Re: No mention of the Hindenburg?
"One of them flew into the ocean for unknown reasons. A prominent theory is that their altimeter was grossly out of calibration, they found themselves suddenly approaching the looming surface in stormy night conditions, and they dipped their stern into the water at speed by applying hard up elevator."
It sounds like the altimeter was working perfectly! An altimeter is just an aneroid barometer configured with a display with a dial that measures in altitude rather than a dial from STORMY to VERY DRY.
In other words, it doesn't actually measure your height from the ground, but the barometric pressure. This will drop the higher you get from ground level so lower pressure = higher altitude as far as an aneroid barometer based altimeter is concerned.
Unfortunately the barometric pressure at ground level will drop when a storm approaches (barometers are widely used for weather forecasting) so the mark on your altimeter may read 200 feet when your actually sitting on the tarmac until you hit the "zero" button. Or in this case they might have been slowly dropping altitude and finally going into the water with the pilot reading the same altitude.