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Airbus Within 6ft of the Ground nearly 1 mile Short of Runway

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Airbus Within 6ft of the Ground nearly 1 mile Short of Runway

Old 14th Jul 2022, 08:05
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Originally Posted by FlightDetent View Post
It does not please us to observe and explain that while flying cannot be reduced to become fully deterministic, much of what we do so proudly can be algorithmized (in the non IT sense). That is where supervised automation (even remotely) will completely circumnavigate the challenges above at a lower overall industry cost.
Agreed... and if one lesson can be learned from the push for autonomy in the automotive world - if you automate everything when nominal, do not expect the driver to take over in an instance when it all goes rats.
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Old 14th Jul 2022, 08:20
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Originally Posted by 1201alarm View Post
That is why the Aircraft should automatically compare the QNH put (during cruise or early descent) into the FMGC approach page with the QNH set on the FCU during transition and give an alarm if off by more than one.

With the increase in PBN, we need more protection against wrong QNH. This would lead to a strong safety net against wrong QNH information or wrong setting.
Quite common for QNH to change by one, so chances are the alerting will go off a lot when it's not needed and the alerting system could be seen as a nuisance 99% of the time when it's not needed. Maybe the manufacturers thought about it already and possibly a reason why it's not implemented already, should be a way around that one perhaps as well... Including pilots comparing forecast to actual, RA... But it's a nasty one if the error is the wrong way additionally and actual alt is lower than indicated...
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Old 14th Jul 2022, 09:04
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Originally Posted by Clop_Clop View Post
Quite common for QNH to change by one, so chances are the alerting will go off a lot when it's not needed and the alerting system could be seen as a nuisance 99% of the time when it's not needed.
The OP said that a difference of Ī1 hPa would not trigger an alert, so why would you expect large numbers of false alarms ?
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Old 14th Jul 2022, 09:11
  #104 (permalink)  

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Perhaps. Airbus put a comparator between THS setting and the MCDU TO Page trim prompt. Unnecessary for the SA fleet where it never was a standard fit.

Comparing FCU Baro selection to MCDU APPR page will be a piece of cake.

Threshold alert 2/3 of MOC = 3 hPa.
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Old 14th Jul 2022, 10:26
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Originally Posted by Herod View Post
An explanation please. I'm way out of the loop, having retired in '04, so before computer-generated approaches had come about. If the aircraft is carrying out a NPA, and has no ILS glidepath, would not the EGPWS be screaming well before this point? Back when, home base on one runway flew over an escarpment. At about 2 miles, suddenly the rad alt went from about 1,000' to 600' almost instantaneously. The GPWS (no EGPWS then) certainly shouted at that point.
My (probably out of date) copy of the A320 FCOM for GPWS suggests that mode 1, mode 4 and mode 5 might not have been triggered.

Mode 1 Excessive descent rate : they were on a 3į approach profile, which might not trigger mode 1?

Mode 4 Unsafe terrain clearance when not in landing configuration : they were in landing configuration.

Mode 5 Descent below glideslope : The approach they were following had no glideslope, so this would not have triggered.

EGPWS has Modes 4A, 4B, and 4C, which should trigger with ground proximity, but only if the aircraft is not in landing configuration?

So it would seem that (E)GPWS cannot help a crew on an NPA with a mis-set QNH? Am I reading that right?

@FlightDetent: good post #95. Perhaps all NPA approach plates should publish Radio Altimeter heights vs distance to the threshold, (having surveyed the actual terrain), instead of altitudes, which of course are based on the QNH set in the cockpit.
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Last edited by Uplinker; 14th Jul 2022 at 10:45.
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Old 14th Jul 2022, 10:49
  #106 (permalink)  
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Originally Posted by Uplinker View Post
Thanks for the info
Not wishing to start an argument, but the ITM controller did mix it up. According to the BEA report, ATC got it wrong twice, by saying one zero one one in English when speaking with two English speaking aircraft, but got the QNH correct when speaking in French to a French speaking crew.
Sorry was not clear when I said no controller will mix up the two, I was taking about the 2 different phaseologies,( digit per digit in English and full numbers in French) Indeed the controller here mixed up 1011 with 1001 but a possible explanation ( speculating I do not have more info on this case) is that it could be due to what we call brain automatism or brain cloud. A well known phenomena, which we find often in call sign confusions . When faced with stress caused by a perticular fact or event , the brain reverts to a similar event in the past, you end up automatically saying things that are not what you meant. Good examples of this is pilots facing an emerncy reverting to an old call sign or , the call sign they used in the simulator when execrcising that emergency. ( e. the Happag Lloyd A310 accident in Vienna , or more recently the BA777 accident in Heathrow ) In all cases the individual is not aware, even afterwards that he/she did this. People are extremely surprised when they listen to their transmissions on the tape.. The only mitigation for this is the 4 eyes/ears principle. The person sitting besides is supposed to pick up these discrepancies .
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Old 14th Jul 2022, 11:16
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Originally Posted by FlightDetent View Post
Perhaps. Airbus put a comparator between THS setting and the MCDU TO Page trim prompt. Unnecessary for the SA fleet where it never was a standard fit.
Comparing FCU Baro selection to MCDU APPR page will be a piece of cake.
Threshold alert 2/3 of MOC = 3 hPa.​​
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I also think it would be a piece of cake. But nevertheless it is not implemented. A pity.

The three things put into some performance page should be automatically crosschecked: trim, flaps, QNH.

It is especially a pity as non-ILS approaches are becoming again more and more popular with the PBN thing.

How does the hardware look on Boeings? Do they have similar prompts in the FMGC that could be used to compare it with FCU settings?
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Old 14th Jul 2022, 13:00
  #108 (permalink)  
 
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Quote:
Originally Posted by AndiKunzi View Post
They used LNAV/VNAV minima and obviously had no GP?
Originally Posted by Jonnyknoxville View Post
😂😂I hope your not in charge of an airliner
Thank you for your educated comment. I fly a Citation Mustang, am single pilot rated and am an IRI and CRI.

An LNAV/VNAV approach using SBAS for GP (not Baro VNAV) will provide you a correct GP regardless of (wrong) altimeter setting.
I assume an A320 today is using SBAS for the GP. If not, you might have corrected me in a less offensive way.
Most modern business jets do use SBAS for GP and for an LPV you don‘t even have a choice.
Baro VNAV is only a back-up for those aircraft and not available at all in some business jets. I consider Baro VNAV to be outdated and much less safe. I assumed that an A320 nowadays is capable of LPV (and, thus, RNP SBAS VNAV).

So for me, if they briefed and flew an LNAV/VNAV (using the SBAS VNAV GP), they would not have arrived at ground level 1 NM before the threshold - unless old avionics using Baro VNAV.
If they flew an LNAV, they should have applied LNAV minima (+ 130 ft here).
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Old 14th Jul 2022, 13:27
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German/English

Had two occurrences in the frankfurt hold when lufthansa changed into German and was taken out from above us and given priority..
The second was much more scary as the eyebrow window was filled with the belly of a lufty 747..declared it was a 1000ft..bollix
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Old 14th Jul 2022, 13:45
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Originally Posted by blind pew View Post
Had two occurrences in the frankfurt hold when lufthansa changed into German and was taken out from above us and given priority..
The second was much more scary as the eyebrow window was filled with the belly of a lufty 747..declared it was a 1000ft..bollix
Maybe ATC should start talking cockney rhyming slang at Heathrow. "Ok me old china airways, up the apples and pears to spirit tom mix" When there is a collision we can come on here and announce there is a large number of ex pearly kings and queens who are now working as pilots and ATC and when they get stressed they revert to talking Jason Pollocks. EASA and ICAO will be falling overthemsleves to allow it on an 'inclusion' ticket.
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Old 14th Jul 2022, 14:11
  #111 (permalink)  

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Originally Posted by AndiKunzi View Post
I consider Baro VNAV to be outdated and much less safe.
That is exactly it. Narrowbody Airbus standard equipment is APV Baro-VNAV flown to LNAV+VNAV mimima. MSN 112xx straight out of factory.

People get aggravated about things they care passionately about, you came out of this as the better gentleman.

Despite the other poster being, after all, actually right. With a wink and a bitter tear. We want your kit.
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Old 14th Jul 2022, 14:35
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Thank you for your educated comment. I fly a Citation Mustang, am single pilot rated and am an IRI and CRI.

An LNAV/VNAV approach using SBAS for GP (not Baro VNAV) will provide you a correct GP regardless of (wrong) altimeter setting.
I assume an A320 today is using SBAS for the GP. If not, you might have corrected me in a less offensive way.
Most modern business jets do use SBAS for GP and for an LPV you donĎt even have a choice.
Baro VNAV is only a back-up for those aircraft and not available at all in some business jets. I consider Baro VNAV to be outdated and much less safe. I assumed that an A320 nowadays is capable of LPV (and, thus, RNP SBAS VNAV).

So for me, if they briefed and flew an LNAV/VNAV (using the SBAS VNAV GP), they would not have arrived at ground level 1 NM before the threshold - unless old avionics using Baro VNAV.
If they flew an LNAV, they should have applied LNAV minima (+ 130 ft here).
Different terminologies across continents and manufacturers...
I flew LPV approaches in the US 13 years ago. In Europe I have yet to fly an LPV approach.

In the lingo I am used to, an LNAV/VNAV minima is based on baro-VNAV. An LPV minima is based on the GPS receiver being SBAS enabled and your glide path is GPS derived. Not sure if there is a single A320 out there that can do that.... I think that's where you were shot down!
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Old 14th Jul 2022, 15:29
  #113 (permalink)  

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Did someone say FMS cold temperature compensation?

#notinstalled
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Old 14th Jul 2022, 15:34
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Originally Posted by Klauss View Post
Just wondering: at 6 ft from the ground.....did anyone look out of the window ??
That’s a good argument for the mplementation of monitored approaches in limited visibility.

plus, does nobody do basic height/distance checks as part of their approaches anymore? It’s considered an SOP at many airlines.

Last edited by Oldaircrew; 14th Jul 2022 at 15:41. Reason: adding commentary
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Old 14th Jul 2022, 15:58
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Originally Posted by FlightDetent View Post
Comparing FCU Baro selection to MCDU APPR page will be a piece of cake.​​​​​​
What system or LRU would perform the comparison and does it currently receive both parameters to be compared?
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Old 14th Jul 2022, 16:44
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Originally Posted by Oldaircrew View Post
plus, does nobody do basic height/distance checks as part of their approaches anymore? Itís considered an SOP at many airlines.
Those checks won't help you one bit, if you are relying on your barometric altimeter for vertical guidance. Your checks can be spot on, yet you will still end up in a smoking hole, if your altimeter isn't set correctly.
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Old 14th Jul 2022, 17:32
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Originally Posted by Oldaircrew View Post
Thatís a good argument for the mplementation of monitored approaches in limited visibility.

plus, does nobody do basic height/distance checks as part of their approaches anymore? Itís considered an SOP at many airlines.
It doesn't capture the error here as mentioned above.

Think if the platform altitude for the FAF was 3000' AGL at 10 miles. With a barometer set 10hPa high, your altimeter will show 3000' but you'd actually be at an altitude of 2700'. This error is maintained the whole way down the approach path - you are reading what appear to be correct altitude readings v the distance, but you are actually 300' lower at each mile. This culminates in you being at 0' at 1nm from the threshold, with your altimeter reading 300'.
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Old 14th Jul 2022, 18:24
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How many training departments actively teach that for Baro-VNAV 3D approach (this case), the altitude distance checks are futile
A big take away point for me, and this incident will be featuring in the next amendment to our ATPL notes together with this warning. It never ocurred to me.
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Old 14th Jul 2022, 18:32
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That's a very good point RE training departments but I do think we should be careful not to throw the baby out with the bathwater here. The height v distance checks are not futile when the correct supporting information is used. There should be an emphasis on the importance of not taking QNH figures for granted, especially when they differ from ATIS values.
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Old 14th Jul 2022, 19:22
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Tech solution: ATC data base automatically transmits current local QNH to aircraft ADCs via data link - no humans involved! (Except to check for disparity between received QNH and expected QNH.)
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