Air France: This One's Gonna Be Tough

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The tragic disappearance of Air France 447 over the South Atlantic this week has reignited the Thomas Aquinas approach to accident speculation. Aquinas's famous proofs held that anything complex, mysterious or too beautiful for man to create was the work of God, therefore God existed. The "god" in this case is the Autoblame switch for the highly complex fly-by-wire system in the Airbus line of aircraft.

Thus, if an Airbus goes down and lacking any other credible information, blame it on the Buses' automation. For a while last winter, the dark theories were swirling around USAirway 1549's plunge into the Hudson, the story being that the software protected the engines, not the airplane, thus preventing a routine restart, 50 pounds of bird guts notwithstanding.

My perception of the airline pilot community is that it's divided on this. (Go see for yourself at sites like PPRuNe.)There's an e-mail making the rounds today citing a little-reported incident in which an A-330's autopilot did an uncommanded pitch over, injuring a number of passengers. The underlying supposition is that this isn't an isolated incident.

Pilots with long experience in the Bus sometimes say that the fear of fatal glitches is overstated. Most of them seem to like the airplanes. I've talked and corresponded with pilots who fly only Airbus airplanes, pilots who fly only Boeings and pilots who have flown both. If there's any consensus that the Airbus is fatally flawed, it has escaped me. And that's not to suggest that it is or it isn't, but to predict that accident investigators—or maybe plaintiff's lawyers—will raise this issue again, as well they should.

Being of relatively simple mind, I favor the Occam's razor approach. In other words, maybe the automation had nothing to do with it and all the ACARs maintenance fault messages that streamed from the airplane in its final moments were effect, not cause. They're meaningless distractions. Maybe the crew just steered the thing into a level 6 cell and the wings got torn off or the windshield was holed by hail or the 10,000-year lightning strike fried the wiring. Students of the Aquinas school may have trouble with that one because it raises the uncomfortable question of an experienced four-stripper making a horrible error. All of us want to believe that this is just not possible.

This is an interesting counterpoint to last week's discussion about a relatively green regional pilot who may have simply stalled an airplane, killing everyone on board. We rationalize that one by saying he should never have been in the left seat in the first place. I don't know how experienced the 11,000-hour Air France skipper was on the route, but I'm confident it wasn't his first day.

I guess I'm just irretrievably cynical. Having read thousands of accident reports (mostly GA) by now, I'm spring-loaded to suspect the human factor first for the same reason cops always suspect the husband. As was my reaction in Sister Clara's second-grade catechism indoc, the God thing doesn't always add up.

FRIDAY MORNING REVISION: I'd highly recommend a careful read of this in-depth weather analysis by Tim Vasquez, not so much because it suggests weather as a cause--it doesn't--but because it illuminates skillful use of satellite, surface reporting and other data available. In the foregoing blog, I have merely raised weather as the largest "what if" factor. Vasquez's work informs that question.

Comments (31)

I saw a commentator on an evening news program state that turbulence could not bring down an airliner. I bet the turbulence in a level 5 or 6 tstorm could handily spit out any airliner in pieces. It will be interesting to see how this develops. If that is the case, it makes one wonder what would ail a crew to fly into such weather.

Posted by: Josh Johnson | June 4, 2009 1:13 PM    Report this comment

This incident prompted me to go back and re-read John Deakin's Pelican's Perch #28 column. I miss seeing new columns from him.

Posted by: brian smyla | June 4, 2009 8:14 PM    Report this comment

Heck, I miss all of the columns. It's been 2 months since the last one.

Posted by: Roger Dugan | June 6, 2009 2:10 PM    Report this comment

Ditto, miss the columns. At least Bertorelli has new stuff every couple of days. Heck, even the letter to the editor only gets updated every couple of weeks. Get the content back!

Posted by: Jeff B | June 6, 2009 9:50 PM    Report this comment

I read an interesting comment by a Spanish pilot at the end of last week, who while flying a B747 on the same route some years earlier in similar weather encountered a rapid and large increase in OAT (from -48C to -19C) which put them firmly in coffin corner (and 15,000kg over gross for the conditions). He says it's the only time he ever had encountered conditions like that in 40 years.

If you read Spanish (unfortunately the Google translation gets it so wrong it's not even wrong - so get a native speaker if you need a translator) - his article is here:

http://www.aeroclubdetoledo.com/content/index.php/component/content/article/20-aviacion-comercial/44-airbus-330-air-france

He speculates that had he remained on autopilot and not descended, he may have been keeping Air France company at the bottom of the ocean today.

Posted by: Dylan Smith | June 8, 2009 5:16 AM    Report this comment

35000 ft altitude in the Stratosphere with no apparent weather that can be seen with the naked eye or measured with Met technology and therefore not able to be forecast, there lurks the meteorological phenomenon of CAT (clear air turbulence); could this be the culprit ??

Posted by: George Brown | June 8, 2009 6:46 AM    Report this comment

just checking that my comment has been posted and I see it has.

Posted by: George Brown | June 8, 2009 6:51 AM    Report this comment

With 5 years of experience flying the Bus, and many more years flying many different Boeings, & having flown thru the inter tropical convergence zone numerous times,I find it hard to accept that the airplane caused the accident. The Bus has many very positive features that Boeing needs, it is extremely reliable, and it is an excellent flying airplane. The Bus would have prevented the accident in Buffalo because it very nicely wouldn't stall and would smoothly fly you out of danger, unless you turned off the automatic protections. The only problem that I found with the Bus was in high altitude mountain wave the autothrottles would get behind the airplane, so that it was adding power when the airspeed was already high and reducing power when the airspeed was already low. This was easily over come by manually controlling the throttles.

Posted by: J H Webb | June 8, 2009 10:11 AM    Report this comment

As usual, there's way too much speculation from people who profess to know better, but then offer their own views anyway. The sides are too predictable -- Boeing vs. Airbus, pilot error vs. systems, "I've seen this before" vs. "This must be something new". How about we all wait for this to play out? And that includes Mr. Bertorelli, who has now placed himself in the "don't blame Airbus" camp with this column. (And, I'm sorry, but his reading countless GA accident reports doesn't have a thing to do with professional pilots flying 4 year old state-of-the-art airliners.) If experience has shown us anything, it is that the most likely scenario is a chain of events occurred to bring down this aircraft. Any one of the events would be simple to recover from, but in combination they overwhelmed the system (human and mechanical). And it takes a lot of money, time, and patience to flesh out the full chain. Remember TWA 800?

Posted by: Stuart Ball | June 8, 2009 12:25 PM    Report this comment

Well, what about the AA587 crash in 2001? It makes me wonder why the Airbus software would allow the flight controls to be manipulated in such a way that the airframe would suffer catastrophic failure. Wasn't the full authority control system designed to prevent that type of issue?

Posted by: brian smyla | June 8, 2009 12:54 PM    Report this comment

The New York Times published an article on June 2 that included this partial sentence about a debris field that included; “an orange life vest, an aircraft seat, a drum, kerosene and oil,” from an earlier statement from the Brazilian military. This was later deemed not to be from the Flight 447. So apparently the airliner seat was from another airliner or other aircraft crash that no one is interested in? I have yet to see a clarification accounting for this second debris field. Two debris fields in roughly the same area; another theory to consider? In any airline disaster all scenarios, no matter how unlikely, must be considered. Don Ledger author "Swissair Down"

Posted by: Don Ledger | June 8, 2009 12:59 PM    Report this comment

My question is why it took so long to find the wreckage. I live in Papua New Guinea and just about every operator here (Bell 206, Cessna 185 thru Boeing 767) has flight following hardware/software that keeps the ops center informed of every aircraft in the fleets location, speed, altitude and heading. This optimises ramp operations - no-one waiting for a late aircraft or late for an early aircraft. A side benefit is that if the aircraft crashes the system locks on the last reported position - they report every few seconds to few minutes and that can be customised - fast aircraft short delay, slow aircraft longer period. This is low cost technology (cheapest is under USD 2,000 so why do Air France not have an equvalent.

Google "satellite tracking" +aircraft

Posted by: Monty Armstrong | June 8, 2009 5:24 PM    Report this comment

Brian: The AA587 crash was with an Airbus A300, which was *not* fly by wire - the A300 first flew in 1972* - but rather "old fashioned" hydraulic controls with no software. The older Airbuses are not fly by wire.

* Fly by wire was used commercially first by the BAC/Aerospatiale Concorde, which entered service a few years after the A300.

Posted by: Dylan Smith | June 9, 2009 3:49 AM    Report this comment

Fellow aviators, I am surprised at the lack of comment to my post of 9th June where I suggested that CAT (clear air turbulence) in the Stratosphere may have been a factor in the tragic event under discussion. Historically, CAT has been cited (see Google references) as a possible factor in difficult to explain air disasters but because CAT is generally defined as a meteorological phenomenon (see Aviation Manuals on Met and Nav for commercial pilots)that can occur in the Stratosphere, perhaps it is not taken seriously because it cannot be seen by the naked eye or met technology and therefore cannot be forecast for the benefit of flight planning and is perhaps considered as an *inconvenient truth* that may serve only to frighten air travellers. I am interested to know if anyone else out there is on the same wave length because as Paul Bertorelli infers, we should not dis-regard any possibility that may help to solve this tough one.

Posted by: George Brown | June 9, 2009 6:08 AM    Report this comment

Thanks, Dylan. I assumed the A300 was also fly by wire.

Posted by: brian smyla | June 9, 2009 7:02 AM    Report this comment

George, it has already been documented that satalite imagery showed massive T-storms at the time of the accident. CAT was not a factor.

Posted by: Roger Dugan | June 9, 2009 7:08 AM    Report this comment

A big frustration with that tragic Air France flight, is that the aircraft was flying "feet wet", i.e. over water. Therefore, the flight recorder may never be recovered. That also happened with the Korean Air Lines 747 that was shot down by the Soviet Union in 1983, by the way.

The late Captain Len Morgan mentioned the possibility of data being continuously transmitted to suitable receiving stations on land, so that the same flight data that a flight recorder records, will be available if an aircraft goes down at sea.

We know the last words spoken by the flight crew of a turboprop commuter aircraft that was recently lost over land. We also know every word exchanged between Captain Sullenburger and ATC on that famous day last January. It would certainly be useful to know the last words spoken by the Air France flight crew, not to satisfy the public's morbid curiosity but to enable duly constituted authorities to determine what went wrong, and how we can make aviation safer for all.

Posted by: Alex Kovnat | June 9, 2009 7:48 AM    Report this comment

I believe we can all agree that at this point all is speculation as to what brought Air France 447 down until the black boxes are retrieved. So with that caveat the following comment is posted. I tend to agree with Mr. Bertorelli that the simplest theory is that the flight came apart in a severe thunderstorm and is the most plausible. The statement that "Common sense is not very common" comes to mind in this matter.

Posted by: Michael Pardis | June 9, 2009 8:40 AM    Report this comment

I think this plane was bombed. Very few have noticed that France the week preceeding the accident opened a French airforce base on arab soil in the UAE. There are numerous militant arab organizations that have programmes to prevent "infidelities" permanently establish themselves on arab soil. The Wall Street Journal Europe May 25 has a full article about the new French airforce base inaugurated by president Sarkosi. This base is only about 100 miles of the land of Iran.

Posted by: Lars Hjelmberg Hjelmco Oil Sweden | June 10, 2009 2:28 AM    Report this comment

2 things: 1)I see a link/lesson with this trajedy and the Scott Crossfield crash-no matter how many hours you have, do not fly into the teeth of a t-storm and avoid them using the satellite tech available.

2)No one has noticed that the stabilizer was found largely intact, clearly sheared off clean from the fuselage ala A300 crash off Long Island. As the industry moves to world-wide manufacture of components that get bolted up at the final assembly plant, it seems that no one engineer has to take responsibility for the whole airframe once bolted together.

Posted by: Stephen Alexander | June 10, 2009 3:46 AM    Report this comment

The software may not be to blame:

Attitude plus power equals performance and we agree on that. However, airline pilots are trained to fly airspeed airspeed airspeed. There is quite a few accidents related to this mentality – two notable ones that come to mind are the 727 out of New York which believed they were going supersonic while pitched up 40-50 degrees due to iced up pitot tubes and the other the Chicago DC 10 where the engine tore off. In that case with the loss of the slats the airplane needed more airspeed to maintain control and the pilot flew the Engine out speed into the ground. Putting the nose down to gain speed would have saved the day for the DC 10.

That aside the picture above has my mind ticking. Remember the airbus A300 out of New York shed its engines after take-off. The co-pilot overworked the rudders which had the authority at manoeuvring speed to tear the rudder off. Finding this rudder whole and separated leads me to believe that there may be a similarity. As I understand they did not limit the rudder authority but issued only an advisory on use of the rudder.

Posted by: Christopher Basham | June 10, 2009 4:11 AM    Report this comment

I am type rated on the Airbus 320 and 330, but currently flying the 757/767 internationally. I had an similar incident 20 years ago like this accident. I was flying a 737 at 35,000' and encountered heavy clear air turbulence, with each jolt the aircraft slowed up a bit to maintain altitude by raising the pitch attitude, the autothrottles responded by a going to maximum thrust, but were unable to maintain our airspeed in the "coffin corner".

I contacted ATC and got a lower altitude before our wings stalled out and lost control of the aircraft, and then started a descent to maintain our airspeed.

The Airbus (or Boeing) is only stressed for heavy turbulence in wings level flight, normal flight control law. Once you lose control and stall, you will roll on your back, it can quickly overspeed and go into basic law. This gives you the ablility to overstress the aircraft and tear the aircraft apart.

I think this is a real possible explanation of this accident, since it usually takes at least 10-15 minutes for ATC to respond to any changes to an Oceanic clearence using antique HF radios (shortwave).

The Oceanic ATC system needs to be overhauled using satellite communications, GPS navigation, and tracking. My car and cell phone both use GPS, why aren't the airlines required to do the same?

I'll also bet the aircraft was in command by the IRO sitting in the Captain's seat with the least amount of experiance, while the Captain was on his rest break on this 11 hour flight.

Posted by: Bob Colvin | June 10, 2009 10:00 AM    Report this comment

Can someone clarify for me my the press (and seemingly Air France, etc) are focusing on pitot tubes? A pitot tube is a pretty simple thing. The Airbus has several of them and all of them are heated. Is this just some oversimplification (the press refers to them as sensors and some say complex sensors) or am I missing something? As far as this tragedy is concerned, pitot tubes seem unlikely culprits (alone), the automatic systems could be a cause, but I am firmly in the flew-into-major-thunderstorm camp. Why did an experienced pilot fly into a major CB? Lots of possibilities -- night flight so he did not see the structure of the CB (flying to the upwind side is relatively safe, the downwind side much less so), radar not properly aligned so looking at precip in the wrong part of the storm, underestimation of intensity (either due to a very strong storm or pilot underestimation).

Posted by: Kingsley Hill | June 10, 2009 10:57 AM    Report this comment

Well the issue with the pitot tubes is that they feed array of systems, and if the sensed value is "#@#@$" then the systems will be confused and they will shoot errors or switch off. Unfortunately this includes also the rudder limiter. I have read an nice account from Air Caraibes (french only, but could be understood) and to me the error messages are quite similar to the ones sent through ACARS from AF here the link http://www.flightglobal.com/cgi-bin/mt/mt-tb.cgi/54847 And yes the cleanly snapped rudder reminded me of the Airbus in New York as well

Posted by: Martin Pavlik | June 10, 2009 4:25 PM    Report this comment

Air Niugini and many other operators had problems some years back with A300/A310 pitots that continuously iced up and it took Airbus a long while to admit there was a problem. As Martin said - they are connected to too many systems on the most modern aircraft and even simple sytems respond to blocked sensors in a dramatic way - see BerginAir and Air Peru crashes

Posted by: Monty Armstrong | June 10, 2009 5:22 PM    Report this comment

I buy the possibility of "other sensors" some of which are more complex and possibly subject to sending "#@#@$" messages. But pitot tubes?? As I said earlier someone has to tell me HOW a pitot tube can fail other than being blocked or icing up and if icing is the issue someone will have to explain to me how several pitots can ice up simultaneously since all are heated. I accept the possibility of an explanation, but I have yet to hear one.

Posted by: Kingsley Hill | June 10, 2009 6:10 PM    Report this comment

Pitot tubes are connected to air data computers can which send the "#@#@$" messages. Likewise AOA sensors feed the air data computers and these are also subject to icing.

Posted by: Monty Armstrong | June 10, 2009 6:38 PM    Report this comment

ok, I am buying that...so still not understanding why the pitots are getting the rap. ...and pitots are usually connected to a number of things including air-data computers and the lowly pressure airspeed indicator.

Posted by: Kingsley Hill | June 10, 2009 6:52 PM    Report this comment

All;

I realize the difficulty in avoiding speculation on the causes of such a unfortunate accident. While the speculation above is producing some great thoughts on non-radar flying, anecdotal experiences with sensor systems, manufacturers, etc, it is not shedding too much light on the actual chain of events that conspired to bring down the A330.

What we OUGHT to do is use this opportunity to remember a few basic but potentially life-saving operational tid-bits: 1. Give thunderstorms ample clearance, even if it means significant deviation. You can be late by an hour, or be late forever...your choice. 2. Regardless of what aircraft you fly, memorize as many pitch/power/speed combinations as possible. In the event of sensor/display failure, knowing what throttle settings and pitch angles yield what performance could very well be the difference between saving the day, or having the aircraft come apart. 3. If you do get caught in a storm, throttle back to maneuvering speed or less, try to keep the aircraft level, hold heading, and don't try to hold altitude.

Posted by: Avi Weiss | June 10, 2009 10:46 PM    Report this comment

Here's some profesional analysis of the weather at the time.

http://www.weathergraphics.com/tim/af447/

Though still speculation on the scientific level, it sure does look like severe turbulance and not iced up pitot; auto-throttles; over-under airspeed. Remember, the autopilot was not engaged and thus being hand flown (whether intentional or an over-ride).

Regardless, this analysis strongly suggest an in flight brake up due to turbulance.

Posted by: Roger Dugan | June 15, 2009 9:20 PM    Report this comment

I am with Paul. The stream of data preceeding the lost of the aircraft reminded me of the data sent by Columbia as she broke up - the heat sensors in the wings and and the flight data information briefly described overheating and automatic corrective actions until contact was lost. I think the telemetry from the airbus may be similar - symptoms rather than a cause. I also don't agree that Paul is ruling out the aircraft - human factors is what I would bet on followed by some unforseeable weather phenomenon. I found the posts about OAT spikes and CAT interesting. I thought that the northern hemisphere Subtropical Jet sat a little higher than the region where the crash occured however.

Posted by: john hogan | June 25, 2009 9:54 AM    Report this comment

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