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Pilot Commands TOGA; A320 lands anyway

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Pilot Commands TOGA; A320 lands anyway

Old 30th May 2001, 04:27
  #1 (permalink)  
SaturnV
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Red face Pilot Commands TOGA; A320 lands anyway

From this week's "Aviation Week":

Incident Prompts Airbus
To Alter A320 AOA Limits
PIERRE SPARACO/TOULOUSE, FRANCE

Revised software, to be implemented soon, will increase pilots' authority over automated systems

In the wake of a serious landing incident, Airbus plans to revise the A319/A320 twinjets' automated angle-of-attack (AOA) protection.

Recently, a 150-seat A320, operated by an unspecified European carrier, made a hard landing, in nose-down attitude, despite the pilot-in-command's decision to go around and the application of maximum power. The aircraft's front landing gear collapsed, and the engine nacelles were damaged. Light turbulence but no wind shear had been reported to the flight crew before the nighttime ILS approach began.

An investigation team, supported by the European manufacturer's flight operations department, determined that during the final approach, the A320 entered into heavy turbulence at about 200 ft. altitude. Wind conditions were significantly more severe than initially reported to the flight crew, with up- and downdrafts and gusts that also involved an inversion of wind direction. The digital flight data recorder and additional inputs helped investigators determine that the A320 encountered strong tailwinds, a 1.25g-updraft, then a downdraft followed at 50 ft. by a tailwind gust.

DURING THE UPDRAFT, the flight crew applied a forward side stick input, then aft input to reduce the aircraft's increasing sink rate. As the Ground Proximity Warning System (GPWS) sounded, they moved engine throttles to takeoff/go around power, but the aircraft nevertheless touched down, according to Capt. Michel Brandt. He is Airbus' deputy director of flight operations support. He added that the A320's estimated vertical speed, when it impacted the runway, was 1,200 ft./min.

The recently completed investigation has shown that the combination of up and down wind gusts and the flight crew's actions on flight controls led the aircraft to hit the automated systems' high angle of attack protection and prevented a normal flare.

The incident was reproduced here in a full-flight simulator and led Airbus to a decision to modify the AOA protection's control laws to increase the flight crew's authority. Such a modification, which has been ratified by DGAC French civil aviation authority and European Joint Aviation Authorities, will cover all in-service A319s and A320s, but will not affect the stretched-fuselage A321.

The revised software is expected to be validated in June, and the retrofit program will be implemented rapidly, Brandt said. He added that in the shorter term, A319/A320 operators will temporarily apply precautionary measures in gusty wind conditions such as a slightly higher approach speed and immediate go-around in case of sink rate GPWS warning below 200 ft.

In an unrelated development, the British transport ministry's Air Accident Investigation Branch (AAIB) this month completed the investigation of a tail strike accident that occurred last year to a Lufthansa German Airlines A321.

DURING THE FINAL approach to Heathrow airport, the aircraft went below nominal glidepath, and the flight crew increased the attitude to reduce the rate of descent. The sink rate GPWS sounded, full aft side stick was applied, and the aircraft bounced on the runway after touching down for the second time. AAIB investigators determined that the aircraft's attitude peaked at 10.6 deg., just above the 9.7-deg. touch down limit with the main landing gear's oleos fully compressed. A similar incident occurred at Heathrow a few months earlier. Brandt noted that A321 landing tail strikes are not a noticeable concern and largely remain within tolerable limits.
 
Old 30th May 2001, 06:40
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411A
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ScareBus, very bad news for pilots. Real pilots, not just system operators. To be avoided like the plague.
 
Old 30th May 2001, 11:14
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wooof
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411A

Please for the benefit of all fellow PPRuNers could you tell us how many hours you have on the Airbus.
 
Old 30th May 2001, 11:18
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planecrazi
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411A, What is your point that you are making?
This A320 landed with probably with no injury to anyone due to it's avanced flight laws and protection.Without this, who knows what would have happened? The Tri-Star didn't have this protection when it encountered the micro-burst in Dallas, if I remember. Both are good aeroplanes and I'm sure the crew were experienced in both cases. Airbus is now improving there aircraft to be even better. I don't believe one should stay away from an airbus because of it's technology. I enjoy the Airbus and believe it to be very safe, so long as it is treated with the due respect that any aircraft would need.
 
Old 30th May 2001, 12:32
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Mishandled
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I sincerely hope that were not going to get another Airbus/Boeing tit for tat again. Maybe there should be a separate forum for these arguments. I dont profess to know much about their respective merits as aeroplanes other than the inhold systems, and other ground handling aspects, but it seems to me that there is a hard core of people who are either for Airbus or Boeing, and will never vary from that opinion. In this thread it would be interesting to hear from pilots who have experienced this situation. (IMHO of course)
 
Old 30th May 2001, 12:36
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CaptainSquelch
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"and immediate go-around in case of sink rate GPWS warning below 200 ft."
Is that a new procedure? In my flyingclub a go-around is compulsary at any altitude. Is this an exeption?

Sq

 
Old 30th May 2001, 12:55
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EGGW
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Anyone know which airline and where the first incident happened?? This is why Airbus have an AD out at present, with procedures for 320's to land in config 3 in gusty conditions!
 
Old 30th May 2001, 13:50
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trend vector
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This incident actually took place in the US and not in Europe from what I am made to beleive and this glitch( if you will call it that) affects only A320's not 319 or 321's.Apparently as the TOGA was applied the aircraft was very close to VLS at which stall protection eases the nose down limiting Nose up authority.Airbus is looking into it but for the moment Flap 3 landing is reccomended if turbulence or wind shear is reported in the approach phase or later.
 
Old 30th May 2001, 14:28
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Thrust
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At the end of the day it is still an aeroplane. Mother nature will win every time if she want's to.

So the AOA protection reduced the chance of a stall and contact was made with the runway. Everyone survived and had the go around been made as per the manual.... who knows. Engineers and system designers can only do their best and I'll take what Airbus offers as it's the best available to me. I'm better off with the protections than without.
 
Old 30th May 2001, 15:11
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Magplug
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This was an Iberia A320 at BLV (Bilboa) the event occurred in early February. The aircraft remained at BLV for some weeks (may even still be there?) due to severe damage to the nose gear.

The crux of this matter is that the crew hit a massive updraft with wind shift below 200' and corrected with a comensurately large amount of forward control. Guess what comes next???

Having got a really good rate of descent going they should have expected the following downdraught. Due to the lack of altitude, full power a max AOA demand was insufficient to stop the aircraft executing a very hard 3-pointer.

The nose gear was written off and they evacuated on the runway.

Evidently Airbus Industrie have been asked to expand the max alpha envelope to accomodate pilots with slow reactions.

Perhaps if they had reacted to the warning signs in the first place & gone around this would not have happened.

Judging by some of the posts above I would say there is not much experience making comment here.

*** A superior pilot is one who uses his superior judgement to avoid situations which might require the use of his superior skill ***

If it balloons before the landing - you know what is coming next.............
 
Old 30th May 2001, 15:32
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iflyboeing747
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Magplug

Well commented indeed..!
Personally I would never try to predict if things could have been another way - after they've happened, but I agree in your points that evaluating the situation and take early action is to be expected from pilots.
 
Old 30th May 2001, 15:36
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DoctorA300
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Magplug,
Hindsight is a wonderful thing. If you know how to foresee such events, why donīt you enlighten your collauges
Brgds
Doc
 
Old 30th May 2001, 15:39
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TEMP0+TSRAGR
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Just after that incident my company introduced a new procedure in gusty conditions with >10kts above the mean windspeed, or moderate/severve turbulence on short finals.

In these cases we MUST land with CONFIG 3 with minimum Vapp of Vls + 10Kt. If 'Sink Rate' below 200' immediate go-around.

This is a procedure to avoid the pitch down affect during the last phase of the approach due gusts causing Alpha protection to kick in close to the runway.

The problem is we are now restricted operating into shorter runways.

I fly the airbus, and ask myslef why design the a/c like this ? Why not have a FBW system which gives proportional movements of the control surfaces, like the 777 ?
Also normal moving throttles that you could 'nudge forward' in gusts would be a great help ....

I dont make the rules, just play the game !
 
Old 30th May 2001, 16:23
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DownIn3Green
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Sum it all up in one word: Airbus.
 
Old 30th May 2001, 18:15
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Flight Safety
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T & T, you've made what I feel are the most informative comments yet on this thread.

I agree with you, why does the aircraft have to be designed this way? Why should a wind gust near the runway be allowed to "trick" the computer into thinking that the AOA is higher than it actually is? I can't imagine as a pilot making a decision to go around at 200 ft or less, applying TOGA power and then trying to hold a pitch attitude suitable for climb out, only to have the airplane decide on its own that a pitch attitude into the runway is better (thus overriding my judgement), at full power no less!!! Man, my speech would be unrepeatable for an hour after an incident like that.

I'm glad that the condition was repeatable in the sim so it can be corrected. But this leads me to think that a gung-ho approach to computerizing every function on an airliner for the sake of claiming to the be most "technologically advanced", can come at a price. These types of systems are new and in some ways untested as this incident proves.

From my experience with computer systems, anytime you choose to automate a process which has enough complexity so that a human being is required to both monitor and exercise judgement over that process, then you'd better think through that automation very carefully. You're proposing no less than to automate human judgement. Automation is good at assisting human judgement in that it can help to prevent common human mistakes and it can react quickly to situations that don't require much analysis, but to override human judgement when many factors have to be considered and many possible choices are available, is sheer folly for the computer automater.

In this case the computer "judged" wrong, and overrode the judgement of the pilot in what could have lead to a tragic outcome. Thankfully in this case it didn't.

------------------
Safe flying to you...

[This message has been edited by Flight Safety (edited 30 May 2001).]
 
Old 30th May 2001, 19:00
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EGGW
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If you have trouble maintaining speed with the Autothrust ON, just push the levers slightly out of the CLB gate, and you will get an increase of power towards the MCT setting. When you have your speed back under control, bring the levers back to the CLB gate.
There is a mentality that the A320 and its FBW bretheren will get you out of trouble, no matter what, you know its made for spear throwers etc.. But its still an aeroplane, and can bite back, it will stall if mother nature chucks its' worse at you. Ever been at 390, made it to the altitude just, perhaps a little early, then it gets turbulent. Like sitting on a knifes edge, no matter what the manuals say
 
Old 30th May 2001, 23:15
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Big Buddha
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BLV, that'll be the VOR then, BIO is the airport.
 
Old 30th May 2001, 23:34
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airforcenone
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The A320 series are designed to fly a 1g trajectory for pax comfort. In part this is done by the use of a 'soft' elevator which operates far more slowly than it should. (Notice next time you do your flight control checks how slowly the elevator moves relative to the stick movement).

This is why overspeeds in the descent are fairly easy to achieve (maximums of .78/320kt generally will prevent this), however I can't help feeling the 'soft' elevator was a contributary factor in Bilbao.

TEMPO is absolutely right when he suggests that a directly proportional response to stick movement would be better. Direct Law anyone?

Edited to give proper credit to TEMPO whose username I had screwed up!

[This message has been edited by airforcenone (edited 30 May 2001).]
 
Old 30th May 2001, 23:46
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Heavens Gate
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To Flight Safety:

Entering Low Level Windshear of sufficient magnitude, can definitely give you an AOA way beyond Alpha Max as several windshear crashes have shown, no matter what your GoAround attitude and thrust.
Therefore it is quite possible that the AOA protection was actually saving the a/c from worse, just as it did in Habsheim.
However, having flown both the B777 and the A330/340 I have to say that my "OPTIMUM" a/c would be a B777 with the envelope protection of the A330/340.


 
Old 31st May 2001, 01:15
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screwjack
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Folks:


step by step. I have reason to believe that AI did sent this article straight forward into the editors laptop. Read it carefully:


1.) the article says "landing incident". Well, I believe everyone here knows the proper definition and the slight little difference between an "incident" and an "accident". The article mentioned a "collapsed nose gear" and "engine nacells damaged". So it would be appropriate to term this thing ACCIDENT!


2.) as a matter of fact it was the Iberia accident in Bilbao. What is not mentioned here is the fact that it was a training flight for the F/O. Maybe nice to know...


3.) never trust ATC: apparently the WX was not as reported to the crew. This might excuse another little "glitch" in the making of this accident:


4.) what "son of a gun" would dare to use full flaps in x-wind and strong gusts? This might explain the French DGAC AD-Note in regards to this case and the +10kts and flaps 3. (BTW: this seems to be the stopgap for all kinds of software related problems with their FBW a/c. I recall that in full flaps your speed brake lever is nothing more than a useless handle. If you don't have (automatic) spoiler deflection after touchdown and you pull, nothing will happen. In flaps 3 you'll get partial flight spoilers - this had been some minor issue in the LH A320 landing accident in WAW some years back.)


5.) "inversion of wind direction" - nice terms! - Wouldn't it be more appropriate to say: "windshear" ? Well maybe but in this case isn't there something like a "windshear warning system" incorporated in the design??? Did it trigger??? What is the procedure? - Maybe add a little bit of power?


6.) TOGA power, "..but nevertheless the aircraft touched down". Well given the specific circumstances of this situation I might be a bit "off" but I still recall a chap named Cpt. Michel Asseline who fried the first A 320 delivered to AF back in 1988 (aka. the "Infamous Chain-Saw"). Different situation, nice weather and so, and obviously too low during a low pass (who is capable of reading French or Japanese should read his book "Le pilot est-il coupable", where you find ,among other pretty interesting stuff a very solid explanation for a wrong altitude indication in the cockpit - a thing that always bothered me that two grown up AF Captains couldn't read their altimeter - but I don't want to go into these details again). He (Asseline) always stated that nothing happened when he applied TOGA... One might conclude that a proper analysis of this sad event might have triggered a warning flag a bit earlier, specially taking adverse wx - conditions into account, - but again, just a thought!


7.) Apparently and sadly AI will never get it...


Just reflect for a second upon the following line from the article: "...the flight crew's actions on flight controls led the aircraft to hit the automated systems' high angle of attack protection and prevented a normal flare."


Excuse me? Here we go again?


The crew's action? Wouldn't a wording similar to "...the design of the alpha protection in this case prevented a normal flare" be a little bit more appropriate? - Was there anything the crew could do different than commanding nose up and hitting TOGA to recover? Did the a/c respond?

As we learned: no - it followed exactly its logic and as designed. Great! Do we learn that, can we read it in the FCOM or AOM? - What does AI teach their crews in their flight training and type-ratings in such an event? "P** in your pants and pray?"


Well "ping*", "careful" Mesdames et Messieurs in TLS! Some people might react extremely 'sensitive' to such statements. I believe you realized that quite 'painfully' in the past..


*(for non Airbus pilots: announcement sound of ECAM-message)

8.) Highest scores for Toulouse in regards to the announced modification of the program. This would have been out of proportions and unthinkable just a few years back. Remember, we are talking the prestigious alpha-protection of AI! Don't mess with that as I truly believe it has saved a couple of these planes, -including what was carried inside, in the past.

9.) Somehow "funny" are the closing remarks of Cpt. Michel Brandt in ref. to A 321 tail strikes: "...A321 landing tail strikes are not a noticeable concern and largely remain within tolerable limits." - Does anyone have any clues what this gentleman might want to say by this? - I recommend to ask some of the operators who had this "unnoticeable concern" in form of heavily damaged airplanes, being grounded and repaired for several weeks...


sj


[This message has been edited by screwjack (edited 30 May 2001).]
 

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