Accident with angle grinder ( warning )

I think it was in 1981... in the cruising days. A buddy of mine was idling along, and he heard a WHAM ! He thought someone threw a beer bottle at his truck. So he got out and ran around to check for damage and a bottle and found nothing.
When he got back in, he noticed a slight vibration like an engine miss, and saw what looked like a louver in his hood. He got back out, and seen a fan blade stuck in the hood.
Crazy..