A frightening computer bug could cause a transportation nightmare by destroying older GPS systems.

Cyber-security expert Bill Malik told the tech publication Tom’s Guide he’d be afraid to fly April 6, the day a computer calendar “roll-over” to zero is triggered, according to Britain’s Sun newspaper.

A similar Y2K disaster was forecast for New Year’s Day 2000, but never happened.

Malik says things are different now because many more computer systems integrated GPS into their operations. Shipping, traffic monitoring systems, and electrical grids could all be affected, he said.

This story originally appeared in the New York Post.