Partnair Flight 394 dived 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.
Partnair Flight 394 was a chartered flight that crashed on 8 September 1989 off the coast of Denmark, 18 km (11 mi; 9.7 nmi) north of Hirtshals. All fifty passengers and five crew members on board the aircraft died, making this the deadliest disaster in Danish aviation history. The crash was caused by use of counterfeit aircraft parts in repairs and maintenance.