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BAW492 diversion at Gibraltar

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BAW492 diversion at Gibraltar

Old 27th Feb 2019, 02:55
  #81 (permalink)  
 
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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...
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Old 27th Feb 2019, 03:18
  #82 (permalink)  
 
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Originally Posted by tartare View Post
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...
Watch the video in the link I attached above. You will have your answer.
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Old 27th Feb 2019, 05:07
  #83 (permalink)  
 
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Originally Posted by AerocatS2A View Post

Neither of those seem relevant. The first one was associated with flaps locked at full and the lever selected to 3 in accordance with an ECAM, the second involved ice accretion.
Mainly from memory but not solely: The other relevant bits in the Dragon event were that during the first approach, the Flaps were already at FULL when the WTB locked the flaps (ostensibly due to a gust causing some asymmetric movement of flaps, even though they were already at the commanded Full position as was flap lever). An OEB was active at that time, effectively overriding the ECAM procedure to leave the flap lever in Full in such circumstances i.e. not place it to 3 as per ECAM. Airbus had repeatedly been asked before this, if control gains were more sensitive in Flaps 3 than Full. "No" was the alleged answer.

As an aside and not directly relevant but more to highlight what pilots are not told as a matter of course: Hamburg A320 LH wing tip scrape in crosswind landing revealed that aileron authority reduced significantly as a/c sensed ground mode even though only one gear on ground and so limiting crew ability to correct the situation more rapidly.
Flight Global A320
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Old 27th Feb 2019, 05:07
  #84 (permalink)  
 
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Originally Posted by Sailvi767 View Post
That looks like a flight control malfunction to me. Possibly direct law in roll mode.

I've wound up in Direct law, and believe me, the airplane flew quite nicely, was like the Pitts S-2 I did a bit of flying in....
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Old 27th Feb 2019, 05:18
  #85 (permalink)  
 
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Originally Posted by AerocatS2A View Post

Neither of those seem relevant. The first one was associated with flaps locked at full and the lever selected to 3 in accordance with an ECAM, the second involved ice accretion.
The Dragon incident has similarities, where the gusty conditions induced a roll upset and the extant FBW roll responsiveness for the various configs (erroneously applied with flaps locked at full on the multiple attempts) meant that PIOs were a lot more likely to occur with both autopilot and manual flight.

One of the outcomes of this incident and others similar at the time was change to the FBW roll laws with additional data points and proper flight testing of the various configs to confirm certification compliance. The question has been raised in this latest incident as to whether this was sufficient, particularly if the autopilot remained engaged.
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Old 27th Feb 2019, 06:31
  #86 (permalink)  
 
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Originally Posted by FCeng84 View Post
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 descent 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!
See my earlier post(s):

a) the altitude traces from the flight-trackers clearly aren't relative to a SL datum (i.e. uncorrected for QNH)
b) the GA started at around 1.6 nm from the THR (so presumably at around 500' AAL)
c) there was no runway contact (the THR was overflown at around 1700')

In other words the tracking data is consistent with the video, as one would expect.
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Old 27th Feb 2019, 06:51
  #87 (permalink)  
 
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Originally Posted by DaveReidUK View Post
See my earlier post(s):

a) the altitude traces from the flight-trackers clearly aren't relative to a SL datum (i.e. uncorrected for QNH)
b) the GA started at around 1.6 nm from the THR (so presumably at around 500' AAL)
c) there was no runway contact (the THR was overflown at around 1700')

In other words the tracking data is consistent with the video, as one would expect.
There had to be a major difference between actual QNH and STD to get that 500 ft difference. What was the QNH at the time?
In my experience, FR24 gives poor altitude information close to airports. Track information is better.
When i follow a flight it often stops at a few hundred feet, flies over the runway and then drops straight down to the ground.
OMG, it nose dived into the ground! No, just FR24 acting up.
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Old 27th Feb 2019, 06:55
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.PF learns how to not PIO as soon as they transition from W/S escape into G/A and set Config 3.
Or perhaps put the autopilot in...

​​​​​
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Old 27th Feb 2019, 07:14
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Originally Posted by ManaAdaSystem View Post
There had to be a major difference between actual QNH and STD to get that 500 ft difference. What was the QNH at the time?
A QNH of around 1030 would account for that difference. I haven't seen a METAR, so I don't know what the actual value was.

In my experience, FR24 gives poor altitude information close to airports.
That hasn't been mine, other than the fact that you obviously need to adjust for QNH. YMMV.

And, regardless of size of the offset, by the time the aircraft was over the threshold it was clearly around 1200' higher than at the lowest point of its approach, so neither the video or the data would indicate any runway contact.
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Old 27th Feb 2019, 07:32
  #90 (permalink)  
 
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For those who are interested, QNH in LHR is 1027. You can watch as all aircraft on FR24 are landing short of the runway.
Probably the same situation as in Gibraltar.

I agree, the difference in QNH can show the opposite, aircraft hanging in the air above the runway in low QNH situations.
How would the resulting plunge to the runway show up on a graph?
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Old 27th Feb 2019, 07:42
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Originally Posted by AerocatS2A View Post

Neither of those seem relevant.
Evidence of several* other incidents of uncommanded severe roll oscillations in strong gusty conditions on A320 family aircraft not relevant? Are you absolutely certain about that???

*the reports cite other previous examples too, also not involving ice, admittedly the details are beyond page 1 however
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Old 27th Feb 2019, 07:42
  #92 (permalink)  
 
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While not wanting to get into the detail of this incident it would seem to me that there is an over reliance on autoflight within the industry and with the lack of hand flying the pilots skill at avoiding PIO has become degraded.
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Old 27th Feb 2019, 17:55
  #93 (permalink)  
 
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Originally Posted by A and C View Post
While not wanting to get into the detail of this incident it would seem to me that there is an over reliance on autoflight within the industry and with the lack of hand flying the pilots skill at avoiding PIO has become degraded.

Very much agree, from what it seems there are far too many pilots who are merely system operators rather than airmen. I recently heard that you're not allowed to remove the Flight Directors in our favourite irish loco airline. Visuals are discouraged in others and more and more outfits are banning visual approaches as they keep messing them up.

Unfortunately in times when real pilot/flying skills are required, they're nowhere to be seen. My two cents.
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Old 27th Feb 2019, 18:43
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Originally Posted by geardown1 View Post
Very much agree, from what it seems there are far too many pilots who are merely system operators rather than airmen. I recently heard that you're not allowed to remove the Flight Directors in our favourite irish loco airline. Visuals are discouraged in others and more and more outfits are banning visual approaches as they keep messing them up.

Unfortunately in times when real pilot/flying skills are required, they're nowhere to be seen. My two cents.
I'm glad you put a value on your opinion.
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Old 28th Feb 2019, 08:12
  #95 (permalink)  
 
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Originally Posted by Just the fax maam View Post
Evidence of several* other incidents of uncommanded severe roll oscillations in strong gusty conditions on A320 family aircraft not relevant? Are you absolutely certain about that???

*the reports cite other previous examples too, also not involving ice, admittedly the details are beyond page 1 however
It just seemed the cause of the other incidents, even if the symptoms were the same, were unrelated to this. I admit I skipped to the summary etc, but my impression was that it was like comparing a runny nose caused by a cold with one caused by allergies.
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Old 28th Feb 2019, 08:15
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Hydraulic reservoir and pump capacity

Looks as though too many control inputs depleted control surface hydraulic jack pressure leading to a lag in movement and eventual over control. Known problem.
solution go around or if clever be patient and use smaller stick deflections but knowing how rough the rock can be easier said than done.
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Old 28th Feb 2019, 09:25
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Originally Posted by MichaelKPIT View Post
Here's a video from outside:
..To me that looks intentional..Maybe a demonstration (for training purposes),
or just saying ``hello`` to somebody on the ground..Or a serious problem with the autopilot..

Fly safe,
B-757
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Old 28th Feb 2019, 09:43
  #98 (permalink)  
 
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..To me that looks intentional..Maybe a demonstration (for training purposes),
or just saying ``hello`` to somebody on the ground..Or a serious problem with the autopilot..
B-757, you forgot to include a smilie to make it clear that you are joking!
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Old 28th Feb 2019, 13:53
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Originally Posted by blind pew View Post
Looks as though too many control inputs depleted control surface hydraulic jack pressure leading to a lag in movement and eventual over control. Known problem.
solution go around or if clever be patient and use smaller stick deflections but knowing how rough the rock can be easier said than done.
Head from a BA mate. He understands that on the approach, Captains landing, so Co Pilot handling the approach-BA SOP. At some point a double R Alt. fault/indication occurred which put the aircraft into Direct Law. (aircraft handles like a normal non FBW plane)
The co-pilot flew the Wind Sheer Go-around. (Capt. hadn't resumed control for the landing) and with little practice in "manual flying" in those conditions, over controlled the sidestick inputs, resulting in the 30deg PIO.
Situation was resolved when the gear selected up, which presumably removed the R Alt fault signal and returned the aircraft to Normal FBW Airbus handling.
I'm not Airbus qualified so excuse the neccesarily rather non technical description.
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Old 28th Feb 2019, 14:20
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Would like to think the FO is now in the sim .........
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