Flight Training - June 2014 - 22

ACCIDENT REPORT

Dan Namowitz
EIGHTY-EIGHT percent of GA
fixed-wing non-commercial accidents
in 2012 occurred in day visual
meteorological conditions.

AFTER THE BOUNCE

DON'T RIDE THE PORPOISE

A

high-wing twin is on final approach on this video found on
YouTube. The airplane nears the threshold, and moments
later, the pilot's belated and excessive rotation results in the
airplane ballooning upward and then slamming down hard
on the runway in a flat, or even a nose-down attitude. A classic
porpoising sequence follows.
Another YouTube video shows a similar
sequence in a Cessna 172. One difference: A go-around breaks the sequence
of bounces and nose-low ground impacts.
The moment of recovery is lost to the
viewer as the airplane passes behind an
intervening snowbank, but the roar of
the engine as it comes up to climb power
provides a comforting reassurance that
corrective action has been taken.
Such videos retain some value as teaching tools for pilots. Watching the two
scenarios unfold, it is only in the last few
seconds of each approach when you can
clearly diagnose the excessive airspeed,
and the failure of each pilot to pitch the
airplane to a proper landing attitude.
Finally, the failure to recover correctly
from the first bounce exacts its toll.
Porpoising takes longer to explain
verbally or in writing than it does to ruin a
landing. That's what makes it so important to recover at the first indication-the
first bounce.
Porpoising is official training lingo
because it is so precisely descriptive. "In
a bounced landing that is improperly
recovered, the airplane comes in nose first
setting off a series of motions that imitate
the jumps and dives of a porpoise-hence
the name," explains the FAA's Airplane Flying Handbook. "The problem is improper
airplane attitude at touchdown, sometimes
caused by inattention, not knowing where
the ground is, mistrimming or forcing
the airplane onto the runway." Improper
airspeed control is another known cause,
PLUS Watch a porpoise go awry
in this video.

22 /

FLIGHTTRAINING.AOPA.ORG

obviously related to the others listed.
Do yourself a favor on your next flight:
Add a practice go-around to whatever else
is on your flying agenda for the day.
The most regrettable thing about porpoising is that the mishaps can be stopped
as easily as they get started-at least
until the out-of-phase oscillations (pitch
increasing as the airplane rebounds into
the air, followed by a desperate lowering of the nose as the aircraft begins to
descend) result in gear damage.

ground. With order restored, the pilot
can proceed to reduce power again and
perform a normal roundout and flare or at
least execute a "cushioned" touchdown.
If the aircraft has rebounded into a
severely nose-high attitude several feet
above the runway, with recovery impossible before the next ground contact, the
other option is a go-around. This may not
avoid the second bounce, but the response
can still terminate the porpoising scenario.
A typical end result of a porpoising left
uncorrected is a collapsed nosewheel,
done in by being made to bear the full
brunt of the aircraft's contact with the
ground. That was the consequence of a
landing attempt pursued (in a tailwind)
beyond safe boundaries last June in Ann
Arbor, Michigan.

THE PILOT MUST RESIST THE URGE TO SHOVE
THE NOSE DOWN, WHICH WILL ONLY RESULT
IN A WORSE IMPACT THAN THE FIRST.
A decision must be made: How you
respond to the problem depends on the
severity of the bounced landing (but a goaround is never a wrong response).
Immediately after a light to moderate
bounce, the pilot should make a simultaneous addition of power and a pitch
correction. The added power buys some
time before the next touchdown, and
should cushion it somewhat. The pitch
adjustment should establish a proper
landing attitude. The pilot must resist
temptation to shove the nose down, which
will only result in a worse impact than
the first as the aircraft sinks toward the

Safety Quiz: Density Altitude
It's getting to be that time of year
again. How well do you understand
density altitude? Take the Air Safety
Institute quiz (www.aopa.org/asf/asfq
uiz/2013/130814densityaltitude/index.
html).

"The pilot was cleared to land on
Runway 30. The recorded wind was 110
degrees at 12 knots, gusting to 17 knots.
The airplane touched down at 50 to 60
knots and about 700 feet short of the
intersection with Runway 6-24. A slight
upward slope at the intersection caused
the airplane to bounce and become
airborne. The pilot contemplated making
a go-around, but elected to continue the
landing. Upon touching down again, the
airplane began to porpoise, the nosewheel
collapsed, and the airplane came to a
stop," a National Transportation Safety
Board accident summary said.
Things happen fast after that first
bounce. So practice your landing technique until your corrective responses are
accurate, instantaneous, and-because of
your growing skill-unnecessary.
Dan Namowitz is an aviation writer and flight
instructor. He has been a pilot since 1985 and an
instructor since 1990.
http://www.aopa.org/asf/asfquiz/2013/130814densityaltitude/index.html http://www.aopa.org/asf/asfquiz/2013/130814densityaltitude/index.html http://www.aopa.org/asf/asfquiz/2013/130814densityaltitude/index.html http://FLIGHTTRAINING.AOPA.ORG
Flight Training - June 2014

Table of Contents for the Digital Edition of Flight Training - June 2014
