The
world's most
popular
airplane, not
surprisingly,
has a great
safety record.
Safety and
simplicity sell.
In this safety review,
the AOPA Air
Safety
Foundation
looked at all
the Cessna 172
accidents that
occurred from
1982 through
1988 — more than
1,600 of them.
With 24,130
Skyhawks in the
fleet, that's a
good record, but
it is sobering
to think that
every year about
237 Skyhawks are
involved in
reportable
accidents —
that's more than
four per week.
Happily, most of
the accidents
result in little
or no injury to
the occupants.
The Cessna was
compared to
other light
four-place
aircraft that
make up the bulk
of the training
and entry-level
transportation
fleet. Included
in the
comparative
aircraft group
were the Beech
Musketeer
series, the
fixed-gear
Cessna Cardinal,
the Piper
Cherokee, the
Gulfstream
American AA-5
Traveler, and
the Aerospatiale
Tobago.
In terms of
overall
accidents per
100 aircraft in
the fleet and
per 100,000
hours of flight,
the 172 had a
very slight edge
over the
comparative
aircraft. But
there are some
significant
differences in
other areas. The
Skyhawk has
fewer serious
accidents, which
may be
attributed to
its almost
universal use as
a trainer.
Instructional
flying is
proportionately
much safer than
personal flying.
Pilots are less
prone to fall
victim to the
high-risk
accident areas
when under an
instructor's
supervision.
The 172 is
involved in
accidents in
instrument
meteorological
conditions (IMC)
about half as
often as other
light singles.
This is not
because of any
inherent
differences in
the stability of
the various
aircraft, but
probably in how
they are used.
The Gulfstream
Traveler and
Beech Musketeer
are not used
widely by flight
schools.
Individual
owners are more
likely to use
these aircraft
in cross-country
flight with more
chances to
encounter
adverse weather.
The same
thinking applies
to the 172s'
having lower
accident
involvement on
IFR flight plans
and at night. As
with many of the
other aircraft
we have studied,
night flying
shows a high
degree of risk
relative to the
hours actually
spent aloft
after dark.
Night accident
rates are
estimated for
the Skyhawk at
7.65 per 100,000
hours, compared
to its 6.17
overall accident
rate.
In keeping
with the role of
a training
aircraft, the
primary accident
cause about 85
percent of the
time is the
pilot, just
slightly more
than the 82.9
percent of the
comparison
group. The
simplicity of
the 172 also
shows up, with
the aircraft
being identified
as the problem
source less than
7 percent of the
time. There's
not much to fail
on a 172 if one
maintains it
properly.
When studying
the pilots of
accident
flights, some
interesting
patterns emerge.
Sixteen percent
of the serious
accidents occur
in the pilot's
first 100 hours
of total time.
The rate jumps
to 23 percent
for the next 100
hours and then
drops sharply
after that. This
indicates that
as new pilots
begin to enjoy
the freedom of
their
certificates,
they also
encounter some
situations that
exceed their
experience level
or defy good
judgment.
For example,
a 23-year-old
private pilot
with 164 hours
total time was
observed
performing
terrain-following
flight at
altitudes
ranging from 50
to 300 feet. A
collision with
electrical
transmission
lines 100 feet
above the ground
ended the
joyride.
A 19-year-old
private pilot
with 71 hours
total time and
only seven in
the 172 took off
with three
passengers from
El Paso, Texas.
The density
altitude was
calculated to be
6,400 feet when
the pilot was
asked by ATC to
make a turn just
after liftoff to
make way for a
departing jet.
The overloaded
Cessna had
climbed to about
300 feet when,
after entering
the turn, it was
observed to nose
over and lose
about half its
altitude. A
witness stated
that the
aircraft climbed
and dipped two
more times
before crashing
in a steep bank
into the desert.
No pre-impact
malfunction was
noted.
A question
that always
comes up after
an accident of
this type is
whether the
pilot has ever
had a full-load
checkout. The
172 has four
seats; but
unless the fuel
load is light,
the odds are
that the
aircraft will be
overloaded when
the seats are
filled — unless
you're carrying
munchkins. Climb
performance is
anemic at sea
level under this
load condition,
let alone at
high density
altitudes.
Stalls tend to
occur more
easily and the
recovery takes
longer.
Half the
pilots involved
in serious
accidents in
both the Cessna
and comparison
aircraft had
fewer than 100
hours in type.
This is not
unique to light
training
aircraft and
indicates that
pilots are
attempting
operations
beyond the skill
level to which
they were
trained. Either
the pilots
should restrict
their activities
until they have
more time in
various
conditions or
the checkouts
need to be more
rigorous. A
combination of
the two is the
most desirable
solution.
Of the 107
accidents
occurring in
IMC, almost
three quarters
involved
non-instrument-rated
pilots. In
perusing some of
the briefs,
located in the
second section
of the review,
it may be
stretching
credibility
slightly to
refer to these
crashes as
"accidents." One
scenario
involved a
184-hour private
pilot with three
passengers on
board who
departed on a
night
cross-country.
The flight
encountered rain
and low clouds,
and the pilot
attempted to
file an IFR
flight plan and
follow radar
vectors. The
pilot informed
the controller
that he had only
35 minutes of
fuel remaining.
The impending
exhaustion
became a moot
point after the
pilot became
spatially
disoriented and
spiraled into
the ground.
Not
surprisingly,
the 172 had
about one third
the number of
fuel starvation
accidents,
compared to the
other airplanes,
all of which
require tank
switching. Fuel
exhaustion and
weather-related
accident rates
were also
significantly
lower in the
172, again
probably related
to heavy
instructional
use, compared to
personal use.
A few
operations stand
out as
moderately
risky. Takeoffs
and landings
during high
winds resulted
in many damaged
aircraft but not
many injuries.
Many low-time
pilots do not
get enough
instruction in
the fine art of
high-wind
flying, with
predictable
results.
Go-arounds
are another area
where problems
occur. The
Cessna is
blessed with
exceptionally
effective flaps.
This
characteristic
allows for short
landings but
also mandates
that the pilot
retract the
flaps to no more
than 20 degrees
on a missed
approach. In an
attempt to
reduce this
problem, Cessna
reduced the
maximum
deflection from
40 degrees to 30
degrees on later
models. The
accident data
used to compile
this safety
report do not
specify year of
manufacture.
As with many
other
single-engine,
fixed-gear
aircraft,
maneuvering was
the leading
phase of flight
for serious 172
accidents. Most
of these mishaps
involved
low-level flight
interrupted by
terrain,
obstacles, or
water. While
flying close to
the ground may
give a great
sensation of
speed, the
sudden stop that
frequently
ensues is
usually lethal.
The Cessna
172 is probably
as docile and
easy to fly as
an aircraft can
be. It's a
simple airplane,
with simple
systems and
simple
procedures. If
pilots maintain
a modicum of
skill and avoid
the big judgment
errors, the 172
is about as safe
as they come.