<a href="https://en.wikipedia.org/wiki/Partnair_Flight_394" id="mwAXg" rel="mw:WikiLink" title="Partnair Flight 394">Partnair Flight 394</a> dives into the North Sea, killing 55 people. The investigation showed that the tail of the plane vibrated loose in flight due to sub-standard connecting bolts that had been fraudulently sold as aircraft-grade.