A remembrance service is to be held in Norfolk for 11 men who died in a helicopter crash six years ago.
The aircraft was taking workers from Norwich Airport to a gas drilling rig in the North Sea on 16 July 2002.
The crew and nine passengers died when the Sikorsky S-76A went down between two gas platforms, 28 miles off Cromer.
A service is to be held in the evening at St Nicholas Parish Church, Great Yarmouth, where the names of the deceased are engraved on a glass porch.
An Air Accidents Investigation Branch report said problems were caused by a manufacturing fault on a rotor blade, dating back to 1981, which had been worsened by a lighting strike in 1999.
The report said manufacturers Sikorsky should have noticed the error.
The helicopter's captain Philip Wake, 42, and co-pilot Philip Dearden, 32, both from Norwich, could have done nothing to avert the crash, the report found.