F-35 pilot held 50-minute airborne conference call with engineers before crash

But why was there water in the hydraulic system in the first place?

"Must be the water."

Ferrari F1 internal meme?[1]

[1] - https://www.youtube.com/shorts/nCoxNLdUSaE

Because US$40 billion was apparently not enough to avoid problems that did not affect cold war era airplanes.

Maybe everything was colder back then so they took it into account ? Dunno.

Likely contamination of ground handling equipment [1]. Unfortunately can happen. I wonder if the hydraulic fluid is hygroscopic or something?

1. https://www.pacaf.af.mil/Portals/6/documents/3_AIB%20Report....

Hydraulic brake fluid is glycol ether based and hygroscopic. Planes usually use mineral based fluids which are not, but heck if I know what the F-35 uses.

Quoting ChatGPT (and after a quick sanity check),

The F-35 Joint Strike Fighter uses a specialized hydraulic fluid that’s based on a synthetic ester formulation, not a petroleum-based fluid.

Specifically, it uses phosphate ester–based fire-resistant hydraulic fluid (commonly in the MIL-PRF-83282 or newer MIL-PRF-87257 class).

Apparently the older phosphate-ester based hydraulic fluids were hygroscopic but I'm not sure if the newer variants are.

It could be condensation in expansion tanks, or it could be rain into open containers on the ground, or someone could have mistakenly poured cooling liquid (or something else) into the containers, or into the hydraulic system itself, or ...

Thanks for the link. This is much more useful than the news article.

Sounds similar to DOT-5 brake fluid.

Maybe this: https://en.wikipedia.org/wiki/Tributyl_phosphate

"The major uses of TBP in industry are as a component of aircraft hydraulic fluid, brake fluid, and as a solvent for extraction and purification of rare-earth metals from their ores"

It might be better if it is hygroscopic as the water won't separate and risk forming ice plugs in the hydraulic lines.

Cold War era planes also had a lot of problems. The YouTube channel “not a pound for air to ground” has some great content about planes from that era, and reliability was sometimes absurdly poor.

I don't get the joke. Did he pee himself, or the pit stop crew member is being useless?

But 1/3 volume? That’s a LOT of contamination.

Avoid problems like humans putting water into the hydraulic system? [Virtually] no amount of money is going to solve that.

Yes, lets condition people to never reveal they used ChatGPT. Even though the response seems accurate.

[1]https://hiigroupasia.com/f-35-aviation-ground-support-equipm...

WW2 planes never suffered from confused sensors bringing the plane down and they were much much cheaper and effective. Look at the kill rate of the spitfire. Even heavy bombers had a decent chance of bringing down fighters.

The latter

Yeh the sanity check involved researching the milspecs listed and the connection to the F35 program.

Got to say the pictures of the hydraulic drum (and pump) in the DoD report are very confidence uninspiring.

But what ground handling equipment? Does the hydraulic fluid need to be replaced after normal usage? Any intervention is an opportunity for mishaps, failure and sabotage. I'd expect the unlimited F-35 budget to come up with some formula that resists fire, cold, heat and pressure and doesn't need refills and/or with water detectors and other safety-critical chemical sensors in the hydraulic system.

Everything leaks hydraulic fluid, it's just an inherent property of any system with dynamic seals.

https://www.youtube.com/shorts/d3ruv-IsGMo