I'm against it, myself

Commenting on a link to Conor Pope, "New poll shows Labour support nose-diving", Irish Times 3/30/2013, B.H. remarks that "If I knew what it was, I might do it for them …"The obligatory screenshot:The OED's entry for nosedive indicates that it originated in reference to airplanes: "Aeronaut. A steep downward descent by an aircraft with [...]