Feeling aircraft sensations

[Ramapriya]

Wanted to ask how easy or natural it gets for pilots to perceive
aircraft positions and movements without actually looking at the
respective indicators.

I've been in the flight deck only once, and confess that I had very
little physical sensation to give me an idea of the 0.7 Mach or
whatever that the A320's airspeed indicator was showing. In fact, at
the end of the journey, there was little to suggest the speeds we were
actually traveling at. Also, nearly throughout the 4-hour flight, the
heading was different from the direction of travel, but I didn't feel
that wind correction angle. I'm not sure whether or not the landing was
a x-wind, which tells you that that went imperceived too. The only
thing I could tell at all was the slightly pitch-up nose attitude
throughout, though I couldn't assess the angle.

Was I just me that was dumb or has anyone else not physically felt
these sensations at the first go?

Ramapriya

[Peter Duniho]

"Ramapriya" > wrote in message
oups.com...
> Wanted to ask how easy or natural it gets for pilots to perceive
> aircraft positions and movements without actually looking at the
> respective indicators.
>
> [...]
>
> Was I just me that was dumb or has anyone else not physically felt
> these sensations at the first go?

You cannot fly without your eyes.

Which is not to say there's not useful information coming through your
physical senses. But whether you are looking out the window or at the
instruments on the panel, you need to be able to *see* what is going on,
because kinesthesia isn't a reliable source of aircraft position and
movement. There are too many illusions caused by the characteristics of
flight maneuvering that have no correspondence to movements naturally
experienced by primitive humans.

Now, if you are asking whether it's difficult to fly without instruments,
but with your eyes, no it's not. In something like an Airbus, it might be a
little more complicated but for light planes generally, flights in visual
conditions could all be safely accomplished without any instruments
whatsoever.

Altitude, airspeed, and power settings are the key performance indicators on
the instrument panel. Altitude is the hardest to estimate, but it's not too
hard to tell the difference between "pattern altitude" and "cruise
altitude". The main reason for needing the altimeter is to comply with
various regulatory issues; either to cruise at an appropriate altitude, or
to avoid (or remain inside) particular airspace.

Airspeed is less difficult than altitude. You get plenty of feedback from
the noise the air makes as it goes past the airframe, and from the feel of
the flight controls (they get more difficult to move as airspeed increases).
In addition, as long as you can maintain a specific power setting and can
tell your pitch attitude, you can pretty fairly predict what your actual
airspeed is going to be.

Power settings are the easiest, at least in a fixed-pitch prop airplane.
You just listen to the airplane. Just as you don't need a tachometer in
your car to tell you when to shift, you don't need a tachometer in the
airplane to tell you if you've got the power set in the right ballpark.
Things get more complicated with a constant speed prop, because two
different controls affect the actual power setting, but only one produces a
change in the engine RPM. But even there, a pilot can estimate the throttle
setting just by the position of the throttle control, and then use the RPM
control to ensure the correct power setting.

It's not really clear to me which question you're asking. But instruments
are by no means critical for visual flight. However, one absolute cannot
trust one's non-visual perception for the purpose of controlling an
airplane. Hopefully one of those two answers addresses whatever question
you're actually asking. :)

Pete

[Ramapriya]

Peter Duniho wrote:
>
> Altitude, airspeed, and power settings are the key performance indicators on
> the instrument panel. Altitude is the hardest to estimate, but it's not too
> hard to tell the difference between "pattern altitude" and "cruise
> altitude". The main reason for needing the altimeter is to comply with
> various regulatory issues; either to cruise at an appropriate altitude, or
> to avoid (or remain inside) particular airspace.
>
> Airspeed is less difficult than altitude. You get plenty of feedback from
> the noise the air makes as it goes past the airframe, and from the feel of
> the flight controls (they get more difficult to move as airspeed increases).
> In addition, as long as you can maintain a specific power setting and can
> tell your pitch attitude, you can pretty fairly predict what your actual
> airspeed is going to be.

Thanks, Pete. I wasn't asking any specific questions as such, and only
wanted to know whether you guys can generally tell these parameters
without actually reading them off the instruments.

"Airspeed is less difficult than altitude" gives me a definite complex,
because that was the one thing I just couldn't estimate at all.

And btw, it was only recently that I learnt that an airplane could also
be landed by looking out the window. A good pilot friend told me that
he routinely landed by purely visual references! Until then, I was
under the belief that nobody sensible could afford to take his eyes off
the instruments in a phase of flight as critical as the final. That's
probably because I can't perceive airspeed :(

Ramapriya

[Stubby]

Ramapriya wrote:
> Wanted to ask how easy or natural it gets for pilots to perceive
> aircraft positions and movements without actually looking at the
> respective indicators.
>
> I've been in the flight deck only once, and confess that I had very
> little physical sensation to give me an idea of the 0.7 Mach or
> whatever that the A320's airspeed indicator was showing. In fact, at
> the end of the journey, there was little to suggest the speeds we were
> actually traveling at. Also, nearly throughout the 4-hour flight, the
> heading was different from the direction of travel, but I didn't feel
> that wind correction angle. I'm not sure whether or not the landing was
> a x-wind, which tells you that that went imperceived too. The only
> thing I could tell at all was the slightly pitch-up nose attitude
> throughout, though I couldn't assess the angle.
>
> Was I just me that was dumb or has anyone else not physically felt
> these sensations at the first go?

Your eyes, behind and your inner ears are more likely to get you into
trouble than give you more control! There are a number of well known
illusions caused by trusting your senses. So the training exercise is
to get you to ignore your senses and trust the instruments. It's a
little terrifying at first but I actually like recovering from unusual
attitudes because it's a confidence builder.

[Gary Drescher]

"Ramapriya" > wrote in message
oups.com...
> Wanted to ask how easy or natural it gets for pilots to perceive
> aircraft positions and movements without actually looking at the
> respective indicators.
>
> I've been in the flight deck only once, and confess that I had very
> little physical sensation to give me an idea of the 0.7 Mach or
> whatever that the A320's airspeed indicator was showing. In fact, at
> the end of the journey, there was little to suggest the speeds we were
> actually traveling at.

A fundamental consequence of Newtonian mechanics is that it's physically
impossible to perceive velocity per se; velocity has no direct influence on
you. You can perceive *acceleration*, but not velocity.

Therefore, any perception of velocity has to be indirect. For instance, you
can look out the window, or use a GPS. Or the plane's velocity relative to
the air can be perceived by the airspeed indicator, because of the
interaction between the plane and the relative wind. Inside the cockpit,
though, you're insulated from the wind, so your only perception of it might
be by virtue of the sound it makes (or, if you're manipulating the controls,
then the response you get is another reflection of the plane's interaction
with the air, from which you can deduce something about airspeed). Also, as
in a car or train, the small accelerations you feel when the vehicle
encounters irregularities in its surroundings may be sharper or more rapid
at higher speeds, making the velocity indirectly perceptible.

> Also, nearly throughout the 4-hour flight, the
> heading was different from the direction of travel, but I didn't feel
> that wind correction angle.

A constant crosswind is a component of velocity, not acceleration, so again
it is physically impossible for you to perceive it directly. You have to
look out the window or whatever.

--Gary

[Stubby]

Gary Drescher wrote:
/snip/
> A constant crosswind is a component of velocity, not acceleration, so again
> it is physically impossible for you to perceive it directly. You have to
> look out the window or whatever.

Actually, the crosswind is a force but it is counter balanced by drag
and the control surfaces of the airplane. If the pilot didn't resist
the cross wind, the plane would drift with the wind and achieve some
terminal velocity limited by drag and the wind velocity itself.

[Gary Drescher]

"Stubby" > wrote in message
...
> Gary Drescher wrote:
> /snip/
>> A constant crosswind is a component of velocity, not acceleration, so
>> again it is physically impossible for you to perceive it directly. You
>> have to look out the window or whatever.
>
> Actually, the crosswind is a force but it is counter balanced by drag and
> the control surfaces of the airplane. If the pilot didn't resist the
> cross wind, the plane would drift with the wind and achieve some terminal
> velocity limited by drag and the wind velocity itself.

In the steady state, with a constant crosswind and constant control
surfaces, the crosswind contributes a constant component to your velocity,
which is not directly perceptible. So, for example, if you're staying on the
runway centerline by crabbing into the crosswind, it feels the same (if you
close your eyes) as unbanked flight without a crosswind; or alternatively,
if you're slipping into the crosswind, it feels the same (if you close your
eyes) as a side-slip with no crosswind.

--Gary

[Jose]

> I had very little physical sensation [of] airspeed...

Right. One cannot feel speed. It's a consequence of the rule that says
"wherever you are, you are right there". =You= are never moving, it is
the rest of the world that moves around while you stay still. (This
isn't strictly true and will probably spawn a subthread for the pedants,
but the first step to understanding is to get your mind around this
concept, which does apply at constant speeds absent general relativity).
As the air goes rushing past there is noise, and if the rushing air
isn't totally steady (for example, due to swirling air currents) then
you will feel the forces of being bumped around, but those feelings are
not feelings of speed itself. The controls feel different at different
airspeeds, but not because the airplane is travelling, but rather,
because there is so much air rushing by the control surfaces. It's the
air that's moving. You are standing still, bucking the fierce wind with
the force of the engines, watching the earth go by beneath you. And the
earth is not even important (except to hold the air down)... if you were
chained to the runway pointing into a (strong enough) hurricaine wind,
you'd feel the same tight control forces as you would flying at high speed.

> Also, nearly throughout the 4-hour flight, the
> heading was different from the direction of travel, but I didn't feel
> that wind correction angle.

Right. A "wind correction angle" is a sort of a fiction. The airplane
(in a steady state) is always pointed directly into the wind. That is,
pointed directly into the wind that it feels. Remember, the airplane is
standing still - the only thing the airplane feels is the wind. It
can't feel the earth three miles below. That would be silly (or require
very long landing gear!) Don't think of the wind relative to the earth
- remember, the earth is irrelevant once the wheels leave the ground.
You're =flying=! If you opened the sunroof(*) of your airplane and
stuck your hand up into the slipstream, the wind would always be
directly from the front (in coordinated flight, more later). The
problem is that the earth keeps trying to slip out from under us one way
or another. So, we as pilots have to be a bit tricky. If we point the
nose at Peoria, we'd find that by the time we got there, the earth will
have slipped Peoria out from in front of us, and replaced it by Des
Plains, which is not where we wanted to go. Just like shooting rabbit
(aim in front of him - aim where he's =going= to be), we have to aim the
airplane at where Peoria is =going= to be... and since Peoria is moving,
we need to lead the target. For people on the ground it looks like
we're flying sideways to some extent, but we're not. Some people would
say "the wind is carrying us away"... but it's not. Remember, the wind
is always from in front of the airplane. What is =really= happeneing is
that the earth is slipping out from under the atmosphere, taking all the
people with it. They are being pulled out from under the airplane's
path, and (mis)-perceive it as wind drift.

You are flying through the =air=, not over the =ground=. Only the air
matters. IF there's a massive earthquake while you're aloft, you won't
feel it at all.

> I'm not sure whether or not the landing was
> a x-wind, which tells you that that went imperceived too.

Well, it gets a little tricky when we need to connect with the ground
too. Remember, the ground is trying to slip away from us, probaby
sideways. That's why it lookes cockeyed when we land in what some
people call a crosswind, but is really just the earth trying to escape
the airplane's wheels by slipping off sideways. So, we have to cheat -
we try to get the airplane to move sideways =through the air= just for a
little bit, so we can catch up with the earth. One technique is to use
uncoordinated flight. If the air were turbulent, you might accuse the
pilot of being uncoordinated, but that's not what I mean. We use the
rudder to point the nose in one direction (say, to the left) while we
use the alerons (wing-tilters) to bank in the opposite direction. As a
result, we are flying crooked through the air - the wind is no longer
directly in front of us, but coming at us from slightly (or not so
slightly) to the right, just enough to catch up with the runway as it's
trying to escape us. Once all three wheels are firmly planted on the
runway, we are no longer flying, and are controlling our direction by
pushing against the ground instead. The air has become irrelevant
(except that it might try to tip us over because it's jealous, but we're
ready for that). We can now return to our illusion that the ground is
solid and the wind rushes over it.

But having experienced flight, we now know better.

Jose
(*) if you airplane doesn't have a sunroof, a bazooka can make one
pretty easily!
--
Money: what you need when you run out of brains.
for Email, make the obvious change in the address.

[Darrell S]

Ramapriya wrote:
> Wanted to ask how easy or natural it gets for pilots to perceive
> aircraft positions and movements without actually looking at the
> respective indicators.
>
> I've been in the flight deck only once, and confess that I had very
> little physical sensation to give me an idea of the 0.7 Mach or
> whatever that the A320's airspeed indicator was showing. In fact, at
> the end of the journey, there was little to suggest the speeds we were
> actually traveling at. Also, nearly throughout the 4-hour flight, the
> heading was different from the direction of travel, but I didn't feel
> that wind correction angle. I'm not sure whether or not the landing
> was a x-wind, which tells you that that went imperceived too. The only
> thing I could tell at all was the slightly pitch-up nose attitude
> throughout, though I couldn't assess the angle.
>
> Was I just me that was dumb or has anyone else not physically felt
> these sensations at the first go?
>
> Ramapriya

Relying on physical sensations (inner ear, seat pressure, etc) Is a quick
way to die in instrument conditions. In visual conditions they all support
vision to provide flight info.

--

Darrell R. Schmidt
B-58 Hustler History: http://members.cox.net/dschmidt1/
-

[Bob Gardner]

Flying up in the flight levels in a jet there is, as you note, no sensation
of movement from the cockpit, especially when those clouds way off in the
distance don't seem to be getting any closer. I can sense pitch changes like
"We're starting down" from seat A19 or wherever.

Any private pilot worth his or her salt should be able to land a general
aviation airplane without an airspeed indicator. Jets are so numbers-driven
that a pilot can give up a lot of efficiency by not using the airspeed
indicator until on very short final....then the eyeballs take over.

Bob Gardner

"Ramapriya" > wrote in message
oups.com...
> Peter Duniho wrote:
>>
>> Altitude, airspeed, and power settings are the key performance indicators
>> on
>> the instrument panel. Altitude is the hardest to estimate, but it's not
>> too
>> hard to tell the difference between "pattern altitude" and "cruise
>> altitude". The main reason for needing the altimeter is to comply with
>> various regulatory issues; either to cruise at an appropriate altitude,
>> or
>> to avoid (or remain inside) particular airspace.
>>
>> Airspeed is less difficult than altitude. You get plenty of feedback
>> from
>> the noise the air makes as it goes past the airframe, and from the feel
>> of
>> the flight controls (they get more difficult to move as airspeed
>> increases).
>> In addition, as long as you can maintain a specific power setting and can
>> tell your pitch attitude, you can pretty fairly predict what your actual
>> airspeed is going to be.
>
> Thanks, Pete. I wasn't asking any specific questions as such, and only
> wanted to know whether you guys can generally tell these parameters
> without actually reading them off the instruments.
>
> "Airspeed is less difficult than altitude" gives me a definite complex,
> because that was the one thing I just couldn't estimate at all.
>
> And btw, it was only recently that I learnt that an airplane could also
> be landed by looking out the window. A good pilot friend told me that
> he routinely landed by purely visual references! Until then, I was
> under the belief that nobody sensible could afford to take his eyes off
> the instruments in a phase of flight as critical as the final. That's
> probably because I can't perceive airspeed :(
>
> Ramapriya
>

[Bob Martin]

> And btw, it was only recently that I learnt that an airplane could also
> be landed by looking out the window. A good pilot friend told me that
> he routinely landed by purely visual references! Until then, I was
> under the belief that nobody sensible could afford to take his eyes off
> the instruments in a phase of flight as critical as the final. That's
> probably because I can't perceive airspeed :(

Percieving airspeed in jets might be harder (never flown one) but it's
generally not too hard in piston singles. Really, as long as you can
see the runway, there's no need to use any instruments. Most people (or
at least the ones I've flown with, myself included) don't look at
anything except the airspeed when in the pattern (and even that is just
checked every few seconds or so as a reference).
Basically, do you need instruments to stay on the road or maneuver the
car while driving? And do you need be constantly looking at the
speedometer? Flying is like driving, in a way, just in three
dimensions. You do it all on outside cues*.

*Obviously, this doesn't include flight in instrument conditions (low
visibility, basically).

[John T]

Ramapriya wrote:
>
> A good pilot friend told me
> that he routinely landed by purely visual references!

It sounds like you need to get this pilot friend to take you for a ride in a
small plane. :)

--
John T
http://sage1solutions.com/TknoFlyer
Reduce spam. Use Sender Policy Framework: http://spf.pobox.com
____________________

[Robert M. Gary]

Yes, you can tell when you are turning, etc to an extent. Part of
training requires that you close your eyes, get disoriented, and then
recover the aircraft. Most of use rarely actually get disoriented in
those tests. However, that is for a short period of time. If you closed
your eyes for several minutes you would certainly lose you ability to
tell if you were turning or not.

-Robert

[Peter Duniho]

"Ramapriya" > wrote in message
oups.com...
> Thanks, Pete. I wasn't asking any specific questions as such, and only
> wanted to know whether you guys can generally tell these parameters
> without actually reading them off the instruments.

Yup. If anything, obtaining the information from outside references can be
easier than using the instruments. The human brain isn't really configured
to process numbers, and even an analog gauge doesn't translate directly to
human perception.

> "Airspeed is less difficult than altitude" gives me a definite complex,
> because that was the one thing I just couldn't estimate at all.

As Bob and Bob have pointed out, estimating airspeed in the situation you
described is different from estimating airspeed when it really matters. At
cruise altitude, you mainly just set your power setting, stay on altitude,
and let the airspeed be what it will be (though it should generally always
be the same for a given weight and power setting).

But during landing, you're close enough to the ground to get a good
perception of airspeed, and of course there's all the other points of
reference I mentioned. Actually though, movement relative to the ground is
the least important reference; even in a jet, your groundspeed can be
significantly different from airspeed (and airspeed is what matters, while
groundspeed is what you can see), and in a light plane, winds can cause as
much as a 50% or more difference in perceived groundspeed versus actual
airspeed.

But again, as far as airspeed goes, the visual reference is the least
important. You can easily tell the actual airspeed from the air noise and
from how the controls feel (again, may not apply in an Airbus, where the
controls are not directly connected to the control surfaces).

> And btw, it was only recently that I learnt that an airplane could also
> be landed by looking out the window. A good pilot friend told me that
> he routinely landed by purely visual references! Until then, I was
> under the belief that nobody sensible could afford to take his eyes off
> the instruments in a phase of flight as critical as the final. That's
> probably because I can't perceive airspeed :(

If you actually were flying, I think you'd be surprised at what you can
perceive. But yes, visual references is *primary* for all pilots. The
instruments are used mainly when the pilot cannot see outside the airplane.

Pete

[Bob Martin]

> And btw, it was only recently that I learnt that an airplane could also
> be landed by looking out the window. A good pilot friend told me that
> he routinely landed by purely visual references! Until then, I was
> under the belief that nobody sensible could afford to take his eyes off
> the instruments in a phase of flight as critical as the final. That's
> probably because I can't perceive airspeed :(

Percieving airspeed in jets might be harder (never flown one) but it's
generally not too hard in piston singles. Really, as long as you can
see the runway, there's no need to use any instruments. Most people (or
at least the ones I've flown with, myself included) don't look at
anything except the airspeed when in the pattern (and even that is just
checked every few seconds or so as a reference).
Basically, do you need instruments to stay on the road or maneuver the
car while driving? And do you need be constantly looking at the
speedometer? Flying is like driving, in a way, just in three
dimensions. You do it all on outside cues*.

*Obviously, this doesn't include flight in instrument conditions (low
visibility, basically).

[Gig 601XL Builder]

"Robert M. Gary" > wrote in message
ups.com...
> Yes, you can tell when you are turning, etc to an extent. Part of
> training requires that you close your eyes, get disoriented, and then
> recover the aircraft. Most of use rarely actually get disoriented in
> those tests. However, that is for a short period of time. If you closed
> your eyes for several minutes you would certainly lose you ability to
> tell if you were turning or not.
>
> -Robert
>

Years ago, 26 to be exact, when I first got my PPL I went to an FAA safety
seminar which are rarely held locally, I'm the youngest person there by at
least 15 years. They have the spinning chair (with a joy stick) where they
sit you down, blind fold you and spin you. Your job is to move the stick
like it is controlling what you are feeling.

The old guys laughed as I was the first and sure enough I steered left when
I was either not spinning at all or was spinning the other way. One of the
old guys who laughed especially hard was next in the chair and when it was
stopped he moved the stick to the right and then the FAA guy said something
to him and he turned his head and then he started pulling back on the stick
like he was climbing. Being a pilot of many 1000 hours he new this could not
be the case so he pushed the stick forward. Laughs were had by all except
for the guy in the chair.

[Bob Moore]

"John T" >wrote

> Ramapriya wrote:
>>
>> A good pilot friend told me
>> that he routinely landed by purely visual references!
>
> It sounds like you need to get this pilot friend to take you for
> a ride in a small plane. :)

That's a real problem, He's in Dubai UAE, and I'm in Tampa, Florida.
:-) I've been trying to get him to go for a short sightseeing flight
for quite a while now. :-)

Bob Moore

[Ramapriya]

Bob Moore wrote:
> "John T" >wrote
>
> > Ramapriya wrote:
> >>
> >> A good pilot friend told me
> >> that he routinely landed by purely visual references!
> >
> > It sounds like you need to get this pilot friend to take you for
> > a ride in a small plane. :)
>
> That's a real problem, He's in Dubai UAE, and I'm in Tampa, Florida.
> :-) I've been trying to get him to go for a short sightseeing flight
> for quite a while now. :-)
>
> Bob Moore


I will, in a few weeks, in that Jet Fox.
Watch this space :o)

Ramapriya