No Gyro Vectors

[InsyleM]

Hello,
I have heard/read that if the gyros on an aircraft malfunction, the pilot is to ask for 'No Gyro Vectors' Ive even heard of a C-141 doing this after one of the INS units failed (Crew for some reason didn't trust AHRS or the remaining INS)

What does ATC tell you when you ask for No Gyro Vectors?
I would imagine if your flying VFR it would be somewhat easyer...
What happens if your flying IFR under IMC?
Thanks,
-Jonathan

[alexm]

I googled this, and it seems that ATC will instruct the pilot to "turn left/right." Pilot should make a standard rate turn, except when turning to final- then it's a half-standard rate turn. ATC will also instruct when to "stop turn."

Hopefully a real expert will chime in here.

[skylab]

alexm's info is pretty much correct.

It all goes back to "needle, ball, and airspeed".

I doubt anyone teaches this stuff any more though.

[InsyleM]

alexm's info is pretty much correct.

It all goes back to "needle, ball, and airspeed".

I doubt anyone teaches this stuff any more though.

When you say needle ball and airspeed....
Isn't the needle gyro controlled?

[skylab]

Yes, but not sure the old ones were electric. Thought they were vacuum. Heck, I dunno any more.....it's been too long. Only thing they got nowadays is slip indicators I think.

[lnuss]

The "no gyro" approach is for loss of the DG (Directional Gyro), also known as a gyro compass, rather than the loss of the "needle."

The "needle" of 'needle, ball and airspeed' is the instrument once called the Turn and Bank which, though similar in purpose, is still quite a bit different from the "turn coordinator" that is much more common today.

Turn and banks came in both vacuum and electric versions, as far as I know, though the electric was preferred in most cases. The main use that I would see for a vacuum T & B would be for aircraft without an electric system, where the vacuum could be supplied by a venturi device, rather than today's more typical vacuum pump. Today's Turn Coordinators are, to the best of my knowledge, all electric.

Alex is, indeed, correct about the gist of the no gyro approach. So far as I know, this approach was available as an alternate form of ASR (Airport Surveillance Radar) approach, in which the controller vectored you to one mile from the end of the runway at a specified MDA (Minimum Descent Altitude). This ASR was, at one time, available for most airports with the ASR radar facility, but seems to be less and less common these days.

Back in the '70s (and up thru the mid-'90s), I would usually get my students some practice with ASRs (yes, Private students) during the night flights required for the Private license (we'd do DF steer's, too, but daytime). We'd typically go through a couple of ASRs (under the hood, yet), then would ask for a No Gyro approach (also under the hood) -- controllers were usually quite happy to oblige, since they needed a certain number of them given every so often to retain certain qualifications.

[skylab]

I knew you'd chime in here and clear that up for for everyone, Inuss.

Thanx.

[InsyleM]

... It sounds like No Gyro vectors sounds like if you loose your
Directional Gyro, but still have others like your Turn Cordinator and
your Attitude Indicator.
That being the case,
why not just steer by the standby magnetic compass?
Isnt that what it's there for?
-Jonathan

[TheAviatorMag]

As a controller that has performed thousands of PAR and ASR approaches the No-Gyro approach is something that is really a fun thing for a controller. It is an Art to some and a math equation to others. There is a difference though from No-Gyro vectors and a No-Gyro ASR or PAR approach. I work several ASR approaches a week and about 1 out of 10 are No-Gyro. Of course these are practice approaches and very rarely do you actually have to give no-gyro vecters for the approach. I have recently had to give no-gyro vectors to an aircraft that had an instument problem of some degree and was not taking the headings I was giving and he was not on an approach. It is an art in my eyes because you have to put yourself in the cockpit and after you give the instruction you have to imagine the pilot actually performing the action and then know when to have the pilot "Stop Turn". On final is a very important time to be able to do this accuratly and that is why it is practiced.

[lnuss]

... It sounds like No Gyro vectors sounds like if you loose your
Directional Gyro, but still have others like your Turn Cordinator and
your Attitude Indicator.
That being the case,
why not just steer by the standby magnetic compass?
Isnt that what it's there for?
-Jonathan

A mag compass is, indeed, for navigational guidance, especially when all other stuff has failed, or on a minimally equipped aircraft. However, it's far from the best device to use when a precise course is needed, since it wobbles around in turbulence and has acceleration/turning errors, which can have its reading more than 30º off the actual heading under some circumstances (close to 40º off in northern Colorado -- the further from the equator, the greater the error). Also, not everyone who might make use of a no-gyro approach is a highly skilled instrument pilot, knowing all the foibles of the compass, and calmly doing the rapid calculations needed to correct for errors (as well as knowing when NOT to correct).

So the DG was designed to provide the stability that the mag compass lacks, though it needs periodic resetting, either by the pilot or, on some aircraft, automatically.

With the DG out, a no gyro vector will be more accurate (all else being equal) than a vector using a mag compass, especially with non-instrument pilots or panicky pilots. It also cuts pilot work load considerably, sometimes a very important factor in the real world. The real world is considerably less stable and less forgiving than the FS world.

John -- glad to see a controller's perspective here, too. Thanks.

[InsyleM]

A mag compass is, indeed, for navigational guidance, especially when all other stuff has failed, or on a minimally equipped aircraft. However, it's far from the best device to use when a precise course is needed, since it wobbles around in turbulence and has acceleration/turning errors, which can have its reading more than 30º off the actual heading under some circumstances (close to 40º off in northern Colorado -- the further from the equator, the greater the error). Also, not everyone who might make use of a no-gyro approach is a highly skilled instrument pilot, knowing all the foibles of the compass, and calmly doing the rapid calculations needed to correct for errors (as well as knowing when NOT to correct).

So the DG was designed to provide the stability that the mag compass lacks, though it needs periodic resetting, either by the pilot or, on some aircraft, automatically.

With the DG out, a no gyro vector will be more accurate (all else being equal) than a vector using a mag compass, especially with non-instrument pilots or panicky pilots. It also cuts pilot work load considerably, sometimes a very important factor in the real world. The real world is considerably less stable and less forgiving than the FS world.

John -- glad to see a controller's perspective here, too. Thanks.

Cool
Thanks for the explination and information :)
-Jonathan