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Transportation Math Space

Could a Meteor Have Brought Down Air France 447? 884

niktemadur writes "In light of an Air Comet pilot's report to Air France, Airbus, and the Spanish civil aviation authority that, during a Monday flight from Lima to Lisbon, 'Suddenly, we saw in the distance a strong and intense flash of white light, which followed a descending and vertical trajectory and which broke up in six seconds,' the Cosmic Variance blog team on the Discover Magazine website muses on the question 'What is the probability that, for all flights in history, one or more could have been downed by a meteor?' Taking into account total flight hours and the rate of meteoric activity with the requisite mass to impact on Earth (approximately 3,000 a day), some quick math suggests there may be one in twenty odds of a plane being brought down in the period from 1989 to 2009. Intriguingly, in the aftermath of TWA flight 800's crash in 1996, the New York Times published a letter by Columbia professors Charles Hailey (physics) and David Helfand (astronomy), in which they stated the odds of a meteor-airplane collision for aviation history up to that point: one in ten."
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Could a Meteor Have Brought Down Air France 447?

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  • The suck! (Score:5, Funny)

    by Scutter ( 18425 ) on Friday June 05, 2009 @09:40AM (#28222315) Journal

    How much does God hate you to put you in a meteor strike, a plane crash, and a lost-at-sea drowning all in the same day?

  • by justleavealonemmmkay ( 1207142 ) on Friday June 05, 2009 @09:41AM (#28222319)

    Yeah, right, Air Comet has no intrest whatsoever to accuse a meteor...

  • Cars (Score:3, Insightful)

    by Krneki ( 1192201 ) on Friday June 05, 2009 @09:41AM (#28222323)
    If meteors can be so dangerous to airoplanes, why we don't see them hitting cars or buildings more often?
  • Deceit (Score:5, Funny)

    by DoofusOfDeath ( 636671 ) on Friday June 05, 2009 @09:41AM (#28222327)

    In light of an Air Comet pilot's report to Air France, Airbus, and the Spanish civil aviation authority that, during a Monday flight from Lima to Lisbon, 'Suddenly, we saw in the distance a strong and intense flash of white light, which followed a descending and vertical trajectory and which broke up in six seconds

    A company called Air Comet is saying they saw a meteor do it?

    Does anyone else smell some blame-shifting?

  • Nobody Knows (Score:5, Insightful)

    by stoolpigeon ( 454276 ) * <bittercode@gmail> on Friday June 05, 2009 @09:44AM (#28222361) Homepage Journal

    So any guess is equally likely/unlikely until there is more information. I think even a lot of the 'debris' they've found is probably not from the jet.
     
    They disengaged the main flight control system because they thought it was flying too fast in the turbulence, or was causing too much passenger discomfort.

    They slowed down to a very narrow margin above stall speed.

    They hit a 100 mph updraft, causing the AOA to go beyond the stall angle.

    They went into a high-speed dive.

    Because they were on manual backup control they could not exert enough force on the controls to recover before Vne or the flutter speed of something was attained.

    Something (wing, tail surface, aileron, spoiler... whatever) tore off.

    The resulting asymmetric forces caused a violent departure from normal flight.

    At a speed probably above Vne, that resulted in the aircraft structure being instantly destroyed.

    This accounts for the fact that there was a an elapsed time of approximately a minute between the first failure messages and the last.

    If it had been a bomb, or simple explosive decompression from another source, that time would have been at most a few seconds, and more likely zero.

    The crew was struggling, all three physically, to pull the aircraft out of a high-speed dive and nobody had a chance to radio what the hell was happening.

    That's my call.

    • Re:Nobody Knows (Score:5, Insightful)

      by Lurker2288 ( 995635 ) on Friday June 05, 2009 @10:16AM (#28222887)
      "So any guess is equally likely/unlikely until there is more information. I think even a lot of the 'debris' they've found is probably not from the jet."

      I don't think you really mean this. It's obvious prima facie that some explanations are more likely than others: regular old human error is more likely than a fatal meteorite strike is more likely than an attack by evil space aliens. It'd be more accurate to say that we lack the information to assign realistic probabilities to the different scenarios.

      Pedanticism thus ended.
    • Re: (Score:3, Insightful)

      by AJWM ( 19027 ) *

      They disengaged the main flight control system because they thought it was flying too fast in the turbulence, or was causing too much passenger discomfort.
      They slowed down to a very narrow margin above stall speed.
      They hit a 100 mph updraft, causing the AOA to go beyond the stall angle.

      So far, so good -- although "very narrow margin" isn't even necessary given the 100mph updraft, they could have been 100 mph above stall speed and had problems. (Of course one has to factor in that their stall speed when con

  • No (Score:5, Informative)

    by Richard_at_work ( 517087 ) <richardpriceNO@SPAMgmail.com> on Friday June 05, 2009 @09:45AM (#28222387)
    The Air Comet aircraft was over 2,000km away from where Air France 447 was supposed to be, and the pilots report has been discounted by everyone in the industry.
  • No (Score:5, Funny)

    by Anonymous Coward on Friday June 05, 2009 @09:46AM (#28222399)

    Gravity Brought Down Air France 447.

    We still don't fully understand it yet, but gravity is probably THE number one reason for aircraft crashes.

  • One in twenty? (Score:3, Insightful)

    by 140Mandak262Jamuna ( 970587 ) on Friday June 05, 2009 @09:52AM (#28222513) Journal
    I don't know what the assumptions were, but it seems to be an over estimate by orders of magnitude. Space, 3D space is really really huge, unimaginably huge. In WW-II they had to protect the lumbering bombers from the swift fighters. So they tried arming a few bombers with very high number of machine guns. Short Sudeland flying boat was actually called a "Flying Porcupine" because of the number of gun barrels sticking out of it. With guns firing at 1000 to 3000 rounds a minute, with tracer bullets, with trained gunners aiming the guns, they still could not reliably hit the fighters. Both Luftwaffe and RAF and USAF independently had to learn the same lesson with very high cost. Yes, meteors could hit an airplane. But if their calculations shows odds of 1 in 20 for the last 20 year period, I am very sure they have over estimated the odds.
  • by 140Mandak262Jamuna ( 970587 ) on Friday June 05, 2009 @09:58AM (#28222589) Journal
    I mean, why do we still have to have the black box in the aircraft? Is it possible to radio the parameters continuously and record it on land? Thus even when the plane is lost, the data is safe. What kind of bandwidth is needed to transmit that level of data?
    • by stoolpigeon ( 454276 ) * <bittercode@gmail> on Friday June 05, 2009 @10:20AM (#28222953) Homepage Journal

      A ton of data is already constantly sent out and recorded, but the amount the black box records is pretty immense and would be pretty expensive. If cockpit voice data was to be included in this I think there would be resistance from pilot unions.

      Tack on the fact that very few people die this way compared to many other ways - it would make more sense to put cameras and microphones in operating and hospital rooms than beam everything live from a cockpit to ground. (The hospital thing is one example- there are many others. Say cameras and microphones in every automobile.)

    • ADS-B (Score:4, Interesting)

      by sponga ( 739683 ) on Friday June 05, 2009 @01:41PM (#28225967)

      UPS uses this system on all their planes, not only for air safety but also for tracking.
      http://en.wikipedia.org/wiki/ADS-B [wikipedia.org]

      Pilots and air traffic control love the system, it allows them to see visually where everyone is located/speed/atlitude/GPS and all broadcasting is done from the plane to ground based radar.

      Doesn't take much bandwidth at all, as they can use the VHF channel, 978 MHz UAT and another mode.

  • by UttBuggly ( 871776 ) on Friday June 05, 2009 @10:19AM (#28222941)

    Nothing I've read or know from flying in the Air Force and working at the USAF Flight Test Center at Edwards AFB indicates this was a collision....with a meteor or anything else.

    I personally believe the aircraft encountered weather conditions that Airbus never tested against or thought possible. 100+ mph updrafts, as some have reported, would definitely cause control issues.

    By that, if the plane was on autopilot or simply "in trim" and suddenly went nose up, it would have required immediate and CORRECT actions to handle. Having recently read the transcripts of the commuter crash, where the pilots were inattentive, then compounded a stall problem by pitching up, I think the real cause was a combination of events, including pilot error.

    If a lightning strike caused electrical and control problems while the pilot(s) were trying to recover from a sudden attitude change, they were screwed. Going into a flat spin at 35000+ feet at 400 knots would have ripped the airframe to pieces. Given the reported debris field, and no apparent evidence of explosion, I'd bet that's what likely happened; unexpected event combined with control/system problems resulted in an unrecoverable spin and the aircraft came apart well before impact.

  • by gnatman64 ( 688246 ) on Friday June 05, 2009 @10:24AM (#28223009) Homepage
    Phil Plait has just put up a blog post explaining that it's probably a lot less likely than than these other guys have made it seem. http://blogs.discovermagazine.com/badastronomy/2009/06/05/flying-the-meteoric-skies/ [discovermagazine.com]
  • by Nibbler(C) ( 574581 ) on Friday June 05, 2009 @10:33AM (#28223147)
    As exciting as meteor or motherships would be, I still think that simplest reason hold true in this case. An ex-Air Force weatherman, gives quite a low down on the weathersystem directly on AF447's path at the time the last messages came. http://www.weathergraphics.com/tim/af447/ [weathergraphics.com]
  • by Ogive17 ( 691899 ) on Friday June 05, 2009 @11:36AM (#28224195)
    For those following the story you might have already read they believe the debris they picked up is not from the Air France flight. Is it possible there was a mid-air collision with an unregistered plane/jet?
  • by SigNick ( 670060 ) on Friday June 05, 2009 @11:41AM (#28224269)

    Here you can see the last automatically transmitted ACARS messages of AF447:
    http://img32.imageshack.us/img32/7547/acarsaf447d.png [imageshack.us]

    Personally, I think this incident was caused by a combination of factors.
    ALL speculations tread on thin air before the CVR and FDR are recovered, but based on current data I would QUESS:
    -it is a dark, stormy night with no horizon or any landmarks visible
    -160km/h updraft brings moist air to a much higher flight level than usual
    -this causes sudden icing of the pitot tubes
    -this causes the flight computer to think that the plane is in danger of stalling, and it lowers the nose automatically
    -the crew switches auto-pilot and flight envelope protection partially off, or a (positive) lightning strike disables them
    -the crew has no good idea about the true speed and orientation of the plane
    -inside the cumulonimbus' horrible gusts the crew over-stresses the composite flight controls while fighting turbulence
    -the place exceeds it's maximum speed and/or structural load (G-) limits
    -two-three minutes later the agony of the 228 souls on board finally ends as the slowly disintegrating plane hits the sea near the speed of sound, instantly ripping them to stamp-sized bits

    Here's more detailed speculation about possible causes and a crude analysis, taken from Usenet:

    1. Terrorism or other malicious use of explosives

    A bomb explodes in the cargo hold, crippling the aircraft's control systems or starting a structural break-up that eventually leads to loss of control.

    Supportive evidence: According to Wikipedia, a bomb threat had been made on an earlier flight. Lack of communications from the flight crew indicates either a sudden event or something which lead to significant problems that the crew had to focus on. This would be consistent with the effects of a bomb. The automatic messages about computer system failures sent by the aircraft could be interpreted either as indications that the aircraft's movements have exceeded the limits that the systems can handle, or as indications about direct damage to the systems. A flash of light has been seen by other aircraft in the area.

    Evidence against: While terrorist organizations exist both in France and Brazil, there has been no recent activity. No organization has claimed responsibility for the act. There is no specific evidence about a bomb. Nothing is known about any individuals or organizations who would have non-terrorism related reasons for malicious acts. It seems too big of a coincidence that a bomb would go off at the same time as the aircraft flies through very rough weather. Finally, what we know about the sequence of ACARS messages indicates that loss of cabin pressure was the last message in the sequence. This appears to rule out an explosion, unless it was contained in the hull and only damaged internal structures and components. This seems unlikely. The flash of light was apparently seen from too far to be caused by AF 447 related problems.

    Open questions: Where are the cargo holds that are used to carry the passengers' luggage? Are they physically close to the computer and navigation systems that ACARS messages reported as failing? And obviously, physical evidence would be useful.

    Verdict: Can most likely be ruled out

    2. Explosion or other rapid, harmful reaction from the cargo

    The sequence of events is as in the terrorism theory.

    Supportive evidence: The sequence of events fits this theory, as it does the terrorism theory. The cargo might have shifted at the time of turbulence, initiating the reaction.

    Evidence against: See the evidence regarding the malicious use of explosives. In addition, there is no information that the cargo could have contained something harmful.

    Open questions: More information is needed about what was in the cargo, and who cargo was taken from.

    Verdict: Can most likely be ruled out

    3. Fire

    Fire starts in cargo hold, in systems, or somewhere else in the aircraft. Eventually the fire either disables a sufficient number of aircraft systems leading to a loss of control, or incapacitates the crew.

    Supportive evidence: Systems turning themselves off one by one could be caused by fire. Cabin pressure warning might have been generated through the crew's actions to let the air out of the cabin in an effort to put out the fire. The location of the debris indicates that the crew might have turned back in an effort to get to the nearest airport (but it has now become uncertain if any debris has actually been found). The long duration of the ACARS messaging (4 minutes) seems to indicate a slowly progressing event like fire, as opposed to sudden event like a bomb or structural failure. The fire might have been initiated when the aircraft hit heave turbulence 10 minutes before the problems began.

    Evidence against: It seems unlikely that the fire could have spread fast enough that the crew would not have notified air traffic control. Why would fire happen exactly at the same time as the aircraft flies through extreme weather? Wouldn't a cargo hold fire lead to an ACARS message?

    Open questions: More information is needed about the ACARS messages and whether they could have been caused by fire.

    Verdict: Possible, but there are several open questions

    4. Weather

    4.1. Turbulence

    Turbulence breaks up the plane, or causes it to enter an uncontrollable dive.

    Supportive evidence: Very high winds and turbulence were detected in the area. Tim Vasquez's analysis indicates that there were strong updrafts in the exact area that the flight was expected to fly through. The crew manually sent a report of turbulence 10 minutes before the accident.

    Evidence against: other flights in the same time frame and route did not encounter significant turbulence.

    Verdict: Possible, but there are several unexplained questions. In particular, why was only AF 447 affected? Or did several issues contribute to the outcome, along with turbulence?

    References: Tim Vasquez's analysis: http://www.weathergraphics.com/tim/af447/ [weathergraphics.com] AP reports that the pilots sent a report about turbulence and timing of the various events: http://hosted.ap.org/dynamic/stories...CJAC&SECTION=HOME&TEMPLATE=DEFAULT [ap.org]

    4.2. Lightning

    Lightning hits the aircraft and causes either structural or systems damage.

    Evidence against: Tim Vasquez's analysis speaks against this.

    Verdict: Unlikely, by itself

    4.3. Hail

    Hail hits the aircraft and causes either structural damage, shuts the engines down, or breaks cockpit windows and incapacitates the crew.

    Supportive evidence: There has been rumors about ACARS icing messages.

    Evidence against: Tim Vasquez's analysis speaks against the occurrence of significant hail. Unless the crew was incapacitated, mere engine shutdown would have lead to the crew contacting the air traffic control. What we know about the sequence of ACARS messages indicates that the cabin pressure loss happened last, which speaks against the accident beginning with the breakage of the cockpit windows.

    Open questions: The sequence of ACARS messages needs to be known in more detail.

    Verdict: Unlikely

    4.4. Ice

    Icing causes the aircraft to lose its flying capabilities.

    Supportive evidence: See the evidence for the hail theory.

    Evidence against: Tim Vasquez's analysis speaks against the existence of supercooled water at the flight level and conditions that the aircraft was flying through.

    Verdict: Unlikely

    4.5. Sensor icing

    Speed or other sensors are iced over or malfunction in some other way, leading to the computers or pilots taking incorrect action, causing the aircraft to stall and/or break up.

    Supportive evidence: There are rumors of icing-related ACARS messages.

    Evidence against: Normally the sensors (such as the pitot tubes) are heated. Icing should not affect them, unless the crew failed to turn the heating on, particularly severe icing conditions existed in the strom cell that they flew through, or hail hit the sensors. Also, Tim Vasquez's analysis speaks against the existence of suitable icing or hail conditions.

    Open questions: More data is needed about the actual ACARS message sent by the aircraft.

    Verdict: Unlikely

    References: BBC article: http://news.bbc.co.uk/2/hi/americas/8083474.stm [bbc.co.uk]

    5. Systems malfunction

    A repeat of the Qantas incident: ADIRU failures cause the aircraft control systems to believe that a steep dive and/or nose-up is needed, leading to a loss of control and/or aircraft break-up.

    Supportive evidence: See GlobeEx's posts.

    Evidence against: It seems unlikely that the crew would have been unable to control the situation at FL35, when crews in the previous incidents were able to regain control with the loss of few hundred feet of altitude. There are some reports that AF uses ADIRUs from a different manufacturer. The long duration (4 minutes) of the automatic messaging speaks against a very sudden event.

    Open questions: At this point, we do not yet know if AF used the same manufacturer's ADIRU (Litton) as was involved in the Qantas incident. Rumors indicate that the equipment comes from a different manufacturer, namely Honeywell. No previous incident is known on a Honeywell ADIRU.

    Verdict: Unlikely, though more information is needed. Perhaps combined with a pilot error and the effects of the bad weather this theory is more likely, e.g., maybe the recovery was not executed in time.

    6. Collision

    Collision with another flying object such as aircraft or meteor.

    Supportive evidence: This could cause similar effects as a bomb, so in some sense it fits the sequence of events. A flash of light was seen, which might also be from a meteor

    Evidence against: There is no known collision with another aircraft. Meteor collision is extremely improbable. The flash of light was apparently seen from too far to be caused by AF 447 related problems.

    Verdict: Very, very unlikely

    References: White flash of light: http://ca.news.yahoo.com/s/reuters/0...orld/international_us_france_plane [yahoo.com]

    7. Fuel tank explosion

    A TWA800 -like event.

    Supportive evidence: Fuel tank explosion, like other explosions, would fit the sequence of events observed through ACARS and lack of a mayday message from the crew.

    Evidence against: By this time, the center fuel tank would have been very cold. TWA800 accident required a warm fuel tank for the vapors to develop in suitable quantity.

    Verdict: Can be ruled out.

    8. Explosive decompression

    A cargo door or other part departs the aircraft, leading to an explosive decompression.

    Supportive evidence: ACARS message about cabin pressure.

    Evidence against: The sequence of messages is wrong, as cabin pressure drop was not the first one.

    Verdict: Can be ruled out

    9. Crew error

    9.1. Flying into severe weather

    The crew flies directly into the most severe part of the storm

    Supportive evidence: Tim Vasquez's analysis of the weather system indicates that it would have been very hard for AF447 to avoid the weather system alltogether, but there is no evidence to suggest that they flew directly into the worst part.

    Open questions: Exact flight path is needed.

    Verdict: They did fly into the weather, but it is unknown if this was avoidable or if they flew to the worst part. Note that in combination with another problem, such as radar failure the likelihood of this theory would be much higher.

    9.2. Flying too high

    Trying to fly over the weather system and exceeding limits of the aircraft, leading to a "coffin corner" situation and an unrecoverable stall.

    Supportive evidence: None, except perhaps the diffult and hard-to-avoid weather system. Tim Vasquez's analysis points to very high updrafts, which might have contributed to an involuntary gain in elevation.

    Open questions: Additional information about the aircraft's altitude is needed.

    Verdict: Unlikely, it is very hard to believe that an experienced crew would on purpose violate the aircraft's limits

    9.3. Excessive corrective action

    The crew over-corrects the effects of turbulence or high wind in a manner similar to AA587.

    Supportive evidence: This might have lead to separation of control surfaces, which in turn might have lead to autopilot and other control systems giving up. The sequence of ACARS messages might match this situation.

    Evidence against: A330 is a fly-by-wire aircraft which may not allow excessive control input. On the other hand, the first ACARS message received indicated disengaging the autopilot and the control systems entering the alternate law mode. This mode has less protection against exceeding the safe flight envelope.

    Open questions: More information is needed about the exact ACARS messages and in what conditions they will be sent. More information is needed about the effects of excessive control inputs in the A330 fly-by-wire system.

    Verdict: Very unlikely, unless something else happened, disabling the autopilot and then the crew accidentally exceeded the structural limits of the aircraft.

    10. Prior damage from a ground collision

    The aircraft in question collided in 2006 with an Airbus A321 aircraft. An undetected problem in the wing of the A330 might have stayed dormant until the airframe was stressed in severe turbulence.

    Supportive evidence:

    Evidence against: The maintenance procedures for inspecting and correcting collision damage are quite extensive, and it is hard to image something was missed.

    Verdict: Unlikely

    References: http://www.jacdec.de/news/years/ALL2006.txt [jacdec.de]

    11. Combination of factors

    11.1. Systems failure and crew error

    A systems failure initiates an event and the crew fails to respond properly or in time. For instance, a radar failure might lead to the crew flying blind into the worst part of the weather. Or disengaging the autopilot or Airbus flight envelope protection leads the crew to overstressing the airframe.

    Supportive evidence: There is no strong evidence of any single event that is know to bring down the airplane. There is evidence of some of the control systems (autopilot, ADIRU) shutting down. While these events should be recoverable, it is easy to imagine a crew error that exacerbates the situation, particularly in bad weather.

    Evidence against: There is no information about any errors by the crew. Many of the systems, such as the radar electronics, have backups, and are not expected to completely fail.

    Open questions: CVR and FDR are needed to find out more.

    Verdict: Possible

    11.2. External event and crew error

    Icing, turbulence, lightning or lightning causes an upset, and the crew reacts in an inappropriate manner or fails to recover in time. Or, alternatively the crew makes an error in setting the proper speed for the type of weather (turbulence, updrafts) which later leads to a stall or a spin.

    Supportive evidence: There is no strong evidence of any single event that is know to bring down the airplane. There is evidence of conditions that are potentially harmful (like turbulence), but that are known to be experienced by a large number of aircraft, so its not clear why these events alone would have caused the accident. But it is easy to imagine a combination of two problems, or one problem and a crew error to lead to a disaster.

    Evidence against: There is no information about any errors by the crew.

    Verdict: Possible

    Open questions: Again, CVR and FDR are needed.

    References: Incorrect speed has been mentioned in the press as a possible cause of the accident: http://ca.news.yahoo.com/s/reuters/0...orld/international_us_france_plane [yahoo.com]

    11.3. External event leading to fire

    Turbulence rocks the plane, leading to a short circuit and fire. Lightning hits the plane and causes a fire. The fire eventually spreads to the whole aircraft.

    Supportive evidence: The crew reported turbulence, and at least turbulence and maybe even lightning is known to exist in the area. For the other evidence, see the fire theory.

    Evidence against: See the evidence regarding fire; it is odd that no ACARS or crew message would have been received from a slowly progressing event such as fire in the cargo hold.

    Open questions: Again, CVR and FDR are needed.

    Verdict: Possible, but there are open questions

  • by cylcyl ( 144755 ) on Friday June 05, 2009 @12:19PM (#28224851)

    Proof is in the video [youtube.com], ~36s mark

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