Compared to a regional jet, a fire truck is built like a tank. The fuselage of a jet is just an aluminum tube and very fragile on impact. The steel beams on a truck chassis are incredibly strong and would tear right through an aircraft fuselage.
Absolutely, that’s a good point — the fire truck is basically a tank compared to a regional jet. The CRJ-900’s fuselage is aluminum and wasn’t built to take that kind of impact.
That said, the plane itself isn’t light by any means — it weighs around 75,000 pounds. At runway speeds over 100 mph, it carries a huge amount of momentum. When it collided with the Oshkosh Striker 1500, which itself is about 60,000 pounds of steel and water, it was essentially two massive machines coming together. The truck’s armored chassis ended up winning out, but the plane’s own weight made the impact devastating. I understand the truck occupants were also injured. Not sure how severely.