AOPA Turbine Pilot Magazine - December 2018 - 16

LETTERS
P&E

SAVVY MAINTENANCE

OPINION

all while scanning for the multiple Boeing 737s that ATC ws
reporting. As an instrument student, I had a CFII who taught
me that pilots only have a certain amount of attention to give,
and any time a pilot can safely
delegate a task to automation,
that's one less item demanding constant attention. As
Zimmerman pointed out with
the unfortunate Asiana 214
example, a lack of understanding about automation systems
can be just as bad as reliance
on them. Automation should
complement solid basic rudder
skills, not compete with them.

home's location hasn't changed
more than a hundred miles.

Stargazing

Touching tribute

Aaron Zink
AOPA 7244689
Benecia, California

I really enjoyed Barry Schiff's
column "Proficient Pilot:
Navigation, R.I.P." As an IFR
pilot who was raised on VOR
tracking and NDB approaches,
now flying a Cessna 172 that is
2020 ADS-B compliant, I can
relate to the apprehension that
would ensue should my autopilot-coupled GPS suddenly quit.
I have to say, I laughed out
loud for a long time when I read
that his Bendix sextant shows his

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Hip to be (over)
square
The myriad benefits of high manifold pressure and low rpm
BY MIKE BUSCH

I BOUGHT MY FIRST AIRPLANE AT AGE 24

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shortly after I relocated from New York to
California. It was a brand-new 1968 Cessna
182 Skylane that I picked up at the Cessna
delivery center in Wichita. In preparation
for that momentous event-and to make my
insurance underwriter happy-I got a thorough checkout in a ﬂight school Skylane
with a very senior CFI.
All my time up to that point had been in
Cessna 150s and 172s and Piper Cherokee
140s-all airplanes with fixed-pitch props
and primitive engine instrumentation.
Knowing this, my instructor placed a lot
of emphasis on teaching me how to use the
Skylane's constant-speed propeller, and how
to manage the powerplant using manifold
pressure (MAP) and rpm and exhaust gas
temperature.
One thing the instructor stressed
repeatedly was the importance of never
operating the engine oversquare-that
is, with manifold pressure greater than
rpm divided by 100. Under his persuasive tutelage, I was taught that a "square"
power setting of 25 inches and 2,500 rpm
was acceptable, an undersquare one of 23
inches and 2,500 rpm was even kinder to
the engine, and an oversquare setting of 25
inches and 2,300 rpm would most likely
blow the heads right oﬀ the cylinders and
had to be avoided at all costs.
To avoid going oversquare for even a
moment, the instructor taught me that a
power reduction-such as going from takeoﬀ power to climb power, or from climb to
cruise-must always be done by first pulling
back the throttle to the desired lower manifold pressure, and only then pulling back the
propeller control to the desired lower rpm

(but never less than manifold pressure times
100). Conversely, a power increase must
be made by first increasing rpm and then
increasing manifold pressure (but never
more than rpm divided by 100).
To lean, the CFI taught me to slowly
lean the engine to peak EGT, then enrich
until the EGT dropped by 125 degrees
Fahrenheit to establish best-power mixture.
The Skylane's Continental O-470 engine
would start getting noticeably rough at peak
EGT, so lean-of-peak operation was never
even discussed.
LESSON FROM LINDY

Four years later, after putting nearly 1,000
hours on my Skylane, I traded my Skylane
for a high-performance retractable-a
brand-new 1973 model Bellanca Super
Viking. My new airplane was powered by a
300-horsepower Continental IO-520.
At first, I ﬂew the Viking the same way
my CFI had taught me to ﬂy the Skylane:
never oversquare, never lean of peak. Then
I got involved with a public-benefit ﬂying
organization called The Flying Samaritans,
and began ﬂying teams of doctors, dentists,
and nurses to free medical clinics in remote
areas of Mexico. The clinic locations were
often at dirt airstrips with no fuel or services, so we had to carry enough fuel to get
there and back without refueling.
I happened across an article describing
how during World War II, Charles Lindbergh
visited the South Pacific and taught fighter
and bomber pilots how to achieve much
greater range through optimal powerplant
management-mostly oversquare operations and lean mixtures. For example, the
P-38 was considered to have an operational

90 | AOPA PILOT October 2018

Bob Fort
AOPA 934477
Virginia Beach, Virginia

Jonathan Sackier's article, "Fly
Well: Close to Home," brought
back memories of a co-worker
and friend years ago who did
this. One thing I remember was
that shortly before his suicide
he didn't care about things that
he normally was passionate
about; his tools, for example.
This was a big indicator I didn't
notice until it was too late.
Stephen Lawton
AOPA 772695
Hillsboro, Tennessee

Finally, Mike Busch has unmasked the
mythology of "oversquare" fervently taught
(and believed) by my primary flight instructor.
I knew back then it was futile to reveal to him
that rpm and inches manifold pressure had no
physical connection.
Chuck Jones
AOPA 873464
Sulphur Springs, Texas

Sackier responds: I thought this
article might resonate with one
or two readers out there and
provide some form of solace or
support. I was wrong. In the
wake of publication I have been
swamped with numerous emails,
largely about friends or loved
ones lost and missed signs: He
wasn't taking care of his tools
was one. He withdrew from
our flying club was another.
Variations on a theme, but the
end result the same. Many
emails were just a chance to
vent, to remember a son, father,
wife. All talked of wanting to do
something to help prevent this
awful event touching the lives of

others, hence this letter. Just as
we focus, rightly so, on our skills
as pilots, lets also focus on our
compassion as humans and be
aware of this scourge.

CLARIFICATION

"Waypoints: WAAS Factor"
states, "In order to provide the
most accurate position information practical, the FAA
insists that the aircraft have
a GPS receiver that incorporates a WAAS correction
factor." In fact, as stated later
in the article, there are other
GPS receivers that can supply
a position source that meets the
ADS-B mandate.

HANGAR TALK

ERRATUM
AOPA Senior Photographer CHRIS ROSE and
Editor at Large DAVE HIRSCHMAN joined a
gaggle of seaplanes splashing down on
Moosehead Lake for the International
Seaplane Fly-In in Greenville, Maine, in
September. With Hirschman at the controls, Rose got to try out his new flying
helmet photographing the Aeroprakt A-22
through the open door of the breezy Piper
Super Cub on floats for "WATER WAR," which
begins on p. 50. Driving to dinner afterward,
Rose and Hirschman got a taste of rural
Maine life: "All of a sudden this big female
moose broke out of the woods with her
calf," Rose said. "We came screeching to a halt and the calf proceeded to trot up the
road." The weekend wasn't all Maine clichés, however: Sorry, no lobster.

16 | AOPA PILOT December 2018

"Just for Fun: Things that
Go Bump in the Night "
(October 2018 AOPA Pilot)
incorrectly states that thenWichita Municipal Airport
is now Wichita Dwight D.
Eisenhower National Airport.
It is now McConnell Air Force
Base. AOPA Pilot regrets the
error.
We welcome your comments.
Editor, AOPA Pilot, 421 Aviation
Way, Frederick, Maryland 21701
or email (pilot@aopa.org). Letters may be edited for length.

AOPA Turbine Pilot Magazine - December 2018

Table of Contents for the Digital Edition of AOPA Turbine Pilot Magazine - December 2018