APP Mode, catching Glide prior Path

[Sk8terboy]

Hi, Pilots and DEV team,

I noticed and tested APP Mode trying to catch the ILS (Glide) during VATSIM and Offline sessions.

It seems to me, that Glide path is not being caught while intercepting the course from the side,

approaching the glide path from below and not being on course OR already intercepting it (turning in).

I now, this is working for other aircraft I have (i.e. x737)

Is this the way, the CRJ APP Mode is working in reality or a "little" misbehavior.

It works excellent when on being on course or intercepting (turning in, APP controlled) and catching the glide AFTERWARDS.

Often you are being vectored to the ILS pretty close and asked to report "established" when intercepting glide and path.

So it happened a couple of times, that glide is ready but your are still off from course, rady to turn in for final.

Can you guys please verify that behaviour and possibly clarify this ?

Thanks a lot

Oliver

[YYZatcboy]

Almost always you have to intercept the LOC first for a proper ILS. If you intercept the LOC above the GS you need to descend to capture it. If ATC vectors you like that you should descend via VS mode keeping pace with the GS until the LOC captures, then do the GS Capture.

[thiengo]

Approach mode generates commands to capture and track the selected navigation source displayed on the primary flight display. Tracking performance is higher, than in navigation mode. Approach mode is armed when selected, but cannot capture if the flight control computer is not receiving valid navigation data.

The capture point is a function of closure rate, with the capture point moving away from the radial/beam for high closure rates. Capture will always occur if VOR deviation is less than 5% of full scale (0.1 dot), or localizer deviation is less than 30% (0.6 dot). If the other side does not concurrently capture, it will continue to operate in heading select until it independently captures. Approach mode may automatically select glideslope mode. An on-side localizer capture clears turbulence mode on both sides.

something was said: Loc fisrt and gs after...

You as a Captain have to be  attentive with the atc issues, and have to be situational knowledge to dont be surprised with a bad vector to final....

If the ils has a NDB as a OM MM or IM have the NDB in bearing, that way will give to you a certain of the runway axis and the momento to stop turning to centralize the cdi line with the loc course... ILS deviation is less then VOR, so, the cdi will escape faster and you will do corrdenator S exercise over ils

Other point, in ils aprouch do the descent in glide with ias as descent, you will mantain the vref desired and to do a descent with right vs control the engines, more power and reduces vs , less power increases vs.

i think strange that i test the ils so so in your scenery said. Almost in back course and the aircraft capture the loc and gs, the right thing to do would be, arm loc and gs and wait a right vector from me to put the aircraft in trajectory to obtain the necessery parameters to capture... and so... flight automaticaly.

but the airplane was capturing ....

[thiengo]

Being more clear, the autopilot is near to real function. The capture for ILS, for example, is happening when CDI is alive, but the capture should happen when CDI deviation is less then 0.6 dot, 30% of total deviation.

[Sk8terboy]

Hi

@thiengo

Thank you for your outstanding description of the APP mode. This SHOULD be in the manual as well. ;-)

Basically the theory was known to me, i was just wondering why i.e. x737 is doing the APP Glide prior Heading and the CRJ is not.

Some of my simmer-friends told me, there is even a button on their aircraft (MSFS Payware) to allow/override this (different a/c though).

If the CRJ is that way in reality (means not a bug) that is fine for me.

Happy flying

Oliver

[thiengo]

you are welcome...

generally, for any airplane, the localizer must be captured first and then the glide slope, and is mandatory intercept the glide from  below.

The instrument approach procedure must be done as is in chart.  To intercept a localizer, normally you will be conducted to the trajectory when your heading will be a intercept course, to determine the course to localizer, normally exist a NDB as a out marker or a VOR with the radial of runway axis or near, wait for turn when the CDI is alive as a localizer will do you pratice S movementes cause the deviation of a localizer is with minor angle compared to the VOR, so, turn to intercept the localizer in ILS procedure you still will be below the glide, localized captured now you wait the glide and see the aircraft initiating the descend to maintaining the glide slope.

Note..... do the procedure with IAS as descent, and put the vref in autopilot, maintain the apropriate vertical speed with throttle.... until 400fts, when disconect the AP and follow by your hands and skills.