flight
training
for helicopters
with thanks to the
helicopterpage
Helicopters are
expensive. Helicopters are slow. Helicopters can't carry very much.
Helicopters run out of fuel before they have flown very far. Compared to
an airplane you sacrifice a tremendous amount of utility in exchange for
the following:
the ability to land
anywhere
the ability to fly very
low and slow (albeit not safely as we'll see below)
Helicopters are also fun
and challenging.
Helicopters suffer from 8
accidents per 100,000 hours flown and about 10 percent of accidents are
fatal (other data suggest that the fatal rate is closer to 1.4 per
100,000 hours). This is a similar safety record to general aviation
airplanes. As an inexperienced pilot of a cheap light helicopter,
however, your risk is at least 5 times higher than that of a Vietnam vet
flying a fancy turbine-powered helicopter. The accident rate for personal
helicopter flights, almost all of which are in cheap light machines, was
44 per 100,000 hours and 16 of those would be fatal. For practical
purposes, therefore, it seems that you're at least 10 times more likely
to kill yourself in a helicopter as you are in a fixed wing trainer such
as the Cessna 172, Diamond DA20/DA40, or Piper Warrior.
The good news about
helicopter safety is that it is largely under your control as the pilot.
If you want to cruise along for 25 miles skimming the ground 100' above
obstacles and then land in your friend's backyard, which is surrounded by
power lines and trees, you are asking for trouble. If you take off and
land at public airports and fly 500' above the terrain your risk is
probably not that different from doing the same trip in a small airplane.
As with other kinds of flying safety depends to a large extent on the
ratio between a pilot's level of confidence and level of skill.
Consider starting with an airplane
On average, you are
required to accumulate least 45 hours of helicopter time before you will
get a Private certificate. In practice most students take much longer.
New pilots have to learn all the rules and regulations, how to read
charts and understand airspace, how to talk on the radio, how to navigate
when on a cross-country flight, and how to fly a helicopter.
If you are already a
certificated airplane pilot you already have all of the required skills
except knowing how to fly a helicopter. Most authorities relax
the flight time requirement to about 30 hours and in practice many
students are able to pass their check ride after 30 hours.
Unless you're completely
fearless the prospect of hurtling towards the ground at a lethal rate of
speed in an unfamiliar machine is frightening. Yet this is a required
manoeuvre when landing any aircraft. Fear makes it harder to learn.
Better to conquer your fear and get comfortable in the air in a much
cheaper rented fixed wing airplane than in an expensive helicopter.
Your trainer
You'll almost surely
start training in a Robinson R22, designed by former Bell engineer Frank
Robinson for folks who want to commute from their country homes in the
woods to their car dealerships, hospitals, or law offices in the city.
The R22 cruises fast and everything in the machine is designed to be as
simple, lightweight, and maintenance-free as possible. It is truly the
perfect helicopter except for one small problem: the market Robinson
designed it for does not exist. It turned out that the haute
bourgeoisie preferred to sit in traffic and melt the pavement
underneath their SUVs rather than take responsibility for learning to
operate a helicopter safely.
Flight schools, however,
were quick to notice that the R22 was the world's cheapest helicopter to
operate and began snapping them up. This proved to be a problem because
Frank Robinson never designed the R22 for training and probably would
have relaxed the high cruise speed requirement and put in a higher
inertia rotor system to allow more time to react to an engine failure.
Fully fuelled, the R22 is
barely capable of hovering with 400 lbs. of pilot and instructor on
board. If you're a tad overweight, now is the time to start your diet. If
you're too fat, you'll have to learn in a turbine-powered Bell JetRanger,
which costs a fortune per hour because of its costly maintenance
requirements and thirst for fuel.
Old school helicopter
pilots will scoff at the Robinsons for a variety of reasons, including
the low inertia rotor system, but basically there are no alternatives.
Schweizer, for example, which bought the old Hughes design, only
manufactures a handful of piston-engine helicopters each year.
Choosing a Flight School and Instructor
There are four ways to
lose a flight: weather is unfavourably cloudy or windy, instructor is not
available, helicopter is down for maintenance, helicopter has been
scheduled by another student. If you are training at a school with only
one helicopter and one instructor, the risk of being unable to fly is
very high.
Look for a school with at
least three training helicopters and two instructors.
Given that you don't know
how to fly, how do you evaluate an instructor? The best instructors are
relaxed and comfortable even as the student makes a lot of mistakes. The
best instructors are able to talk a student through a manoeuvre rather
than putting their hands on the controls and "demonstrating". Once you've
learned how to hold a hover and fly straight-and-level, take at least one
lesson with each instructor at your school and then pick the one whose
style suits you best. You'll probably learn at least 50 percent faster
with a really good instructor compared to an average instructor.
First Lesson: Ground
Because so many students
have crashed R22s there are a bunch of special legal requirements
associated with the aircraft. You aren't allowed to get into the machine
at all until you've received and logged ground instruction.
The ground lesson is
partly about energy management in the event of an engine failure and
partly about not getting the helicopter into unusual attitudes.
As with airplanes, much
of the key to safety in a helicopter is energy management. In an airplane
you have potential energy (altitude) and kinetic energy (forward speed)
that can be traded off against each other to bring the airplane down
gently in the event of an engine failure or ordinary landing. The
helicopter has three kinds of energy: potential (altitude), kinetic
(forward speed), and angular momentum (blade speed).
In an airplane you can
make decisions about trading forms of energy very late in the day. For
example, if you pull the stick all the way back at 6000' above the ground
you will gradually slow down and eventually stall and perhaps enter a
spin. With many airplanes you could spin nearly all the way to the ground
before applying forward stick and opposite rudder to get back to a normal
flight condition. All without an engine.
In a helicopter, by
contrast, if the blades spin down more than 10-15% from their normal
velocity, there is no way to convert potential or kinetic energy into
spinning such that the helicopter will start to fly again. If you can't
restart your engine, therefore, your helicopter can very quickly become a
rock.
In a turbine-powered
helicopter like a Bell 206 JetRangers the blades are heavy and the blades
won't slow down for several seconds after an engine failure. In the
flyweight Robinson, however, after an engine failure you have no more
than 1.2 seconds to take exactly the right actions or the helicopter
cannot be recovered.
What if you do take all
the right actions? Suppose that you're up at 4000' and the engine quits.
You lower the collective pitch (lever on your left) immediately to
flatten the blades and allow them to be driven by the wind through which
the helicopter is now falling at 2000 feet-per-minute. You adjust the
cyclic (stick in front of you) for about 65 knots of forward speed. You
aim for a landing zone. The good news is that you don't need a very large
one but the bad news is that the glide ratio is 2:1 instead of an
airplane's 10:1 and therefore you don't have as large an area from which
to choose. As you get within about 50' from the ground you pull back the
cyclic to flare the helicopter and shed most of the forward speed. Just
as in an airplane this flare also arrests most of the vertical speed. At
the second to last moment you stop flaring and return the helicopter to
being parallel to the ground. Ideally at this point you are hovering 5'
or so above a soccer field and the blades are still spinning. Finally you
raise the collective as the helicopter falls, using the stored energy in
the blades against the force of gravity. You land gently on the skids.
(In practice the cyclic flare is more important than the "hovering
autorotation" at the end; a lot of people walk away from helicopter
engine failures if they get the cyclic flare right but can't manage to
pull the collective smoothly at the last moment.)
This all sounds good
until you look at the "deadman's curve". The marketing literature for
helicopters says "if the engine fails, you can autorotate down to a
smooth landing." The owner's manual, however, contains a little chart of
flight conditions from which it is impossible to landing without at least
bending the helicopter. Unfortunately these conditions are the very ones
in which nearly all helicopters seem to operate. If you're above 500',
for example, you're pretty safe. But TV station helicopters are often
lower than that when filming. Flying along at 65 knots is also good but
if the camera needs the pilot to hover the helicopter slows to a crawl.
First Lesson: Air
Before you get into the
air you'll probably spend about half an hour on a pre-flight inspection
of the helicopter. With most airplanes most of the critical pieces are
hidden underneath bodywork and not accessible except to a mechanic during
an oil change or 100-hour inspection. With the Robinson R22 the engine is
mostly flapping in the breeze and what is hidden can easily be accessed
via a flip-up door.
If the weather is nice
you'll probably remove the doors. This ensures that you'll be nice and
cool inside the machine. In theory you could look straight down while in
flight and scare yourself but in practice your attention will be focussed
on looking out the front and trying to hold the machine in a fixed
attitude relative to the horizon. So don't hesitate to fly your very
first lesson with the doors off. When the doors are off, it is good
practice to take everything out of your pockets and put them in the
baggage compartment underneath the seats. You don't want loose items
getting sucked out of the helicopter and contacting the tail rotor, the
fastest-rotating and most fragile part of the whole machine.
Sadly a big part of your
first lesson will be practicing the most difficult helicopter manoeuvre:
hovering. Hardly anyone is able to become proficient at hovering in less
than 5 or 6 hours of flight training. Every one of those hours is
exhausting. Much of the time is frustrating.
Learning to Hover
A big selling point of
helicopters is that you can land in your backyard. Where then would be
the best place to learn to hover? An airport with a 12,000' runway and a
7,500' crosswind runway. You want a lot of open space where you're
guaranteed not to hit anything. You want somewhere that neighbours won't
complain about the noise. You want somewhere with long sight lines to the
horizon so that you won't concentrate your gaze in too close. You want
somewhere that you can get fuel when you run out. All roads lead to the
big airport! Generally the tower and ground controllers will give you
permission to practice hovering on whichever runway isn't be used that
day and/or over a seldom-used taxiway.
Most instructors will
start by giving you one control at a time. You take the anti-torque
pedals and they handle the cyclic and collective pitch. You practice
pedal turns. Then you take the collective while the instructor controls
the cyclic and pedals. You go up, you go down. Maybe you land. Then you
take the cyclic and the instructor takes the other controls and ... 1
second later the helicopter is oscillating like crazy and you hear "I
have the controls" in your headset. Any good instructor will alert you to
the fact that you need to be very light on the controls: "you fly with
pressures, not movements." The instructor will also tell you that there
is a bit of lag between the time that you put in a control input and the
time that the helicopter reacts. What most instructors
Focus your gaze
at least 1/2 mile in the distance if the sightlines in your
practice area are long enough.
As soon as the
helicopter is handed to you it will start to drift to the right.
The tail rotor is counterbalancing engine torque but at the same
time is pushing the machine to the right. Expect to hold a little
bit of left pressure on the cyclic to avoid this translational
drift.
Don't put
in and hold a control input pressure.
Suppose the helicopter is moving forward a bit. You press back on
the cyclic and hold that pressure. One second later the
helicopter has responded to the initial pressure by arresting its
forward creep. One second after that the helicopter has responded
to two seconds of continuous pressure by rushing backwards at a
frightening clip. If the helo is moving forward, press backwards
for a split-second then try to return the cyclic to a neutral
position. See if the helicopter stops creeping. If so, great. If
not, try another little stab of back pressure. Although every
second or two you are doing something with the cyclic, in any
given instant you need not be putting in any cyclic input. Nudge
the cyclic and then return to centre. Nudge and then return.
After an hour or
two the instructor might be doing more harm than good in handling
the other two controls. Everything is cross-coupled so if he is
messing with the collective or the pedals it will require you to
take action with the cyclic. It is actually easier to handle all
three controls because at least the machine isn't doing
completely unpredictable things from your point of view.
Take a break
every 20 minutes by practicing takeoffs, trips around the
pattern, and approaches to landings.
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