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.

https://59.149.187.215:8082/share.cg...pen=normal&ep=

If you arm the apch after NERAS and managed your descent.You should have ALT CSTR until MN404 and after this one the FMGS should manage the descent to 3000 ft.At MN410 FINAL APP should engage.
I can't find any reason the acft maintained 4000 ft.
I can see a warning that's a non standard procedure!

mi68guel and Check Airman
The blue arrow does not become visible before arming approach or even after arming approach if APPNAV only becomes armed (APPNAV in blue). Only when the APPNAV mode becomes active the blue arrow will appear so the SOP rightly does not say the arrow must be blue when arming approach because it can't be. Conditions for engagement of FINALAPP are not for arming the approach but for FINALAPP to become active mode to begin final descent. If the arrow is not blue it will not descent unless that condition which is not fulfilled gets fulfilled before reaching the final descent point. Sequencing of DECEL is one of the conditions. The aircraft must be in approach phase even if you manually activate approach it's OK.

mi68guel
The answer by airbus to your company's strange question is equally strange. First your company's question: 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"
The answer should be it is not possible. Because FINAL APP can only be armed before FAF and only becomes active after FAF or VIP. Perhaps your company meant is it OK to arm the approach. Now the second part of the question, your company wants to know if it's OK to do managed approach without proper FMS coding and again the answer should have been "Hell NO" because before embarking on managed approach it is mandatory to check proper lateral and vertical profile in the MCDU with approach chart and FPA is one of them. FCTM explains all the points that need to be checked. When armed FINALAPP mode will not become active unless you are on track and at FAF altitude before FAF or VIP as it is called.

There has been an OEB called 'incorrect vertical profile during non precision approaches', OEB 30 (A330) and OEB 42 (A320) in a effect for a number of years now.

This OEB explains that, due to a possible FMS coding problem, your operator has to have compiled a list with affected approaches, OR, you have to check the coding of the FMS against the plate yourself. Depending on the result you are either permitted to fly this non precision approach in Fully managed mode or laterally managed, vertically selected. So I agree with what vilas is saying.

I THINK the reason your company doesn't want you to ARM APP until you're established on the platform altitude is to guarantee that all the conditions for arming the FINAL APPROACH mode are met (this will automatically cause the blue arrow on your FAF to display). In other words to make sure that you're not going to be too high over the FAF.

If you would be too high over the FAF, I can see how thing can get a bit hairy quite quickly. On the other hand, if you arm APP early, you can check earlier if you have met all the conditions, but checking if the blue arrow is indeed displayed over your FAF.

What happened to me in my case, was that FINAL APP engaged at 8000+ft, and the blue arrow appeared well before the FAF. It seemed to be the last point at which the FMS figured we'd be level.

I really like this reply!
The problem is in the question. They asked something that's not possible..."to have active final approach mode prior to the FAF". This is not clear, because we can't understand if they mean "armed"( FINAL blue) or "engaged" (FINAL APP green). If they mean armed it's the normal situation, but if "active"means engaged, then we'll have to writte down this defect on the techlog and probably to fill an ASR.
So If we want a proper answer from AIRBUS, the question should have been more precise and using FCOM terms (armed and engaged) and that's the reason I consider they didn't fully understand the question but they tried to help and replied generic things.
I also don't understand from the question where it says "active final apch mode prior to the FAF without proper FMS coding, i.e. a defined FPA". What matters is to check max 0.1 degree of difference between MCDU and the chartered final vertical path.
Before the FAF when you arm the apch, only lateral mode is engaged: vertical mode is still under FMS that should comply with ALT CSTR's if descend is managed .So there's nothing illegal on it, the only difference is that we are arming FINAL (in blue) to have it ready before the FAF .At FAF in FINAL APP mode the lateral separation is still under NAV control (RNP 0.3 for us) and vertical guidance is different, the primary means of obstacle clearance is then provided by the VNAV system rather than the altimeter, and adherence to the vertical flight path within reasonable tolerance is required. .So this FINAL APCH mode needs an augmented GNSS system (ABAS in A320 and A330) with Baro-VNAV that uses barometric altitude information from the aircraft's pitot-static system and air data computer to compute vertical guidance for the pilot (for RNAV (GNSS) with LNAV/VNAV minima).
Conclusion: if we armed the approach before FAF at intermediate APCH the lateral and vertical profile is gonna be the same as if we wait until reaching the FAF altitude.In the first case, if something goes wrong, we are following official documentation (FCOM, FCTM, Instructor's media..) but in the second case we are relying on an email that has no legal validity (I'm not a lawyer, but I would be ashamed to defend myself against investigators using an email as SOP reference)

In fact the conditions are not for arming, are for engagement.
You ARM the Apch and then if all the conditions are met it engages at FAF
You don't need "guarantee" for arming.Checks are: APP NAV... check armed or engaged and FINAL...check armed, and check FINAL APP engages at FAF. Depending the type of apch you fly, if FINAL APP doesn't engage at FAF , you can revert to NAV/FPA ( in case of RNAV (GNSS) with LNAV/VNAV minima, you should fly FINAL APP and reverting to NAV /FPA with only LNAV minima needs MDA instead of DA.

There are many issues, such as the criteria, differences between manufacturers, and the coding. It is interesting to see that there is quite a bit discussion on how the coding and FMC actually perform.

There are the differences between armed and engaged, and the flow matrix/sequencing for engagement. The code and criteria have not kept up with the more complicated or the advanced procedures.

As examples, while some systems let you arm on the ground, others do not, and some engage on wheels up and some at 500 feet.

Technically, with an approach, there is the initial segment, one intermediate segment, and a final approach segment. With RNP, there are frequently more than 3 segments to an approach procedure.
In the beginning, some systems would disco if you had more than one intermediate segment, or had a turn after the FAF. The first RNP procedures into the airports in China were done with Airbus, as the Boeing Smiths box would not accept a RWY over 10,000 feet.
Currently working on the RNP transitions to GBAS final, one can see just how difficult the flow management is with all of the if/then and arm/engage scenarios.

As a procedure designer, this is a very interesting thread to review, in fact, many of the threads have been used to show what the operators are actually experiencing and/or how they got there.

The certification process of aircraft avionics has kept the FMS stuck in the mid 80's, with 'new' versions simply being addendum to the coding with add ons, rather than re-writes. As you can imagine, this leaves many paths, and many potential scenarios that are very difficult to desktop/sim or even flight verify other than by thousands of different operators, hence the value of these types of conversations.

Cheers

Regulations RNAV(GNSS)
 

AMC 2027
Airworthiness Approval and Operational Criteria for RNP
APPROACH (RNP APCH) Operations Including APV BAROV-NAV
Operations
- The Performance-based Navigation (PBN) Manual (Doc 9613)
- ICAO Appendix 6
Part I – 9th edition July 2010 - International Commercial Air Transport – chapter 7.2.2
Part II – 7th edition July 2008 - International General Aviation - chapter 2.5.2.2
- Commission Regulation (EC) N°859/2008 of 20th August 2008 (EU OPS)
Sections 1.225, 1.230, 1.243, 1.290, 1.295, 1.297, 1.340, 1.400, 1.405, 1.430, 1.950, 1.965.
- Arrêté du 23 septembre 1999 concerning technical conditions for helicopter operation by a public air
transport company (OPS 3).
Article 4.
Appendix: sections 3.225, 3.230, 3.290, 3.295, 3.297, 3.340, 3.400, 3.405, 3.430, 3.950, 3.965.
- Arrêté du 24 juillet 1991 concerning the conditions for the use of general aviation civil aircraft (aerial work
and private use).
Article 1, second paragraph.
Appendix: chapter IV, sections 4.1.2 and 4.1.3.1 - chapter V, section 5.5.
- Arrêté du 20 mars 1998 concerning the use of aircraft operational minima in general aviation (aerial work
and private use).
Article 1.
Appendix: sections MIN 2.225, 2.295, 2.297, 2.400, 2.405, 2.430

For those operators for whom approval is granted under EU OPS 1, the following events
should be the subject of Occurrence Reports (see EUOPS
1.420):
Technical defects and the exceeding of technical limitations, including:
a) Significant navigation errors attributed to incorrect data or a data base coding error.
b) Unexpected deviations in lateral/vertical flight path not caused by pilot input or
erroneous operation of equipment.
c) Significant misleading information without a failure warning.
d) Total loss or multiple navigation equipment failure.
e) Loss of integrity (e.g. RAIM) function whereas integrity was predicted to be available
during the preflight
planning.

There is a certain VOR approach in our route network whereby if we arm the APP prior to reaching the FAF platform altitude of 2600ft, it does strange things. We were descending to 2600 and the "brick" constantly shows that we are above the profile (full deflection down) when we are certain that we are not and we will be able to be at 2600ft well before the FAF. And then prior to the FAF the brick comes up and the aircraft intercepts the vertical profile, leaving us hanging at about 3000ft below intercepting the final descent slope. So we are encouraged to arm the APP only at the FAF platform altitude.

I still don't quite understand what exactly the FCTOM means by "stabilised laterally and vertically before the point of descent starts". Because in this case we will definitely be level at 2600 at the FAF, let alone be within 150 feet and yet this happens.

mi68guel,

What are you trying to explain by your post #29?

underfire:

If anybody needs more information about certification,regulations , approval and operational criteria regarding RNAV, APV baro-VNAV,RNP, etc these are some references where I got my information from, as the information from Airbus FCOM is not 100% clear (for me it's clear enough but the interpretation of the SOP's regarding this matters is different amongst my company's instructors and training managers).

3.5 Occasional operational procedures

Occasional procedures suited to the architecture of the navigation system, the failures and alarms linked to the
RNAV/GNSS equipment and to the display system, must be developed by the operator on the basis of the
information supplied by the aircraft manufacturer (AFM, FCOM, etc.).
In the event of a redundant or complex installation (e.g. multi-sensor), partial or multiple failure situations must be
envisaged and the associated procedures developed.

http://www.developpement-durable.gou...NSS__ENGv3.pdf

It's not very well explained on the FCTM, but they include this picture:

https://59.149.187.215:8082/share.cg...pen=normal&ep=

thanks for clarifying mi68...

The regulatory background is helpful.

One would think that 424 coding and the criteria would be the standard, but it is more of a guideline for intent, with exemptions being the rule.

Cheers

APPR pb pushed at intermediate apch for managed VOR apch. In RNAV (GNSS) with LNAV/VNAV minima the pb is pushed at initial apch. It looks like the SOP's are different.

https://miguelllodra.myqnapcloud.com...pen=normal&ep=

mi68guel,

This is really interesting. I noticed that the revision for your PDP ( Procedure Data Package ) is REV12. I bought mine in 2014 for the A320 and it is REV09. On my revision, for an NPA, the Flying Ref is TRACK/FPA and on yours is HDG/VS.

whatever happened to just fly the fekking thing, this is no flying, this is buttonbush management pure, i am sooooo glad to have experienced DC8 trough B744, i am out, enjoy your stupid buttons.

NPAs with vertical guidance are now flown ILS like with FD cross bar. When vertical is not managed then use the FPV.