From the Wikipedia article on Atmospheric Refraction

"The atmospheric refraction is zero in the zenith, is less than 1′ (one arcminute) at 45° altitude, still only 5′ at 10° altitude, but then quickly increases when the horizon is approached. On the horizon itself it is about 34′ (according to FW Bessel), just a little bit larger than the apparent size of the sun. Therefore if it appears that the setting sun is just above the horizon, in reality it has already set."

"As the atmospheric refraction is 34′ on the horizon itself, but only 29′ above it, the setting or rising sun seems to be flattened by about 5′ (about 1/6 of its apparent diameter).

I misread the minutes for degrees due to the need for some glasses.

I still think that given altitude that a flash of light would be visible well over the horizon especially at 35 thousand feet.

From the Wikipedia article on Atmospheric Refraction

"The atmospheric refraction is zero in the zenith, is less than 1′ (one arcminute) at 45° altitude, still only 5′ at 10° altitude, but then quickly increases when the horizon is approached. On the horizon itself it is about 34′ (according to FW Bessel), just a little bit larger than the apparent size of the sun. Therefore if it appears that the setting sun is just above the horizon, in reality it has already set."

"As the atmospheric refraction is 34′ on the horizon itself, but only 29′ above it, the setting or rising sun seems to be flattened by about 5′ (about 1/6 of its apparent diameter).

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If the locations are correct that is about 20 degrees and that is within the range of Atmospheric Refraction. I know it is a difficult concept - 20 degrees of curvature and 20 degrees of bend make viewing possible.

http://www.csmonitor.com/2009/0610/p02s08-usgn.html

Sorry it took so long to fabricate the news story.

Apparently the CS Monitor has bought into the theory, or at least found enough merit to publish the following article:

http://www.csmonitor.com/2009/0610/p02s08-usgn.html

As it happens, two people with "Al Qaeda ties" were found on the manifest for whatever that's worth.

I do think that it's been determined that the Spanish pilot who saw a flash was too far away from where Flt 447 was to have seen anything though.

Let's stop feeding the trolls.

Maybe a laser air speed sensor:

http://www.baesystems.com/Newsroom/NewsReleases/2005/press_130620058.html

Thank you! This explains why I'm always seeing those White Sands missile explosions from my home in Portland, OR :)

Refraction is a phenomenon which requires fairly abrupt changes in density of the refracting substance (like the surface of water or glass). In air, refraction occurs as a result of local mixing of layers of air with varying density ("heat waves" are a common example). It is "possible" that the air between the two flights was very precisely configured so as to create the exact degree of refraction necessary for an explosion to be seen, but it is far less likely than getting thousands of people to tell perfectly consistent lies about almost all of the significant facts of the incident currently known.

Look, what we currently know about this incident makes a terrorist attack very unlikely as the cause, but not impossible. But your insistence on ignoring or twisting every piece of evidence inconvenient to your conspiracy theories makes me wonder if your real name is not Robert F. Kennedy Jr.

@jared2:

But there must be some technology better than pitot tubes for measuring airspeed.

I've often wondered why. Inertial navigation (http://en.wikipedia.org/wiki/Inertial_navigation) should do it. I've assumed that INS is too expensive. OTOH, airspeed at the wings is needed in order to know what the lift/drag values are. I suspect this is why Pitot is used; not so much to know how fast the plane is going relative to ground.

Jared, pitot tubes are a very simple and highly reliable mechanism for measuring airspeed. The only real failure mode is blockage, due ice or other conditions (several failures have been blamed on wasp infestations, for instance). Obviously, there are characteristics of high-altitude weather in very special circumstances which were not well-enough understood by the makers of this particular pitot, which lead to icing.

Off the top of my head, I can't think of another way to reliably detect airspeed other than to measure pressure differences (which is what a pitot does).

Borduin,

Thank you for information re: pitot icing. This is obviously highly significant and I don't understand why Patrick would dismiss it.

As for the LW who pointing out that pitot tubes measure airspeed, and GPS would measure groundspeed - I realized my error soon after I posted. Thanks. But there must be some technology better than pitot tubes for measuring airspeed.

Atmospheric refraction.

It was only 19 degrees away.

Guess how many degrees the atmosphere bends light.

The following blog post describes two of the Airbus 330 pitot icing incidents I mentioned in my first post:

http://www.flightglobal.com/blogs/unusual-attitude/2009/06/af447---the-air-caraibes-story.html

Of note:

- The A330s in these incidents had the same model of pitot airspeed sensor as AF447.

- Pitot icing was experienced at cruise altitude while flying through clouds (not storms, per se), causing unreliable speed indication.

- The unreliable speed indication led to a sequence of flight control system reconfigurations very similar to those seen from AF447 ACARS messages.

- One of the warnings issued as a result of unreliable speed indication was a warning of imminent stall. The pilots' checklist for unreliable speed indication was inconsistent (contradictory) in how this message should be treated; the pilots chose to ignore it, which was the appropriate response.

- The airline (Air Caraibes) chose to replace their pitot sensors with an upgraded model as a result of these incidents, and requested Airbus to clarify unreliable speed indication checklists.

Of course, these incidents do not prove anything about what occurred in the case of AF447. Still, the correlation is obvious, and easily explains the early focus on pitot sensor icing as a very possible significant factor.