Going the distance

[Lange_666]

Is there an easy way to determine how far i have flown a certain distance if i don't fly directly to any steerpoint?

 

Like when you get ATC inbound directories like: fly heading XXX for YY miles and land on runway ZZ. How do i know if i have flown those YY miles if i don't have a steerpoint to that point?

[nomdeplume]

The easiest way I think would be to create an overhead mark point at your current location, then set your nav to mark point mode and make that your active steerpoint. Then you can just watch the distance tick up.

 

Unless flying that exact distance is really important, you can also just do a time calculation, i.e. work out how long you need to maintain your current speed for in order to cover the specified distance. Won't be quite as accurate but for following ATC directions should suffice.

[effte]

Or use ded reckoning and clock the distance.

 

Time in hours = distance/speed

 

Time in minutes = distance/speed*60

 

If you want to be exact, the true air speed (ground speed with no wind) is your indicated air speed with 2% adder per thousands of feet of altitude. There's probably a GS reading somewhere in the CDU as well.

 

Wind will affect this, probably to a complexity beyond what most sim pilots are willing to get involved with - but do ask, if I am mistaken.

 

More fun than fiddling around with the electronic gizmos for sure!

 

Cheers,

Fred

[sobek]

There's probably a GS reading somewhere in the CDU as well.

 

There is, you have to put the right CDU dial in (uh, dunno what it's called, POS or something) and then there is a speed indicator on the CDU page that can be cycled between IAS, TAS, and GS.

[miguelaco]

Try Selective Course Steering (SCS). CDU page NAV>ATTRIBUTES SCS: ON.

Interesting! Little off-topic, but never understood SCS purpose. Can anyone elaborate on its practical use?

[nomdeplume]

There is, you have to put the right CDU dial in (uh, dunno what it's called, POS or something) and then there is a speed indicator on the CDU page that can be cycled between IAS, TAS, and GS.

There's also a speed indicator on the steerpoint page which can be cycled between IAS/TAS/GS.

[NoJoe]

Or use ded reckoning and clock the distance.

 

Time in hours = distance/speed

 

Time in minutes = distance/speed*60

 

And if you want the easy shortcut to this method, just remember:

 

180 knots = 3 miles per minute

240 knots = 4 miles per minute

300 knots = 5 miles per minute

 

:thumbup:

( pilots are lazy, we like to do things the easy way! :smilewink: )

 

--NoJoe

[effte]

And if you want the easy shortcut to this method, just remember:

 

180 knots = 3 miles per minute

240 knots = 4 miles per minute

300 knots = 5 miles per minute

 

( pilots are lazy, we like to do things the easy way! :smilewink: )

 

 

Sure, but that goes below my guesstimate threshold, and are a few too many figures to remember... especially considering that I usually plod along a wee bit slower. :)

 

Have to concur with the lazy bit though, so I go a different route:

 

[WildBillKelsoe]

Is there an easy way to determine how far i have flown a certain distance if i don't fly directly to any steerpoint?

 

Like when you get ATC inbound directories like: fly heading XXX for YY miles and land on runway ZZ. How do i know if i have flown those YY miles if i don't have a steerpoint to that point?

 

I think ATC guides you to the airport heading, not the runway heading. Once established visual on the runway, align the aircraft.

[GGTharos]

You really don't need to do /any/ of this stuff with the CDU. If you really want to use your nav system, then:

 

Fly the course as directed. You can ignore his directions and turn right into the airfield if it's a 1 or 2 mile flight to initial. Judge this one on your own.

 

Switch CDU to Airport WP.

 

Set HSI to runway course as directed by ATC.

 

Set altimeter as desired based on ATC baro report.

 

Intercept course to runway at pattern altitude by watching the HSI and dead-reckoning the flight time for a cross-check in case you're flying IFR only and need to do your due dilligence.

 

Either fly VFR from there on, or IFR as required.

 

/All/ you have to do is hit your numbers, which is speed, altitude, and heading. You know speed and altitude, and direction is given by the ATC. You turn into the runway by using either your eyes or your instruments.

[miguelaco]

When out of FLT PLN mode and turn on SCS it throws a waypoint out onto the ground. On the TAD it will look like a waypoint with a green line extending off into infinity along the course chosen by the CRS knob. The HSI shows steering for this course line and range. It's sort of like a virtual TACAN station in your pocket.

 

There's a bug where the steering is reversed, if you're to the right of course the needle will be deflected left but if you remember that you can compensate. Should be fixed in 1110.

Many thx!!

[Lange_666]

I think ATC guides you to the airport heading, not the runway heading. Once established visual on the runway, align the aircraft.

No it does not. It guides you to the Fina Approach Fix which is around 10 miles out of the airport to intercept the runway/pattern/glideslope. But if it's foggy or clouds are hanging low there is no visual and if there is no ILS you have nothing to guide you. So for me the distance to the intercept point is crucial because unlike in Lock On you can only tell the ATC once that you're inbound and you will only get one distance message.

Edited August 3, 2011 by Lange_666
typo

[GGTharos]

Except for the part where it isn't crucial at all. You can easily use your nav system to intercept the runway heading without the distance.

 

And if your CDU dies so you can't do it with those instruments, your best bet is dead reckoning, and that's only assuming you're IMC and unable to see the runway. Even then, the ILS system will help you out if functional and if it isn't ... fun.