The aircraft was at approximately over Lake Michigan , NNW of Benton Harbor , Michigan when it vanished from radar screens after requesting a descent to . A widespread search was commenced including using sonar and dragging the bottom of Lake Michigan with trawlers , but to no avail . Considerable light debris , upholstery , and human body fragments were found floating on the surface , but divers were unable to locate the plane 's wreckage . The disappearance was the deadliest aviation disaster since the Llandow air disaster earlier that year , which killed 80
Llandow air disaster
Llandow air disaster
Northwest Orient Airlines Flight 2501