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

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.pdf?ver=z-QJglR9Qm7slupMlo6zeA%3d%3d https://www.pacaf.af.mil/Portals/6/documents/3_AIB%20Report....

the__alchemist 1y ago
Thanks for the link. This is much more useful than the news article.
MBCook 1y ago
But 1/3 volume? That’s a LOT of contamination.
- grumpy-de-sre 1y ago
  Got to say the pictures of the hydraulic drum (and pump) in the DoD report are very confidence uninspiring.
HelloNurse 1y ago
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.
- grumpy-de-sre 1y ago
  Everything leaks hydraulic fluid, it's just an inherent property of any system with dynamic seals. https://www.youtube.com/shorts/d3ruv-IsGMo https://www.youtube.com/shorts/d3ruv-IsGMo
4gotunameagain 1y ago
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.
- grumpy-de-sre 1y ago
  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.
  - yobbo 1y ago
    Sounds similar to DOT-5 brake fluid. Maybe this: https://en.wikipedia.org/wiki/Tributyl_phosphate 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.
  - cwmoore 1y ago
    [dead]
  - Workaccount2 1y ago
    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-equipment/#:~:text=Test%20Medium%20:%20Hydraulic%20fluid%2C%20MIL,GPM%20at%205000%20PSI%20combined. https://hiigroupasia.com/f-35-aviation-ground-support-equipm...
    - grumpy-de-sre 1y ago
      Yeh the sanity check involved researching the milspecs listed and the connection to the F35 program.

the__alchemist 1y ago

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

MBCook 1y ago

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

grumpy-de-sre 1y ago
Got to say the pictures of the hydraulic drum (and pump) in the DoD report are very confidence uninspiring.

HelloNurse 1y ago

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.

grumpy-de-sre 1y ago
Everything leaks hydraulic fluid, it's just an inherent property of any system with dynamic seals. https://www.youtube.com/shorts/d3ruv-IsGMo https://www.youtube.com/shorts/d3ruv-IsGMo

4gotunameagain 1y ago

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.

grumpy-de-sre 1y ago
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.
- yobbo 1y ago
  Sounds similar to DOT-5 brake fluid. Maybe this: https://en.wikipedia.org/wiki/Tributyl_phosphate 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.
- cwmoore 1y ago
  [dead]
- Workaccount2 1y ago
  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-equipment/#:~:text=Test%20Medium%20:%20Hydraulic%20fluid%2C%20MIL,GPM%20at%205000%20PSI%20combined. https://hiigroupasia.com/f-35-aviation-ground-support-equipm...
  - grumpy-de-sre 1y ago
    Yeh the sanity check involved researching the milspecs listed and the connection to the F35 program.