93 light bombers Operation Oyster was a bombing raid made by the Royal Air Force (RAF) on 6 December 1942 upon the Philips works at Eindhoven, Netherlands.

[3] Prior to the war Philips made major advances in the design and production of vacuum tubes and had some of the best research scientists in the world.

An appraisal by the Air Ministry estimated that the plants in Eindhoven produced a third of the radio tubes used in German military equipment.

[3][1] The location of the Philips works in the middle of a Dutch city precluded Bomber Command from putting on a big night raid, as this would result in a great many civilian casualties.

Using Lancaster bombers for the raid was considered and rejected, as they were too vulnerable to fly through the middle of the German fighter belt in daylight.

Low level flight would avoid radar detection, limit the exposure to anti-aircraft fire and make it more difficult for German fighters to attack.

It was decided after the third trial that a Boston from each squadron would fly at low level all the way to the target to draw the attention of German Flak gunners down and away from the larger force that was climbing up to 1,500 ft (460 m) behind them.

The low flyers' four 500 lb (230 kg) bombs were to be fused for eleven seconds delay to prevent the aircraft from being caught in the explosions.

[24] The two 250 lb (110 kg) high explosive bombs on the Venturas were to be fuzed for 30 or 60 minutes' delay, to hamper or injure the firefighters and rescue workers.

[27] Further efforts to protect the bombers involved diversionary raids by the United States Army Air Forces (USAAF), with a formation of Consolidated B-24 Liberator heavy bombers sent to the German airbase at Abbeville, and a larger formation of Boeing B-17 Flying Fortresses sent to Lille, with Spitfire escorts.

[30] The day started with the Eighth Air Force launching its diversionary raids; nineteen B-24s from the 44th Bomb Group were sent out at 9:30 a.m. to attack the German airfield at Abbeville.

There were no large features to guide their approach; landfall was intended to be at a small town called Colijnsplaat, at the mouth of the Oosterschelde estuary, on the north coast of the island Beveland.

[33] The Bostons followed their track up the Oosterschelde estuary, hugging the north coast for 30 mi (48 km) to reach their main landfall at Bergen op Zoom.

In the estuary, the first hazard arose in the form of sea birds, which were startled by the sound of the aircraft approaching and rose into the air.

As the aircraft flew through them, some birds shattered wind screens, penetrated cockpits and injured aircrew, others bent fuel pipes and caused wing damage.

The Venturas had missed their landfall and arrived a mile to the south over the island of Walcheren where German flak defences were more numerous.

Rudolph Rauhaus brought his Focke-Wulf 190 in behind a Ventura as it cleared Walcheren and damaged the aircraft, which crash landed on the Zealand peninsula Reimerswaal; three of the six crew survived and were taken prisoner.

[38] As the aircraft approached the top of the estuary they came within sight of the Woensdrecht airfield, the home of II Gruppe, just to the south of Bergen op Zoom.

[39] A Mosquito pilot said, They looked so normal, just like Spitfires taking off in England, that it was hard to realise they were coming up to kill you.Hugging the ground, the aircraft continued south–east into Belgium, sideslipping and weaving as they went.

Pelly-Fry came up on the factory and delivered his bomb load but as he cleared overhead his aircraft was hit in the starboard engine and wing.

German gunners on rooftops were seen firing their guns as the buildings they were standing on burned underneath them or exploded; several other Venturas were lost in the attack.

Pelly-Fry's aircraft, hit during the bomb run, had its starboard aileron shot off, making turns to port very difficult.

The attacks at the rear of the formation were awkward at such low altitude; coming from above the Focke-Wulf pilots had to turn away early to the side, as there was no room below to dive through the group.

A Boston was hit and crashed; as they pulled away larger guns joined in, creating huge splashes with their shells to bring down an aeroplane with the spray.

[57] Patterson decided it might be safer to avoid the planned route the Bostons were taking, as German fighters might have gathered over the west coast to intercept them.

Low-level navigation was excellent and around 83 per cent of the aircraft involved delivered 60 long tons (61 t) bombs with a high degree of accuracy and concentration.

Philips had been obstructing the plant's production for some time but the overstated reports he had been sending to Germany had apparently found their way to the Air Ministry.

[60] He began work to clear the debris, providing his German overseers with optimistic projections of the plant's return to production but ensured that the repairs proceeded in a deliberate manner.

The RAF sent ten Mosquitos to revisit the Philips plants on 30 March 1943 to slow the recovery and it took six months to restore production.

[63] Sixty-two aircrew were lost; nine Venturas, four Bostons and a Mosquito were shot down, including one in the sea and another crashed in England, a loss rate of 16 per cent.