Flight Training - March/April 2022 - 13

ASI TIPS
BY ALICIA HERRON
INTO THIN AIR
BEWARE DENSITY ALTITUDE
be cruising in at a density altitude above
10,000 feet. What's your service ceiling?
Do you really want to fly at the altitude
where your airplane can't climb anymore?
Probably not.
The cooler months are a good time
DENSITY ALTITUDE IS MORE THAN A PHRASE YOU LEARN TO PASS A CHECKRIDE-IT'S
an insidious threat whose hazards can go overlooked even by experienced pilots. We're
taught the basics even if we don't have to contend with very high density altitudes in
our day-to-day flying. But what we're typically taught can be a significantly limited
view on the hazards of high density altitude flying.
Sometimes, the only performance factor we consider is how density altitude will
affect takeoff and landing. We'll need more runway for both because the engine won't
make as much power, the wings won't make as much lift, and our true airspeed will be
higher. Takeoff is only one part of the go/no-go decision though we often think of it as
the deciding factor.
Just because you can take off doesn't mean that a flight can be accomplished safely.
There's also your climb performance, climb gradient, turn radius, true airspeed, and
other performance factors to consider that are easy to forget if you fixate on takeoff
and landing. If the airport is reporting an 8,000 feet plus DA, guess what? You'll likely
NEW FROM ASI
THERE I WAS: EDGE 540 FIRE
On a November afternoon, GA pilot
Henry Coffeen was practicing
aerobatic maneuvers when he
experienced a fire in the cockpit
of his Edge 540.
airsafetyinstitute.org/thereiwas
to explore your airplane's performance
(and your skill limits), what you feel
comfortable with, and what's safe. As
it gets warmer, take notes on how that
performance and your comfort level
changes with the seasons.
Unfortunately, not all pilots prepare
sufficiently for the potential dangers
of high density altitude before they're
dealing with it in real time. In the early
evening of July 3, 2021, two pilots in a
newly purchased Beechcraft Bonanza
G36 departed Aspen, Colorado, for
their home base on the East Coast.
They planned to cross the Sawatch
Mountains-with peaks topping 14,000
feet-after an initial climb out of Aspen.
The AOPA Air Safety Institute team
follows the Bonanza's likely encounter
with high density altitude-an inherent
hazard in high terrain significantly
degrading aircraft performance. Deceptively
upsloping terrain would leave no
escape for the flatland pilots facing the
canyon trapping them.
airsafetyinstitute.org/ACS/IntoThinAir
alicia.herron@aopa.org
+
DENSITY ALTITUDE TRAINING TIP:
Either with your CFI or on your own,
look at the density altitudes of these
airports. Calculate your performance for
takeoff, landing, and climb. Then, calculate
performance at maximum gross weight.
Would you feel comfortable flying to or from
these fields?
Big Bear City Airport (L35)
McCall Municipal Airport (MYL)
San Angelo Regional Airport (SJT)
Flagstaff Pulliam Airport (FLG)
Furnace Creek Airport (L06)
FLIGHT TRAINING MARCH/APRIL 2022
13
http://www.airsafetyinstitute.org/ACS/IntoThinAir http://www.airsafetyinstitute.org/thereiwas
Flight Training - March/April 2022

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