Pilots, help me understand the Cavalese Cable Car disaster

I'm not a pilot, so I'm coming here for some thoughts from people who have experience as pilots with the environment and norms of that profession, which I won't know. Military pilots, extra good.

Background: https://en.wikipedia.org/wiki/1998_Cavalese_cable_car_crash#cite_note-lastampa-25

TLDR: 1998, EA-6B does a low level training flight in the Italian mountains. Weather is clear, time is 3pm. Aircraft ends up flying just under a cable car cable at 370ft, doing 470kts, cutting the cable. 20 people die in the cable car. Airframe and pilots make it back to base. Pilot and navigator are charged with Article 92 (Dereliction of Duty) , Article 108 (Destruction of Military Property) , Article 109 (Wasting or Spoiling Non-military Property), and Article 119 (Involuntary Manslaughter), all of the Uniform Code of Military Justice (UCMJ). Captain was found not-guilty of all charges and specifications. Navigator charges were dropped. I'm not sure how none of that sticks, especially the negligence element of involuntary manslaughter.

There's a lot of back and forth on this story and I've been reading things about it for days now, and I feel like people don't have answers for the important bits.

• 1. The altitude: Regardless of what the legal minimum altitude was (and there is a GIANT rat-hole about this) their flight plan said minimum altitude 1000ft, maximum speed 370kts, they were at 260ft, 470kts where the cable car was. Is flying lower and faster than your filed flight plan not negligence? At that speed, avoiding anything in the air is basically impossible, as it goes from the edge of visibility to impact in under a second. Is it common for pilots to deviate so much from flight plans that it is not negligence to do so on a low level training flight? These people are directly acquitted in court martial for negligence a year later, so the jury seems to think that's not negligence. I don't know how to square that.
• 2. Setting aside the altimeter, which tested fine after the flight but pilots claim must have been faulty...the pilots were using a sort of valley horizon as a visual estimation of altitude. The pilots were acquitted based on arguments for being tricked by a "false horizon", which they depended on for knowing how high they were. Are those visual artifacts serious enough to cause a pilot to believe they are at 1000 ft when they are at 300? Does that really happen? You can see the expert witness talking through it starting at 37 minutes in this video about the incident: https://www.youtube.com/watch?v=rl8HnWN6Sz8 ) Even if it's true it doesn't seem to indicate anything except a pilot unqualified to be flying low.
• 3. Flying low level at high speed means there is not time to react to unexpected objects in the air in front of you. At these speeds, the pilots are fully dependent on the maps telling them about cables or power lines because avoiding them is not likely. So do military pilots not have a policy of flying each training route at a high level to check for low level obstacles, before they fly the mission? I guess the maps are normally that good? I would have expected that low level training only be done on routes that had been previously cleared, both by overflights and by agreement with local government. Either could have noticed a cable car and brought it up as a hazard to be avoided.

Ultimately, I'm trying to understand any counterargument to why a jury didn't think it was negligence.

Please let me know your thoughts on these three questions.