I just recently saw an episode of "Air Emergency" that talked about an
Air Peru flight (I may have the details wrong). Basically a 757 take
off at night over the dark ocean and no static system. The pilots never
figured out the problem. They knew their instruments were wrong but
they assumed ATCs altitude readout was correct (which it wasn't the
transponder is also served by the static system). In short, the cause
was a $1/hr aircraft washer who put duct tape over the static ports
before washing the plane. Boeing ended up sending a lot of money to
family members. The interesting thing is that the 757 maint manual says
to only use special Boeing tape (bright orange) when coving up static
ports.

-Robert