North Sea

The strategic bomber departed Severomorsk Airbase on a survey flight over west Europe. While cruising over the North Sea, the crew made two first passes over the USS Essex then a third pass was completed at a very low height. The the pilot-in-command decided to leave the area when control was lost. The airplane crashed into the sea in a huge explosion, killing all six crew members. Debris were found about 240 km west of the Norwegian coast.
Crew:
Cpt Andrey Pliyev +5.

The aircraft crashed in unknown circumstances into the North Sea, about 100 km northeast of RAF Sculthorpe, Norfolk, while on a maritime patrol flight. Two crew members were rescued while 11 others were killed.

The aircraft left Amsterdam-Schiphol Airport at 0525LT on a cargo flight to London. Fourteen minutes later, it went out of control and dove into the North Sea, about 66 km west of the Dutch coast. All seven crew members were killed. According to the testimony of a Danish boat's captain, an engine was on fire when the aircraft came down.

Left its base at 0930LT for a training mission over the North Sea. At 1435LT, the crew informed ground about his position and that he was flying at an altitude of 15,000 feet some 192 km from his departure point. Few minutes later, the aircraft crashed into the sea in unknown circumstances. No trace of the aircraft nor the crew was ever found.

The crew left RAF Leuchars on a training mission over the North Sea, on behalf of the General Reconnaissance School. While flying about 144 km east of Dundee, radar contact was lost with the aircraft that crashed into the sea. SAR operations were conducted but eventually suspended after few days as no trace of the aircraft nor the crew was found.

The crew departed RAF Wymeswold for a routine training mission. It is believed that the airplane crashed somewhere into the North Sea as no trace of it nor the crew was found.
Crew (108th OTU):
F/Sgt Walter William Pinfold, pilot,
Sgt William Dean, navigator,
Sgt James Lindsay Cameron, wireless operator.

Bound for Reims Airbase, in France, the aircraft crashed in unknown circumstances into the North Sea. No trace of the aircraft nor the four crew members was ever found.

While overflying the North Sea, the bomber was shot down by the pilot of a German fighter and crashed into the sea some 112 km of the Norwegian coast. All nine crew members (Czech citizens) were killed.
Crew:
P/O Jaroslav Hara,
W/O Štefan Jaros,
F/Sgt Karel Katz,
F/O Frantisek Koranda,
F/Sgt Michal Kubina,
F/Sgt Jozef Remenár,
Sgt Bedrich Sklár,
F/Sgt Alois Stocek,
F/Sgt Frantisek Veitl.

The C-47 took off at 1240LT on a glider tow mission towing a Waco CG-4A. The objective was to tow the glider to Landing Zone W, located north of Eindhoven, the Netherlands. Over Breda at 1600LT the flight ran into an intense concentration of light flak and the left engine was hit and began trailing smoke. The pilot continued to the LZ and released the glider at 1615LT. While returning to the U.K., about 22 miles from the Dutch coast the left engine went out. The left prop was feathered, but it immediately unfeathered. By this time the aircraft was filling up with smoke and the radio operator caught sight of flames under the floor. The pilot nosed the plane down at 220 mph indicated airspeed from 4,000 feet indicated altitude, turned into the wind and started to level at 1,000 feet. The plane was brought in a tail low attitude and was ditched at 1652LT. The crew escaped and deployed a dinghy from which they were rescued after about 15 minutes.
Source:
http://aviation-safety.net/database/record.php?id=19440918-22

Lost without trace in the North Sea while performing a flight from Brussels to RAF Down Ampney.