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There’s another interesting spleen fact that I remember reading: people who survive flight ejections and hitting water at high speed tend to have had their sple

There’s another interesting spleen fact that I remember reading: people who survive flight ejections and hitting water at high speed tend to have had their spleens removed. Probably because otherwise the impact causes a rupture and you bleed out too quickly to survive.

krisoft 5y ago
What do you mean by “flight ejections”? Are we talking about ejection seat activations in military aircraft? This factoid sounds very suspect. Doesn’t most people who need to activate an ejection seat survive spleen or no spleen? Deaths may occur of course, an ejection is not without risks, but if everyone or nearly everyone with a spleen dies then my understanding of the risk associated with an ejection is seriously miscalibrated. Also the group of “active military pilots who had their spleen removed” must be a small group, likewise “military pilot who needed to activate an ejection seat” is a small group (but probably a bigger one than the spleenless group). So one would expect that there is almost nobody in the intersection of these two rarefied sets. Obviously this is all very handwavy reasoning, so who knows. But if you have a source that would be highly appreciated.
- sokoloff 5y ago
  The risk of injury in ejection is quite a bit higher than most people expect (typically over 25% towards 50% for older tech ejection seats). It’s still a way better scenario than riding it in. It is not uncommon for an ejection to end a pilot’s tactical jet flying days for medical reasons.
  - AvocadoPanic 5y ago
    Doesn't everyone remember what happened to Goose?
  - krisoft 5y ago
    > The risk of injury in ejection is quite a bit higher than most people expect I agree with you on that. But the question here is risk of death, not risk of injury. I don’t have reliable statistics but found this[1] article which says about ejections: “If you look at statistics around the world, the survival rate is greater than 92 per cent.” 1: https://amp.smh.com.au/education/how-dangerous-is-it-to-eject-from-a-fighter-jet-20120730-239mp.html https://amp.smh.com.au/education/how-dangerous-is-it-to-ejec...
  - dbcurtis 5y ago
    > It is not uncommon for an ejection to end a pilot’s tactical jet flying days for medical reasons. This exact thing happened to a friend of mine. Combat-rated Harrier pilot in the RAF. Had to punch out after a bird strike. Came out of the infirmary 4 months later, 1/2 inch shorter, flying career over.
  - Hallucinaut 5y ago
    Obviously if you're ejecting at or near supersonic speeds there are other stresses, but if the trauma is mainly from the ejection booster itself why is it still done with such force? It seems like a majority of ejections shouldn't be benefited by half a second less time to achieve clearance (or the jet itself could detect altitude and adjust the speed to increase survivability). I'm guessing this is also a function of trying to achieve lateral separation from the ensuing fireball in a crash but it surprises me rates are so high for injury.
    - TylerE 5y ago
      Because you have to get up and over the tail of the airplane without it slicing you like a cleaver.
      - londons_explore 5y ago
        A cleverer ejection seat could track the tail and body of the craft, and adjust the rocket force based on the trajectories in each case. Then you don't have to use enough force to avoid the tail in every case, but merely enough force to avoid the tail in this case, which will normally be far less.
        sokoloff 5y ago
        The aircraft being exited is often not in a factory nominal condition.
        TylerE 5y ago
        Solid fuel rocket, so no throttle.
        krisoft 5y ago
        Yes. And if someone is curious why are we using solid fueled rockets in this application: The big benefit of solid fueled rockets is that they are very reliable, and require no maintenance. They are basically a big “candle” composed of a mix of fuel and oxidizer. You can lit it a day after it was made or twenty years later it will work the same. The liquid fueled options have valves and other moving parts which can jam, corrode and degrade with time. So it would require frequent maintenance and would still be likely less reliable than the solid fueled variety.
- kayodelycaon 5y ago
  Ejection seats are likely to cause spinal fractures (20~30% by one study) and broken legs (no numbers). Tests on the F-35 showed lighter pilots could have their necks broken by the heavier helmet, so they had to add a switch that will slow down the ejection sequence. https://www.popsci.com/what-aircraft-ejection-is-like/ https://www.popsci.com/what-aircraft-ejection-is-like/
- inglor_cz 5y ago
  An ejection seat is basically a rather powerful small rocket with huge acceleration - much more forceful than what astronauts nowadays experience. Human bodies aren't built for riding such rockets. Injuries from ejections are pretty common and some of the ejectees are never fit to be combat pilots again.
  - krisoft 5y ago
    Yes, ejections are violent. Can cause injury, can cause death. No question about that. Spinal injuries are likely and ejections frequently end the flying career of pilots for medical reasons. What does this have to do with the claim in question? They claimed “people who survive flight ejections and hitting water at high speed tend to have had their spleens removed” This implies that if you look at the group of people who survived a flight ejection (over water and hit the water at high speed) you would find that most have no spleen. Do you find this plausible?
    - inglor_cz 5y ago
      A trauma surgeon would be a better fit to answer that question, but crushed spleens seem to be common in high speed impacts (car crashes, falls from ladders etc.), at least as far as I can judge it from my limited circle of friends who have had such experience.
theobeers 5y ago
This does come up in the story of Cliff Judkins, a Marine Corps pilot who, in 1963, survived a fall of 15,000 feet into the Pacific Ocean. He had had his spleen removed a few years earlier, and a doctor told him that was probably a factor in his not being killed by the impact. Judkins' account is worth a read: https://uss-la-ca135.org/60/1960Judkins-Knott.html https://uss-la-ca135.org/60/1960Judkins-Knott.html
- gonehome 5y ago
  Thanks - this is probably the exact story I was remembering.
- ohmahjong 5y ago
  Thank you for sharing such an incredible story - I would never have expected to read something so entertaining in the comments of a post about mouse splenectomies.
- ecf 5y ago
  Primary and secondary ejection systems failed and then his main parachute didn’t deploy. Whoever was maintaining that gear failed miserably.

krisoft 5y ago

What do you mean by “flight ejections”? Are we talking about ejection seat activations in military aircraft? This factoid sounds very suspect. Doesn’t most people who need to activate an ejection seat survive spleen or no spleen? Deaths may occur of course, an ejection is not without risks, but if everyone or nearly everyone with a spleen dies then my understanding of the risk associated with an ejection is seriously miscalibrated. Also the group of “active military pilots who had their spleen removed” must be a small group, likewise “military pilot who needed to activate an ejection seat” is a small group (but probably a bigger one than the spleenless group). So one would expect that there is almost nobody in the intersection of these two rarefied sets. Obviously this is all very handwavy reasoning, so who knows. But if you have a source that would be highly appreciated.

sokoloff 5y ago
The risk of injury in ejection is quite a bit higher than most people expect (typically over 25% towards 50% for older tech ejection seats). It’s still a way better scenario than riding it in. It is not uncommon for an ejection to end a pilot’s tactical jet flying days for medical reasons.
- AvocadoPanic 5y ago
  Doesn't everyone remember what happened to Goose?
- krisoft 5y ago
  > The risk of injury in ejection is quite a bit higher than most people expect I agree with you on that. But the question here is risk of death, not risk of injury. I don’t have reliable statistics but found this[1] article which says about ejections: “If you look at statistics around the world, the survival rate is greater than 92 per cent.” 1: https://amp.smh.com.au/education/how-dangerous-is-it-to-eject-from-a-fighter-jet-20120730-239mp.html https://amp.smh.com.au/education/how-dangerous-is-it-to-ejec...
- dbcurtis 5y ago
  > It is not uncommon for an ejection to end a pilot’s tactical jet flying days for medical reasons. This exact thing happened to a friend of mine. Combat-rated Harrier pilot in the RAF. Had to punch out after a bird strike. Came out of the infirmary 4 months later, 1/2 inch shorter, flying career over.
- Hallucinaut 5y ago
  Obviously if you're ejecting at or near supersonic speeds there are other stresses, but if the trauma is mainly from the ejection booster itself why is it still done with such force? It seems like a majority of ejections shouldn't be benefited by half a second less time to achieve clearance (or the jet itself could detect altitude and adjust the speed to increase survivability). I'm guessing this is also a function of trying to achieve lateral separation from the ensuing fireball in a crash but it surprises me rates are so high for injury.
  - TylerE 5y ago
    Because you have to get up and over the tail of the airplane without it slicing you like a cleaver.
    - londons_explore 5y ago
      A cleverer ejection seat could track the tail and body of the craft, and adjust the rocket force based on the trajectories in each case. Then you don't have to use enough force to avoid the tail in every case, but merely enough force to avoid the tail in this case, which will normally be far less.
      - sokoloff 5y ago
        The aircraft being exited is often not in a factory nominal condition.
      - TylerE 5y ago
        Solid fuel rocket, so no throttle.
        krisoft 5y ago
        Yes. And if someone is curious why are we using solid fueled rockets in this application: The big benefit of solid fueled rockets is that they are very reliable, and require no maintenance. They are basically a big “candle” composed of a mix of fuel and oxidizer. You can lit it a day after it was made or twenty years later it will work the same. The liquid fueled options have valves and other moving parts which can jam, corrode and degrade with time. So it would require frequent maintenance and would still be likely less reliable than the solid fueled variety.
kayodelycaon 5y ago
Ejection seats are likely to cause spinal fractures (20~30% by one study) and broken legs (no numbers). Tests on the F-35 showed lighter pilots could have their necks broken by the heavier helmet, so they had to add a switch that will slow down the ejection sequence. https://www.popsci.com/what-aircraft-ejection-is-like/ https://www.popsci.com/what-aircraft-ejection-is-like/
inglor_cz 5y ago
An ejection seat is basically a rather powerful small rocket with huge acceleration - much more forceful than what astronauts nowadays experience. Human bodies aren't built for riding such rockets. Injuries from ejections are pretty common and some of the ejectees are never fit to be combat pilots again.
- krisoft 5y ago
  Yes, ejections are violent. Can cause injury, can cause death. No question about that. Spinal injuries are likely and ejections frequently end the flying career of pilots for medical reasons. What does this have to do with the claim in question? They claimed “people who survive flight ejections and hitting water at high speed tend to have had their spleens removed” This implies that if you look at the group of people who survived a flight ejection (over water and hit the water at high speed) you would find that most have no spleen. Do you find this plausible?
  - inglor_cz 5y ago
    A trauma surgeon would be a better fit to answer that question, but crushed spleens seem to be common in high speed impacts (car crashes, falls from ladders etc.), at least as far as I can judge it from my limited circle of friends who have had such experience.

theobeers 5y ago

This does come up in the story of Cliff Judkins, a Marine Corps pilot who, in 1963, survived a fall of 15,000 feet into the Pacific Ocean. He had had his spleen removed a few years earlier, and a doctor told him that was probably a factor in his not being killed by the impact. Judkins' account is worth a read: https://uss-la-ca135.org/60/1960Judkins-Knott.html https://uss-la-ca135.org/60/1960Judkins-Knott.html

gonehome 5y ago
Thanks - this is probably the exact story I was remembering.
ohmahjong 5y ago
Thank you for sharing such an incredible story - I would never have expected to read something so entertaining in the comments of a post about mouse splenectomies.
ecf 5y ago
Primary and secondary ejection systems failed and then his main parachute didn’t deploy. Whoever was maintaining that gear failed miserably.