When do you press APPR pb RNAV (GNSS) APCH (AIRBUS)
 

My company doesn't allow to press the APPR pb when cleared for apch on last track or hdg to incercept the final track.We have to wait until we are at the same altitude of the FAF to do it.
I would like to know how other airlines do it.If any one knows a link to the EASA certification for managed NPA (Airbus) I will appreciate.

Thanks

Would be curious as to why you have that policy. No restriction for us. Only last week, I had FINAL APP active at 8000+ft.

Obviously, we wait to be cleared for the approach first.

Cleared for the approach, then when ready push it.....

That policy comes from Airbus:

This is the question from my company to Airbus (customer email):

"Is it legal and permissible under Airbus recommendations, to have active final approach mode prior to the FAF without proper FMS coding i.e. a defined FPA"

This is the answer from Airbus:

"The FINAL APP mode is designed to fly final approaches.Therefore, Airbus recommendation is to use this mode to fly the portion of the approach situated after the final descent point (or Vertical Intersection Point) for RNAV(RNP) approaches).The flight crew should plan the approach so that the FINAL APP mode engages at or soon before this point. As a consequence, the APPR pushbutton should be pushed during the level segment preceding the FDP...."

Thanks mi68guel,

I'll bring it up with my company. It did a flawless job of flying the DME arc and descending as published to join the VOR approach. Of course, just because it worked doesn't make it right. Appreciate it.

The Airbus FCOM states that it is not permitted to modify any waypoints from the FAF to the MAPT. So maybe Airbus are taking the legal approach with their advise. I.e. FINAL APP mode should be used during this phase where waypoints are not modified. Prior to the FAF we can make changes to the altitude constraints which allows for some human error to be added to the mix when FINAL APP mode will be following the descent profile based on altitude constraints.

Airbus teach to arm the approach when cleared for the approach.

My reading of the Airbus reply above isn't so much saying that you must do it at the level segment, rather that you would do it before the FINAL APP point and the level segment is an example of a perfect place for that.

I regularly GNSS RNAV into uncontrolled airports. I see no reason not to do arm it as Check Airman did at 8000' above the airport. If there's no controller to clear you for an approach (which in itself reminds you to arm it) what harm is there in putting it on early whilst you remember it? Much better option than wondering at o dark o'clock where the blue arrow is on the ND and why it's not going into FINAL APP....

Besides the answer from Airbus.I'm not very happy arming the apch at the final altitude.In fact the workload is higher and I can't see any benefit doing it like this.I really think the pilot from Airbus who answered didn't fully understand the question as the wording at the question wasn't perfect (they used "active" instead of "armed" or "engaged". In fact if you arm at IAF (APP NAV)you are still responsible for the vertical navigation (you can take over if not happy) and final mode is "armed" so the vertical/lateral navigation (FINAL APP) will engage at the FAF if all the conditions are met.So I don't really understand this recommendation.Another thing that makes me feel that is wrong is that is not written anywhere (FCOM, FCTM, AIRBUS instructors media..etc).That is the reason I wanna know the certification document for APV approch with ABAS+ Baro VNAV (A320, A330, etc) with LNAV/VNAV minima

mi68guel
When passing the FAF if aircraft is not at the final approach fix altitude then FINALAPP will not engage. If the A/C is below FAF altitude FINALAPP will engage but not FAF but at the interception point of the approach path. That is why your company may be not wanting you to engage FINALAPPR before reaching the FAF altitude.

I know the final app mode will not engage if the acft is more than 1.5NM lateral (From final track) or 150 ft high.But if I arm the APP NAV before the final altitude, that is not gonna prevent me to be at the right altitude before the FAF to have all the conditions for engagement of final app mode.If you have a look at TEL-AVIV RNAV(GNSS) APCH RWY 30 (you can google it and you'll have it from ISRAEL AIP) you will see that IF and FAF tracks have 30 degrees difference and the altitudes are also different. If you manage to reach 1500 feet after the IF, maybe your lateral deviation from the final track would be more than 1.5 NM so if you push the APPR pb right there you won't have the conditions for FINAL APP engagement and the arrow will still be white, instead of blue

Yes indeed the final track is 30 different than IF. But if you arm the approach after IF it will be armed and if you get on final track before FAF it will get active provided you are at FAF altitude before the FAF. You are allowed to do direct to FAF also provided the turn after FAF is not sharp. FINALAPP will engage but descent may take place outside protected path after FAF.

What happens when the RNP procedure begins at the STAR? Why wait until the FAF?

I have experienced in a couple of NPAs with base turn flown in FINAL APP that the airplane descended below the FAF altitude and caught the vertical profile whilst still in the base turn and well outside of the 1/2 dot of the radial inbound of the procedure. APPR was armed leaving the IAF (VOR). The procedures were perfectly coded in the FM database and where verified during the approach briefing. By reading the answer from Airbus to mi68guel that makes sense and could have possibly avoided that situation *BUT* chances are that the airplane would have been higher than 150ft on profile once established on the radial inbound and FINAL APP would have not engaged. In the remaining 95% of the NPAs that I flown I have never had any issue by arming APPR when cleared for the approach as per Airbus Sops. Regarding APVs, here as well never had any issue provided that the coding of the FM database was correct which is of course a precondition to fly the approach.
Cheers.

There's also a risk of false G/S captures and we still arm the apch when cleared by atc and and on final intercept trajectory for the final approach course with LOC deviation available.
If you had that misbehaviour on a NPA, the best thing you can do is to fill an ASR.
Thanks for your reply

In NCE rwy 22 the aircraft will level off at 4000 feet if you arm the Approach too soon.

Thanks for the image. Interestingly, it lists the decel sequencing as one of the conditions required. In my case, the decel waypoint was not yet sequenced. It was still some distance away.

You guys have mentioned APV. Are EU operators doing APV appeoaches now? I know a hand full of US airports have GLS approaches, but as far as I know, no operator utilizes the far more widespread LPV approach.