Carrying around liquid hydrogen in an airplane sounds like a pretty big deal.
Why? Airplanes routinely carry around tens of gallons of explosives.
You can either carry it as a rather ordinary, albeit very very cold, liquid in cryo tanks, or as a highly compressed gas in heavy pressure cylinders. Both ways have drawbacks and it’s not yet clear which way the future will go. But the betting is cryo-liquid, not pressurized gaseous.
As @Johnny_L.A just said, it’s not like filling flimsy sheet aluminum tanks with 10s, or 10s of thousands, of gallons of liquid avgas or jet fuel is exactly a safe, sane, or smart thing to do.
But we’ve learned how to make it work well enough. Most of the time. Sometimes we still have pretty big oopsies though.
A T-28 Trojan flight yesterday in Hungary:
That was odd looking. Started out as a barrel roll sort of maneuver, but by the end was more falling than flying.
Dishing out of the bottom of a barrel roll is pretty easy to do. Start out level to slightly climbing but finish with the long axis of the roll inclined down 30 or 45 degrees. It takes a lot of altitude to recover from that. Done right, the early phases have a large climb angle and the later phases have a matching descent angle so the long axis of the whole thing nets to roughly level with a hump in the middle.
Maybe they got past 180 towards 270 degrees of roll and got scared they were too low with too much downward vector. And then pulled hard enough to do an accelerated stall while still partly inverted. Not gonna work.
For aerobatics you need to have a practiced plan for how to abort each maneuver in the best way possible. And clear criteria for declaring an abort because you’re too steep / slow / fast / low to finish the planned maneuver.
There are lots of ways to drive past the point of no possible recovery while things still look decent enough to the undiscerning eye. The only fix is to not be undiscerning.
To my non-professional aerobatic eye they could have recovered from their early mistakes with the right escape plan. I see no reason to assume a malfunction, but if there was one that certainly would not help. Ditto for G-LOC; that was probably not a factor.
Welp, it’s over. I am done.
I’ve flown my last airline flight. It’s vanishingly unlikely I’ll fly professionally again. And not all that likely I’ll do much, if any, hobbyist flying. We shall see, and never say “never”.
Like so many before me, it’s boggling to contemplate the total amount of knowledge of places and routes and rules and procedures and techniques and specifications and limitations rattling around in my noggin that suddenly are so much useless trivia, good only for bar bets with other retired aviators.
I finished with fighters and USAF 35 years ago. I’ll be doing damned good to get another 35 years post-airline. But I’ma gonna try.
Congratulations (?), LSL. I hope you won’t be retiring from the SDMB. I always enjoy reading your contributions to this thread (and others as well).
I recommend looking into flying gliders (sailplanes). I tried this a good while back “just to see what it’s like” and was completely captured.
Great suggestion!! Thank you.
I’ve got 5 whopping hours of sailplane time from back in my high school days. Enjoyed it greatly, and that was all in low-performance Sch 2-33 or equivalent. I always wanted to at least try some of the actually performant sailplanes.
A challenge for me now is living in South Florida, hardly a mecca of sailplaning. Taking a month and going to e.g. Colorado Springs or Reno / Tahoe or someplace in NZ and living at the gliderport for a month sounds great.
Frankly, sorting out how much togetherness & how much apartness from my fairly new wife will work for both of us is very much a work in process. And over what durations subject to what limitations. We shall see how that settles out.
Kinda related to sailplanes, around here there are a lot of powered parachutists. They can do ridge soaring along the beach riding the updrafts as the sea breeze hits the beachfront high-rise condos, apartments, and hotels. Looks like great fun and relatively affordable. Shame about the noise.
Well, dang. Maybe you could be a flight instructor. Fly when you want to, and get paid to do it. I’m still hoping and praying to be able to afford to get back into the saddle.
The moral tradeoff between passing along my wealth of experience vs. denying some young pilot the chance to gain experience and break the 1500 hour barrier by me taking his job is an interesting dilemma.
LSL: Do you have an estimate of the total hours flying you have done?
After reading your posts for many years, I was kind of hoping to be in a plane flown by you at some point (not that I would have known). You’re a credit to your profession. We could all ask for as much. Congrats.
Not many really for as long as I’ve done this. I keep old fashioned paper log books and it’s about 10,500 total pilot hours and as I recall about 2,000 Flight Engineer hours on top of that.
I’ll be adding the last couple trips and finalizing my totals in the next day or so. I’ve done a special bottom-line summary at each major milestone along the way. Whether this is the last, or just the next milestone remains to be seen. But it’ll have some totals and if my vague recollections are far wrong I’ll update y’all here.
Thanks all for the kind words.
You could learn rotary wing… Just sayin’! Keep posting for sure!!!
You see that big fan on top? That’s actually a paper shredder for $100 bills. Works great I’m told; shreds whole packets of ‘em to nothin’ in no time at all. 
I have a bit of unofficial time in OH-6s and UH-1s courtesy of the US Army and the long-suffering taxpayers. Thank you all. That was fun and I’d love to do it again if we can do something about that shredding problem.
This must be a very powerful bittersweet moment, I imagine pretty emotional both in terms of nostalgia and in terms of happy anticipation of a well-earned life of leisure. I hope the happy anticipation dominates your thoughts. Most of us retired codgers will tell you it’s great. I’ve had many happy years of varied work life, including some greatly satisfying jobs where I had a tremendous amount of independence, but having settled into retirement I wouldn’t go back to any of it. Wishing you all the best on this celebratory occasion! 
Maybe you can get a flying car.
Good luck and have some fun!
As long as it comes with a matching treadmill.
I was taught by 2 pilot friends. One was a high time airline pilot and the other had serious hours in a variety of planes and eventually flew commercial. They knew how to fly. They taught me stuff that was the result of real flying experience. The kind of things that got me out of a bad situation. The kind of stuff you know how to do.
New pilots need to learn from people like you.