BAW492 diversion at Gibraltar
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It certainly was 'lively' in Gib that day. Sitting near the threshold myself the winds were (mostly) down the runway but, as we know, the Rock is a unique environment with frequent windshear - hence Capts landings only. There were also several waterspouts reported in the area around the time of the approach. I've loved operating in Gib and the decision to immediately divert (for whatever reason) was a smart one!
Thanks Chillpill for that explanation. Being very much pre-FBW and even then 10 yrs before, I couldn't get the hang of the A320 sim except in what I think is direct rule ie fly it like any aircraft I had previously flown. Not being a 12-year-old any more I couldn't make head nor tail of the pre-flight programming but you have shown me where I was going wrong. I'm going to treat myself to another hour or two, then I'll be ready to take over when the experts fall ill on our next trip to the Canaries 
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There are 2 'types' of Airbus pilots.
1. Those taught directly by Airbus.
2: Those taught 'in-house' by the Airline.
An old and wise first gen Airbus A320 Captain once told me you can always tell the difference between 1 and 2 as above by watching A320's on approach on a gusty cross-wind day...
The Airbus taught pilots ... the A320 rolls slowly (max 33 degrees AOB), stops, regains wings level slowly but does not overshoot wings level.
The 'in-house' pilots... the A320 rolls slowly (max 33 degrees AOB), stops, then rolls the other way invariably over-shooting wings level... then back the other way. A PIO.
Te difference is the Airbus taught pilots are taught to truly understand the theory AND practice of the 'zero roll rate/1G flight' regime in 'Normal Law'... and that the aircraft will strive to maintain that without any pilot input. By contrast, many 'in-house' pilots, (no blame, just a systemic fact), often with a 'classic' Boeing background, chase the roll deviation with a 'traditional opposite' control input, even though the aircraft is already doing that. But they are in fact 'lagging' that aircraft input... and by the time they sense the side-stick against the roll 'stop', the aircraft is already going the other way... so they chase that... to a developing PIO.
The solution... simply 'let go' of the side stick and let the aircraft flight control software system look after things. It's hard to do (learn (un-learn) pre FBW software), but when you do, flying the A320 series is a hell of a lot simpler... and less likely to result in vids like this.
I am however not saying there was no a FC degrade going on here as a result of a systems failure, but this certainly looks like classic PIO to me.
1. Those taught directly by Airbus.
2: Those taught 'in-house' by the Airline.
An old and wise first gen Airbus A320 Captain once told me you can always tell the difference between 1 and 2 as above by watching A320's on approach on a gusty cross-wind day...
The Airbus taught pilots ... the A320 rolls slowly (max 33 degrees AOB), stops, regains wings level slowly but does not overshoot wings level.
The 'in-house' pilots... the A320 rolls slowly (max 33 degrees AOB), stops, then rolls the other way invariably over-shooting wings level... then back the other way. A PIO.
Te difference is the Airbus taught pilots are taught to truly understand the theory AND practice of the 'zero roll rate/1G flight' regime in 'Normal Law'... and that the aircraft will strive to maintain that without any pilot input. By contrast, many 'in-house' pilots, (no blame, just a systemic fact), often with a 'classic' Boeing background, chase the roll deviation with a 'traditional opposite' control input, even though the aircraft is already doing that. But they are in fact 'lagging' that aircraft input... and by the time they sense the side-stick against the roll 'stop', the aircraft is already going the other way... so they chase that... to a developing PIO.
The solution... simply 'let go' of the side stick and let the aircraft flight control software system look after things. It's hard to do (learn (un-learn) pre FBW software), but when you do, flying the A320 series is a hell of a lot simpler... and less likely to result in vids like this.
I am however not saying there was no a FC degrade going on here as a result of a systems failure, but this certainly looks like classic PIO to me.
As about 3 of us are trying to say - this is a fault, supposedly fixed.
Some links from "Just the fax maam":
Honk Kong Dragon Airlines, 1994, mad roll oscillations:
https://aviation-safety.net/wikibase/wiki.php?id=140547
http://ebook.lib.hku.hk/HKG/B35840213.pdf (full report)
Air Canada, 2002:
http://www.bst-tsb.gc.ca/eng/rapport...6/a02o0406.pdf
Some links from "Just the fax maam":
Honk Kong Dragon Airlines, 1994, mad roll oscillations:
https://aviation-safety.net/wikibase/wiki.php?id=140547
http://ebook.lib.hku.hk/HKG/B35840213.pdf (full report)
Air Canada, 2002:
http://www.bst-tsb.gc.ca/eng/rapport...6/a02o0406.pdf
That's quite a point. If the W/S G/A was flown with the autopilot, and the aircraft was behaving like that, then the crew are in the unenviable position of being in a FBW aircraft that really is not doing what it should do. From the armchair, it appears that returning it to a known working configuration (ie not config full) would have caused some relief in there - and personally I may have elected to land flap 3 at the alternate....
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[QUOTE=HundredPercentPlease;10400989- and personally I may have elected to land flap 3 at the alternate....[/QUOTE]
Looking at the weather, I may elected to land at GIB with Conf 3 in the first place!
Looking at the weather, I may elected to land at GIB with Conf 3 in the first place!
Making an approach to 09 at GIB with a strong wind out of the east is very demanding. With the draconian airspace restrictions imposed by the Spanish (purely for political reasons) aircraft are forced to fly northbound on a right base for 09 where they are directly downwind of the rock at a height where they are in in extremely turbulent air. Gibraltar requires great respect from the pilot, particularly with regard to wind limitations. In this case the surface wind was quite within limits but the turbulence generated by the stronger 1000' wind on base leg can be so strong that it feels like your teeth are going to fall out just as you fly abeam the dockyard. Passengers.... Welcome to the world of the over-paid and under-worked pilot. On the days where I earn my money - you really would not like to be sat behind me!
As you can see from the graphic, the turbulence that lies just west of the rock in strong easterly winds could be completely avoided by the Spanish permitting straight-in approaches over Algeciras on days like this.
Politics standing in the way of Flight Safety... Who would have thought it!
As you can see from the graphic, the turbulence that lies just west of the rock in strong easterly winds could be completely avoided by the Spanish permitting straight-in approaches over Algeciras on days like this.
Politics standing in the way of Flight Safety... Who would have thought it!
Needless to say, the ADS-B data is too coarse to be able to see any short-period oscillations. One thing it does show is that, understandably, keeping clear of Spanish airspace wasn't a high priority under the circumstances.
I deliberately haven't shown a vertical profile because, as referred to in a previous post, the data does contain a "0 ft" point (not on the runway, as was suggested, but at about 1.6 nm short of the threshold). That, of course, doesn't mean it's bad data, simply that it's showing pressure altitude (i.e. FL0) relative to 1013.2 hPa and not height AMSL, which makes plotting in 3D somewhat academic (though it does indicate approximately where the GA was initiated).
All military traffic flown into GIB have to remain outside spanish airspace. But the arrival procedures for civilian aircraft are designed/ built/ flown into a small portion of Spanish airspace, so that flight track is perfectly typical for civilian arrivals.
Thanks for that - in fact I've only just noticed the date (1967!) on that airspace graphic. Glad to hear that the Spanish are a bit more flexible, at least for civil aircraft.
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All I can say is that anyone with an underwear cleaning business in Malaga made a killing that day. When I first saw the ground video I thought that has to be PIO. At least to an extent. No way it should rocking and rolling that long from whatever wind condition it was they encountered. My feeling is that the reaction was a bigger problem than the cause.
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NOT PIO
Why are posters persisting in blaming the flight crew when evidence of a known and documented FCC fault, which causes PRECISELY this roll oscillation, has been presented above?
Have we reached the stage where Airbus FBW logic is beyond fault or criticism?
Have we reached the stage where Airbus FBW logic is beyond fault or criticism?
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From the videos that has been linked above it appears that the airplane was well above the ground when the roll oscillations documented occurred. The speed altitude trace shows decent to a very low altitude prior to executing the go-around. I am left with a couple of questions that others may be able to help with:
1. Were there roll oscillations during the final approach that led to the go-around? Did any passengers (particularly those who submitted interior videos) comment on the altitude when worrisome roll oscillations occurred?
2. Did the go-around involve touching down or was it executed without wheel to runway contact? Were there any objectionable pitch or roll motions associated with the flight just prior to initiation of the go-around or during the go-around itself?
3. Has the airline made any statement about this event with regard to either the equipment or the crew?
As is often the case, more questions than answers!
1. Were there roll oscillations during the final approach that led to the go-around? Did any passengers (particularly those who submitted interior videos) comment on the altitude when worrisome roll oscillations occurred?
2. Did the go-around involve touching down or was it executed without wheel to runway contact? Were there any objectionable pitch or roll motions associated with the flight just prior to initiation of the go-around or during the go-around itself?
3. Has the airline made any statement about this event with regard to either the equipment or the crew?
As is often the case, more questions than answers!
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From the videos that has been linked above it appears that the airplane was well above the ground when the roll oscillations documented occurred. The speed altitude trace shows decent to a very low altitude prior to executing the go-around. I am left with a couple of questions that others may be able to help with:
1. Were there roll oscillations during the final approach that led to the go-around? Did any passengers (particularly those who submitted interior videos) comment on the altitude when worrisome roll oscillations occurred?
2. Did the go-around involve touching down or was it executed without wheel to runway contact? Were there any objectionable pitch or roll motions associated with the flight just prior to initiation of the go-around or during the go-around itself?
1. Were there roll oscillations during the final approach that led to the go-around? Did any passengers (particularly those who submitted interior videos) comment on the altitude when worrisome roll oscillations occurred?
2. Did the go-around involve touching down or was it executed without wheel to runway contact? Were there any objectionable pitch or roll motions associated with the flight just prior to initiation of the go-around or during the go-around itself?
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I'm also convinced it's PIO..
Go on https://www.airbus-win.com/ TRAINING-- Training to Basic Flying Skills. It's a video and at 29m15s, You will see a good example of real case of PIO over stick free aircraft after an upset from a vortex.
And at 36m15s, The Airbus test pilot strongly recommends to fly raw rata during line operations. Does BA comply with those recommendations by Airbus?
Go on https://www.airbus-win.com/ TRAINING-- Training to Basic Flying Skills. It's a video and at 29m15s, You will see a good example of real case of PIO over stick free aircraft after an upset from a vortex.
And at 36m15s, The Airbus test pilot strongly recommends to fly raw rata during line operations. Does BA comply with those recommendations by Airbus?
Last edited by pineteam; 27th Feb 2019 at 03:32. Reason: Typo
As about 3 of us are trying to say - this is a fault, supposedly fixed.
Some links from "Just the fax maam":
Honk Kong Dragon Airlines, 1994, mad roll oscillations:
https://aviation-safety.net/wikibase/wiki.php?id=140547
http://ebook.lib.hku.hk/HKG/B35840213.pdf (full report)
Air Canada, 2002:
http://www.bst-tsb.gc.ca/eng/rapport...6/a02o0406.pdf
Some links from "Just the fax maam":
Honk Kong Dragon Airlines, 1994, mad roll oscillations:
https://aviation-safety.net/wikibase/wiki.php?id=140547
http://ebook.lib.hku.hk/HKG/B35840213.pdf (full report)
Air Canada, 2002:
http://www.bst-tsb.gc.ca/eng/rapport...6/a02o0406.pdf
What happens in a PIO if you simply let go of the sidestick during the roll?
Will the aircraft stabilise at a certain level of roll - or does it all depend on what law you're in?
Never understood Airbus's...
Will the aircraft stabilise at a certain level of roll - or does it all depend on what law you're in?
Never understood Airbus's...