Frequently Asked Questions about Aerobatics
Frequently Asked Questions about Aerobatics
This document is Copyright © 1995 by Guenther Eichhorn. It may be
freely distributed in its entirety provided that this copyright notice
is not removed. It may not be sold for profit nor incorporated in
commercial documents without the author's written permission. This
article is provided "as is" without express or implied warranty.
I would like to thank everybody who took the time to send
me their comments. Many of them contributed substantial material for
In particular I would like to thanks Steve Pennypacker for
writing some of the paragraphs in this FAQ list and the list of
Last Update: 21 March 1998
Table of Contents
- General Comments
- International Aerobatic Club
- IAC E-mail Distribution List
- Aerobatics Books
- Aerobatic Airplanes
- Basic Aerobatics Figures
- Advanced Aerobatics Figures
- The Aerobatics Box
- Aerobatics Contests
- Specific Questions
First a Disclaimer: Any descriptions of aerobatics figures should
not be interpreted as instructions. No pilot should attempt to fly
any of these figures in aircraft not certified for aerobatic flight.
Further, no pilot should attempt these figures without training from a
competent aerobatics instructor. These descriptions are incomplete as
instructional material and will get you into trouble if you believe
that they are.
Aerobatics competition flying is organized in the USA by the
International Aerobatic Club (IAC). It is a sport that requires
skill and practice. If all the rules are followed, it is quite safe.
There are several dozen regional competitions each year in the US.
Once every two years, the World Aerobatics Championships are held.
They are in different countries each time and attract the best of the
world of aerobatics competition. If you have information about the
aerobatics organization in your country, please let me know so I can
include it in this FAQ.
International Aerobatic Club
EAA Aviation Center
P.O. Box 3086
Oshkosh, WI 54903-3086
The International Aerobatic Club, Inc is a Division of the
Experimental Aircraft Association, Inc. All IAC members are required
to be members of the parent organization, the EAA. Membership is open
to all who are interested in aviation. The IAC is also a Division of
the National Aeronautics Association and is responsible for the
administration, management, and promotion of the sport of aerobatics
in the United States under the applicable regulations of the
Federation Aeronautique Internationale; Paris, France. FAI is the
world governing body for all sport aviation competitions and record
attempts. IAC represents the United States at meetings of the FAI's
CIVA committee which establishes rules worldwide for aerobatics
A list of the officers of the IAC is available at: /ACRO/bod.html
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This e-mail distribution list is intended to distribute information
about aerobatics flying and the IAC in general. We plan to distribute
contest schedules and contest results, as well as safety tips, etc. We
hope it will also be used as a forum for discussions about aerobatics
flying, questions and answers concerning IAC rules, etc. How it is
used is up to you all.
There is just one restriction: It cannot be used for any commercial
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If you have any questions, need help with anything, or something
doesn't work, please contact
Guenther Eichhorn. You can just click on his name and send a note
through the form that comes up.
Probably the most popular instructional book for learning aerobatics is
"Fly For Fun", by Bill Thomas (available from EAA). It does a very good
job of explaining the maneuvers and how to fly them. The book has a couple
of shortcomings, however. One is that it doesn't go much beyond the
maneuvers themselves into other things you'll probably want to know. The
other is that it assumes you're flying a Pitts, which isn't the best choice
for beginning acro. This does make a difference, as performance
characteristics and visual cues are quite different than a lower
performance trainer, such as a Decathlon. If you're interested in
competition, Thomas' "Fly For Fun To Win" is also recommended.
The second book is Mike Goulian's and Geza Szurovy's new book,
"Basic Aerobatics". Few people on this list had seen the book yet. It
also does a good job of describing the maneuvers, but it also goes into
lots of other subjects like physiology and conditioning, safety, aerobatic
preflights, and costs of ownership. It also assumes you're in a Decathlon,
which is probably what you'll be flying.
Another book is Primary Aerobatic Flight Training with Military
Techniques" by Lt. Col. Art Medore, USAFR (ret). It has five sections
which include detailed ground study on a variety of topics and a
curriculum for 12 flight lessons. It also offers a section on
transition from tricycle gear to tail-draggers. There are appendices
for manufacturers' recommended entry speeds for maneuvers covered in
the text. The aircraft covered are: Beech Musketeer Sport III, Cessna
Aerobat, Champion Citabria, Beech T-34, Stearman PT-17, and North
The lesson curriculum begins with simple warm-up exercises (air
work), military chandelles, and lufberry turns. Advanced maneuvers
covered at the end include the reverse Cuban eight, the avalanche,
inverted spins, hesitation rolls, and inverted turns.
Simple sequences of maneuvers are covered and there is an
introduction to Aresti diagrams.
Other books that people seem to like are:
- "Roll Around a Point", by Duane Cole
- "The Conquest of Lines and Symmetry", by Duane Cole
- "Aerobatics", by Neil Williams
- "Aerobatics Today", by Bob O'Dell
- "Flight Unlimited", by Eric Mueller
- "The Basic Aerobatic Manual", by Bill Kershner
- "Stalls, Spins and Safety", by Sammy Mason
- The new second edition printing is now
available from a dealer (and aerobatic pilot) in England.
18, Woodhurst Road.
Berkshire SL6 8TF
Tel: +44-1628 37732 (evenings only)
FAX: +44-1628 777083
First I want to emphasize that you should do aerobatics only in
airplanes that are approved for aerobatics. It is potential suicide
to try aerobatics in any other airplane. Other planes are not
stressed for this type of maneuvering and they WILL break. Please
don't do it!
A list of aerobatic airplanes is available at
/ACRO/acro_planes.html with a summary of
their features. If you know any of the numbers that are missing, or
know of any other aerobatic airplane (not one-of-a-kind planes though)
please let me know about it.
Which aerobatic plane to use is almost a religious question, but here
are some pointers:
The most common aerobatic planes for beginners are probably:
For more advanced aerobatics the most popular trainer is probably the
Pitts S-2A or Pitts S-2B. Most other higher performance aerobatic
planes are experimental and cannot be used for regular flight instruction.
- C-150 Aerobat
Now on which trainer should you get started? It depends on various
things, not the least on the amount of money that you want to spend. Here
are some rough figures for hourly rates:
It obviously is much less costly to get started in a Citabria or a
Decathlon than in a Pitts. And both are good enough to teach the
basics of aerobatics. The C-150 Aerobat is very limited in the type
of aerobatics it can do. It seems to be a consensus on the IAC e-mail
list that it makes sense to get started in one of these trainers and
then move up to a Pitts to work on more advanced aerobatics.
- Citabria: $60 - $90
- Decathlon: $70 - $120
- C-150 Aerobat: $50 - $80
- Pitts S-2A: $130 - $200
- Pitts S-2B: $160 - $220
Basic Aerobatics Figures
A description of a list of aerobatics figures is available at /ACRO/acro_figures.html.
Here is a summary that tries to explain the difference between
maneuvers that are often misunderstood on the rec.aviation.*
There are four different types of rolls:
- Aileron Roll
- Slow Roll
- Snap Roll or Flick Roll
- Barrel Roll
Aileron rolls are flown with the rudder and elevator in the neutral
position during the roll. The aileron is fully deflected in the
direction of the roll. This is the easiest of the rolls to fly.
The aileron roll is started by pulling the nose up to 20 - 30 degrees
above the horizon. The elevator is then neutralized and the aileron
fully deflected in the direction of the roll. The controls are
maintained in that position till the roll is completed. After the
roll is completed the nose is usually 20 - 30 degrees below the
The aileron roll is not a competition maneuver.
Slow rolls have to be flown normally on a straight line (exception is
the avalanche). The roll rate has to be constant and the longitudinal
axis of the plane has to go straight. This requires constantly
changing rudder and elevator control inputs throughout the roll.
Hesitation or point rolls include stops at certain roll angles. The
number on the base of the roll symbol describes the number of points
the roll would have if it were a 360 degree roll. Allowed are 2
point, 4 point and 8 point rolls. The fraction on the arrow of the
roll symbol describes what fraction of a full roll is to be executed.
If no points are specified, rolling is done without hesitations. If
no fraction is specified, a roll symbol that starts at the line
specifies a half roll (see description of the Immelman). A roll
symbol that crosses the line specifies a full roll (first figure).
The second figure shows the symbol for 2 points of a 4 point roll
(adding up to half a roll) from upright to inverted flight.
Snap or flick rolls also have to be flown normally on a straight line.
A snap roll is similar to a horizontal spin. It is an autorotation
with one wing stalled. In the regular snap, the plane has to
be stalled by applying positive g forces. In an outside snap, the
plane is stalled by applying negative g. In both cases rudder is then
used to start autorotation just like in a spin.
The Barrel Roll is a not competition maneuver. I
The barrel roll is a combination between a loop and a roll. You
complete one loop while completing one roll at the same time. The
flight path during a barrel roll has the shape of a horizontal cork
screw. Imagine a big barrel, with the airplanes wheels rolling along
the inside of the barrel in a cork screw path. During a barrel roll,
the pilot experiences always positive G's. The maximum is about 2.5
to 3 G, the minimum about 0.5 G.
There was a confusion about the difference between a wingover and a
hammerhead turn on the rec.aviation.* newsgroups a while ago. Here is
a description of the two maneuvers.
The Wing-Over is a competition maneuver in glider aerobatics. You
pull up and at the same time bank the plane. When the bank increases
past 45 degrees, the nose will start to drop while the bank keeps
increasing and the plane keeps turning. Halfway through the maneuver,
the plane has turned 90 degrees, the fuselage is level with the
horizon and the bank is 90 degrees. The plane is above the original
flight path. The nose then keeps dropping below the horizon and the
plane keeps turning, while the bank is shallowed. When the bank drops
below 45 degrees, the nose is pulled up towards the horizon and the
plane reaches horizontal flight with wings level after 180 degrees of
turn. At the completion of the maneuver, the plane is at the same
altitude as on entry and flying in the opposite direction.
It starts with a quarter loop into a vertical climb. When the plane
stops climbing, it pivots around its vertical axis (which is now
horizontal).The nose moves in a vertical circle from pointing up
through the horizon to pointing down. After moving vertically down to
pick up speed again, the maneuver is finished with the last quarter of
a loop to horizontal flight. This figure can have optionally rolls on
both the up-line and the down-line.
The quarter loop is flown just like the first part of a loop. When
the plane is vertical, the elevator backpressure is released
completely. During the vertical line up, some right aileron and right
rudder is needed to maintain the vertical attitude because of the
engine torque and p-factor. When the plane has slowed enough, full
rudder initiates the turnaround. It is followed by right-forward
stick (right aileron and forward elevator) to keep the plane from
torquing off. The pivot is stopped with opposite rudder when the nose
points straight down. When the pivot is completed, the ailerons and
rudder are neutralized. Elevator and rudder are used to keep the nose
pointing straight down. The pivot must be completed within one
wingspan. Rolls on the downline require only aileron input if the
plane is trimmed correctly.
This maneuver is sometimes called a hammerhead stall. This is not an
accurate name because the airplane never stalls. The airspeed may be
very low, close to zero, but since there is no wingloading during the
turn-around, there is no stall (at zero g wing loading, a wing does
not stall). The plane is flying throughout the maneuver with all the
control surfaces effective (although sometimes only marginally so).
The previous paragraph is true even for gliders that don't have the
support of the propeller slip stream. The missing slip stream makes
it much more difficult to keep some flow over the control surfaces
during the turn-around in a glider.
The Aerobatics Box
The aerobatics box is the area in which aerobatics competitions take
place. The competitor has to stay within the lateral limits of the
box and within the height limits. During competition there are
boundary judges in place that determine when a competitor leaves the
box. Boundary infringement penalties subtracted from the score in
such cases. The dimensions of the aerobatics
box are as follows:
1500' AGL: Basic and Sportsman Categories
1200' AGL: Intermediate
800' AGL: Advanced
328' (100m) AGL: Unlimited
3280' (1000m) AGL: Unlimited
3500' AGL: All Others
3300' x 3300' centered on the judges line.
The lower limits of the box are, for safety reasons, strictly enforced.
The International Aerobatic Club (IAC) has over 6000 members.
Probably about 800 of these are active competition pilots.
Competitions are held locally throughout the US. There are two
national competitions, one in August in Fond du Lac, Wisconsin, and
the other in September in Dennison, Texas. In regional competitions
there are usually between 30 and 60 competitors, in the national
competitions there are usually between 100 and 150 competitors. The
regional competitions are3 held on weekends, the national competitions
last one week. There are five categories of aerobatics competition:
Basic (the beginners category), Sportsman, Intermediate, Advanced, and
Every competitor flies three sequences of aerobatics maneuvers, a
Known sequence, a Freestyle and an Unknown. A competition sequence is
composed of set of aerobatic maneuvers selected from a catalog of
allowed figures. The Known sequence is the same for each competitor
in a category. It is the same throughout a competition year, and
changes each year. The Freestyle is a sequence that each competitor
designs according to certain rules. The Unknown is selected by IAC
headquarters for each contest. The competitors receive these Unknowns
the day before they fly it and are not allowed to practice the
The competition is flown in the aerobatics box (see above). Penalties
are assessed for flying outside the box. The number of points
deducted for each boundary infringement depends on the competition
category and is higher in the higher categories. The most severe
penalties are given for violiting the bottom of the box. For Basic
and Sportsman, a violation of the lower altitude limit zeroes the
complete flight. This is designed to enhance the safety of aerobatics
fling by enforcing safe altitudes during a contest.
The flying is judged by judges on the ground. There are specific
judging criteria for each figure. All allowed figures are specified
in a catalog. These aerobatic figures are the same world-wide. Each
figure is assigned a difficulty factor. The final score for each
figure is then calculated from the score that the judges give for each
figure (in the range of 0 - 10), multiplied by the difficulty factor.
The total score for a sequence is the sum of the scores for each
figure. To become a judge requires participation in a judges school
and assisting judges during several competitions. Each judge has to
complete a re-validation exam every year and needs to judge a minimum
anumber of competition flights in order to remain on the current list
How do I find an instructor?
The IAC maintains the most comprehensive list of aerobatics schools.
If you have a World Wide Web browser, you can access the list at
Aerobatic Schools. It is also
periodically published in the IAC magazine, Sport Aerobatics. You can
also call IAC at 920-426-6574 and ask for a list of local schools.
In addition to names, locations and phone numbers, the IAC list also
includes aircraft types and rates used by each school. Note that
inclusion or exclusion from the list does not constitute any sort of
endorsement or qualification by IAC.
If you don't find what you're looking for on the IAC list, the next step
might be to contact a nearby IAC chapter and ask for recommendations. A
list of IAC chapters is on the World Wide Web at
/ACRO/chapters.html, or you can call IAC at the
number listed above.
Of course, you can always ask around at your local airport, or put out a
request on the rec.aviation newsgroups.
Once you've found a school, check them out! This can't be stressed enough.
Get references from pilots who have taken instruction with them. Find out
how long they've been in business, and how much and what type of aerobatics
experience they have. What kind of a reputation do they have? Are they
self-taught weekend warriors who recently bought an aerobatic airplane, or
are they Unlimited-level competition pilots with 20 years of experience?
What kind of airplanes do they fly? What condition are they in? Have they
had any accidents? Will they rent the airplane to you (solo) after you've
completed the course?
Will I feel sick?
Aerobatics entail forces and visual situations that are new to just about
everyone. Each person will respond differently to these. Typically, on
your first few flights you may feel queasy after some number of maneuvers.
With each flight, your tolerance will build and you will feel a bit better
and better, until you eventually find that you feel perfectly fine at the
end of a flight. Don't let the initial discomfort discourage you. It's
natural, and the end result is well worth it! The more often you practice,
the higher your tolerance will become.
There are a few ways to minimize the discomfort. The first is to know when
to quit. Once you start feeling queasy, flying one or two more maneuvers
is a great way to get yourself sick. Instead, take the controls. This
will help take your mind off of how you're feeling, and will also help your
brain resolve what it's feeling with what it's seeing. Fly straight and
level for a few minutes. Open the vents wide, and keep your eyes looking
outside the cockpit. If you continue to feel sick, you may want to think
You'll probably also find that when you fly the maneuvers yourself, you
won't feel bad as quickly as if someone else (i.e.- your instructor) is
flying. This is probably because when you're handling the controls, you
have a better idea of what to expect. Seating position is also a factor.
For example, people seem to do better in the front seat of a Decathlon than
in the rear.
Can I do acrobatics in a non-Aerobat C-152?
Sure, you *can*. HOWEVER: If the maneuvers are not listed as approved in the
Pilot's Operating Handbook, you have done something illegal (and quite
stupid to boot, since it would be quite dangerous).
The changes made to the C-150 & C-152 are not very visible, but are
extensive. Cessna was worried about people doing aerobatics in the
non-aerobatic version, so the original paint jobs given the aerobatic versions
were quite distinctive.
What might confuse things a bit for the uninformed is the appearance
of a "normal" airplane doing aerobatics at a local airshow. An
experienced acro pilot should be able to put on a decent aerobatic
show in many of the "standard" category aircraft. There are a couple
of problems with this, though. THERE IS NO ROOM FOR ERROR! Aerobatic
category ships have a strength reserve for the maneuvers for which
they are approved. For example, even a low power/weight craft should
be able to do a nice loop and not exceed +3 G's. A normal category
plane is certificated to +3.5, aerobatic to +6. A Bob Hoover can do
it safely, you can't. The other problem is, if you do maneuvers
outside what's listed in the POH, you now have an experimental
airplane. Hoover's Shrike and other "normal" category airplanes on the
airshow circuit, have been re-certificated under
Do I have to wear a parachute when I do aerobatics?
Wearing parachutes for aerobatics flying is regulated in FAR
91.307. It specifies that whenever you carry a passenger, you may
not exceed 60 degrees of bank or 30 degrees of pitch up or pitch down
unless both occupants wear an approved parachute. This means that you
do not have to wear a parachute when you fly alone. It does not say
anything about aerobatics, it just specifies the bank and pitch
limits. So any maneuver that exceeds these limits falls under this
rule and requires you and your passenger to wear a parachute.
How safe is aerobatics?
Many (most?) people contemplating getting involved in aerobatics feel a bit
apprehensive at first. By it's very nature, aerobatics involves risks that
are not involved in non-aerobatic flight. But as with most anything else
in aviation, it is only as safe or dangerous as the pilot makes it.
Discipline, planning, common sense, and knowledge are basic prerequisites
to safety. Aerobatics can be quite safe if certain safety rules are
followed religiously. Examples include:
An example of how safe aerobatics can be is that there has never been a
fatality in IAC-sanctioned competition, where strict safety rules are
- Get proper training, especially in all types of spins and botched
- Fly at a safe and conservative altitude.
- Know your equipment and yourself, and keep both well maintained.
- Don't overstress the airplane (and never fly aerobatics in non-
- Always perform a proper, thorough aerobatic preflight.
- Set and observe strict personal limits (altitude, g-limits, flight
duration, health, etc).
- Stay current and take recurrency check rides.
- Don't run out of fuel! (should be obvious, but it happens a lot)
- Stay clear of conflicting traffic, either with regular clearing
turns or an observer on the ground.
- Know how to handle emergency situations.
- Always leave yourself a way out.
- Always wear a parachute. Know how to bail out and use it.
- Learn by others' mistakes, not your own.
The penalty for ignoring safety procedures can be quite high. A review
of NTSB accident data for the 8KCAB Decathlon (probably the most common
aerobatic trainer) from 1983 through 1993 shows 14 accidents related to
aerobatics. Eight of them involved attempting aerobatics at low
altitudes. One was caused by lack of training, one by lots of unsecured
loose baggage (ie- lawn chairs and more) floating around the cockpit, and
one by structural failure. Causes of the remaining three are less clear
from the reports, but two appear to have been due to low level
aerobatics, and the third by failure to recover from a spin. So, of the
14 accidents in ten years, all but one (structural failure) could have
been prevented by following the few simple rules listed above. The
structural failure was in a known problem area and *might* have been
avoidable if the pilot was more familiar with his equipment.
With higher performance aircraft and more advanced aerobatics, there are
additional risks. The airplanes are less forgiving, the forces on plane
and pilot are higher, some of the equipment is newer and less proven, and
much of the flying is done at lower altitudes. Also as skills and
experience build, complacency and bad habits can begin to creep into the
picture. By the time you get to this level, you won't need this FAQ to
learn how to manage these risks.
One thing is for certain. Once you have learned to fly aerobatics, your
increased knowledge will make all the rest of your flying safer.
If you want to answer one of these so I can include it in this FAQ,
please send me something.
- What is aerobatics?
- Why do people learn aerobatics?
- How do I learn aerobatics?
- What type of plane should I learn in?
- How do I get involved in competition?
- What is the Aresti system, and how do I read the symbols?
© Dr. Günther
Email Guenther Eichhorn