Edfromlondon
Posts: 5
Joined: Mon Feb 25, 2019 8:28 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 12:00 am

SuseJ772 wrote:
I have to admit I almost didn’t click it as I assumed it was click bait crap from a 30 degree BHX flight doing a go around again.

This was way different. Never seen that for that long of a duration. Sure a wing dip, over correction, wing level from time to time. But this had quite a few of them for an extended period of time. I probably would have gotten a bit worried on this flight after the first three or so.


Yes that’s what I was trying to say
 
sonicruiser
Posts: 405
Joined: Sun Nov 04, 2018 4:18 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 4:15 am

Not gonna lie, I was shocked when I saw the video for the first time. I have no problems with turbulence but this would definitely have concerned me.
 
User avatar
Airbus747
Posts: 144
Joined: Thu Mar 13, 2014 12:18 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 4:23 am

I wonder what may have caused this, and how often it happens (has it ever happened before?).

Also, was the plane going out of control? And wouldn't this be rated an incident?
 
GalaxyFlyer
Posts: 2949
Joined: Fri Jan 01, 2016 4:44 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 4:48 am

Pretty common at GIB. The Rock causes lots of turbulence.

GF
 
jpetekyxmd80
Posts: 4289
Joined: Fri Aug 01, 2003 3:16 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 5:22 am

I also think it was a stall. Having the gear down way too long after the go around didn't help matters. Things didn't start to get unusual until they pitched up for the go around. You can tell the ailerons are not operating very effectively during this period. The aircraft seems basically out of control.
The Best Care in the Air, 1984-2009
 
User avatar
lebda
Posts: 128
Joined: Tue Mar 04, 2014 10:46 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 5:32 am

Drinking and flying, not even once.
Denver Tower: Gulfstream 592, you’re cleared to 9,000 feet. For a vector to Hector, contact the sector director.
 
nm2582
Posts: 174
Joined: Tue Jun 26, 2007 2:15 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 5:38 am

I'm surprised AA587 hasn't been referenced; the video kind of reminds me of the NTSB re-enactment of that flight based on the FDR data.
 
carlokiii
Posts: 124
Joined: Sun Oct 04, 2015 11:03 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 6:47 am

ktof wrote:
Another onboard view here, the oscillating lasted around 20 - 30 seconds with a steep climb.

Although the steep climb may be accentuated in the video by the camera.

https://youtu.be/78ZDaQ0UYZg

I wish I was exaggerating but watching this video did make me a bit dizzy.
 
MON
Posts: 98
Joined: Tue Jul 24, 2012 8:54 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 7:39 am

115Kts ground speed on final approach onto Gibraltar’s fairly short runway in a narrow body Airbus is not unusual - I did it for many years.

Gibraltar itself has significant crosswind restrictions, in fact the A320 has a max crosswind limit of 39Kts but at Gibraltar that can be limited to as low as 15Kts (see special Jeppesen “Wind Effects” plate). To my humble eye, some of it looks like induced pilot oscillation that is quite easy to do by over imputing and thus overcorrecting the fbw system.
 
speedbird217
Posts: 372
Joined: Fri Feb 03, 2012 2:27 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 7:50 am

jpetekyxmd80 wrote:
I also think it was a stall. Having the gear down way too long after the go around didn't help matters.


First of all it’s pretty much impossible to stall an Airbus in normal law, so that’s unlikely.

Second, it’s SOP to leave the gear down after a go around in gusty conditions as you don’t want any config changes during that phase. So retracting the gear at that stage may have made things even worse and they did the right thing leaving it down.

That first gust hits quite violently, I wonder if it caused some confusion to the Airbus logic and exposed a flaw in the flight law. Thinking along the lines of “FBWIO”. Will be interesting to see what comes out of this as it’s certainly a strange one.
 
oldannyboy
Posts: 2264
Joined: Wed Jun 15, 2016 8:28 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 9:26 am

Quite scary me thinks even for a seasoned flyer, if you are onboard....
And to be bluntly honest, I'm not really convinced I am seeing great airmanship skills there....
 
BA777FO
Posts: 265
Joined: Sun Apr 22, 2018 2:58 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 11:49 am

A lot of uninformed nonsense here! It was a gusty day at Gibralter, with the wind blowing around the rock the go-around was almost certainly caused by a windshear warning. From a more informed source on Airbus behaviour:

After looking at the longer passenger footage, it looks to me like it’s the old ‘roll inconsistency in config full’ with “wind peturbation” rearing its ugly head again.

I say this because the flaps appear set in the FULL position at the start of the footage. Immediately the roll oscillations stop, you can see that the flaps are in a lower config. Shortly after, the chime of gear retraction can be heard.

So I’m guessing that they got a windshear (coincident with the first jolt in the video), then commenced the windshear escape, all the while maintaining the current config. as required, hence no change in flap and gear remaining down.

Once out of the shear and on the “go around, flaps” actions, the FCCs resumed their normal behavior.


Seems as though this is not an uncommon occurence with a windshear warning in a flap full config.
 
Breathe
Posts: 475
Joined: Sat Mar 18, 2017 8:06 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 11:52 am

Hopefully nobody was sat on the toilet when this happened...
 
Chaostheory
Posts: 1131
Joined: Wed Mar 06, 2013 2:09 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 12:36 pm

On the face of it, I would say this was PIO.

However I recall when I was living in Hong Kong pre takeover, there was an incident involving an A320 at the old airport. The aircraft had severe lateral control issues following a map carried out near the checkerboard.

The memory is hazy though and I can't find any reference to it online. I will persevere.
 
emiratesdriver
Posts: 257
Joined: Tue Dec 27, 2016 9:04 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 12:47 pm

Low level windshear/rotor encounter followed by a clear case of PIO.
Easy to get into close to the ground in the minibus...but also counter intuiative to resolve..thanks to the genuises in TLS not thinking through the FBW law process close to the ground.
 
CX Flyboy
Posts: 6118
Joined: Sun Dec 26, 1999 6:10 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 12:57 pm

Chaostheory wrote:
On the face of it, I would say this was PIO.

However I recall when I was living in Hong Kong pre takeover, there was an incident involving an A320 at the old airport. The aircraft had severe lateral control issues following a map carried out near the checkerboard.

The memory is hazy though and I can't find any reference to it online. I will persevere.


https://aviation-safety.net/wikibase/wiki.php?id=140547

This is what you are thinking about.
 
Boeingphan
Posts: 200
Joined: Fri Apr 01, 2016 10:29 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 1:27 pm

Listening to the video inside the cabin why did it take so long for the pilots to hit touch and go power? It seems there is a good 15 seconds where the engines weren't spooled up. Seems like a slight oversight to me.
 
IADFCO
Posts: 91
Joined: Sun May 22, 2016 4:20 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 2:05 pm

Following up on the PIO comments...

Strictly speaking, to have PIOs you must have a pilot in the loop. So, letting go of the controls by definition stops the PIOs because there is no longer a "P". Then it's up to the flight control system to keep you wings level.

Do airlines train pilots to realize that they are triggering PIOs? And if so, is the recommended corrective action to let go of the controls?
 
glideslope900
Posts: 104
Joined: Sun Feb 24, 2019 5:27 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 2:14 pm

IADFCO wrote:
Following up on the PIO comments...

Strictly speaking, to have PIOs you must have a pilot in the loop. So, letting go of the controls by definition stops the PIOs because there is no longer a "P". Then it's up to the flight control system to keep you wings level.

Do airlines train pilots to realize that they are triggering PIOs? And if so, is the recommended corrective action to let go of the controls?


No, letting go of the controls is not trained...

The pilots likely botched the go around. This is not the “airline” triggering PIO, it is the pilots.
 
richierich
Posts: 3560
Joined: Sat Nov 04, 2000 5:49 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 2:33 pm

OK, I've read all of the posts so far and they range from 'it was nothing at all' to 'this was almost a catastrophe.'

I don't want to get all Scary Mary on everybody, but how serious was this? Nobody seems too freaked out on the in-cabin videos, which is good, but even if one was expecting turbulence, this seems a bit extreme. It may have been caused by turbulence initially but this is simply the plane is just flailing back and forth. Some of the dips appear to be very steep. So here goes: how close was this to becoming an uncontrollable situation? What was likely going on in the flight deck during these wild swings?

I fly frequently, maybe more than the average person but less than many on a.net. I have never seen anything even approach this kind of flight. I can tell you I would definitely have had a sense of fear creeping through me after two or three of those dips and turns.
None shall pass!!!!
 
Edfromlondon
Posts: 5
Joined: Mon Feb 25, 2019 8:28 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 2:49 pm

richierich wrote:
OK, I've read all of the posts so far and they range from 'it was nothing at all' to 'this was almost a catastrophe.'

I don't want to get all Scary Mary on everybody, but how serious was this? Nobody seems too freaked out on the in-cabin videos, which is good, but even if one was expecting turbulence, this seems a bit extreme. It may have been caused by turbulence initially but this is simply the plane is just flailing back and forth. Some of the dips appear to be very steep. So here goes: how close was this to becoming an uncontrollable situation? What was likely going on in the flight deck during these wild swings?

I fly frequently, maybe more than the average person but less than many on a.net. I have never seen anything even approach this kind of flight. I can tell you I would definitely have had a sense of fear creeping through me after two or three of those dips and turns.


Yep - I was on the flight and that is how I feel.
 
mm320cap
Posts: 293
Joined: Wed Jul 14, 2004 12:35 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 3:53 pm

jpetekyxmd80 wrote:
I also think it was a stall. Having the gear down way too long after the go around didn't help matters. Things didn't start to get unusual until they pitched up for the go around. You can tell the ailerons are not operating very effectively during this period. The aircraft seems basically out of control.


It wasn’t a stall. The A320 won’t stall in normal law. It was a PIO exacerbated by the fact that the control laws limit the speed at which the roll rate can be corrected - particularly at landing speeds. The pilot puts in a large input to correct an initial upset caused by turbulence. The result is that it takes longer than expected to roll the airplane back the other way. This causes the pilot to hold the correction in longer than normal and the Airplane starts to roll the other way. The pilot puts in opposite airleron to counteract, but that roll rate is also limited by the computer so it goes past wings level to the other side. Rinse. Repeat. I’ve seen it countless times, but never to this level.
 
IADFCO
Posts: 91
Joined: Sun May 22, 2016 4:20 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 6:27 pm

Following up on mm320cap post: large pilot input to correct = high roll attitude feedback gain = lower (or negative) closed loop stability margin = textbook PIO. But what would have happened if the pilot had not tried to correct the roll attitude perturbation? Would the flight control system have flown the aircraft back to wings level, even if at an intentionally limited roll rate?
 
airbuster
Posts: 363
Joined: Fri Mar 30, 2007 12:43 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 8:08 pm

Yes deffinetly Airbus PIO going on there. Just let go of the stick and it’ll sort itself out.
FLY FOKKER JET LINE!
 
User avatar
Channex757
Posts: 2342
Joined: Sat Jun 18, 2016 7:07 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 8:47 pm

Gibraltar is tracherous and requires special training. Monarch in particular were very hot on that.

The problem isn't PIO my little armchair CEOs. It is a thing called a rotor. Spinning masses of air like a horizontal tornado that come rolling off the Rock in certain circumstances. There were quite a few aircraft losses in the postwar days of unpressurised airliners until this phenomenon was fully understood.

The BA pilot recovered beautifully here after a spinning mass of air with the strength of a bomb hit his plane. The immediate necessity is to get over the top of it and away to an alternate.
 
chicawgo
Posts: 364
Joined: Tue Nov 29, 2011 5:09 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 9:02 pm

Channex757 wrote:
Gibraltar is tracherous and requires special training. Monarch in particular were very hot on that.

The problem isn't PIO my little armchair CEOs. It is a thing called a rotor. Spinning masses of air like a horizontal tornado that come rolling off the Rock in certain circumstances. There were quite a few aircraft losses in the postwar days of unpressurised airliners until this phenomenon was fully understood.

The BA pilot recovered beautifully here after a spinning mass of air with the strength of a bomb hit his plane. The immediate necessity is to get over the top of it and away to an alternate.


How kind of you, as a true CEO, to put all of us armchair CEOs in our place!

There's NO way it was a rotor the entire time. Quite possibly that started it. But constant rolling back and forth for that long of a time? No. The initial rotor turned into a different issue. The pax never all gasp together after the initial jolt. There were no more jolts. Just rolling.
 
User avatar
Channex757
Posts: 2342
Joined: Sat Jun 18, 2016 7:07 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 9:09 pm

I was being facetious and I never got high enough to be a CEO, but I did work for an airline that serviced GIB.

It is incredibly treacherous and the shape of the rock can create windshear events like you would not believe. That runway was built from tunnels mined in the Rock itself, and the spoil it created. Nobody in their right mind today would put a runway there. But back to this. The oscillation was NOT pilot induced. It was the initial contact of the rotor and then riding the 'wave'. If anything the pilot would use his extra training and let the aircraft stabilise itself as he initiates a steep climb. That's why the oscillation stops suddenly.
 
airbuster
Posts: 363
Joined: Fri Mar 30, 2007 12:43 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Tue Feb 26, 2019 9:16 pm

Channex757 wrote:
I was being facetious and I never got high enough to be a CEO, but I did work for an airline that serviced GIB.

It is incredibly treacherous and the shape of the rock can create windshear events like you would not believe. That runway was built from tunnels mined in the Rock itself, and the spoil it created. Nobody in their right mind today would put a runway there. But back to this. The oscillation was NOT pilot induced. It was the initial contact of the rotor and then riding the 'wave'. If anything the pilot would use his extra training and let the aircraft stabilise itself as he initiates a steep climb. That's why the oscillation stops suddenly.


Have you flown a FBW Airbus? It might have been started by a rotor but to me (A330 pilot) it resembles classic Airbus PIO. We’ve all overreacted on the stick and felt PIO, only not to his extent luckily.
FLY FOKKER JET LINE!
 
joeycapps
Posts: 103
Joined: Tue Jul 15, 2008 5:24 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 7:17 am

So, my UK friends... Just out curiosity. Late at night, maybe when you're watching Jeremy Kyle or something like that, do you guys have attorneys running commercials?

Because I know what the headlines would read here in the US if that would've happened... And besides the obvious "State of the art Boeing A320X Nearly Crashes, 260 On Board" headline, there'd for sure be a "Lawsuits filed against Airbus and ___ Airlines For Near-Fatal, Almost Crashed Incident".

Insane. Glad everyone - including our friend on here who was on board - made it out okay.
 
BA777FO
Posts: 265
Joined: Sun Apr 22, 2018 2:58 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 8:42 am

PIO...with the autopilot engaged?

Interesting theory a lot of people have.
 
Calpe
Posts: 38
Joined: Sat Feb 04, 2012 11:59 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 8:51 am

BA777FO wrote:
PIO...with the autopilot engaged?

Interesting theory a lot of people have.


Now I am definitely no expert and most certainly not a pilot! However maybe some of the pilots on here who have flown into GIB in the past could enlighten us but I always thought that the approach to rwy 09 at GIB, as in the video, was a visual approach with no ILS due to the curved approach path so does this not mean that it would have to be manually flown or is there someway of getting the autopilot to fly it still?

If it was being hand flown then does this mean that PIO could well be factor as the autopilot wasn't engaged?
 
AAMDanny
Posts: 276
Joined: Wed Apr 30, 2008 4:06 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 9:11 am

I was thinking more along the lines excessive flight control inputs from one or both of the pilots during the panic?
 
User avatar
Channex757
Posts: 2342
Joined: Sat Jun 18, 2016 7:07 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 9:27 am

airbuster wrote:
Have you flown a FBW Airbus? It might have been started by a rotor but to me (A330 pilot) it resembles classic Airbus PIO. We’ve all overreacted on the stick and felt PIO, only not to his extent luckily.

I would never have passed the medicals. Worked on the ops side.

What I am saying is that Bus pilots are given specific training to operate into and out of GIB. I can't accept that that BA pilot suddenly forgot all his training and experience despite being on approach to that very airport and therefore aware of possible conditions. To me it looks like he followed company procedure which is get fast and get above it as well as trusting his aircraft to stabilise.
 
TTailedTiger
Posts: 1038
Joined: Sun Aug 26, 2018 5:19 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 9:57 am

mm320cap wrote:
jpetekyxmd80 wrote:
I also think it was a stall. Having the gear down way too long after the go around didn't help matters. Things didn't start to get unusual until they pitched up for the go around. You can tell the ailerons are not operating very effectively during this period. The aircraft seems basically out of control.


It wasn’t a stall. The A320 won’t stall in normal law. It was a PIO exacerbated by the fact that the control laws limit the speed at which the roll rate can be corrected - particularly at landing speeds. The pilot puts in a large input to correct an initial upset caused by turbulence. The result is that it takes longer than expected to roll the airplane back the other way. This causes the pilot to hold the correction in longer than normal and the Airplane starts to roll the other way. The pilot puts in opposite airleron to counteract, but that roll rate is also limited by the computer so it goes past wings level to the other side. Rinse. Repeat. I’ve seen it countless times, but never to this level.


Isn't that a little disingenuous? The Airbus will stall, it'll just go into alternate law first. On a forum for Airbus pilots one one of them mentioned this:

"Or you could get into a heavy windshear (say 100kts within a second or so), so that the aircrafts authority to pitch down wouldn't be enough, but split seconds before stall you would lose valid speed information and crash in alternate law, too."

Any airplane will eventually bite back. You never know which system will not the fan at a critical moment on flight.
 
User avatar
ro1960
Posts: 1102
Joined: Wed Jan 04, 2006 8:19 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 10:23 am

zeke wrote:
Sure it’s not a photoshop job ?


Photoshop is not a video editing/effect program. Still images only.
You may like my airport photos:
https://www.flickr.com/photos/aeroports
 
User avatar
ro1960
Posts: 1102
Joined: Wed Jan 04, 2006 8:19 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 10:25 am

ktof wrote:


Would be more informative if shot in landscape mode. On the second video you barely see the ground, just the wing.
You may like my airport photos:
https://www.flickr.com/photos/aeroports
 
User avatar
ro1960
Posts: 1102
Joined: Wed Jan 04, 2006 8:19 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 10:35 am

george77300 wrote:

This video is best to see height: https://youtu.be/78ZDaQ0UYZg


The full video shows the approach before the incident:

https://www.youtube.com/watch?time_continue=313&v=tjv3xBB-HmY
You may like my airport photos:
https://www.flickr.com/photos/aeroports
 
Flow2706
Posts: 178
Joined: Sat Jan 28, 2017 7:20 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 12:05 pm

Channex757 wrote:
airbuster wrote:
Have you flown a FBW Airbus? It might have been started by a rotor but to me (A330 pilot) it resembles classic Airbus PIO. We’ve all overreacted on the stick and felt PIO, only not to his extent luckily.

I would never have passed the medicals. Worked on the ops side.

What I am saying is that Bus pilots are given specific training to operate into and out of GIB. I can't accept that that BA pilot suddenly forgot all his training and experience despite being on approach to that very airport and therefore aware of possible conditions. To me it looks like he followed company procedure which is get fast and get above it as well as trusting his aircraft to stabilise.

As an A320 Captain I can tell you that this looks absolutely like PIO which are indeed rather common on the A320. On the video from the cabin you can clearly see the flight controls deflections which are almost constantly near the maximum deflection (left/right/left etc.). Normal law limits the roll rate to around 15 degrees per second which can contribute to the oscillations in gusty conditions. It is correct that releasing the side stick will result in stabilization, but it might take a short while for a pilot to figure out what's going on.
 
BHM
Posts: 28
Joined: Sun Aug 28, 2016 2:03 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 12:30 pm

ro1960 wrote:
george77300 wrote:

This video is best to see height: https://youtu.be/78ZDaQ0UYZg


The full video shows the approach before the incident:

https://www.youtube.com/watch?time_continue=313&v=tjv3xBB-HmY




I will agree with the passenger's comment at the end... Jesus Christ
 
BA777FO
Posts: 265
Joined: Sun Apr 22, 2018 2:58 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 1:06 pm

Calpe wrote:
BA777FO wrote:
PIO...with the autopilot engaged?

Interesting theory a lot of people have.


Now I am definitely no expert and most certainly not a pilot! However maybe some of the pilots on here who have flown into GIB in the past could enlighten us but I always thought that the approach to rwy 09 at GIB, as in the video, was a visual approach with no ILS due to the curved approach path so does this not mean that it would have to be manually flown or is there someway of getting the autopilot to fly it still?

If it was being hand flown then does this mean that PIO could well be factor as the autopilot wasn't engaged?


There's no ILS but normal to fly an Rnav approach where the autopilot would be engaged. In the case of the Rnav (RNP) 09 at GIB the DA is 380ft and can be flown automatically until the aircraft's minimum autopilot disengage height for a non-ILS approach, typically 200ft.
 
Aliqiout
Posts: 222
Joined: Wed Oct 05, 2016 6:10 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 1:43 pm

People are quick to blame the pilots. I am not a pilot, but I am an atmospheric scientist. Becasue of The Rock, if the ground speed of the plane was somewhere between 150 and 350 km/hr this could have been Kármán Vortex Shedding. I dont know how planes are designed and pilots are trained to avoid this. I wouldnt think there would be much the pilots could do except climb above it or go around it.
 
User avatar
CitizenJustin
Posts: 495
Joined: Thu Nov 30, 2017 10:12 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 2:01 pm

Erebus wrote:
zeke wrote:
Reminds me of this

https://youtu.be/9mMLvNxHyuM


Reminded me of this more!

https://youtu.be/AgvzhJpyn10

ktof wrote:
Another onboard view here, the oscillating lasted around 20 - 30 seconds with a steep climb.

Although the steep climb may be accentuated in the video by the camera.

https://youtu.be/78ZDaQ0UYZg


Passenger reactions were mildly amusing but nice to see no one screamed their heads off. :silly:




I have to say that video tricked me for a couple seconds.
 
User avatar
CitizenJustin
Posts: 495
Joined: Thu Nov 30, 2017 10:12 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 2:05 pm

I took BA to Gibraltar a few years back, and the landing was perfectly smooth. I’m thankful, because I’d probably be one of those dramatic Americans everyone talks about.
 
buzzard302
Posts: 149
Joined: Sat Jun 06, 2015 12:06 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 2:22 pm

Aliqiout wrote:
People are quick to blame the pilots. I am not a pilot, but I am an atmospheric scientist. Becasue of The Rock, if the ground speed of the plane was somewhere between 150 and 350 km/hr this could have been Kármán Vortex Shedding. I dont know how planes are designed and pilots are trained to avoid this. I wouldnt think there would be much the pilots could do except climb above it or go around it.


I don't know that everyone is blaming the pilots 100%. I think mostly everyone just wants to know how this long series of oscillations could have happened. If the plane was in autopilot as BA777FO seems to imply, why wasn't it able to stabilize more quickly?
 
Calpe
Posts: 38
Joined: Sat Feb 04, 2012 11:59 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 4:37 pm

There's no ILS but normal to fly an Rnav approach where the autopilot would be engaged. In the case of the Rnav (RNP) 09 at GIB the DA is 380ft and can be flown automatically until the aircraft's minimum autopilot disengage height for a non-ILS approach, typically 200ft.[/quote]

Thanks for the explanation, I didn’t realise there was an alternative when there is no ILS present. Would be interesting to know if this was the aircrafts own systems struggling to cope with the wind off the rock because I would estimate from the video that they never got below 200ft so as you said earlier, the autopilot would more than likely have been engaged the whole time.
 
phugoid1982
Posts: 52
Joined: Sat Sep 10, 2016 4:02 am

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 7:58 pm

It's been years since I used my Aeronautical Engineering flight dynamics knowledge but it looks to my like PIO in response to an atmospheric perturbation excited the Dutch Roll Mode. I can't tell from the inside cabin view but the outside view shows a fair amount of Roll/Yaw coupling although the yaw amplitude seems much smaller than the roll amplitude. Is it possible that overly aggressive rudder input (rudder doublet) and a possible failure or disengagement of the yaw damper triggered this? I remember years ago, I flew a Boeing 737-800 in a simulator as an amateur enthusiast and was surprised when the instructor told me to keep the yaw damper engaged during the entire flight regime. I assumed that would require more rudder input during coordinated turns but I guess that washout filter in the Control Law removes inputs during steady control inputs and yaw rate.
 
Aliqiout
Posts: 222
Joined: Wed Oct 05, 2016 6:10 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 8:35 pm

buzzard302 wrote:
Aliqiout wrote:
People are quick to blame the pilots. I am not a pilot, but I am an atmospheric scientist. Becasue of The Rock, if the ground speed of the plane was somewhere between 150 and 350 km/hr this could have been Kármán Vortex Shedding. I dont know how planes are designed and pilots are trained to avoid this. I wouldnt think there would be much the pilots could do except climb above it or go around it.


I don't know that everyone is blaming the pilots 100%. I think mostly everyone just wants to know how this long series of oscillations could have happened. If the plane was in autopilot as BA777FO seems to imply, why wasn't it able to stabilize more quickly?

If it was vortex shedding there would have been no way to stabilize. The plane would have encountered blast after blast of astonishing amounts of energy. There is not much you can do while you are in it, except try to get out of it. Which they did.
 
User avatar
ACCS300
Posts: 427
Joined: Thu Jun 16, 2016 4:05 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Wed Feb 27, 2019 11:06 pm

Metour Pilot just posted his account of the event on his YouTube channel. Great perspective.

https://www.youtube.com/watch?v=3BkOgZPjZX4
 
mm320cap
Posts: 293
Joined: Wed Jul 14, 2004 12:35 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Thu Feb 28, 2019 3:30 am

Channex757 wrote:
Gibraltar is tracherous and requires special training. Monarch in particular were very hot on that.

The problem isn't PIO my little armchair CEOs. It is a thing called a rotor. Spinning masses of air like a horizontal tornado that come rolling off the Rock in certain circumstances. There were quite a few aircraft losses in the postwar days of unpressurised airliners until this phenomenon was fully understood.

The BA pilot recovered beautifully here after a spinning mass of air with the strength of a bomb hit his plane. The immediate necessity is to get over the top of it and away to an alternate.


A rotor doesn’t affect an airplane with consistent back and forth roll for 30 seconds. It rolls and keeps rolling one way. Hence, a rotor. The movements of the aircraft are way too consistent to be rotor turbulence.

Signed “a little armchair CEO with 10,000+ hours of A320 Captain time”.
Last edited by mm320cap on Thu Feb 28, 2019 3:58 am, edited 1 time in total.
 
mm320cap
Posts: 293
Joined: Wed Jul 14, 2004 12:35 pm

Re: BA492 Unstable Go-Around at GIB / Diverted to AGP

Thu Feb 28, 2019 3:40 am

TTailedTiger wrote:
mm320cap wrote:
jpetekyxmd80 wrote:
I also think it was a stall. Having the gear down way too long after the go around didn't help matters. Things didn't start to get unusual until they pitched up for the go around. You can tell the ailerons are not operating very effectively during this period. The aircraft seems basically out of control.


It wasn’t a stall. The A320 won’t stall in normal law. It was a PIO exacerbated by the fact that the control laws limit the speed at which the roll rate can be corrected - particularly at landing speeds. The pilot puts in a large input to correct an initial upset caused by turbulence. The result is that it takes longer than expected to roll the airplane back the other way. This causes the pilot to hold the correction in longer than normal and the Airplane starts to roll the other way. The pilot puts in opposite airleron to counteract, but that roll rate is also limited by the computer so it goes past wings level to the other side. Rinse. Repeat. I’ve seen it countless times, but never to this level.


Isn't that a little disingenuous? The Airbus will stall, it'll just go into alternate law first. On a forum for Airbus pilots one one of them mentioned this:

"Or you could get into a heavy windshear (say 100kts within a second or so), so that the aircrafts authority to pitch down wouldn't be enough, but split seconds before stall you would lose valid speed information and crash in alternate law, too."

Any airplane will eventually bite back. You never know which system will not the fan at a critical moment on flight.


There was nothing in that video that shows something that would have caused an a transition to Alternate Law. The airplane stayed firmly within the Normal Law envelope.

The recovery in the A320 for windshear or terrain escape is full back stick and hold. It won’t stall. That’s the way Airbus designed it.

I suppose that it’s possible that a 100 knot sudden wind shear would trigger Alternate Law through a crazy pitch or roll, but the video doesn’t show that happened to this airplane.

Not sure why it’s so hard to believe that this is a PIO incident for some of you. For anyone with significant time on the Airbus, it’s not a huge surprise. It happens to us all eventually... just normally not to this extent.

I’m guessing they got smacked with a good size rotor and in trying to counteract that event they got into a good sized, increasing PIO. They eventually got it sorted after making a good decision to go around. No harm, no foul.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos