Motivated by a desire to help find Malaysia Airlines flight MH370, which is believed to have crashed into the southern Indian Ocean in March 2014, we proposed a way of working out where objects hit the surface of the ocean using underwater acoustic waves. Unfortunately this didn’t lead to finding the plane. However, our research into these waves has moved on since we first proposed the idea in 2017, and we have now been able to identify two locations where the aeroplane could have impacted with the ocean, as well as an alternative route that the plane may have taken.