AOPA Pilot Magazine - August 2022 - 77

conditions. In a Caravan, the tail will ice
first-a treacherous, insidious condition
that can cause loss of control.
The smokestacks at Burley inside a
mile on final were at least a distraction
and at worst causal. They wouldn't normally
be a factor; a nuisance, yes, but not
treacherous. Dozens of pilots had flown
hundreds of approaches over those
smokestacks and in poor weather. On
this day, however, conditions were perfect
for ruinous impact. She approached
them almost directly downwind from
the plumes, which would have been substantial
on such a cold day. The FAA's
guidance warns against flying through
smokestack plumes, especially on cold
days: turbulence, airframe distortion,
reduced visibility, engine problems, icing,
flight control deficiency. Any of these
could have occurred and would have
been potentially serious in ugly weather
so close to the ground.
The RNAV 20 approach into Burley
has a high MDA and a steep, 3.75-degree
vertical descent angle because of the
smokestacks so close to the runway
threshold, directly on the runway centerline.
The steep VDA requires an
aggressive descent from the MDA at
the missed approach point to the runway.
Did the first missed approach, and
steep descent angle, nudge the pilot to
get low, early, on the second approach,
or did something else cause her to drop
below the MDA? Something mechanical?
Engine problems or structural icing? Did
the emanations from the smokestacks
cause problems that were unsurmountable
in her flight regime?
Perhaps there was a visual illusion.
Approaching Burley on the RNAV to
Runway 20, the roof tops and highways
could all appear to be a runway to a pilot
yearning for visual pickup. Perhaps she
descended below the MDA early believing
she saw the runway, which turned out
to be something different entirely. Then,
she suddenly went back in IMC because
of the plume and lost situational awareness
and aircraft control. Perhaps.
AOPA PILOT / August 2022
77
Single pilot, in winter conditions, on a
demanding approach, with nonstandard
obstacle clearance, nonstandard vertical
descent angle, directly over a smokestack,
and downwind of a debilitating plume.
Clearly all the factors proved too much.
Our lesson learned may be the perils of
risk-stacking. One risk element by itself
may not be dangerous, but when we stack
several of them together, the synergy is
a negative accumulation that even the
most talented and motivated pilots cannot
overcome. It's easy for us to identify
the risks and stack them in hindsight,
sitting casually at zero knots and one G.
One takeaway from this tragedy must be
that we learn strategies to identify our
accumulating risks in the moment, and
develop methods to recognize when the
stack gets too precarious and it's time to
exit. richard.mcspadden@aopa.org
airsafetyinstitute.org
NW-1, 19 MAY 2022 to 16 JUN 2022
NW-1, 19 MAY 2022 to 16 JUN 2022
http://www.airsafetyinstitute.org
AOPA Pilot Magazine - August 2022

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