gone to with the instructor was, IMHO a bit risky.:=

[Algirdas]

The books are right - though the actual effect on the pilot may vary: on the way up, if your passages are blocked, you get what is called a 'reverse block' in scuba parlance (this can be horrendously painful -I once had one on a 5 hour flight from the Middle East - 5 hours of agony until decent into Heathrow) - and there is no relief method other than to descend - but if the blockage is only partial, then your passages may equalise enough for you to feel nothing.
If you have a blockage on descent, and this is the most common form, then it can be relieved by the old scuba methods of either holding your nostrils shut with your fingers, closing the mouth, and blowing gently against them - (blow too hard and you will damage things). If the blockage is partial, it may clear itself sufficiently on the way down that the symptoms either stabilise or disappear entirely, despite coming on down.

PS the other method on the way down is to open your mouth and work the jaw, yawning if possible - a lot of scuba divers (myself included) use this method exclusively - and bear in mind on a dive you ALWAYS get enough pressure increase to necessitate some clearing.

[Ripline]

One of the worst aspects of long-haul commercial SLFing for me was the final descent, which on one occasion left me half-deaf for a couple of days (how nasty to have your ear canals bubbling at random when you eat, gross...).

Now I pop a couple of Piriton tabs an hour before flight and this really deals with the problem. Cheap and non-prescription.

I also use the yawn and scuba pinch'n'blow technique - and now enjoy the landings as well!

Obviously I don't use them while piloting, but 3500' is as high as I want to go anyway! :eek:

Ripline

[S-Works]

Gertrude,

What you experianced was a reverse squeeze. This is a very common problem in people diving when they have a cold, in your case your reverse squeeze was actually the reverse of the diving condition if you understand me!

When you dive the water pressure doubles for every 10m that you descend. When you have a cold your eustation tubes are blocked usually for some days after the symptons of the cold have gone.

When you ascended the gas in your tubes expanded out of the tubes and mucus then blocked the tubes, as you descended again the airspaces were unable to equalise and you experianced the squeeze on your ears. A carefull valsalva manouver would probably have helped flex the tubes enough to allow the gas to pass back. As you neared the surface the pressure is less prone to change hence the reason that your condition did not feel any worse.

15 years of training technical diving Instructors and I have seen a few squeezes, the great ones look like a scene from aliens!!!