More newbie Qs

7. What is "density altitude", and how to compute it?

The best I've found about calculating it is he

http://wahiduddin.net/calc/density_altitude.htm

The author's main interests seem to be "spiritual life" and
"density altitude". Haven't read the "spiritual life" part, but
the "density altitude" part is profound.

Tobias

Couldn't have said it better Dudley...

My personal opinion is "he" likes the attention from the newsgroup vets
rather than the information from those trying to help. Most questions are
easily answered on his own computer and using a search engine.

BTW Dudley, I have been flying for over 22 years now with over 1800
hours,
I still have many things to learn. I have learned from you and the others
in this
newsgroup.

Thank You for your contribution....

Terry
N6401F + Flightstar Ultralight


"Dudley Henriques" wrote in message
nk.net...

"Ramapriya" wrote in message
ups.com...

I have a question for you, after watching these endless series of
questions, and it's not meant to be hostile in any way; just curious.

snipped

Don't you think it's time you did some learning on your own?
No offense meant, and for those who wish to deal with you on a daily
basis, I have no problem at all. I just won't offer my assistance to you
for the reasons I've given.
Best of luck
Dudley Henriques
International Fighter Pilots Fellowship
Commercial Pilot/CFI Retired
for email; take out the trash

"Terry" wrote in message
k.net...
Couldn't have said it better Dudley...

My personal opinion is "he" likes the attention from the newsgroup
vets
rather than the information from those trying to help. Most questions
are
easily answered on his own computer and using a search engine.

BTW Dudley, I have been flying for over 22 years now with over 1800
hours,
I still have many things to learn. I have learned from you and the
others in this
newsgroup.

Thank You for your contribution....

Terry
N6401F + Flightstar Ultralight

Thank you.
I've always told instructors I've trained that the two best learning
tools in aviation are the airplane and the student in that order. Each
one will teach you something every second you're exposed to them if
you're receptive to continuous learning. I'm still learning after fifty
years in aviation :-)
Dudley

Ramapriya wrote:

1. How does a pilot get to know the distance to the airport that he has
to land in, so that he plans his descent accordingly, in planes that
don't have an onboard computer?

If the aircraft has no electronic means of determining position, the pilot uses
"pilotage" to keep track of his location. Basically, the pilot notes things on
the chart close to his course that can be seen from the air; these are called
"waypoints". Once in the air, the speed over the ground can be determined by
timing how long it takes to fly between two of these waypoints. The pilot can
then figure out the point at which he wants to start the descent and how long it
will take to reach that point from the closest waypoint to it. Pass over that
waypoint and start your descent at the appropriate time.

2. What exactly is a VOR? Sounds like it's a constant all-direction
radio transmission from a fixed point on the airport to help locate
where the airstrip is.

Pretty much, except that VORs aren't always (or even usually) located at
airports. The transmitter broadcasts a signal that is modulated in such a way
that the receiver can tell in what direction the transmitter lies. The pilot can
then twist a dial to center a needle on an instrument called a "course deviation
indicator" and read off the direction.

3. If a pilot needs to land at an airport that doesn't have a control
tower, how does he figure its elevation so that he may plan his
descent?

The elevation is recorded on charts and in airport directories.

4. When a pilot says, "Give me a vector", what does he actually mean?

He's asking someone to tell him what heading to fly.

5. When pilots use miles in conversations, does it mean the miles we
normally use, or is it always nautical miles?

In conversation with ATC, we use nautical miles.

6. The difference between airspeed and groundspeed is that airspeed is
the net of the plane's speed and opposing windspeed, while groundspeed
is just the plane's speed. Right?

Airspeed is the speed the aircraft is traveling through the air. Groundspeed is
the speed the aircraft is traveling over the ground. The speedometer in an
aircraft measures airspeed (with varying degrees of accuracy). This is called
"indicated airspeed". Pilots can correct this for inaccuracies to determine the
actual (or "true") airspeed. Let's say that I'm flying into a 20 knot wind and
my airspeed indicator shows I'm going 100 knots and it's accurate. My
groundspeed will be 80 knots. If I then turn around and go the other way, my
groundspeed will be 120 knots, but my airspeed will not change.

7. What is "density altitude", and how to compute it? If I'm not wrong,
its use is to plan the length of takeoff roll and angle of climb.

It's a measure of air density and, yes, we use it to calculate the effects of
atmosperic conditions on the performance of the plane. Low pressure, high
temperature, and high humidity all reduce air density and reduce performance. An
airport may be at 90' ASL, but the plane performs as if the airport were at
3,000' ASL if the density altitude is 3,000' (as it may be in high summer).
Usually charts or calculators are used to determine density altitude. I get the
current figures as part of weather briefings.

First, set the altimeter to 29.92 Hg and read the altitude. This is called the
"pressure altitude" and will frequently be different from the actual elevation
of the airport. Then I would use a graph from my pilot's manual to determine the
density altitude for that pressure altitude and the current temperature. It's 7
degrees C at the moment and I am close to sea level. From my graph, that
temperature at that level reduces density altitude by about 800', so an aircraft
will perform better than usual. If the temperature were 30 degrees C, the
density altitude at sea level would be about 2,000' when the air pressure is
29.92 Hg.

George Patterson
The desire for safety stands against every great and noble enterprise.

Ramapriya wrote:

Is it because I'm unknowingly using terms that are nonstandard, being
not a mainstream aviator?

Not in this post, at least.

George Patterson
The desire for safety stands against every great and noble enterprise.

"Ramapriya" wrote in message
ups.com...
I haven't failed to notice that some of my threads have generated
confusion among contributors, with folks disagreeing with each other,
etc.

Is it because I'm unknowingly using terms that are nonstandard, being
not a mainstream aviator?

No, not always. Most recently anyway, it's simply due to incorrect answers
being given initially (and then subsequently as well).

To reiterate a previous reply: you are asking these questions on Usenet.
Not everyone answering is necessarily qualified to answer. Regardless of
the outcome, you should be VERY wary of believing without question answers
you receive here.

I agree that in general, when a correction doesn't degenerate into a long
debate, probably the correction was correct (and the original answer
incorrect, of course). But even that's not 100% reliable.

If you want to know the absolutely most accurate answers to your questions,
you need to do the work to study the material yourself. If you get a kick
out of the immediacy of the Internet and dozens of people stumbling over
themselves to be the first to respond to your pop quizzes, and don't mind
not knowing whether an answer you receive is actually correct, then right
here on Usenet is the place to be.

Pete

wrote:
When the density altitude is
high you need to carefully plan this out... even allowing for some
extra margin of safety. That's part of flight planning.

I have a simpler trick.
The longest takeoff distance in my POH mentioned is 350mtr (1150ft).
I multiplied this by 2(grass, upslope, etc.) , so anything longer
than
700 mtr (2300 ft) is fine.
I know this number, only if I'm going to something shorter I
calculate
the whole thing again.


That may work well if you only fly out of lower elevations, but go
back and look at your first sentence. When density altitude is high,
you need to CAREFULLY plan this out. The simple trick that you
mentioned in your post has resulted in many flatland pilots getting
killed while operating out of high mountain airports in the summer.

To illustrate this, one of my primary instructors had me plan some
flights out of high mountain airports on a hot summer day. In several
cases, the density altitude was slightly higher than the plane's
service ceiling and the takeoff distance exceeded the (apparently) long
runway length.

It's possible that your particular plane could get out of any 2,300
ft. field at any density altitude, but that rule of thumb will not work
with many planes.

John Galban=====N4BQ (PA28-180)

Man.. just sign up for and take a ground school..

Ground school by Newsgroup or Usenet is getting old..

BT

"Ramapriya" wrote in message
oups.com...
I wish you all a very cheery 2005. You really are a nice set of guys
here (those branding me a terrorist notwithstanding), mostly patient
even at clarifying elementary stuff

Some more Qs, if you don't mind.

1. How does a pilot get to know the distance to the airport that he has
to land in, so that he plans his descent accordingly, in planes that
don't have an onboard computer? Maps I know would give the distance
between two fixed points, but how does he keep track of distance
covered in flight and that sort of thing? To inquire ground stations
such info would be embarrassing, I guess

2. What exactly is a VOR? Sounds like it's a constant all-direction
radio transmission from a fixed point on the airport to help locate
where the airstrip is. If so, does it necessarily have to be from *a*
standard designated point in the airfield, right across all airfields
on earth?

3. If a pilot needs to land at an airport that doesn't have a control
tower, how does he figure its elevation so that he may plan his
descent?

4. When a pilot says, "Give me a vector", what does he actually mean?

5. When pilots use miles in conversations, does it mean the miles we
normally use, or is it always nautical miles?

6. The difference between airspeed and groundspeed is that airspeed is
the net of the plane's speed and opposing windspeed, while groundspeed
is just the plane's speed. Right?

7. What is "density altitude", and how to compute it? If I'm not wrong,
its use is to plan the length of takeoff roll and angle of climb.
Cheers,

Ramapriya

"Ramapriya" wrote in message
oups.com...
I wish you all a very cheery 2005. You really are a nice set of guys
here (those branding me a terrorist notwithstanding), mostly patient
even at clarifying elementary stuff

Some more Qs, if you don't mind.

1. How does a pilot get to know the distance to the airport that he has
to land in, so that he plans his descent accordingly, in planes that
don't have an onboard computer? Maps I know would give the distance
between two fixed points, but how does he keep track of distance
covered in flight and that sort of thing? To inquire ground stations
such info would be embarrassing, I guess

It's called pilotage, you always know where you are.


2. What exactly is a VOR? Sounds like it's a constant all-direction
radio transmission from a fixed point on the airport to help locate
where the airstrip is. If so, does it necessarily have to be from *a*
standard designated point in the airfield, right across all airfields
on earth?


not on all airfields and not always at airfields..

3. If a pilot needs to land at an airport that doesn't have a control
tower, how does he figure its elevation so that he may plan his
descent?

he looks up the airport information before he starts out, the control tower
is not going to tell you the airfield elevation unless you ask, and then it
just shows that you did not do your preflight planning., very unprofessional

4. When a pilot says, "Give me a vector", what does he actually mean?

he needs a heading to fly to get somewhere, normally to get started while he
sorts it out in the cockpit, or the navigational aid he is heading to is to
far away to recieve

5. When pilots use miles in conversations, does it mean the miles we
normally use, or is it always nautical miles?

professional pilots use nautical, it is one arc minute of latitude on the
navigational charts

6. The difference between airspeed and groundspeed is that airspeed is
the net of the plane's speed and opposing windspeed, while groundspeed
is just the plane's speed. Right?

you got that backwards, ground speed is the net of airspeed and wind
effect..
airspeed is the speed of the aircraft through the air mass, regardless of
how the airmass is moving in respect to terra firma

7. What is "density altitude", and how to compute it? If I'm not wrong,
its use is to plan the length of takeoff roll and angle of climb.

there you are correct, density altitude will affect engine, propellor and
wing performance.
it is the air at elevation, normally measured by pressure and affected by
temperature.

high hot and humid is a bad combo

Cheers,

Ramapriya

These are questions that EVERY student pilot has. Hence the reason that you
are a student pilot. You need to talk face to face with an instructor
and/or take a ground school at your local FBO. ALL of your questions will
be answered, as well many other things.

It is ridiculous to think that you can try to get your groundschool
knowledge and studying done by writing to a usenet group. It doesn't matter
how qualified the respondants are, you are wasting your time. You are not
gonna get any sign offs for this studying, if you wanna call it that. Take
the ground school and start flying. Get off your bum and make it happen.
The world will open up and the sun will shine so much brighter on your
knowledge level and you won't be wasting everyone else's time either. By
the way, everything that you don't understand on the ground will be a whole
lot clearer when you are in the air seeing how it works first hand.





"Tobias Schnell" wrote in message
...
On 30 Dec 2004 02:43:33 -0800, "Ramapriya"
wrote:

1. How does a pilot get to know the distance to the airport that he has
to land in, so that he plans his descent accordingly, in planes that
don't have an onboard computer? Maps I know would give the distance
between two fixed points, but how does he keep track of distance
covered in flight and that sort of thing? To inquire ground stations
such info would be embarrassing, I guess

What do you mean by "onboard computer"? Most airplanes nowadays (even
small single-engine-ones) have GPS receivers, for which the easiest
task is "tell me the distance to airport XYZ". Modern airliners are
equipped with flight management systems. These derive information
about the airplane's position from various sources (ground-based
navaids, inertia, GPS...), so no problem there, too.

If you don't have all those toys, it is likely that you have at least
a VOR receiver (see below), an ADF or a DME. With those you can also
calculate distances to a fix, but that may require some mental math to
be done.

Airplanes without any onboard electronics are normally flown day-VFR
only, so distance calculation can be made by dead reckoning or
pilotage. But if you are unsure you can of course ask a radar
controller for assistance.

2. What exactly is a VOR? Sounds like it's a constant all-direction
radio transmission from a fixed point on the airport to help locate
where the airstrip is. If so, does it necessarily have to be from *a*
standard designated point in the airfield, right across all airfields
on earth?

VORs are not necessarily located on airports. For technical details do
a google search, I am sue you will find better explanations than what
can be given here in text-only-mode.

Basically a VOR receiver in the airplane tells you the bearing from
the station to the airplane. Pilots are talking about so-called
"radials", e.g. if an airplane is on radial 270 of a VOR, its position
is due west of the VOR.

Most VORs are used for enroute navigation, but there are also
instrument approaches relying on VORs. But as VORs used for approaches
can be located anywhere on the field or even be off-airport, minimums
are usually higher than for an ILS approach.

3. If a pilot needs to land at an airport that doesn't have a control
tower, how does he figure its elevation so that he may plan his
descent?

The elevation of an airport is published. And even non-attended
filelds often have automatic weather reporting that provides an
altimeter setting. If not, you can use the altimeter seting from a
nearby airport which is nomally not too far off.

4. When a pilot says, "Give me a vector", what does he actually mean?

He requests heading instructions from a radar controller, for example
to intercept an ILS or to an airport.

5. When pilots use miles in conversations, does it mean the miles we
normally use, or is it always nautical miles?

Pilots are using nautical miles.

6. The difference between airspeed and groundspeed is that airspeed is
the net of the plane's speed and opposing windspeed, while groundspeed
is just the plane's speed. Right?

If a plane would fly at sea level with an airspeed of 100 kts and
there was a headwind of, let's say 50 kts, its groundspeed would be 50
kts. With calm winds, the groundspeed would also be 100 kts.

When flying higher, air- and groundspeed differ even with no wind, as
the air becomes less dense with altitude, so indicated airspeed
decreases.

Look for "indicated" and "true" airspeed in the books you should have
bought by now ;-).

7. What is "density altitude", and how to compute it? If I'm not wrong,
its use is to plan the length of takeoff roll and angle of climb.

Uh, I'll leave that to someone else now...

Regards
Tobias