Flight Training - March/April 2021 - 20

PREFLIGHT ACCIDENT REPORT

BY DAN NAMOWITZ

FROZEN-LAKE FEVER
GETTING INTO-AND OUT OF-A SLIPPERY SITUATION
RECREATIONAL FLYING DOESN'T GO INTO HIBERNA-

tion when winter sets in. In some ways it expands.
That's good for aviation; most mechanics will tell you
that an aircraft that's flying regularly is probably in
better condition than one that waits out the season
banished to the rear recesses of the hangar.
Winter flying is a tonic for pilots, too, provided
they adapt safely to the challenging conditions of a
changing and sometimes extreme environment. When
they don't give this obligation its due, the perils of
impulsive decision-making and risky maneuvering
increase-sometimes beyond the point of recovery,
as the examples of a botched buzz job over a friend's
place and a trouble-plagued touchdown while landing
on a frozen waterway to socialize with a group of ice
fishermen bear witness.
Light aircraft pilots love calm, windless conditions,
but hazards may still abound. Take flat-light conditions: When lighting and/or snow-covered ground
obscure terrain features, an illusion may be created
that gives the pilot the impression that the aircraft has
more terrain clearance than it actually has.
A Cessna 170B pilot was returning to a private
airport in New Hampshire from a brief cross-country
with three passengers aboard on December 22, 2007,
when, according to a National Transportation Safety
Board accident report, a decision was made to deviate
from the arrival and " make a low pass over an adjacent
lake, near a friend's property. "
Often prelude to trouble, the decision to maneuver
down low ended the flight then and there, although
fortunately, without injuries: " The pilot said that his
depth perception was negatively affected due to the
flat light and snow on the ground. While maneuvering
over the lake, the right main landing gear contacted
the snowy frozen surface, which resulted in the right
wing impacting the surface, " the report said.
Although the NTSB said the probable cause of the
accident was the 1,700-hour, 48-year-old pilot's failure
to maintain clearance from the frozen lake while
maneuvering, it noted the contributing influence of
" unfavorable lighting conditions, " which, as reported

JARGON
Flat light

20 FLIGHT TRAINING MARCH/APRIL 2021

at an airport 10 miles away, included calm winds and
an overcast at 2,200 feet.
Not every airplane that ends up scuffed and
stranded on a frozen lake winds up on the surface by
chance. Landing an aircraft on frozen water bodies is
not an uncommon winter pastime and in some places
takes the form of scheduled entertainment for skiequipped aircraft or airplanes still rolling through the
season on regular aircraft tires or large tundra tires.
Seven days after the flat-light incident in New
Hampshire, the 62-year-old, 1,800-hour pilot of an
older model Cessna 172 dropped in on a frozen lake
in Crystal Falls, Michigan, to socialize with a group
of ice fishermen.
So far that day, the NTSB reported, the pilot's outing had been going well: " He stated that he had landed
at one end of the lake and spent about 20 minutes
talking to some fishermen and then got back in the
airplane and flew to the opposite end of the lake. Upon
landing, the nose landing gear struck a crack in the ice
and collapsed. The airplane then slid about 400 feet
before coming to rest. Examination of the airplane
revealed damage to the engine, propeller and firewall. "
The pilot was not injured in the accident, of which
the probable cause was determined to be the " rough,
unsuitable terrain encountered during the landing "
that resulted in the failure of the nosewheel.
Would you recognize flat-light conditions in a
forecast or upon encountering them in flight, and
be on guard for the kind of optical illusion they
can induce?
What technique would you use for landing on a
frozen lake? How much information about existing
surface conditions or obstructions at an off-airport
destination, and what level of personal proficiency
and aircraft familiarity would satisfy you of the safety
of conducting the flight?
It is no illusion that these are weighty questions to
answer before putting yourself-and perhaps a planeload of trusting passengers-into a slippery situation.
dan.namowitz@aopa.org

Flat light usually occurs with overcast skies and snow-covered ground, or
over dust, sand, or on glassy water. Pilots see less shadow and contrast,
and may have difficulty distinguishing distance; the lighting may give the
illusion the pilot is climbing or descending even in level flight.

Flight Training - March/April 2021

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