Gatwick STAR ASTR4D Cannot capture G/S

[Richard Myers 1]

The last few entries on my FMC Legs page are as follows...

CI26L 240/2000
FI26L 170/2000
RW26L 170/253

Having armed the LOC it is captured but I can't then capture the G/S. Plane just overflies airport or goes into a series of circles at 2000feet

What am I doing wrong or not doing?

Richard Myers 85 yr old Noob !

[Silicus 850]

Richard,

it is important to approach the G/S from below and that you are established on the LOC before the GS. Only arming the LOC does not do it you have to arm APPR as well.

Hope this helps!

 

Cheers

[downscc 1,327]

1 hour ago, Richard Myers said:

What am I doing wrong or not doing?

What is the FMA telling you?  You should see the GS in small white letters to indicate that GS is armed.

No name is incorrect, it is a best practice to capture the GS from below but it can be captured from above as well; however, this maneuver should be avoided until you gain experience in the aircraft.

When in doubt about what the automation is doing, always look to the FMA where it is telling you exactly what state it is in.  It is a practical requirement that the Tutorial be flown to become familiar with the simulation.

[Richard Myers 1]

I think my problem is a matter of timing. If I arm LOC too soon the tendency is for the aircraft to slew onto the runway heading immediately. and then leave the path altogether. If I get the arming timing correct, ie leave it until we are on the correct heading it then seems too late to arm the G/S. I am of course checking the FMA all the time and understand the meanings of the various messages.

Just made the approach again and this time apart from "Too Low - Terrain" warnings (which I ignored) I did manage to land, Mind you I almost ran out of runway!

BTW I have of course run the Tutorial several times but it is too specific to that route to give me any general guidance as to the approach/landing sequence.

I have been flying the A/S A319 for some months now and of course that bird does all the correct settings for you, so I guess I've got to learn how to fly PROPERLY !

Regards from Canada - Richard

[blazer05 15]

I am not an experienced Airbus flyer so ignore this if you like.  But from your original post - are you still at 170 knots at touchdown?  That seems really fast for the A321.

That could be the cause for "almost ran out of runway".

Franklin Duncan

 

 

[kevinh 409]

1 hour ago, blazer05 said:

I am not an experienced Airbus flyer so ignore this if you like.  But from your original post - are you still at 170 knots at touchdown?  That seems really fast for the A321.

That could be the cause for "almost ran out of runway".

Franklin Duncan

 

 

No his post is about the 777, which doesn't decelerate to Vref for you, hence it stays at 170 in the FMC LEGS page. The A321 will decelerate you to Vref, like the NGX.

[kevinh 409]

2 hours ago, Richard Myers said:

I think my problem is a matter of timing. If I arm LOC too soon the tendency is for the aircraft to slew onto the runway heading immediately. and then leave the path altogether. If I get the arming timing correct, ie leave it until we are on the correct heading it then seems too late to arm the G/S. I am of course checking the FMA all the time and understand the meanings of the various messages.

Just made the approach again and this time apart from "Too Low - Terrain" warnings (which I ignored) I did manage to land, Mind you I almost ran out of runway!

BTW I have of course run the Tutorial several times but it is too specific to that route to give me any general guidance as to the approach/landing sequence.

I have been flying the A/S A319 for some months now and of course that bird does all the correct settings for you, so I guess I've got to learn how to fly PROPERLY !

Regards from Canada - Richard

Richard,

You can't arm LOC too far out, it will not wander off path (unless you are so far out that the localiser is not being received). However, if you arm it too close in you might miss the GS altogether. You might be late in arming the G/S too. Better to arm LOC and G/S at the same time by pressing the APP button (you don't have to wait till LOC is engaged before selecting APP). Try to intercept the localiser no closer in to the runway than the waypoint named CI26L. You should intercept the LOC and then the G/S correctly.

btw, although your user name is your full name, PMDG still expect you to put your full name in your signature.

[downscc 1,327]

I'm concerned there might be a speed management issue here as well.  As Kevin mentioned, the 777 requires speed intervention on final, in fact I am using intervention well before FAF and GS intercept.  A correct speeds, the aircraft will turn to the LOC (please don't use the word slew because it has a specific meaning in the flight simulator), lock onto and easily hold the LOC as long as the intercept angle was 30 deg or less.  Even at 90 deg there is one overshoot and correction and she is on track within 2 nm.