VECTORS

[vamac53]

i thought that in ifr flights, the atc was supposed to vector you so you can catch the opening of the ils feather, but i get vectored to go perpindicular to the feather, and no turn orders to line up to establish localizer, so i go blasting through, unable to establish. why is that?
thx

mike

[n00B]

roger mike
alpha papa zulu
Hi jack
idk

[SteveFSX/P3D]

I typically get a 45 degree slanting angle to intercept the feathers. If hand flying it's up to you to line up and intercept the ILS, and report to ATC when you have done so. When ATC tells you to report ILS capture (established) you can also activate Approach mode on the autopilot to make it capture the ILS.

[wim1234]

vectoring is not always fullproof, thats why i fly my own plans manualy.

[vamac53]

Originally posted by Steve Mak:

I typically get a 45 degree slanting angle to intercept the feathers. If hand flying it's up to you to line up and intercept the ILS, and report to ATC when you have done so. When ATC tells you to report ILS capture (established) you can also activate Approach mode on the autopilot to make it capture the ILS.

i lower to 2800 ft approaching k ont ontario, click approach, and nav, but planes never decreases to runway. just flys right over. i must not be clicking app at the right time.

mike

[SteveFSX/P3D]

Originally posted by mmccarthy53:

Originally posted by Steve Mak:

I typically get a 45 degree slanting angle to intercept the feathers. If hand flying it's up to you to line up and intercept the ILS, and report to ATC when you have done so. When ATC tells you to report ILS capture (established) you can also activate Approach mode on the autopilot to make it capture the ILS.

i lower to 2800 ft approaching k ont ontario, click approach, and nav, but planes never decreases to runway. just flys right over. i must not be clicking app at the right time.

mike

The key thing to remember is that the ILS is composed of two signals (glideslope and localiser) that can be captured independently - and sometimes the glideslope can fail to capture if you have flown though it already or are above it. This can lead to the aircraft being guided by the localiser but failing to descend and over-flying the airfield.

So as an example approaching straight in on a Cessna at 3000ft at 30 miles out - on autopilot heading mode with altitude hold:

I tune the runway ILS frequency into NAV 1 - then change or make sure my NAV / GPS toggle near the top of the dash is on NAV selection. The autopilot is now slaved to the navigation source that is entered into the NAV 1 radio (and not set for direction from the GPS)

I then click approach on the autopilot. The approach will typically activate at somewhere around 25 miles and the heading hold button on my autopilot will not be illuminated now. The localiser capture, and activated APR mode automatically cancels heading mode. When both buttons are illuminated it is still awaiting capture of the localiser.

When just approach (APR) and (ALT) are illuminated we have captured the localiser. The aircraft is being lined up to the runway 'laterally' using the localiser.

The ALT button on the autopilot is still illuminated because we have not captured the glideslope and we will not capture that until around 10 miles out or a bit sooner. At that time the ALT button illumination will turn off to signal that the glideslope has been captured. The aircraft will now be guided vertically to the runway using the glideslope portion of the ILS.

The glideslope will be intercepted at different distances depending on the aircraft height - at 3000ft the glideslope will be at 10 miles and at 1500ft you will intercept at 5 miles. This represents the glideslope heading up and away diagonally from the airfield - so you fly through that at distances dependent on your height.

You can obviously do this all manually and follow the glideslope interception using the CDI. You see the glideslope needle travel down toward interception. The same thing happens on glass cockpits but depicted differently.

You don't need to be as far out as my example to capture that first localiser signal. That can be done much nearer, but you must be under that glideslope or before interception point as you intercept the glideslope part of the ILS.

If you look at ILS approach charts you can see how this looks in profile. Vectoring is supposed to put you in a position to be aligned with the runway before flying through the glideslope - and ILS charts are designed to do it by design.

The long run in to the ILS in my example is not typical, but it's the best way to start doing them to see the 'mechanics' of it.

[vamac53]

thx alot. i still dont understand, but will keep fiddling.

mike

[Sixshot]

I need Vectors Victor.

[BillsFanMike]

Roger, Roger.

[WhiteKnight77]

Don't call me Shirley.