8 Captivating Facts About the Air France Flight 447 Mystery

Illustration for article titled 8 Captivating Facts About the Air France Flight 447 Mystery

Over two years ago, Air France Flight 447 crashed midway through a flight from Sao Paulo, Brazil and Paris, France. It took weeks to find any trace of the Airbus A330 plane, and to this day, investigators are unable to determine with 100% certainty what caused the crash.

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New York Times reporter Wil S. Hylton revisited the scene of the crash this week in an epic, 7500 word feature article that not only retells the story of the crash, but goes deep into the efforts to uncover what happened. Here are a few highlights from the article which might help you tackle this beast and wrap your head around it:

• Flight 447 crashed in Tasil Point, which is sort of a no mans land between South America and Africa. It's the point at which a plane's air traffic control station switches between the two continents. Radio frequencies become harder to pick up, conditions can turn ugly fast, and if something goes wrong, you're a long way from anywhere familiar. It's home to a vast sprawl of underwater mountains, and it is where over 3,000 pieces of wreckage have been found.

• Most recently, three autonomous Remus 6000 submarine units developed by the Woods Hole Oceanic Institute have been scouring the ocean floors of Tasil Point in search of clues. Searching the bottoms for 20 hours at a time, these units collect over 15,000 photos per run, while research teams pore over the data non-stop in 12 hour shifts. In their most recent run last month, these units uncovered new photos of wreckage on the ocean floor.

• Much of the speculation regarding the Flight 447 incident revolves around sensors on the front of planes called Pitot probes. Before crashing, the plane auto-beamed 24 alerts regarding the Pitot probes to the air control station in Brazil They help measure airspeed, which is essential for the fly-by-wire system to properly work. As it happens, the Thales AA Pitot probes have had a history of freezing and malfunctioning in conditions similar to those at Tasil Point on the night of the crash (17 Airbus flights reported problems between 2003 and 2008). When the probes aren't working, the plane has to be manually controlled until they regain functionality. That, in turn, allows for a thin margin of error. To fully understand why this would make a pilot nervous, read this paragraph about manual plane control:

For a passenger jet like the A330, the ideal cruising speed is about 560 miles per hour. If you go much faster, the center of lift moves back on the wing, pushing the nose down and increasing velocity, until you soon approach the speed of sound. At that point, shockwaves develop on the wings, interrupting the flow of air and reducing lift. The nose of the plane then gets forced into a dive that the pilot may not be able to pull out of. Then again, if you go too slow, the airplane stalls and falls. A plane must maintain a minimum speed to generate lift, and the higher it travels, the faster it must go. At 35,000 feet, the gap between too fast and too slow narrows ever closer. Pilots call it coffin corner.

The author even recounts a tale of a plane crash once caused by an insect nest that built up in a Pitot probe, causing it to malfunction. Yikes.

• The article points out that the black box is one of the most archaic, unchanged pieces of technology in all of commercial flight. Existing in its current form for over 50 years, many aerospace experts believe planes should stream data back to a central location via satellite. However, there might not be enough available satellite bandwidth to stream as much data as a plane would generate. One proposed solution is a button that would begin livestreaming data when a pilot suspected their plane was malfunctioning, which some believe could be implemented soon.

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• The official investigation is being conducted by the French Bureau of Inquiry and Analysis. Normal. Things get interesting however, when you add in the fact that France is also a key investor in both Air France and Airbus. The New York Times points out that this is common practice for many nations, but some still believe France is trying to sweep this mystery under the rug.

• One interesting fact extracted from the autopsies of the crash victims is that there were no signs of burns on any bodies. Just fractures, bruising and blunt trauma. What does this mean? The plane probably didn't explode and likely hit the water in one piece. While unlikely, it's possible some could have survived the crash, and if they did, could have lasted as long as 12 hours in the 80 degree waters of Tasil Point.

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• After the crash, nobody arrived at Tasil Point until 11 hours after the plane disappeared. Protocol for a situation like this is to generate a virtual flight that takes different known factors into consideration such as weather. But after that, the traffic controllers spent a few hours casually confirming with other air traffic controller had spotted or contacted Flight 447. No one alerted a search and rescue team until 4 hours after the crash, and a boat wasn't sent out until 10 hours.

• Whether or not anyone can definitively figure out what caused the crash remains to be seen. However the path between Brazil and France remains unaltered. The only thing that's different now is the flight number, which has been changed to flight 445. To date, more than $25 million has been spent investigating this crash. Be sure to read the whole story over at [NY Times]

DISCUSSION

ted-alexandre-old
Ted Alexandre

Hmm. At the risk of being pedantic, can I help? Editing or the lack of it at the Times, is one thing, but at Giz, I do expect the tech writing to be a little more on its game.

TASIL isn't a place at all, it's a waypoint (after INTOL, another non-place) on the airway that AF447 was using that night, and it's about 350 nm out at sea. It's one of the last waypoints IIRC before the handoff from Brazilian control to Senegalese control for planes enroute from Brazil to Western Europe. World airspace consists mostly of mnemonic or pronounceable waypoints. The waypoint that roughly corresponds to Ground Zero in NYC is HEROS, for example. This is Hilton's and the NYT's editing issue, not yours.

This flight was sending data back to Paris in the form of ARINC. This is the "auto-beam" you're describing later, although certainly no one in Brazil at a "control station" was listening. These usually maintenance-related messages are forwarded via land stations to a subscriber, in this case Air France, so that the subscriber/airline has an idea of what to expect when the aircraft returns home to a maintenance base. There was a final cascade of data (the "24 messages") that came from AF 447 as it was meeting its demise, all of which was received by AF. It wasn't examined in real time, because that's not the purpose of the information being sent. Reading it is like hearing Dave pulling the memory blocks on HAL-9000; a robot slowly dying.

The Pitot tubes in question were, in fact, in question at the time of the flight, as you mention. There are known "pitch & power" procedures for dealing with suspected pitot tube failures. Why the crew of AF 447 seems to have not been able to apply these procedures is one of the matters at hand.

The buffet margin, which is the "thin margin of error" you mention, exists at all times, and is dependent mainly on weight, altitude and speed. Normal flight regimes are always inside the this margin, but the thinness of the margin you cite means that any lack of reliability of airspeed indication should have put the pilots on a specific checklist immediately. There's nothing per se about an A330 or any Airbus that makes those margins thinner however.

Any aircraft since the 777 is tube-shaped computer with fuel tanks and turbines attached to it. Other than the operational flow and installation location, I will wager that most aeronautical engineers of 50 years ago wouldn't recognize a modern black box if it fell on their head.

France was a key investor in Air France; since its merger with KLM, the French state owns less than 20%. EADS, the parent corporation of Airbus, is by design 30% a "French" company, partially held by the government and partially by Lagardère, a private company. It is also a "German" company and a "British" company and a "Spanish" company, partially held by governments, none of which have anything to gain from Airbuses falling from the sky. Airbus, like Boeing, is intensely involved in investigating crashes when they happen, and does so with BEA (in France) and with the FAA in the US. The FAA and the NTSB play very much the same political game in the US.

"Some still believe" doesn't really pass muster, though. Alongside Air France, Airbus is facing a mandatory manslaughter investigation in France in the matter. Its reputation is on the line; people are dead. The company has staked its larger reputation on two things in the 21st century, the A380 (not relevant here) and the extremely automated nature of its approach to commercial transport, even more so than Boeing: the plane is always right. For an A330 to fall out of the sky without a near-certain explanation as to why it happened leads pilots and more importantly airlines down a logical path that could mean they will select a Boeing for their next order until the issue is explained. Airbus is absolutely not served by leaving the matter unresolved, nor is modern commercial aviation.