SID chart LSGG rwy 05 North advice

[Driver 170]

This is not real world flying but i use real world charts and FMS data. I use Lido charts and also had a look at Switzerland AIP charts.

The SID out of rwy 05 North (SIROD 5N) (ARBOS 7N) procedure is, straight ahead R045 GVA - at 7000 or D8 GVA, Whichever is later, turn left. But the FMS data still has you proceeding outbound another 2nm to D9.5 GVA then it proceeds left, this is also shown for the SID chart?

Why the two procedures? Or am i missing something? Be good to hear from a pilot :)

[HeartyMeatballs]

I would check the FMS prediction to see what altitude its estimating by the GVA8 point. It could be that it is expecting to be below 7000 at the GVA8 point. As the SID is 7000 or GVA8 whichever is later you need both criteria to be met before the turn is started. By that I mean 7000 has to be achieved and GVA8 has to be achieved.

As there is a ridge to the north it is important that both conditions are met before the turn.

Most jets will have achieved 7000 by GVA8 and therefore will turn at GVA8 as both criteria (7000 and GVA8) has been met and therefore it is safe to turn.

Pilots can either wait until the turn is started before setting STD (to ensure that the 7000' criteria is met and not FL070 which could be below 7000' and therefore not safe to turn. Or pilots may set standard as normal, keeping an eye on the backup altimeter which is set to QNH. If the aircraft starts before 7000' has been met then they will select and track straight ahead as per the SID and then re-engage NAV once 7000' has been achieved.

Personally I like to wait for the first turn but each to their own.

I hope this helps but I could be completely wrong!

[Doug E Style]

I suppose heavy aircraft could well get to D8 GVA before reaching 7000' in which case the actual track over the ground after the turn would vary for individual flights. Our FMS does not show this extra 2 miles, just the overfly for D8 GVA and the left turn at 7000'.
Incidentally I did one of these SIDs earlier today and ATC cleared us after 6000' direct to GOGOL.

[Driver 170]

Thanks guys for the reply will read through both. But i have two pictures in my dropbox account of my CDU.

First picture - showing the SID leg waypoints, D045J is the 9.5 GVA with the A3750 when i delete that waypoint without executing it, you can see on the second picture, it now shows the predicted altitude of 6600. So still under 7000ft but it has still not met both conditions, only D8 GVA.

Picture 1

https://www.dropbox.com/s/y900usez68twuk0/Photo%2028-02-2016%2C%2015%2049%2051.jpg?dl=0

Picture 2

https://www.dropbox.com/s/zkc4gjh0sn2mx97/Photo%2028-02-2016%2C%2015%2049%2030.jpg?dl=0

[Driver 170]

Great explanation and makes sense pretty much common sense to wait till both conditions met. But i'm still scratching my head why my FMS data still has you proceeding straight ahead even if both conditions are met at D8 GVA!?

I have took that question to the support forum from where i purchased it from.

[HeartyMeatballs]

The FMS is different to mine however it does look like it's still expecting to be FL062 at D8 and should not yet turn.

It's odd because it's got the D045H at the 8 mile point, but then actually has a hard coded 10 mile point at D045J but then creates a track after the D045J point which it will mean it'll continue on the track to 7000 then turn.

I'm confused because it should do this (I'd track) at D045H and so D045J is obsolete. Where does D045J coke from? Is it there when you load in the SID or have you put it in manually? What happens if you take D045J out as an experiment?

I'd expect that if you took D045J out, D045H would be estimating FL062 and thus should then track 045 until 7000 is reached.

Like I say the FMS set up looks different from the one I use so I'm not the best help. Hopefully someone will be able to clear it up!

[Driver 170]

Quick update that Track with the hard altitude restriction of 7000ft is at the same point as D045J.

Its all coded in my AIRAC nothing has been manually modified.

I can't delete D045J it won't let me.

[Driver 170]

https://www.navigraph.com/forum/download/file.php?id=1141&mode=view

[Driver 170]

Switzerland AIP even shows a turn at 9.5 GVA

[Flying Fred]

Hi Driver 170

If you look at the LIDO SID plate for the two SIDs in question, there is a minimum altitude restriction of 3750ft at GVA 9.5d. The only way this can be coded into a FMS is to have it associated with a waypoint. Obviously climbing straight ahead is acceptable because the turn commences at the later of 8d or 7000ft, so they code the 9.5d restriction as a straight ahead waypoint.

It is quite difficult to make 7000ft by 8d anyway and in your second picture, your are crossing 8d at 6200ft and 9.5d at 6600ft, largely because you are still accelerating towards 250kt.

If you are light and can make 7000ft by 8d, then just go HDG SEL onto the appropriate heading and then re-engage LNAV as you approach the appropriate SPR radial, but quite honestly it is easier just to leave it in LNAV and go to 9.5d before turning.

From ATC's point of view, they have no idea of your weight or performance so would be expecting you to go ahead past 8d anyway.

Hope that helps

FF

p.s. I don't know if you have worked it out or have been told but the letters at the end of the DME waypoints (e.g. D045H, D045J) refer to the number in the alphabet the letter corresponds to, 'H' being the eighth letter of the alphabet and 'J' being the tenth

[Driver 170]

That certainly helps and squishes any doubts to the coding being wrong on my side.

Yeh A,B,C etc - The radius is expressed by a letter of the alphabet where A = 1 mile, B = 2 miles, C = 3 miles, and so forth.

[Doug E Style]

A couple of other points... You may have noticed that ICAO noise abatement procedure A applies at GVA (thrust reduction at 1500' and acceleration at 3000' above the aerodrome altitude). Also, whenever I fly this SID, I keep the speed back at about 220 in the hope of getting an early turn north on radar vectors. I suspect many people do the same.

[Driver 170]

Thanks doug thats good to know :)

[Driver 170]

Since were on the subject on LSGG, has any pilot used the RNAV approach to either runway? If so, what is the ATC procedure for both runways?

Runway 23: do you load up that SPR transition or get radar vectors to PETAL and fly the 3* glide from 17nm out?

Runway 05: radar vectors to INDIS and what altitude because flying down a 3* glide 17nm out isn't ideal and could be hard to slow down.

Would ATC bring you in lower to both runways but within MVA?

[blind pew]

In the good old days we would ask for a visual climb out passing 5,000 ft and once the turn was complete accelerate to 290 knots (or a bit more)...eyes outside to look for hang gliders and pass the Jura with the RA audio warning screaming......tell that to the youngsters and they won't believe you ;-)