Re: Looks good to me
What is often overlooked with Hindenburg and other airship disasters (R101) is that these airships were not filled with pure Hydrogen, but rather with a mix of Hydrogen and various gasses found in the air.
Low internal pressure, low technology membranes (see goldbeater's bladder) and long periods between hydrogen exchange meant that hydrogen could slowly permeate out of the lifting bladders, while atmospheric gases, including oxygen could permeate in.
After a while, a Hydrogen airship of that era would fly with a pre-mixed combustible gas-mix.
Should anyone decide to build a modern airship with Hydrogen lifting gas, then the would need to find a way to scrub all oxygen out of the lifting gas. The first thing that comes to mind is to use something similar to a mining lamp to burn off Oxygen while consentrations are low.
I have little experience with liquid Hydrogen, but we have flown using pressurised Hydrogen.
The pressure vessels are massive, and I would expect them to be found intact on the crash-site. Safety systems like in-tank valves prevent uncontrolled leakage.
As long as the system is not allowed to leak into a large enclosed volume, like a garage or a hangar, the assosiated risks are limited.
The ease of ignition of Hydrogen vs. JP1 is somewhat a moot point. There have been more than enough airliner accidents to demonstrate that a hot jet engine can easily ignite JP1. With Hydrogen, escaped gas moves up, up and aawaaay. JP1 can trickle towards the hot engine minutes after having been released.