From: "Jim Carter" <jim.carter@[EMAIL PROTECTED]
>
Date: Sun, 13 May 2007 18:55:14 -0500
Message-ID: <000601c795ba$2730e540$4b01a8c0@[EMAIL PROTECTED]
>
I Learned About Icing From That...
If we tempt fate often enough, sooner or later we are going to get
taught a lesson. The hope we all share is, that the lessons are not
too painful, or as they often are in this world of aviation - harshly
fatal. Since I am still here these many, many years later
to tell of an im****tant lesson, you can surmise fate was gentle with
me that day in November 1974.
I worked for a small flight school in Seattle, Wa****ngton on the
East side of Boeing Field. Having grown up in the windy flat-lands of
Oklahoma and Kansas, the calm, moist, temperate climate Seattle
offered was a pleasant experience. The winds never got near what we
experienced in Oklahoma, and there was no such thing as hail stone big
enough to come though hanger skylights. Prices were still very
reasonable, with a one bedroom top floor apartment on Alki Point only
$300.00 per month including off-street parking. Newly married at 22
years of age and fresh out of USAF active duty, I was living the good
life - for $6.50 per flight hour.
The school had a dealer****p that sold the new Aerocommander 112
aircraft, some of which we used in our instrument and CFII training.
As a favor to their customers who had purchased 112s, the school
offered to ferry the aircraft back to Norman, Oklahoma for an upgrade
that had just come out. (I think it upped the gross weight and
strengthened the door latches.) We instructors began ferrying a few
birds back overnight and catching the big iron back home the next day.
I had made a couple of these flights during the late summer and
early fall - one was non-stop with an unbelievable tailwind and
long-range tanks - so I was getting comfortable with the route and the
environment. So when I had a commercial student ready for a long
cross-country, an instrument student ready for a final flight in the
system, and a brand new commercial student who just wanted to go
along, the school arranged for us to take one of the ferry birds and
pick three up to bring back to Seattle.
The morning for our departure found low fog (duh!!) in the Seattle
basin, and a low, thick solid overcast all the to the Rockies. The
forecast was for very cold (-15 F), strong tailwinds at our altitude
and after we turned South at Cheyenne the wind even tapered off. Tops
were not forecast to be above FL200 and there was no hint of CBs
anywhere along our route. We would be in serious trouble if we had to
make a landing anywhere before Denver or Garden City, Kansas. I
allowed myself to be coerced into the flight despite a nagging worry.
So we joked about working on our tans while we zoomed along on top of
the deck below us, which is exactly what we did all the way to
Bozeman, Montana.
The Victor Airway takes a little dog-leg to the South between
Bozeman and Livingston, but not having been on the ground there
before, and not having topographical features on the old Jepp Charts,
I only found it to be an interesting point of reference. Never the
matter, we come cruising along past Bozeman and request direct to
Livingstone fat, dumb, happy, and warm inside our flying Cadillac.
What is that ahead? So that's what a line of upslope ***ulous
looks like from the top; how interesting. They sure looked soft, and
not very tall - FL180 was probably right and was only about 6,000'
above us. Carry on young airmen, but prepare to learn about ice.
Although we all commented about how cold it was outside, none of
ever put two and two together to realize that the moisture in the
***ulous was super cooled water va**** because the winds were forcing
it uphill so fast. We entered the side of the line of clouds at
cruise speed and got to see what only an uncooked foodstuff should
ever see - flash freezing. The wind****eld iced over completely, the
long-wire for the ADF snapped off, the ram air filter on the intake
iced over completely, the engine started starving for air until the
alternate air damper could be opened, and then the prop slung its ice
load indiscriminately and tried to shake the engine
out of its mounts.
We immediately executed a standard rate 180, but were falling out
of the sky so fast we never saw clear air again until we came out the
bottom of the overcast in a canyon known locally as Bridger Canyon.
Oh, and it was snowing.
There was no way we were going to be able to stay in the air so
flying down the valley was not an option, especially with less than 2
miles visibility in the snow. I remember hearing the new commercial
student in the back ask what was happening, and I remember my
instructor student's answer - we're cra****ng.
Bridger Canyon had a paved, two-lane road running up the West side
of the valley floor. That two lane road looked a lot more inviting
than anywhere else, so for a short period around noon that day it
became an impromptu landing strip.
The engine was shaking so badly from the ice load on the prop that
anything over about 1500 RPM was way too scary. The stall speed was
hard to determine because of the ice and none of us were enjoying
being test pilots at the time - we knew we had a buffet at 135 during
the descending turn so flying this bird any longer was out of the
question.
Everyone was so calm; everything was so quiet, thinking back on
the event it seems surrealistic. We kept the gear up, shut down the
engine before we shook something loose because it was getting worse
and aimed for the road. Turned on all the lights so the two vehicles
on the road could see us coming. Cleared the wires, threw down the
gear, shut off the fuel valve, and planted that sucker right on the
yellow stripe after seeing the guy's tonsils in the old IH Travelall
we flared over. Knocked down a couple of mailboxes and knocked the 2
or 3 feet of the wing tips off, but that 112 held together just fine
for being around 1600# over gross and 50 or 60 K over normal landing
speed at touchdown. Gotta love those Rockwell guys...
What did I learn? Terrain can make clouds do funny things. Upslope
***ulous can be unfrozen even when the air around them is way below
zero. Take a very cold airframe and stick it in a moist cloud and you
get instant, and very rapid ice ac***ulation. (We still had over 2"
on the leading edge of the wings when we stopped rolling.) I have a
whole different understanding and respect for ice now than I did when
I picked up little bits of rime doing a hold over the Olympic
Peninsula. Ice builds very fast and can ruin your day very quickly.
We picked up at least 2" in a standard rate 180 - that's an
ac***ulation rate of 1/2" every 15 seconds. 1/2" is enough to bring a
lot of planes down and 15 seconds is not much time to think about it.
Finally, I've never let myself be coerced into a flight that didn't
feel right since that learning experience. I and my three
passenger/pilots were extremely lucky to come down where we did - I
never win at cards - there has to be a higher power.
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