OK. I’d strongly recommend not using IFA for your ULH. IFA also states not to use it in low-power-mode.
So, when you looking at the terrain, it gets loaded. Again, I’d strongly recommend following the night settings and floor view I mentioned earlier (after you get to cruise) for best results, and hopefully no more crashing for you. I know it’s unfortunate, but this is probably what you’ll have to do as you have a much older device.
One additional thing that hasn’t been mentioned yet, also try keeping your iPad volume down to a minimum during cruise. Your battery will thank you.