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Posted for JIMRHER@aol.com:
Some of you might remember that in Jan 06 I had a loss of pressurization at
FL 210 and had to make an emergency decent. I now have the CFS data log from
that flight which graphs many different things. I thought I would share some
thoughts for your information and critical analysis.
I have attached one of the graphs that show my climb profile from SL to FL
210 with altitude holds at 13K and 19K before leveling at 210, 28 min. after
take off. Shortly after that I had the pressure switch for the door seal flip
to the off position. (I still don't know how or why, but everything checks
out
perfect.) I put it into a dive at 250 KIAS (280 is the Limit) and descended
4,000 ft in the first minute and 2000 ft in the next minute. So a 6000 ft
loss in 2 min. from FL 210 to 15K ft. You can see that I hit turbulence in
the
decent where G's were up to 2.3 and down to .2 which is why I had to slow my
decent rate. Then since I was over the peak in the Sierra Mountains the
controller told me the minnum enroute alt. was 17k but since they had 2K
clearance
and if I could see maybe I would like to use 16K? He also gave me a heading
to the nearest airport so that is why the Bank angle changes. Then I found
the
pressurization problem, repressurized it, and chose to stay at 17K for the
remainder of my trip. I didn't know that I had dropped the manifold pressure
from 30 to 25.5 in. in the decent until I saw the graphs. There is much more
information in the graphs but I didn't bore you with that.
Lessons learned; I had my O2 mask around my neck. I pulled it on then had to
move it to tell my wife to turn on the bottle, all while diving in
turbulence, she never heard or understood me because of the noise. Now she
knows to do
that automatically if this happens again. Frankly, I don't see how any pilot
could turn the bottle on with this kind of workload. Also, I know that I can
go to 280 KIAS and I think deploying the speedbrakes would steepen the
angle. Not sure how much faster one would come down? If I were 4K higher at
FL250
that would have taken another min. at that higher altitude.
Jim Hergert
N6XE (An Sexy)
L4P 380 hrs.
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