Air France plane missing?

[Evan]

the latest - standard (pitot) has been developed to enhance water drainage encountered during heavy rain conditions on take-off or landing phases.

regards

I assumed that it had to do with drainage and possibly anti-ice improvements. What would make these improvements specific to take-off and landing phases?

[Drizzt]

Hello again,
A quick search about the pitot thing leads here....

http://www.mediapart.fr/club/blog/michbret/080609/af-447-air-france-lenteur-ou-laxisme

I hope someone here could translate that because it seems very interesting.
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[beachfront]

The wind speed and its direction is never the issue per-se.
The CHANGE in the wind speed and/or direction is. Specially if that change is of great magnitude and sudden.

Examples:

1) You are flying with no wind and suddenly a gust of 100mph hits you from behind. The air flowing over the wings is suddenly going 100mph slower. The wings could be simple unable to produce enough lift with so less air flowing over them, and if so you must let the plane sort of "fall" (under control) or face a stall if you try to hold the altitude.

2) Say that you are flying with no wind and suddenly a vertical gust of 100mph hits you directly from below. The air that was flowing parallel to the wing is now coming partially from below (combined speed of the horizontal plane speed and vertical gust speed). That will make the AoA increase a lot, possibly stalling the wing or braking it.

I appreciate the response. Makes perfect sense w/ your explanation.

[Jpmkam]

Engineer decodes Air France Flight 447 emergency messages

I just finished listening to a podcast where an avionics engineer goes over the final messages sent by the Air France Flight 447 plane before it crashed.

The error messages sent by the plane show that multiple computer failures happened simultaneously, starting at 02:10 GMT, when a series of 14 warnings and failures emerged at once.

Addison Schonland, president of Innovation Analysis Group, and Michael Ciasullo, IAG's managing director of consulting services, led the podcast discussion. The engineer, who went only by Darryl, and his interviewers were careful not speculate.

Darryl is introduced as an engineer familiar with the the Honeywell ACARS system. His full name is not given because of the sensitivity over the crash, Schonland said. He does not work for Air France or Airbus.

He explains each ACARS message line by line. The ACARS is the aircraft's communications addressing and reporting system, which sends short pieces of data to other aircraft and satellites. When investigators talk of the "automatic messages" that give clues as to why the plane crashed, they are referring to the ACARS messages.

(You can see the ACARS for Flight 447 here. PDF.)
The cryptic lines contain chilling meaning.

First, the auto pilot system disengaged. Then came a basic auto flight message warning. Next, something within the flight control computer failed. Then, warning flags appeared on the personal flight displays of the captain and co-pilot. Then the rudder exceeds the limits of normal flight. And on it goes.

"With all of these failures, they don't have the information that they need to fly the aircraft in a safe environment," Darryl says. "If the pilot or first officer don't have any display functioning, then they're flying blind in the night. ... You're trying to fly the aircraft with no technology."

The last message received is a cryptic "213100206ADVISORY" warning at 02:14 GMT. It indicates loss of cabin pressure.

"There's so much going on, the pilots don't know what to do other than take a hold of the stick and fly the aircraft, because the airplane is not flying itself," Darryl said. "If this was happening in a clear day in the middle of the day, you'd still be in serious trouble, but at least you'd know if you were climbing or descending."

http://blog.seattlepi.com/aerospace/archives/170669.asp?source=mypi

[Timmerich]

Hello again,
A quick search about the pitot thing leads here....

http://www.mediapart.fr/club/blog/michbret/080609/af-447-air-france-lenteur-ou-laxisme

I hope someone here could translate that because it seems very interesting.
@@++

But there is nothing new in it, not what we had already discussed here....

[Timmerich]

A question to our 330 Pilot here, DN,

what will happend, when you lost all 3 pitot tubes? Is the next effect, that the system switch to alternate law? And what will the system do in alternate law with the wrong data?

Do you have a posibillity to switch manually to direct law so you have the bird without control computers??

Does pilots train this situation?

[the dave]

Interesting info in post #904.

Does the A330 not have any backup gauges that aren't computerized? Not even an artificial horizon that will stay operational even in the event of a computer failure?

[old timer]

I assumed that it had to do with drainage and possibly anti-ice improvements. What would make these improvements specific to take-off and landing phases?

i am not a pilot and hope that any pilot correct me but i assume:

1- because both are critical phases of the flight and not enugh time to perform any troubleshooting by the pilot in case of ice bulding up unlike the situation during cruse where the procedure allow the crew to maintain throtel angel and steady flight till they figure out the the reasons

2- rain / snow at low alt. and moisture at hi alt will lead to ice build which will lead to clogges then to wrong readings and this is why these tubes are heated by 115 volts (from the ACFT AC electrical power ) during flight to prevent ice build up and to drain the water
it is important to highlight that airbus or the authority are not mandating to change these tubes but only recomending it
note: 3 type of pitot tubes curently exists

be safe

[Vincentomoh]

Louis Gonzalez, the tail failed after the copilot made multiple unecessary rudder commands going in the opposite direction, so the A300's tail went back and forth before it finally failed. The copilot wasn't blamed, though. It was American Airlines training that was blamed.

You expressed my thoughts much better than I ever could!

What troubles me most about what happened to AA537's tail was how quickly it failed (have you seen the computer simulation from the FAA?). It happened in seconds & the pilot was blamed. Is it acceptable to passengers to fly an airliner whose tail can be catastrophically damaged in a second or two by a pilot by moving the rudder pedals full left then right? Tails have broken off before, but I've never seen it happen so quickly under such weather conditions - there was only wake turbulence, maybe.

The Air France A330 in question is a newer design and FBW (unlike the A300) yes, but isn't its construction & materials similar to the A300?

I am very concerned about the A300, A330/340 vertical stabilizers under loads (design loads and added safety factors - are they enough?).

[AVION1]

Interesting info in post #904.

Does the A330 not have any backup gauges that aren't computerized? Not even an artificial horizon that will stay operational even in the event of a computer failure?

Basic stand-by electric horizons with an emergency power pack is a NO-GO in many MEL lists, it sometimes depends on the airline, some airlines will buy one and install it to the panel !!!...I wonder why Air France did not have one?

[Evan]

Au Contraire

But there is nothing new in it, not what we had already discussed here....

There are some very useful new things to note in that article.

1) the ACARS fault code 34111506 as sent from AF447 specifically references a pitot tube (anemometer) failure.

2) Thales, the pitot tube manufacturer, had issued a bulletin indicating a weakness on this model by September 2007 and advised to change them on all types of aircraft (A320, A330, A340). It cited a lack of drainage that would make them susceptible to icing. However, the bulletin was not binding (that means, the change is not mandatory. The problem was observed in the A320 and not the A330/A340 because short haul a/c are more at risk, spending more time in icing conditions (This answers a question I raised earlier). This contradicts earlier reports which said that Airbus raised the recommendation themselves. (An earlier post also mentioned that the Pitot tubes on AF447 were BFGoodrich products, not Thales products.)

2) In August and September 2008, on two occasions, Air Caraïbes Airbus A330 encountered severe icing conditions at 35,000 feet in areas of turbulence (probably tropical clouds). The pitot tubes malfunctioned and airspeed became erroneous. The pilots mentioned in their report the same warnings as the ones on flight AF447 (messages reported by ACARS are also displayed in the cockpit on the screen ECAM). The pilots eventually forced a manual defrost of the pitot tubes and the end is happy. However, the pilots wisely ignored STALL alarms or it could have ended much worse. To read, because it is very instructive: http://www.eurocockpit.com/docs/ACA.pdf


3) In September 2008, Air Caraïbes replaced their pitot tubes immediately after the incidents. Air France had been implementing the changes with less urgency.

[AVION1]

The complete rudder and vertical fin folks...nothing is missing, the whole assembly came off from the airplane.

[Jpmkam]

The complete rudder and vertical fin folks...nothing is missing, the whole assembly came off from the airplane.

Good photo thanks for posting. Too bad the lower attach point area isn't more visible in it.

[wktaylor]

In the early 90's I investigated a mid-air collision mishap where an F-16 "gently" [walking speed] collided with the OB wing of a tanker. The radome failed upward tearing out the pitot/AOA sensors. As a result, the aircraft pitched up and rolled violently off the taker wing. After struggling a few seconds trying to regain control, F-16 flight control system appeared in-op to the pilot who finally left the acft at about 7000-ft msl.

During discussions with the F-16 engineers, it was determined that the catastropic loss of the radome and subsequent tensile/shear tearing of pitot/AOA wire harness undoubtedly led to shorting of the air data computer; and subsequent false/random out-puts to the flight control surfaces. Recovery would NEVER have been possible.

Unfortunately, the curse of fly-by-wire systems is the dependance on the flight control computers recieving reliable air data and the absence of electrical system discontinuities (shorts, power surges, dead-circuits, etc).

OH Yeah, the 35+year-old tanker [fly-by-cable] the F-16 collided with, flew +2-hours to the nearest airfield with significant outer-wing and aileron damage... and a very scared crew (everyone had parachutes on).

[3WE]

Can we question composite rudders?

There's a general tendency for composite and plastic stuff that we encounter in day to day life to be stiff and brittle.

We now have two composite vertical stabilizer things that have broken off quite cleanly.

As Gabriel pointed out, we have evidence that one was as strong as (actually stronger than) it was supposed to be. And, we have every reason to believe that this one was over-stressed too.

Given that they were significantly over-stressed , it's not really valid to rant that they are cheap plastic things that are going to predictably break everytime we stress them.

BUT...

Is it valid to ask if traditional, metallic rudders would have performed differently, and if we can remember any metallic tails being fished out of the water, in excellent condition with such clean breaks?