| Some
information ought to be read by every serious pilot. I put
this information (gained the old fashioned way through experience)
in that rather elusive category. The is a slightly edited
version of a post by Doug Rozendaal originally made on the
Matronix RV board. He made it response to a post about an
RV that had encountered icing and in sharing his experiences
and understanding he may help one of us out of a jam. Whether
it saves a life or just reduces the pucker factor, the knowledge
is worth having. We must to learn from others. In aviation
in particular, we can't make all the mistakes ourself and
expect to survive long. Doug was kind enough to give me permission
to reprint his note on this web site and put it in our EAA
Chapter 231 Newsletter (Jan 2004). Don
Icing
– by Doug Rozendaal
It has
been a long weekend, and I seem to have nothing better to
do so I
will respond to a recent post on icing. I flew night freight
in Twin Beeches and C-402s part-time for 10 years in Iowa
and along the way, I got a little experience with ice.
A sick
engine and no airspeed equals no fun. Pitot heat is a NO GO
item for IFR, in all but the low altitude summer time, and
even then you can have freezing temps at fairly low altitudes
when convective activity gets rolling.
If you
plan to fly IFR out here in the Midwest, you have to remember
we only have 2 WX briefings from FSS, when we call, we get
a message that says, "if it is between April 1 and November
1 press 1 for the summer briefing, otherwise press 2 for the
winter briefing." The summer briefing says "afternoon
thunderstorms with tops to FL 450, hail to 2", and wind
gusts to 50kts." The winter briefing says "Scattered
snow showers with visibility reduced to 1/2 mile and Moderate
Mixed Ice in the clouds from the freezing level to FL180.
The only
way to fly IFR out here in the winter is to "manage ice"
Ice is like turbulence, there is almost always some, and it
is usually not a big deal. Without knowing the WX pattern
etc, I don't know what Jim's plan was or should have been,
but "plan" is the key word and with a "plan"
usually you can "manage" ice pretty effectively.
Flying IFR in the winter up north is not for marginal instrument
pilots. Flying and navigating needs to be easy enough for
the pilot to leave plenty of mental horsepower available for
gathering weather information and planning.
Deicing
equipment on light airplanes is highly overrated, the best
friend you can have in the ice is climb performance, and RVs
have good climb performance!
The whole
icing syllabus can not be reduced to a post on this list,
but here are some points that might be useful for managing
ice.
#1 Never
fly in Freezing Rain.
#2 Have a Plan, and a plan B.
#3 Upon encountering Ice, take immediate action, in accordance
with #2
#4 Never fly in Freezing Rain
#5 If the plan falls apart, implement Plan B and formulate
Plan C. Repeat as necessary.
#6 Pilots almost always stop flying before the airplane. NEVER
QUIT
FLYING!!! Most airplanes (fat wing, RV included) will fly
with OBSCENE
amounts of ice on them. NEVER QUIT FLYING!!!!
#7 Never fly in Freezing Rain.
#8 95% of all icing encounters are less than 3000 feet vertically.
#9 Upon encountering ice, the default reaction should be to
climb
immediately. Descending is always an option, but if you descend
and guessed wrong, climbing is no longer an option.
#10 Never Fly in Freezing Rain. This is the exception to #9
if you
encounter freezing rain turn around, as quickly as you can.
#11 Do not let ATC fly your airplane. If you are on top and
they want you to descend into the ice 40 miles from the airport,
do not do it. Stay up high, then dive for the airport as late
as possible. If you need to climb, ask once, and then insist
on a climb even if it means you have to change heading to
clear traffic.
#12 You guessed it, Never Fly in Freezing Rain.
With these
rules in mind, the "plan" might be, Get a briefing,
If the tops are below 8000 feet, and the freezing level is
4000 feet. Plan A might be try to stay below it. Upon encountering
the ice, Plan B is immediately request an unrestricted climb
to 8 or 9000 feet and use FULL power. RV's climb well in cold
weather and within 5 minutes you should be on top. Plan C
then becomes turning around and beginning a decent to a nearby
airport for a straight in approach. Do not pussy foot around
with (unnecessary) procedure turns if you are accumulating
ice at a rapid rate. If you are in radar coverage get vectors,
if not they won't know you skipped the procedure turns anyway.
Now you
are up on top at 9000 feet and the clouds are sneaking up
beneath you. Ask center for a pilot report or get on the flight
watch, ask what is going on below. Remember that 95% thing,
it came from a big study done by some Ph.D. types that I got
as a reference for an icing article in IFR magazine. You punch
into the clouds, and if you start getting ice you may want
to climb to 10 or 11, or you may want to request 4 or 5 thousand.
But once you start the decent if you start picking up ice,
you either have to climb back up, or you are committed to
descend till you get out of it, or pick a place to land if
you can't get below it (have a alternate in mind when you
start the decent). Ninty-five percent of the time you will
be below it in 3000 feet and you can continue to your destination.
Try to
visualize the weather system in the briefing, planning, and
flying. Where the cold air and where the warm can be found.
Either one is fine, it is the kinda cold air that causes the
problems. Unless you are flying parallel with the weather
system, the altitudes on the top and bottom of these areas,
will move up or down as you cross the fronts. So in the previous
example where the tops of the clouds, and ice, are rising,
the chances are the base of the icing layer is rising as well
and on a trip like that you could cross the icing layer twice
and never spend more than 10 minutes total exposed to the
ice. Unless you are in freezing rain, 10 minutes of ice will
seldom cause you any more trouble than a frozen windshield.
Something to consider if you are shooting a non-precision
approach. If you can't see the runway, fly to the airport,
and circle looking out the side using a carrier type approach.
That is
the short version.
Some quick
war stories:
You may
have determined by now that I have a healthy respect for freezing
rain. I descended into freezing rain in a Cessna 402 at 3000
ft on an ILS with the gear up planning to circle. I broke
out of the clouds at 2000 feet with full power, the gear was
still up and the airplane was barely flyable, at DH I put
the gear down. The windshield was covered so I kept the localizer
centered till I saw the runway lights out the side window
and smashed it on to the runway. It was the closest I have
ever been to buying the farm. I was in the clouds for less
than a minute and had over 2" of clear ice that ran back
to the spar. NEVER QUIT FLYING the airplane (you wonder why
I fly warbirds on weekends instead of night freight?).
Another
time, I was flying VFR underneath the clouds, at night, the
ceiling got below 1000 ft and I was 40 miles from my destination.
I asked for my clearance (which I had briefed ATC would be
my plan if the ceiling got too low) and climbed to 4000 ft.
With only 40 miles to go, why climb higher, besides I had
deice equipment. I climbed into a 30 kt headwind, and started
picking up rime ice. I did not want to climb any higher, I
only had 40 nm to go.... I thought I would just slug it out.
I kept cycling the boots, and kept the wings clear, but every
unprotected leading edge of anything just kept piling on ice,
which reduced my ground speed even further. I just kept adding
power and when I started down the glide slope I was at 110
knots with climb power. No options, no climb performance left,
nothing, just shoot an approach and make it. No excuses. I
was in the ice for over 30 minutes including the approach
maneuvering and it was too long. There were three to four
inches of mixed ice on the unprotected areas.
The more
winters I flew the less ice I seemed to encounter, and the
weather never changed. I can honestly say there have been
entire winters when I never cycled the boots.
Sorry
for the long post, but it really is the short version.
Tailwinds,
Doug Rozendaal |
