Why The Hell... (random rant)

Ron Natalie writes:

Because we don't have a TRUE NORTH indicator in the cockit.

You do if you have systems like GPS or INS.

Just a magnetic compass and instruments derived from it. Real flying
ain't a stupid-assed computer simulation.

Maybe you should take a tranquilizer; you seem very upset.

--
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On Apr 4, 6:05 am, Mxsmanic wrote:
EridanMan writes:
I'm sorry... call me lazy, but if your not going to keep them all
updated with Magnetic north, then at least stick them on a standard
baseline... True North, for example?

I think aviation should have started moving towards true north for everything
long ago, but that's just me.

Bwahahwhawhawhawhawhawhawhawhawhahwawhawhawh

OH BTW doooofus, I'm getting closer and closer. Oh wait, you're not
birght enough to even know what a header eeez.

bertie

In rec.aviation.piloting EridanMan wrote:
Are VOR's all MH based?

I was flightplanning the other day (I must be one of the few poor
souls left who flight-plans by hand... I guess I just haven't been
flying long enough to get sick of it yet, I consider my flight
planning to be 'part of the experience') And I got to thinking-

Why in gods name are VOR's Mag heading based?

You got a true north compass in your airplane?

I know, ideally, that means that you can sync your DG and your VOR
indicator to fly to a waypoint... except that most VOR's around here
have long since fallen behind Magnetic drift... so - now, not only do
you have to flightplan in True Heading, convert to Mag Heading to get
your vectors, THEN you have to get the corrective factor for each of
the VOR's your using for navigation and note that as well? huh?

Center the needle and keep it centered?

I'm sorry... call me lazy, but if your not going to keep them all
updated with Magnetic north, then at least stick them on a standard
baseline... True North, for example?

If the drift is sufficient ( 2 or 3 degrees, I forget the number; it's
in the AIM ) they are supposed to be recalibrated.

The uncertainty in the wind drift angle is usually a lot more than
that.

There are lots of free flight planners that do all that for you.

Golden Eagle for DUATS corrects for everything but your compass
error and is free.

--
Jim Pennino

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wrote:
If the drift is sufficient ( 2 or 3 degrees, I forget the number; it's
in the AIM ) they are supposed to be recalibrated.

FAR 91.171, VOR Equipment checks.

4 degree variation if using a VOT or other ground-based testing
sites/equipment.

6 degrees if using a designated airborne test point, or using a dead
reckoning technique.

No more than 4 degrees variation between the radios of a dual VOR setup.

Nothing about the accuracy of the VOR station itself, though. If they're
really bad, I would file a report with the nearest FSDO.

TheSmokingGnu

In rec.aviation.piloting TheSmokingGnu wrote:
wrote:
If the drift is sufficient ( 2 or 3 degrees, I forget the number; it's
in the AIM ) they are supposed to be recalibrated.

FAR 91.171, VOR Equipment checks.

4 degree variation if using a VOT or other ground-based testing
sites/equipment.

6 degrees if using a designated airborne test point, or using a dead
reckoning technique.

No more than 4 degrees variation between the radios of a dual VOR setup.

Nothing about the accuracy of the VOR station itself, though. If they're
really bad, I would file a report with the nearest FSDO.

TheSmokingGnu

I thought I saw somewhere in there a spec for the VOR station drift.

Maybe it was somewhere else; so many regs, circulars, advisory letters,
so little time...

I know there are limits somewhere.

--
Jim Pennino

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TheSmokingGnu writes:

Nothing about the accuracy of the VOR station itself, though.

1-1-3 (1): Accuracy of better than 1 degree.

--
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writes:

You got a true north compass in your airplane?

Both GPS and inertial navigation platforms can easily determine true north.
In fact, they work with true north, and must apply an unpredictable conversion
factor to true north to get current and local magnetic north.

--
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In rec.aviation.piloting Mxsmanic wrote:
writes:

You got a true north compass in your airplane?

Both GPS and inertial navigation platforms can easily determine true north.
In fact, they work with true north, and must apply an unpredictable conversion
factor to true north to get current and local magnetic north.

No, they can't.

INS has to be initialized from something known and updated because
gyros in the real world precess.

GPS can tell you which direction you are going, but can not tell you
where the nose of the airplane is pointing.

INS is too big and expensive for GA aircraft.

Not all real airplanes have electrical systems.

--
Jim Pennino

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writes:

INS has to be initialized from something known and updated because
gyros in the real world precess.

No, not for true north. An INS determines true north by sensing the rotation
of the Earth. It doesn't require any data input to do this.

GPS can tell you which direction you are going, but can not tell you
where the nose of the airplane is pointing.

If you are moving, it can tell you your ground track. If you have more than
one receiver on different parts of the aircraft, you can also determine which
way the nose is pointing.

INS is too big and expensive for GA aircraft.

That's one reason why I often like to fly big aircraft.

Not all real airplanes have electrical systems.

True, and some are powered by rubber bands as well, but there's a lower
threshold below which I don't bother.

--
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In rec.aviation.piloting Mxsmanic wrote:
writes:

INS has to be initialized from something known and updated because
gyros in the real world precess.

No, not for true north. An INS determines true north by sensing the rotation
of the Earth. It doesn't require any data input to do this.

You are talking about a gyro compass.

A gyro compass is huge, expensive and heavy.

They can take hours to settle on a usable reading.

They don't work if they are moving much faster than a slow ship, and not
at all at aircraft speeds.

An INS system has to be initialized with it's current position and just
tells you where you have moved relative to the starting position.

Wrap some smarts around it with a built in map and it shows you where
you are.

Since real gyros in the real world precess, you have to update the
calculated position to the true position on a regular basis.

You have no idea what you are talking about.


GPS can tell you which direction you are going, but can not tell you
where the nose of the airplane is pointing.

If you are moving, it can tell you your ground track. If you have more than
one receiver on different parts of the aircraft, you can also determine which
way the nose is pointing.

Theoretically you could do that, but no such thing is available for GA
aircraft.

INS is too big and expensive for GA aircraft.

That's one reason why I often like to fly big aircraft.

You don't fly anything, ever.

Not all real airplanes have electrical systems.

True, and some are powered by rubber bands as well, but there's a lower
threshold below which I don't bother.

You don't fly anything. You sit on your ass and watch a computer monitor.

Lots of real airplanes don't have electrical systems.


--
Jim Pennino

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