Gyroplanes are quite reliable, however emergencies do
occur, whether a result of mechanical failure or pilot
error. By having a thorough knowledge of the
gyroplane and its systems, you will be able to more
readily handle the situation. In addition, by knowing
the conditions which can lead to an emergency, many
potential accidents can be avoided.
ABORTED TAKEOFF
Prior to every takeoff, consideration must be given to a
course of action should the takeoff become undesirable
or unsafe. Mechanical failures, obstructions on the
takeoff surface, and changing weather conditions are
all factors that could compromise the safety of a take-
off and constitute a reason to abort. The decision to
abort a takeoff should be definitive and made as soon
as an unsafe condition is recognized. By initiating the
abort procedures early, more time and distance will be
available to bring the gyroplane to a stop. A late deci-
sion to abort, or waiting to see if it will be necessary to
abort, can result in a dangerous situation with little time
to respond and very few options available.
When initiating the abort sequence prior to the
gyroplane leaving the surface, the procedure is quite
simple. Reduce the throttle to idle and allow the
gyroplane to decelerate, while slowly applying aft
cyclic for aerodynamic braking. This technique pro-
vides the most effective braking and slows the aircraft
very quickly. If the gyroplane has left the surface when
the decision to abort is made, reduce the throttle until
an appropriate descent rate is achieved. Once contact
with the surface is made, reduce the throttle to idle and
apply aerodynamic braking as before. The wheel
brakes, if the gyroplane is so equipped, may be applied,
as necessary, to assist in slowing the aircraft.
ACCELERATE/STOP DISTANCE
An accelerate/stop distance is the length of ground roll
an aircraft would require to accelerate to takeoff speed
and, assuming a decision to abort the takeoff is made,
bring the aircraft safely to a stop. This value changes
for a given aircraft based on atmospheric conditions,
the takeoff surface, aircraft weight, and other factors
affecting performance. Knowing the accelerate/stop
value for your gyroplane can be helpful in planning a
safe takeoff, but having this distance available does not
necessarily guarantee a safe aborted takeoff is possible
for every situation. If the decision to abort is made after
liftoff, for example, the gyroplane will require consid-
erably more distance to stop than the accelerate/stop
figure, which only considers the ground roll require-
ment. Planning a course of action for an abort decision
at various stages of the takeoff is the best way to ensure
the gyroplane can be brought safely to a stop should the
need arise.
For a gyroplane without a flight manual or other pub-
lished performance data, the accelerate/stop distance
can be reasonably estimated once you are familiar with
the performance and takeoff characteristics of the air-
craft. For a more accurate figure, you can accelerate the
gyroplane to takeoff speed, then slow to a stop, and
note the distance used. Doing this several times gives
you an average accelerate/stop distance. When per-
formance charts for the aircraft are available, as in the
flight manual of a certificated gyroplane, accurate
accelerate/stop distances under various conditions can
be determined by referring to the ground roll informa-
tion contained in the charts.
LIFT-OFF AT LOW AIRSPEED AND
HIGH ANGLE OF ATTACK
Because of ground effect, your gyroplane might be able
to become airborne at an airspeed less than minimum
level flight speed. In this situation, the gyroplane is fly-
ing well behind the power curve and at such a high
angle of attack that unless a correction is made, there
will be little or no acceleration toward best climb
speed. This condition is often encountered in
gyroplanes capable of jump takeoffs. Jumping without
sufficient rotor inertia to allow enough time to acceler-
ate through minimum level flight speed, usually results
in your gyroplane touching down after liftoff. If you do
touch down after performing a jump takeoff, you
should abort the takeoff.
During a rolling takeoff, if the gyroplane is forced into
the air too early, you could get into the same situation.
It is important to recognize this situation and take
immediate corrective action. You can either abort the
takeoff, if enough runway exists, or lower the nose and
accelerate to the best climb speed. If you choose to con-
tinue the takeoff, verify that full power is applied, then,
slowly lower the nose, making sure the gyroplane does
not contact the surface. While in ground effect, acceler-
ate to the best climb speed. Then, adjust the nose pitch
attitude to maintain that airspeed.
COMMON ERRORS
The following errors might occur when practicing a
lift-off at a low airspeed.
1. Failure to check rotor for proper operation, track,
and r.p.m. prior to initiating takeoff.
2. Use of a power setting that does not simulate a
“behind the power curve” situation.
3. Poor directional control.
4. Rotation at a speed that is inappropriate for the
maneuver.
5. Poor judgement in determining whether to abort
or continue takeoff.
6. Failure to establish and maintain proper climb
attitude and airspeed, if takeoff is continued.
7. Not maintaining the desired ground track during
the climb.
PILOT-INDUCED OSCILLATION (PIO)
Pilot-induced oscillation, sometimes referred to as por-
poising, is an unintentional up-and-down oscillation of
the gyroplane accompanied with alternating climbs and
descents of the aircraft. PIO is often the result of an
inexperienced pilot overcontrolling the gyroplane, but
this condition can also be induced by gusty wind con-
ditions. While this condition is usually thought of as a
longitudinal problem, it can also happen laterally.
As with most other rotor-wing aircraft, gyroplanes
experience a slight delay between control input and the
reaction of the aircraft. This delay may cause an inex-
perienced pilot to apply more control input than
required, causing a greater aircraft response than was
desired. Once the error has been recognized, opposite
control input is applied to correct the flight attitude.
Because of the nature of the delay in aircraft response,
it is possible for the corrections to be out of synchro-
nization with the movements of the aircraft and aggra-
vate the undesired changes in attitude. The result is
PIO, or unintentional oscillations that can grow rapidly
in magnitude. [Figure 21-1]
In gyroplanes with an open cockpit and limited flight
instruments, it can be difficult for an inexperienced
pilot to recognize a level flight attitude due to the lack
of visual references. As a result, PIO can develop as the
pilot chases a level flight attitude and introduces climb-
ing and descending oscillations. PIO can also develop
if a wind gust displaces the aircraft, and the control
inputs made to correct the attitude are out of phase with
the aircraft movements. Because the rotor disc angle
decreases at higher speeds and cyclic control becomes
more sensitive, PIO is more likely to occur and can be
more pronounced at high airspeeds. To minimize the
possibility of PIO, avoid high-speed flight in gusty
conditions, and make only small control inputs. After
making a control input, wait briefly and observe the
reaction of the aircraft before making another input. If
PIO is encountered, reduce power and place the cyclic
in the position for a normal climb. Once the oscillations
have stopped, slowly return the throttle and cyclic to
their normal positions. The likelihood of encountering
PIO decreases greatly as experience is gained, and the
ability to subconsciously anticipate the reactions of the
gyroplane to control inputs is developed.
Normal□
Flight
Variance from desired□
flight path recognized,□
control input made□
to correct□
□
Gyroplane□
reacts
Gyroplane□
reacts
Gyroplane□
reacts
Overcorrection□
recognized, larger□
control input made□
to correct
□
Overcorrection recognized,□
larger input control made□
to correct
□
Figure 21-1. Pilot-induced oscillation can result if the gyroplane’s reactions to control inputs are not anticipated and become
out of phase.
BUNTOVER (POWER PUSHOVER)
As you learned in Chapter 16—Gyroplane
Aerodynamics, the stability of a gyroplane is greatly
influenced by rotor force. If rotor force is rapidly
removed, some gyroplanes have a tendency to pitch
forward abruptly. This is often referred to as a forward
tumble, buntover, or power pushover. Removing the
rotor force is often referred to as unloading the rotor,
and can occur if pilot-induced oscillations become
excessive, if extremely turbulent conditions are
encountered, or the nose of the gyroplane is pushed for-
ward rapidly after a steep climb.
A power pushover can occur on some gyroplanes that
have the propeller thrust line above the center of grav-
ity and do not have an adequate horizontal stabilizer. In
this case, when the rotor is unloaded, the propeller
thrust magnifies the pitching moment around the center
of gravity. Unless a correction is made, this nose
pitching action could become self-sustaining and
irreversible. An adequate horizontal stabilizer slows the
pitching rate and allows time for recovery.
Since there is some disagreement between manufactur-
ers as to the proper recovery procedure for this
situation, you must check with the manufacturer of
your gyroplane. In most cases, you need to remove
power and load the rotor blades. Some manufacturers,
especially those with gyroplanes where the propeller
thrust line is above the center of gravity, recommend that
you need to immediately remove power in order to pre-
vent a power pushover situation. Other manufacturers
recommend that you first try to load the rotor blades. For
the proper positioning of the cyclic when loading up the
rotor blades, check with the manufacturer.
When compared to other aircraft, the gyroplane is just
as safe and very reliable. The most important factor, as
in all aircraft, is pilot proficiency. Proper training and
flight experience helps prevent the risks associated
with pilot-induced oscillation or buntover.
GROUND RESONANCE
Ground resonance is a potentially damaging aerody-
namic phenomenon associated with articulated rotor
systems. It develops when the rotor blades move out of
phase with each other and cause the rotor disc to
become unbalanced. If not corrected, ground resonance
can cause serious damage in a matter of seconds.
Ground resonance can only occur while the gyroplane
is on the ground. If a shock is transmitted to the rotor
system, such as with a hard landing on one gear or
when operating on rough terrain, one or more of the
blades could lag or lead and allow the rotor system’s
center of gravity to be displaced from the center of rota-
tion. Subsequent shocks to the other gear aggravate the
imbalance causing the rotor center of gravity to rotate
around the hub. This phenomenon is not unlike an out-
of-balance washing machine. [Figure 21-2]
To reduce the chance of experiencing ground reso-
nance, every preflight should include a check for
proper strut inflation, tire pressure, and lag-lead
damper operation. Improper strut or tire inflation can
change the vibration frequency of the airframe, while
improper damper settings change the vibration fre-
quency of the rotor.
If you experience ground resonance, and the rotor
r.p.m. is not yet sufficient for flight, apply the rotor
brake to maximum and stop the rotor as soon as possi-
ble. If ground resonance occurs during takeoff, when
rotor r.p.m. is sufficient for flight, lift off immediately.
Ground resonance cannot occur in flight, and the rotor
blades will automatically realign themselves once the
gyroplane is airborne. When prerotating the rotor sys-
tem prior to takeoff, a slight vibration may be felt that
is a very mild form of ground resonance. Should this
oscillation amplify, discontinue the prerotation and
apply maximum rotor brake.
EMERGENCY APPROACH AND
LANDING
The modern engines used for powering gyroplanes are
generally very reliable, and an actual mechanical mal-
function forcing a landing is not a common occurrence.
Failures are possible, which necessitates planning for
and practicing emergency approaches and landings.
The best way to ensure that important items are not
overlooked during an emergency procedure is to use a
checklist, if one is available and time permits. Most
gyroplanes do not have complex electrical, hydraulic,
or pneumatic systems that require lengthy checklists.
In these aircraft, the checklist can be easily committed
to memory so that immediate action can be taken if
Rotor□
Center of Gravity
122ϒ
122ϒ 116ϒ
Figure 21-2. Taxiing on rough terrain can send a shock wave
to the rotor system, resulting in the blades of a three-bladed
rotor system moving from their normal 120° relationship to
each other.
needed. In addition, you should always maintain an
awareness of your surroundings and be constantly on
the alert for suitable emergency landing sites.
When an engine failure occurs at altitude, the first
course of action is to adjust the gyroplane’s pitch atti-
tude to achieve the best glide speed. This yields the
most distance available for a given altitude, which in
turn, allows for more possible landing sites. A common
mistake when learning emergency procedures is
attempting to stretch the glide by raising the nose,
which instead results in a steep approach path at a slow
airspeed and a high rate of descent. [Figure 21-3] Once
you have attained best glide speed, scan the area within
gliding distance for a suitable landing site. Remember
to look behind the aircraft, as well as in front, making
gentle turns, if necessary, to see around the airframe.
When selecting a landing site, you must consider the
wind direction and speed, the size of the landing site,
obstructions to the approach, and the condition of the
surface. A site that allows a landing into the wind and
has a firm, smooth surface with no obstructions is the
most desirable. When considering landing on a road, be
alert for powerlines, signs, and automobile traffic. In
many cases, an ideal site will not be available, and it
will be necessary for you to evaluate your options and
choose the best alternative. For example, if a steady
wind will allow a touchdown with no ground roll, it
may be acceptable to land in a softer field or in a
smaller area than would normally be considered. On
landing, use short or soft field technique, as appropri-
ate, for the site selected. A slightly higher-than-normal
approach airspeed may be required to maintain ade-
quate airflow over the rudder for proper yaw control.
EMERGENCY EQUIPMENT AND
SURVIVAL GEAR
On any flight not in the vicinity of an airport, it is
highly advisable to prepare a survival kit with items
that would be necessary in the event of an emergency.
A properly equipped survival kit should be able to
provide you with sustenance, shelter, medical care, and
a means to summon help without a great deal of effort
on your part. An efficient way to organize your survival
kit is to prepare a basic core of supplies that would be
necessary for any emergency, and allow additional
space for supplementary items appropriate for the
terrain and weather you expect for a particular flight.
The basic items to form the basis of your survival kit
would typically include: a first-aid kit and field
medical guide, a flashlight, water, a knife, matches,
some type of shelter, and a signaling device. Additional
items that may be added to meet the conditions, for
example, would be a lifevest for a flight over water, or
heavy clothing for a flight into cold weather. Another
consideration is carrying a cellular phone. Several
pilots have been rescued after calling someone to
indicate there had been an accident.
Best Glide Speed
TooFast
TooSlow
Figure 21-3. Any deviation from best glide speed will reduce the distance you can glide and may cause you to land short of a
safe touchdown point.