I was flying a C172 once, and needed to get down quick (bad planning, ended up too close too high), so I shut the throttle and pointed the nose somewhere near Vne - as an aside, it was a diesel aircraft with liquid cooling, so took this kind of abuse in its stride.
Started at 10,000 descending at about 1,500 fpm, about 7,000 feet I felt a tiny nagging pain above my left eyebrow, but passed it off as a blood vessel getting irritable or some other cause of life's sometimes unknown temporary pain.
Approaching 6,000, it was clear that this was a sinus issue, so I leveled off immediately. Obviously there was still equalising trying to occur in my head, and the pain became so great that I instinctively covered my left eye with my hand for fear of it popping out or disintegrating! Whilst doing this, I initiated a climb at full power, stopping every couple of hundred feet, trying to meet the 'mid-point' where I'd be equalised and the pain would gradually reduce. I was attempting to cure what I decided to term 'cold induced pressure inertia syndrome'!
The descent from 6,500 or so was the longest (literally, and metaphorically) I'd ever experienced, and of course as I came below 3,000 and the density change increased exponentially, the descent was extremely slow.
Seriously, do not fly with a cold. Do not fly if you have recovered from a cold within the past week (as I had during this occasion). As Pace mentioned above, it probably wasn't the cold that caused the agony I experienced, but a side effect of the cold, such as some kind of infection that I was unaware of.
It took less than a minute between feeling the initial symptoms to nearly passing out through the pain, on my own, in a plane. Not clever.
edited to say - The bad planning was probably a result of a lack of concentration caused by the aforementioned malady, ironically
Last edited by Halfbaked_Boy; 17th May 2012 at 21:54.