Bay of Biscay

The floatplane was involved in a maritime patrol flight when it was shot down by a German submarine. Out of control, it crashed into the Bay of Biscay, off the Spanish coast. No trace of the aircraft nor the crew was found.
Crew (201st Squadron):
S/L William Dennys Butterworth, pilot,
F/O Colin John Griffith, pilot,
F/S John Charles Leleux, flight engineer,
F/S James William Hobson, flight engineer,
F/O Peter Anthony Cavendish Hunt, navigator,
F/O Anthony Valentine Philp, wireless operator,
F/S Duncan Jamieson McCormick Currie, wireless operator and air gunner,
Sgt Dennis Edward South, wireless operator and air gunner,
F/S Dennis Sharland, air gunner,
Sgt Frederick Foster, air gunner,
Sgt Jesse Robert French, air gunner,
F/S Edwin Watson, air gunner.

The crew was involved in a maritime patrol flight over the Bay of Biscay and left RAF Pembroke Dock at 1810LT on June 11. The floatplane should return to its base on June 12 with an ETA at 0725LT but failed to arrive. The British authorities confirmed that no trace of the aircraft nor the crew was found and that the aircraft has probably been shot down during the night by enemy fire, maybe by a German night fighter or a submarine.
Crew (228th Squadron).
Source: ASN

Short Sunderland flying boat T228 took off from RAF Station Pembroke Dock at 0715LT on 24 December 1943 to carry out an anti-submarine patrol. At 1225LT a distress signal was received from the aircraft. At this time T228 was over a force of enemy destroyers and in company of another Sunderland. At 1310LT a message was received from the other Sunderland aircraft which stated that wreckage of a Sunderland aircraft had been sighted and one survivor seen on the wing float of the aircraft. A dinghy was dropped but the survivor disappeared a few minutes later. Although the crew of the accompanying aircraft did not actually see T228 shot down, it was believed that T228 was shot down by an enemy surface vessel.
Source:
http://www.aviation-safety.net/database/record.php?id=19431224-0

The crew left Rabat at 2340LT on November 17 bound for RAF Coningsby. While overflying the Bay of Biscay north of the Portuguese coast, the aircraft was lost around 0555LT, probably after being shot down by a German fighter. No trace of the aircraft nor the crew was found.
Crew (617th Squadron):
F/Lt E. E. G. Youseman, pilot,
F/S S. Wittingham,
F/O E. Fleshka,
F/O W. C. Grimes,
W/O A. Laughland,
F/Sgt R. Florence,
W/O J. B. O'Grady.

While approaching the Spanish coast, the aircraft was shot down by the pilot of a German fighter and crashed into the Bay of Biscay, killing all 12 occupants.

Shot down by the pilot of a German fighter (JU.88) over the Bay of Biscay, while on a patrol flight. No trace of the aircraft nor the crew was ever found.

Shot down by the pilot of a German fighter (JU.88) over the Bay of Biscay. The captain was able to ditch the aircraft and all occupants were rescued while the aircraft sank.

The seaplane was engaged in an attack against German U-boat when it was shot down by enemy fire and crashed into the Bay of Biscay off the French coast. All 11 crew members were killed.
Crew:
F/Lt Desmond Fairfax Hill,
F/Lt Leonard Bertrand Lee,
F/O George Lough,
F/O Alfred Keith MacDougall,
F/O Robert Jasper Agur,
W/O Vincent Murray Goldstone,
F/Sgt Robert Alexander Shaw,
Sgt Andrew Carmichael,
Sgt Dewi Madoc Davies,
Sgt James Watt Fraser,
Sgt Richard Evelyn Joseph Smith.

The airplane departed RAF Hamworthy (Poole, Dorset) at 1900LT on a maritime patrol flight over the Bay of Biscay and was scheduled to return the following day around 1400LT. The seaplane failed to return and crashed in unknown circumstances into the sea. Lost without trace.
Crew:
P/O William Reginald Gardiner,
F/O Robert Beckett Albon,
F/O William Rrandolph,
F/O Geoffrey Silva,
F/Sgt Stanley Charles Everitt,
Sgt Nicholas John Brokenshire,
Sgt Benjamin Joseph Fosh,
Sgt Antony Kenneth Hodges,
Sgt Henry Robert Mears,
Sgt James Reid.

The airplane departed Lisbon-Portela de Sacavém at 0730LT on a regular schedule flight to RAF Whitchurch, Bristol. While cruising over the Bay of Biscay, it was intercepted and shot down by eight German Junkers JU.88 fighters. The airplane entered an uncontrolled descent and crashed into the sea some 350 km north of La Coruna, Spain. All 17 occupants, among them the British actor Leslie Howard, were killed.
Crew:
Cpt Quirinus Tepas Obe, pilot,
Cpt Dirk de Koning, pilot,
Cornelis van Brugge, radio operator,
Engbertus Rosevink, flight engineer.
Passengers:
Leslie Howard,
Alfred T. Chenhalls,
Kenneth Stonehouse,
Evelyn Peggy Margetts Stonehouse,
Rotha Hutcheon
Petra Hutcheon,
Carolina Hutcheon,
Cecelia Emilia Falla Paton,
Tyrrell Mildmay Shervington,
Ivan James Sharp,
Wilfrid Israel,
Francis German Cowlrick,
Gordon Thompson MacLean.