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AF447 wreckage found

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AF447 wreckage found

Old 28th May 2011, 07:12
  #641 (permalink)  
 
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The people I feel truly sorry for in this tragic situation are the poor moderators. When you read some of the rubbish that is posted here it makes you wonder what they actually remove.

At this tragic time spare a thought for your mods.

My favourite to date......"Nigel get the standby horizon out"
"......errrrr......sorry sir I've drunk mine"
"....bugger....finished mine too. Don't worry I'll get my torch out and look at red and yellow ribbon fluttering outside the window"
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Old 28th May 2011, 07:14
  #642 (permalink)  
 
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Says Graybeard:
The A330 Autopilot can't handle varying erroneous airspeed from 3 sources, so it disconnects and hands the task to the pilot. That shows a lack of forethought.
Tell me... if the computer knows it is getting "varying erroneous airspeed from 3 sources" and does not know which one to believe, what should the computer do... keep flying the plane itself basing its judgments on known bad data or hand the job to a human?

Did ya even think that comment through before you made it?
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Old 28th May 2011, 07:32
  #643 (permalink)  
 
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Cool

Hi,

Tell me... if the computer knows it is getting "varying erroneous airspeed from 3 sources" and does not know which one to believe, what should the computer do... keep flying the plane itself basing it's judgments on known bad data or hand the job to a human?

Did ya even think that comment through before you made it?
Methink .. if I understand the idea of the poster....
The autopilot can't rely on bad datas of course ... but it's possible to have another law for the autopilot in this case:
Immediately .. when bad data detected .. autopilot keep speed and altitude attitude (freeze settings) and warn the pilot for check what is wrong .....
The plane continue to fly with same settings as before all go bad ....
It's almost what AF ask in their procedure ......
Actually .. seem's that the autopilot is used as a alarm (by disconnecting) for warn something is wrong ......

Last edited by jcjeant; 28th May 2011 at 07:49.
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Old 28th May 2011, 07:38
  #644 (permalink)  
 
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Yipoyan post#626, to that accident you can add 2 VERY near misses with the A310 involving Tarom at Orly & Interflug somewhere in the former E Germany ?

If you look them up in Aviation Safety Net you will be gobsmacked that they got away with it.

I too am gobsmacked, that in this day and age Airbus have managed to design another generation of machine that doesn't do what you could reasonably& logically expect.
Just as illogical as the trim system on the earlier generation, I cannot fathom any logic in a system that will trim back if YOU are pushing forward to unstall the aircraft.

As THY & Thomson proved in 737's, a dispute between the stab & the elevator will always be won by the big guy in an underwing engine configured jet transport.
I am also gobsmacked, given the history of previous pitot problems & indeed the need to design & fit uprated ones, why the crew were not taught & made comfortable with this scenario during their recurrent (if not initial ) training.
Surely this should have loomed LARGE in the recurrent sim syllabus as soon as the possibility was identified some time before.
Anyone familiar with Airbus ops in AF care to tell us if they were made sufficiently aware, & or trained , to cope with this scenario ?
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Old 28th May 2011, 07:38
  #645 (permalink)  
 
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For anybody else that couldn't download the report yesterday.

Accident to the Airbus A330-203
flight AF 447 on 1st June 2009
Update on Investigation
Bienvenue sur le site du Bureau d'Enqutes et d'Analyses
27 May 2011
SPECIAL FOREWORD TO ENGLISH NOTE
This note has been translated and published by the BEA to make its reading easier for Englishspeaking
people. As accurate as the translation may be, the original text in French should be
considered as the work of reference.
History of Flight
On Sunday 31 May 2009, the Airbus A330-203 registered F-GZCP operated by Air France was
programmed to perform scheduled flight AF447 between Rio de Janeiro Galeão and Paris
Charles de Gaulle. Twelve crew members (3 flight crew, 9 cabin crew) and 216 passengers
were on board. Departure was planned for 22 h 00(1).
At around 22 h 10, the crew was cleared to start the engines and to leave the parking space.
Take-off took place at 22 h 29. The Captain was PNF, one of the co-pilots was PF.
The take-off weight was 232.8 t (for a MTOW of 233t), including 70.4 t of fuel.
At 1 h 35 min 15 , the crew informed the ATLANTICO controller that they had passed the
INTOL point then announced the following estimated times: SALPU at 1 h 48 then ORARO at
2 h 00. They also transmitted the SELCAL code and a test was undertaken successfully.
At 1 h 35 min 46, the controller asked the crew to maintain FL350 and to give their estimated
time at TASIL.
At 1 h 55, the Captain woke the second co-pilot and said "[…] he’s going to take my place".
Between 1 h 59 min 32 and 2 h 01 min 46 , the Captain attended the briefing between the
two co-pilots, during which the PF said, in particular "the little bit of turbulence that you just saw
[…] we should find the same ahead […] we’re in the cloud layer unfortunately we can’t climb much
for the moment because the temperature is falling more slowly than forecast" and that "the logon
with Dakar failed". The Captain left the cockpit.
The airplane approached the ORARO point. It was flying at flight level 350 and at Mach 0.82
and the pitch attitude was about 2.5 degrees. The weight and balance of the airplane were
around 205 tonnes and 29% respectively. Autopilot 2 and auto-thrust were engaged.
At 2 h 06 min 04, the PF called the cabin crew, telling them that "in two minutes we should enter
an area where it’ll move about a bit more than at the moment, you should watch out" and he
added "I’ll call you back as soon as we’re out of it".
(1)All times
are UTC.
At 2 h 08 min 07 , the PNF said "you can maybe go a little to the left […]". The airplane began a
slight turn to the left, the change in relation to the initial route being about 12 degrees. The level
of turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8.
From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the
controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall
warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt
to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments
later in the speed displayed on the integrated standby instrument system (ISIS).
Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed
displayed on the right side is not recorded.
Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight.
At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".
Note 1: The angle of attack is the angle between the airflow and longitudinal axis of the airplane.
This information is not presented to pilots.
Note 2 : In alternate or direct law, the angle-of-attack protections are no longer available but a
stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain
threshold.
The airplane’s pitch attitude increased progressively beyond 10 degrees and the plane started
to climb. The PF made nose-down control inputs and alternately left and right roll inputs. The
vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied
between 12 degrees right and 10 degrees left. The speed displayed on the left side increased
sharply to 215 kt (Mach 0.68). The airplane was then at an altitude of about 37,500 ft and the
recorded angle of attack was around 4 degrees.
From 2 h 10 min 50, the PNF tried several times to call the Captain back.
At 2 h 10 min 51 , the stall warning was triggered again. The thrust levers were positioned
in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of
around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable
horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and
remained in the latter position until the end of the flight.
Around fifteen seconds later, the speed displayed on the ISIS increased sharply towards 185 kt;
it was then consistent with the other recorded speed. The PF continued to make nose-up
inputs. The airplane’s altitude reached its maximum of about 38,000 ft, its pitch attitude and
angle of attack being 16 degrees.
Note: The inconsistency between the speeds displayed on the left side and on the ISIS lasted a little less
than one minute.
At around 2 h 11 min 40 , the Captain re-entered the cockpit. During the following seconds,
all of the recorded speeds became invalid and the stall warning stopped.
Note: When the measured speeds are below 60 kt, the measured angle of attack values are considered
invalid and are not taken into account by the systems. When they are below 30 kt, the speed values
themselves are considered invalid.
The altitude was then about 35,000 ft, the angle of attack exceeded 40 degrees and the vertical
speed was about -10,000 ft/min. The airplane’s pitch attitude did not exceed 15 degrees
and the engines’ N1’s were close to 100%. The airplane was subject to roll oscillations that
sometimes reached 40 degrees. The PF made an input on the sidestick to the left and nose-up
stops, which lasted about 30 seconds.
At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have
no valid indications". At that moment, the thrust levers were in the IDLE detent and the
engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In
the following moments, the angle of attack decreased, the speeds became valid again and the
stall warning sounded again.
At 2 h 13 min 32, the PF said "we’re going to arrive at level one hundred". About fifteen seconds
later, simultaneous inputs by both pilots on the sidesticks were recorded and the PF said "go
ahead you have the controls".
The angle of attack, when it was valid, always remained above 35 degrees.
The recordings stopped at 2 h 14 min 28. The last recorded values were a vertical speed of
-10,912 ft/min, a ground speed of 107 kt, pitch attitude of 16.2 degrees nose-up, roll angle of
5.3 degrees left and a magnetic heading of 270 degrees.
New findings
At this stage of the investigation, as an addition to the BEA interim reports of 2 July and 17
December 2009, the following new facts have been established:
ˆˆ The composition of the crew was in accordance with the operator’s procedures.
ˆˆ At the time of the event, the weight and balance of the airplane were within the operational
limits.
ˆˆ At the time of the event, the two co-pilots were seated in the cockpit and the Captain was
resting. The latter returned to the cockpit about 1 min 30 after the disengagement of the
autopilot.
ˆˆ There was an inconsistency between the speeds displayed on the left side and the integrated
standby instrument system (ISIS). This lasted for less than one minute.
ˆˆ After the autopilot disengagement:
„„the airplane climbed to 38,000 ft,
„„the stall warning was triggered and the airplane stalled,
„„the inputs made by the PF were mainly nose-up,
„„the descent lasted 3 min 30, during which the airplane remained stalled. The angle of
attack increased and remained above 35 degrees,
„„the engines were operating and always responded to crew commands.
ˆˆ The last recorded values were a pitch attitude of 16.2 degrees nose-up, a roll angle of
5.3 degrees left and a vertical speed of -10,912 ft/min.
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Old 28th May 2011, 07:45
  #646 (permalink)  
 
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Try the water bottle next time you are up to see.
clearly any acceleration will impart a distortion from the g vector. however at constant velocity the water surface will remain parallel with the surface of the earth.
obviously the water bottle is not a substitute for the avionics. but it does make a quick and dirty sanity check for which way up you are.
do you have any better suggestions?
thats why 3 orthogonal gyros are used to overcome any acceleration from movement.
if you want a more advanced solution you could have multiple gps receivers at extremities of the plane to compare timing pulses on the gps signal to figure out attitude to a v high precision.
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Old 28th May 2011, 07:54
  #647 (permalink)  
 
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Hi,

Water bottle ... (2min05)
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Old 28th May 2011, 07:55
  #648 (permalink)  
 
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a. Based on BEA factual report, that wasn't the case with AF447.
b. In such case, a few system design options to consider for autothrottle logic:
1. Use FMGC last known flight phase (climb, cruise, descent) as autothrottle reference to maintain optimal AOA, or
2. Set engine thrust used before the onset of airspeed indication error, or
3. Set CONT thrust.

The accident, onset by airspeed erratic readings (which lasted for one minute) and autoflight disconnect, the problem was lack of stall recovery by the pilot, for which he had 3:30 minutes and a mostly functional aircraft. A pilot descending 10,000 FPM with 107 KT indicated, should not expect a pitot system to generate correct dynamic pressure readings. He should get the aircraft under proper control firsdt, and only then carry out non-normal checklists.


As military flight academy commander, to me this case clearly shows the lack of proper selection (for personality and psycho-motoric skills) and training of pilots (complete flight envelope mastering in aerobatic trainers including deep stalls and spins, for better understanding of flight mechanics and human impact. Not necessarily to be used, but rather avoided. In case they are encountered, a pilot at any level should recognize and counteract out-of-controlled flight. It could also help him understand as captain, why full repeated pedal deflections in A300 might shear the vertical tail, what entering an aircraft wake feels like and how to avoid it. All is basic flying stuff). AF447 is just one of many such cases, including B737-800 in automatic ILS approach, throttles in idle, stalling before touchdown in Schipol, or a captain woken-up around FAF to watch his A320 demolish. Everything I wrote in this paragraph is 100% applicable to transports, even if many never thought about it.
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Old 28th May 2011, 07:58
  #649 (permalink)  
 
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jcjeant say:
Methink .. if I understand the idea of the poster....
The autopilot can't rely on bad datas of course ... but it's possible to have another law for the autopilot in this case:
Immediately .. when bad data detected .. autopilot keep speed and altitude attitude (freeze settings) and warn the pilot for check what is wrong .....
OK so... rather than hand the plane back to the pilot, you want the computer to keep flying the plane but to not even try to respond to inputs, just freeze itself at the last setting.

I'm REAL glad you don't design autopilots for a living.

As I asked the last guy... Did you even think that comment through before you made it?
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Old 28th May 2011, 08:01
  #650 (permalink)  
 
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Originally Posted by xcitation
however at constant velocity the water surface will remain parallel with the surface of the earth.
No it won't. In a steady-state turn, for example, it'll be parallel with the wings, just like the iphone "AH"... Are you seriously suggesting that these guys, in the dark of night with all hell breaking loose, should have pulled a waterbottle out of their bag and held it up to see whihc way was up?

do you have any better suggestions?
Yes, an aeroplane that presents attitude, angle of attack and has controls that do what the pilot wants and tells him what he needs to know eg if AoA indicates a stall, keep the stall warning going, not stop when the speed drops off the clock.
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Old 28th May 2011, 08:04
  #651 (permalink)  
 
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Cool

Hi,

OK so... rather than hand the plane back to the pilot, you want the computer to keep flying the plane but to not even try to respond to inputs, just freeze itself at the last setting.

I'm REAL glad you don't design autopilots for a living.

As I asked the last guy... Did you even think that comment through before you made it?
The pilot can disengage the autopilot when he want ... at least he is warned of something wrong instead a brutal disconnection.
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Old 28th May 2011, 08:07
  #652 (permalink)  
 
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When I read the Accident Update (27th May) two things jump out at me.

At around 2 h 11 min 40, the Captain re-entered the cockpit. During the following seconds, all of the recorded speeds became invalid and the stall warning stopped.

At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications". At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again.

So the system is such that entering extremely high angle of attack invalidates the speeds, which in turn silences the stall warnings. Conversely, reducing the angle of attack causes the stall warning to reactivate. The crew are in a situation where they are getting the exact wrong feedback. Couple this with possible mind-sets about turbulence, overspeed and structural damage – just my thoughts.
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Old 28th May 2011, 08:15
  #653 (permalink)  
 
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BUSS

The BUSS is only displayed once ALL ADRs are switched off iaw QRH.
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Old 28th May 2011, 08:23
  #654 (permalink)  
 
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jcjeant

Bottle of water

That should do it for Xcitation. NOW he will be embarrassed - perhaps?
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Old 28th May 2011, 08:26
  #655 (permalink)  
 
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I too am gobsmacked, that in this day and age Airbus have managed to design another generation of machine that doesn't do what you could reasonably& logically expect.
That's not how the system works. Yipoyan is confusing an autopilot trimming against a pilot induced control input with the normal FBW response. If the crew here had pushed on the stick with sufficient authority, at any speed, the trim would move nose down to match that response.
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Old 28th May 2011, 08:47
  #656 (permalink)  
 
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At 2 h 12 min 02, the PF said "I don’t have any more indications", and the PNF said "we have no valid indications"....snip... In
the following moments, the angle of attack decreased, the speeds became valid again and the stall warning sounded again."
So PF doesn't think anything is working and lowering the nose appeared to trigger a stall warning. How many people in that situation would continue to trust the stall warning system was working?
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Old 28th May 2011, 08:52
  #657 (permalink)  
 
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>So PF doesn't think anything is working and lowering the nose appeared to trigger a stall warning. How many people in that situation would continue to trust the stall warning system was working?

The question was asked in a private forum I am on and every pilot there (about 2-3 dozen) said they would have pushed the nose down. At 38,000 feet it is an absolute no-brainer.
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Old 28th May 2011, 08:58
  #658 (permalink)  
 
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I find the crash details very worrying in terms of pilot skills, however, I find the chatter on here absolutely terrifying! My god please tell me that most of you don't fly commercially?
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Old 28th May 2011, 09:05
  #659 (permalink)  
 
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Power PLUS attitude = Performance

On my A330-300, set 2.5 nose up and 78% N1 for S + L flight at most weights.

You should also know what sound levels to expect in the cockpit from the Airspeed in cruise.

If you think that you might indeed be too slow then set CLB detent and lower the nose to 0, wait till the noise level returns to near normal then set it back to 2.5 and 78%.

All the while checking the GPS groudspeed from the FM to use as a gross error check whilst flying the Aircraft as smoothly as possible until I exit the area and hopefully all returns to normal.

Anytime I approach an area of suspect wx I cannot avoid I try to do 4 things:
1/ sit the cabin crew down, 2/ check the current GS and listen to the noise
levels, 3/ note the current attitude and N1 to achieve current speed and finally 4/ brief the FO on all of the above just incase all hell breaks loose.

I've done this for the last 10 years or so. Why did I consciously do this? Because our Airline has had it's share of Iced up Pitot static systems causing overspeed and stall warnings On the 744, 777 and A330 types where the crew did what I suggest above ( ie: fly the damn plane on Attitude and N1 ) to a successful outcome.


At the end of the day

Power + Attitude = Performance.
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Old 28th May 2011, 09:08
  #660 (permalink)  
 
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jcjeant, thanks for the Bob Hoover video. I see him and Chuck Yeager every year at the Reno Air Races. He would come out to Riverside to a small airport to see Art Scholl a lot in the 60's. I was instructing aerobatics back then for Art. What a gentleman and great pilot. He is 89 now so we are lucky to still have him. I saw his last Shrike show about 10 years ago at Reno.

Also takes care of the water container being parallel to the earth idea.
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