The first raids on Ploiești from Italy

On the afternoon of 5 April 1944 American bombers appeared over Ploiești in Romania for the first time in eight months. This time they had not come from Libya but from the airfields around Foggia in southern Italy, and they did not attack from a few dozen metres, as in Operation Tidal Wave in August 1943, but from about 6–7 kilometres, in tight formations, with fighter cover for part of the route. Some 230 Boeing B-17 Flying Fortress and Consolidated B-24 Liberator heavy bombers of the American Fifteenth Air Force had been given the city’s marshalling yard and railway junction as their official target. Many bombs, however, fell on the neighbouring refineries and oil tanks, starting fires visible from afar.

The raid opened a campaign against Romanian oil – the largest natural source of fuel at the Reich’s disposal – that lasted until August 1944. In April the Americans returned to Ploiești on 15 and 24 April, each time formally against railway targets, and from the night of 8/9 April British bombers based in Italy began dropping mines into the Danube, along which Romanian oil travelled by barge to Germany. War chronologies often describe this first April attack as a raid on the oilfields paid for with heavy losses. Both descriptions need qualifying: the target was the railway junction, and the losses, though painful, were nothing like the disaster of August 1943.

Oil for the Reich

Romania was the only significant producer of crude oil in the part of Europe allied to Germany, and almost its entire oil industry was concentrated in the Prahova valley, around Ploiești and Câmpina, some 60 kilometres north of Bucharest. From the German–Romanian economic agreement of March 1939, and especially from the move of Marshal Ion Antonescu’s government into the Axis camp in 1940, Romanian oil was, alongside the synthetic petrol produced in Germany from coal, the mainstay of the Wehrmacht’s fuel supply. Its share is estimated differently depending on whether one counts crude oil, all petroleum products or only military fuels. American literature repeatedly states that the Ploiești refineries gave Germany “perhaps one third” of its oil; other studies give lower percentages, but no one disputes that for the German army fighting in the east, and for its allies, it was a resource with no substitute.

The low-level attack of 1 August 1943 had cost the Americans 53 bombers, and its effects were repaired within a few weeks. The Germans and Romanians drew their own conclusions from it. The air defences of the district were directed by the German air attaché in Bucharest, General Alfred Gerstenberg, who strengthened them further after the August raid. According to American studies, at the start of the 1944 campaign Ploiești was defended by some 140 heavy and medium anti-aircraft guns, a number that eventually doubled; barrage balloons were set up around the refineries and, above all, a network of smoke generators, of which about 1,900 were eventually counted. According to the same estimates, some 200 German and Romanian fighters were stationed on the airfields of Wallachia, among them Romanian IAR-80s and IAR-81s and German night-fighter squadrons and heavy fighters, used by day against the bombers.

The second change took place on the Allied side. The capture of Apulia after the British landings at Taranto and Bari in September 1943 gave the Allies airfields about 900 kilometres from Ploiești. On 1 November 1943 the American Fifteenth Air Force was formed there, commanded from January 1944 by Major General Nathan Twining. In February its bombers took part in Big Week – the massed offensive against the German aircraft industry – and in March they attacked Vienna. In the spring of 1944 Romania’s own position changed too: at the end of March the Red Army reached the Romanian border, and Romania’s railways and waterways became the main supply lines of the southern wing of the Eastern Front.

Why “the railway junction”

At the beginning of April 1944 oil was not yet an official priority of the Allied strategic air forces. The commander of the US Strategic Air Forces in Europe, General Carl Spaatz, had for weeks been arguing that striking the German refineries and synthetic-fuel plants would paralyse the Wehrmacht faster than anything else. His opponents, led by the scientific adviser Solly Zuckerman and the commander of the invasion air forces, Air Chief Marshal Trafford Leigh-Mallory, demanded that the bombers concentrate on the railways of France and Belgium before the Normandy landings. The dispute was settled by Dwight Eisenhower, who at the end of March came down in favour of the so-called Transportation Plan and agreed to attacks on oil only in April, and at first only as a supplement.

In these circumstances the strike on Ploiești was dressed up as part of the Transportation Plan. According to American air historians, among them Spaatz’s biographer Richard Davis, the Fifteenth Air Force was ordered to bomb the marshalling yards of Ploiești and Bucharest as supply hubs for the German forces fighting the Red Army. The justification was no fiction, since supplies for the front in Moldavia really did pass through these yards, but the staffs made no secret of their hope that bombs dropped on tracks lying right next to the refineries would also hit the oil installations. In April, then, the railways were officially the target, and in practice oil as well. The raid on Ploiești was also part of a wider series of strikes on the Romanian and Hungarian railway networks: two days earlier, on 3 April, bombers from Foggia had attacked Budapest, and on 4 April Bucharest, where thousands of civilians were killed (the raids on Budapest and Bucharest).

5 April

On the morning of 5 April bombers of three bomb wings – nine groups of Liberators and four groups of Fortresses – took off from the airfields of Apulia. The weather over the Balkans was changeable and one of the wings turned back, so two reached the target. The route was more than 900 kilometres each way, across the Adriatic, Yugoslavia and the Danube valley, and the long-range Lockheed P-38 Lightning fighters could cover the formation for only part of the way. Short of the target some 230 bombers met German and Romanian fighters. According to the crews’ reports, Romanian IAR-81s attacked head-on, while twin-engined Messerschmitt Bf 110s and Junkers Ju 88s fired rockets into the formation from the side, out of range of the bombers’ machine guns.

The bombs fell at around 2.30 p.m. from 6–7 kilometres. The report of one of the participating units, the 450th Bombardment Group, speaks of 28 Liberators that dropped 84 tons of high-explosive bombs, of direct hits on distillation plant, on four large tanks and on buildings identified as a tank-car loading station, and of numerous hits on the marshalling yard itself. The same group lost five aircraft shot down by fighters; its gunners claimed several dozen enemy aircraft destroyed – a figure that, as usual in such reports, was inflated many times over. On the way home, over Craiova, the bombers met the P-38s sent out to meet them.

The USAAF’s official chronology of combat operations puts the Fifteenth Air Force’s total losses that day at 13 bombers, or about six per cent of the aircraft that reached the target. For the crews this was a severe loss – more than a hundred airmen from the downed aircraft did not return, killed or taken prisoner – but compared with August 1943, when 53 of 177 Liberators failed to return and others landed in Turkey and were interned, the raid was relatively cheap for the Americans. The greater surprise for both sides lay in the results: several refineries were badly damaged, and the columns of smoke from the burning tanks confirmed the Allied command in its belief that Ploiești could be attacked effectively from high altitude.

Holy Saturday and 24 April

The second April attack came on 15 April. That day the Fifteenth Air Force sent several hundred bombers over Romania: some of them struck Ploiești, while the Liberators of the 449th and 450th Bombardment Groups struck the marshalling yards of Bucharest. A thick layer of cloud lay over the targets, and some groups bombed blind, guided by the radar of their lead aircraft; one of them noted in its report that the photographs showed only a “solid undercast” and the results could not be assessed. For the Romanians the date had a special significance: 15 April 1944 was Orthodox Holy Saturday, the eve of Easter, which the Orthodox celebrated that year on 16 April, a week after the Catholics and Protestants.

Many chronologies describe 15 April as the day of heavy raids on the Ploiești oilfields, carried out jointly by the RAF and the American air force. The available records do not fully bear this out. By day only the Americans flew over Ploiești, and their official target was again the railway. The RAF’s No. 205 Group, also based in Apulia and equipped mainly with Vickers Wellingtons as well as Halifaxes and Liberators, was then conducting a different operation: since the night of 8/9 April its Wellingtons, flying at night a few dozen metres above the water, had been dropping naval mines into the Danube. The RAF’s night raids on Ploiești, Bucharest and Turnu Severin – more than twenty by August, according to British records – belonged for the most part to the following months of the campaign, and the RAF’s share of the total number of sorties over Ploiești is estimated at a few per cent. The campaign was thus a joint one, but the division of roles was clear: the Americans bombed by day, the British mined the river and attacked by night.

On 24 April the bombers returned to Ploiești for the third time, while other groups attacked Bucharest at the same time. This time the weather was good. According to the report of the 450th Bombardment Group, its Liberators dropped 84 tons of bombs on the marshalling yard, and a huge fire broke out in the eastern part of the Vega refinery. There were fewer fighters than on 5 April, but the anti-aircraft fire proved “intense and accurate” – in that group alone it riddled twenty aircraft with splinters. The Fortresses of the 2nd Bombardment Group returned – according to that unit’s history – with 28 of their 36 aircraft damaged.

The city and the river

The Ploiești refineries lay in a ring around the city, and the marshalling yard within it, so the “railway” raids struck residential districts as well. Figures for civilian casualties in the individual April raids differ between the available sources and cannot reliably be added up. What is known is that the city quickly emptied: according to local studies, after the series of April raids as much as 85 per cent of the inhabitants left, and only government offices and refinery staff remained in Ploiești. The damage-repair service at the refineries, expanded after August 1943, switched to working round the clock. Every new raid required it to repair the damage in whatever time was left before the next one.

The second artery for Romanian oil was the Danube. Barges carried it from the port of Giurgiu upriver, through the Iron Gates, to Hungary, Austria and Germany; by estimates roughly a third of Romania’s oil exports went this way. The mining of the river by No. 205 Group’s Wellingtons proved one of the cheapest and most effective operations of the whole campaign. The Germans sent minesweeping units to the river but could not prevent traffic on the Danube from falling, according to various estimates, to about a third of its former level. Aircraft losses in the minelaying were small – a dozen or so machines between April and October 1944.

Place in the war

The April raids on Ploiești were the prelude to one of the longest and costliest air campaigns of the war. On 5 May 1944, 485 bombers of the Fifteenth Air Force flew to Ploiești, and on 12 May the American Eighth Air Force from England struck the German synthetic-fuel plants, among them Leuna. From then on oil ceased to be a target “in passing” and became a target in its own right, and in the autumn of 1944 the top priority of the strategic air forces. In June an attack on the refineries by P-38 fighters diving with bombs was even attempted; it ended with heavy losses. The Germans responded with ever thicker smokescreens, which in the summer of 1944 often hid the refineries completely; the Americans then had to bomb blind, by radar.

According to American figures, by August 1944 some 5,700 bomber sorties had been flown against Ploiești and nearly 14,000 tons of bombs dropped; the Fifteenth Air Force lost about 280 aircraft in the campaign, the RAF several dozen. The refineries’ output fell in the summer of 1944 to a fraction of its former level, and American authors estimate that 90 per cent less Romanian oil was reaching the Wehrmacht than before the campaign; these estimates are sometimes challenged as exaggerated, but the direction of the change is not in doubt. The last big raid took place on 19 August. On 23 August 1944 King Michael I had Antonescu arrested, and Romania broke its alliance with Germany and went over to the Allies; at the end of the month the Red Army occupied the oilfields. Germany thereby lost its main source of natural oil, and combined with the bombing of the synthetic plants this meant that in the last months of the war the Luftwaffe and the panzer divisions increasingly ran short of fuel.