RNAV vs IFR GPS

Steven P. McNicoll wrote:
wrote in message ...

He did not say that right. There is VOR/DME-RNAV as well as
INS RNAV, IRS RNAV, GPS RNAV, and LORAN RNAV.



IRS RNAV?



Yes, a straight line is the fastest way to get away from the IRS.

Matt

My apologies - I was overly critical.

"Richard Hertz" wrote in message
et...
You are filing /G and you don't know the answer to this?

Where do people get their IFR 'training' these days?


"PaulaJay1" wrote in message
...
Coming into CLE the other day the controller ask if I had RNAV and I
said
no,
that I was /G ,that is, IFR GPS. He said that it was the same and gave
me
direct.....
Is it the same, should I have answered yes to his question? Of course I
can
navigate direct but do I have "RNAV"?

Chuck

"John R. Copeland" wrote:

wrote in message ...


john smith wrote:

Richard Hertz wrote:
You are filing /G and you don't know the answer to this?
Where do people get their IFR 'training' these days?

That's not necessarily a fair criticism.
For those of us who have been flying since the 70's, we still think and
refer to airspace as TCA's, TRSA's and ARSA's. So we still remember RNAV
as VOR/DME, while LORAN and GPS are essentially global navigation
systems (although, technically, that's still another, different form
altogether).

I;ve been flying since the late 1950s and I adjust. TCA, and ARSAs seem
quite alien to me these days. Then again TRSAs don't because we still have
those.

I think the criticism is quite justified.


Me too, Sammy.
I've been flying since the middle fifties, and I've adjusted pretty well, too.
GPS approaches are a far cry from 4-course Range orientations,
and the Range Approaches that I learned to do without an ADF.
(Follow the edge of a leg into the cone of silence, then turn to xxxº and descend.)
Oooh, those were fun!
And why do I remember 3023.5 kHz? (Except they were kc back then.)
---JRC---

Right, that was before Ms. Hertz took over from Mr. Cycle.

I remember 3023.5, except I can't recall what it was for. Was it a common HF tower
frequency even though most of the equppage was VHF by then? Perhaps you had a VHF
receiver, but only an HF transmitter? From the day I started the aircraft I flew
either had no radios or they had VHF transceivers (perhaps with only a few transmit
crystals and an analog receiver turner.) I remember my first IFR set well, the Narco
Omnigator. Did a lot of ATCS en route communications with that equipment.

"Steven P. McNicoll" wrote:

wrote in message ...

He did not say that right. There is VOR/DME-RNAV as well as
INS RNAV, IRS RNAV, GPS RNAV, and LORAN RNAV.


IRS RNAV?

Not in the airplanes you fly, Steve. In the big ships, three IRUs that
provide the attitude platform and the basic inertial reference. If the GPS
failes, the DME/DME fails, the VOR/DME fails, and the VOR/VOR fails then a
slightly degraded, but noneless very good position is provided by the IRUs
via the FMS, which in combination is known as the IRS (inertial reference
system), which in turn is IRS RNAV when all external sensors are not
available.

From Chapter 7 of the current FAA Instrument Flying Handbook:

INS Components
INS is considered a stand-alone navigation system, especially when more than
one independent unit is onboard. The airborne equipment consists of an
accelerometer to measure acceleration—which, when integrated with time,
gives velocity—and gyros to measure direction.
Later versions of the INS, called IRS (inertial reference systems) utilize
laser gyros and more powerful computers; therefore, the accelerometer
mountings no longer need to be kept level and aligned with true north. The
computer system can handle the added workload of dealing with the
computations necessary to correct for gravitational and directional errors.
Consequently, these newer systems are sometimes called strapdown systems, as
the accelerometers and gyros are strapped down to the airframe, rather than
being mounted on a structure that stays fixed with respect to the horizon
and true north.
INS Errors
The principal error associated with INS is degradation of position with
time. INS computes position by starting with an accurate position input
which is changed continuously as accelerometers and gyros provide speed and
direction inputs. Both the accelerometers and the gyros are subject to very
small errors; as time passes, those errors likely will accumulate.
While the best INS/IRS display errors of 0.1 to 0.4 NM after flights across
the North Atlantic of 4 to 6 hours, smaller and less expensive systems are
being built that show errors of 1 to 2 NM per hour. This accuracy is more
than sufficient for a navigation system that can be combined with and
updated by GPS. The synergy of a navigation system consisting of an INS/IRS
unit in combination with a GPS resolves the errors and weaknesses of both
systems. The GPS is accurate all the time it is working but may be subject
to short and periodic outages. The INS is made more accurate because it is
continually updated and will continue to function with good accuracy if the
GPS has moments of lost signal.

wrote in :

I remember 3023.5, except I can't recall what it was for. Was it a
common HF tower frequency even though most of the equppage was VHF by
then? Perhaps you had a VHF receiver, but only an HF transmitter?
From the day I started the aircraft I flew either had no radios or
they had VHF transceivers (perhaps with only a few transmit crystals
and an analog receiver turner.) I remember my first IFR set well, the
Narco Omnigator. Did a lot of ATCS en route communications with that
equipment.

3023.5 KHz is 3.0235 MHz, and I doubt this is what you remember. 3023.5 Hz
is possible, since this is in the HF band, being just over 3 KHz.
MegaHertz band receivers weren't in general use in the 50's.

--
Regards,

Stan

Stan Gosnell wrote:

wrote in :

I remember 3023.5, except I can't recall what it was for. Was it a
common HF tower frequency even though most of the equppage was VHF by
then? Perhaps you had a VHF receiver, but only an HF transmitter?
From the day I started the aircraft I flew either had no radios or
they had VHF transceivers (perhaps with only a few transmit crystals
and an analog receiver turner.) I remember my first IFR set well, the
Narco Omnigator. Did a lot of ATCS en route communications with that
equipment.

3023.5 KHz is 3.0235 MHz, and I doubt this is what you remember. 3023.5 Hz
is possible, since this is in the HF band, being just over 3 KHz.
MegaHertz band receivers weren't in general use in the 50's.



Like I said, the equipment I used had the same basic VHF comm frequencies we
use today, except there were a maximum of 90 channels (100 KC spacing?). Most
of the equipment I used had 4 to 27 transmitting crystals and a continuous
tuning receiver. Those were around in late 1956, for sure.

I only remember seeing 3023.5 on the charts, and I presume, as you say, it was
Cycles, not KiloCycles (no Ms. Hertz back then ;-)

"Stan Gosnell" wrote in message =
...
wrote in :
=20
I remember 3023.5, except I can't recall what it was for. Was it a
common HF tower frequency even though most of the equppage was VHF =
by
then? Perhaps you had a VHF receiver, but only an HF transmitter?=20
From the day I started the aircraft I flew either had no radios or
they had VHF transceivers (perhaps with only a few transmit crystals
and an analog receiver turner.) I remember my first IFR set well, =
the
Narco Omnigator. Did a lot of ATCS en route communications with =
that
equipment.=20
=20
3023.5 KHz is 3.0235 MHz, and I doubt this is what you remember. =
3023.5 Hz=20
is possible, since this is in the HF band, being just over 3 KHz. =20
MegaHertz band receivers weren't in general use in the 50's.
=20
--=20
Regards,
=20
Stan
=20
No, Stan, it was 3023.5 kHz AM, in the HF Aeronautical Mobile band,
which spans 2850-3155 kHz even to this day.
3.0235 kHz would be VLF, with a 100-km wavelength!
As VHF gear began to be emplaced in the 1950s,
they couldn't just suddenly abandon HF communications.

And as Sammy said, it was either the common Tower frequency,
or the common "Radio" frequency (meaning Flight Service Station).
I *think* 3023.5 kHz was for calling "Radio", who could respond
either on VHF or on the local LF/MF 4-course Adcock Range station.
If that's right, then 3105 kHz probably was the frequency for calling =
the Tower,
who could respond on the fixed frequency of 278 kHz as standard,
or on a small number of alternative HF frequencies if other towers were =
nearby.

Whew. I'd have to dig through some old stuff to remember this exactly,
but I'd lay money on Steven P. McNicoll's ability to turn it up easily.
---JRC---

"John R. Copeland" wrote:

"Stan Gosnell" wrote in message ...
wrote in :

I remember 3023.5, except I can't recall what it was for. Was it a
common HF tower frequency even though most of the equppage was VHF by
then? Perhaps you had a VHF receiver, but only an HF transmitter?
From the day I started the aircraft I flew either had no radios or
they had VHF transceivers (perhaps with only a few transmit crystals
and an analog receiver turner.) I remember my first IFR set well, the
Narco Omnigator. Did a lot of ATCS en route communications with that
equipment.

3023.5 KHz is 3.0235 MHz, and I doubt this is what you remember. 3023.5 Hz
is possible, since this is in the HF band, being just over 3 KHz.
MegaHertz band receivers weren't in general use in the 50's.

--
Regards,

Stan

No, Stan, it was 3023.5 kHz AM, in the HF Aeronautical Mobile band,
which spans 2850-3155 kHz even to this day.
3.0235 kHz would be VLF, with a 100-km wavelength!
As VHF gear began to be emplaced in the 1950s,
they couldn't just suddenly abandon HF communications.

And as Sammy said, it was either the common Tower frequency,
or the common "Radio" frequency (meaning Flight Service Station).
I *think* 3023.5 kHz was for calling "Radio", who could respond
either on VHF or on the local LF/MF 4-course Adcock Range station.
If that's right, then 3105 kHz probably was the frequency for calling the Tower,
who could respond on the fixed frequency of 278 kHz as standard,
or on a small number of alternative HF frequencies if other towers were nearby.

Whew. I'd have to dig through some old stuff to remember this exactly,
but I'd lay money on Steven P. McNicoll's ability to turn it up easily.
---JRC---

I have some 1945 WACs for Southern California. I don't see that frequency on those charts. I do see
126.18 all over the place, and some 140+ MHz. And, some really low frequency stuff as well.

"John R. Copeland" wrote:

And as Sammy said, it was either the common Tower frequency,
or the common "Radio" frequency (meaning Flight Service Station).

Air Traffic Communications Station, not FSS. ;-)