Operation Tidal Wave was an air attack by bombers of the United States Army Air Forces (USAAF) based in Libya on nine oil refineries around Ploiești, Romania, on 1 August 1943, during World War II. It was a strategic bombing mission and part of the "oil campaign" to deny petroleum-based fuel to the Axis powers. The mission resulted in "no curtailment of overall product output but a drastic reduction in spare capacity".
Due to the number of aircraft available and the long distance, the mission was conceived as low level attack using Consolidated B-24 Liberator with the advantage of surprise against relatively undefended targets. However the aircraft were not designed for low level use and the targets were well defended by many anti-aircraft guns and German and Romanian fighter squadrons. As a result the operation was one of the costliest for the USAAF in the European Theater, with 53 aircraft - about a third of those committed - and 500 aircrewmen lost. It was proportionally the most costly major Allied air raid of the war, and its date was later referred to as "Black Sunday".
Five Medals of Honor and 56 Distinguished Service Crosses, along with numerous other awards, went to Operation Tidal Wave crew members. A 1999 research report prepared for the Air War College at Maxwell Air Force Base in Alabama concluded that the bombing campaign in Ploiești was "one of the bloodiest and most heroic missions of all time". One of the downed American planes crashed into a women's prison in Ploiești, resulting in about half of the civilian casualties from the total of 101 killed and 238 injured.
Background
Romania had been a major power in the oil industry since the 1800s. It was one of the largest producers in Europe, and Ploiești was a major part of that production. The Ploiești oil refineries provided about 30% of all Axis oil production.
Axis air defenses
In June 1942, 13 B-24 Liberators of the "Halverson project" (HALPRO) attacked Ploiești. Though damage was slight, Germany and Romania responded by putting strong anti-aircraft defenses around Ploiești. Luftwaffe General Alfred Gerstenberg built one of the heaviest and best-integrated air defense networks in Europe. The defenses included several hundred large-caliber 88mm flak guns and many more small caliber guns. The latter were concealed in haystacks, railroad cars, and mock buildings. German and Romanian AA artillery at Ploiești consisted of 36 heavy (88 mm) and 16 medium and light (37 mm and 20 mm) anti-aircraft batteries. The heavy batteries were further supplemented by 15 Würzburg radar stations used for fire control.
The defenses were divided between two regiments of the German 5th Flak Division (21 heavy, 10 medium and light batteries) and the Romanian 7th AA Regiment (15 heavy, 6 medium and light batteries). Half of the manpower of the German 5th Flak Division was Romanian. Additionally, smoke generators and 23 barrage balloons were deployed. The Axis had 57 fighters within flight range of Ploiești (Messerschmitt Bf 109 fighters and Messerschmitt Bf 110 twin-engined night fighters, plus assorted types of Romanian IAR 80 fighters). For the defense of Ploiești, the Royal Romanian Air Force had aircraft from five Escadrile (squadrons): 61 (IAR 80A), 62 (IAR 80B), 45 (IAR 80C), 53 (Bf 109G) and 51 (Bf 110C). The Germans had another four Staffeln: 1, 2, 3./JG4 (Bf 109G) and 10./NJG6 (Bf 110). These defenses made Ploiești the third or fourth most heavily defended target in Axis Europe, after Berlin and Vienna or the Ruhr industrial region, and thus the most heavily defended Axis target outside the Third Reich.
Mission plan
The case for targeting Romania's oil refineries was set forth at the Casablanca Conference by Winston Churchill, who believed that destroying them would deal the "knockout blow" to the German war effort. However, due to a lack of resources for organizing other attacks, the plans were put on hold.
The plans were resumed in April 1943, when General Henry H. Arnold commissioned his staff to continue their development. Two plans were conceived: one called for a high-altitude attack to be launched from Syrian bases, while the other called launched from Libya. Colonel Jacob E. Smart conceived a very low-altitude attack reasoning that a smaller force of bombers at low level with the element of surprise against weak defenses could achieve the same effects as many more aircraft bombing from high altitude. The aircraft available were the B-24s but it was not designed for low level flight. The code name for the mission was Operation Statesman, which was later changed to Operation Soapsuds, and finally to Operation Tidal Wave. In charge of the operation was General Lewis H. Brereton. Brereton made the choice of low-level attack and stuck with it despite petitioning from the group commanders and Brigadier General Uzal Ent chief of IX Bomber Command and the planner of the details of the operation. Air Chief Marshal Sir Arthur Tedder, the commander of air forces, both British and American, in the Mediterranean, suggested a postponement or cancelling and making attacks on aircraft factories instead but Brereton opposed it on grounds that the refineries were more important than factories, training was almost complete and cancelling would be bad for morale. At a conference in July Brereton did not invite discussion of the plan and stressed that any commander who showed lack of leadership, aggression or confidence in the mission should be immediately relieved.
The Ninth Air Force (98th and 376th Bombardment Groups) was responsible for the overall conduct of the raid. To reach the necessary number of bombers, the partially formed Eighth Air Force from England provided three additional bomb groups (44th, 93rd, and the new and inexperienced 389th). Due to the distance involved, all the bombers employed were B-24 Liberators.
Based on HALPRO's experiences, the planners decided Tidal Wave would be executed by day and that the attacking bombers would approach at low altitude during the last leg of their run to avoid detection by German radar. Training included extensive review of a detailed 1:5000 three dimensional map provided by the RAF, practice raids over a mock-up of the target in the Libyan desert, and practical exercises over a number of secondary targets in July to prove the viability of such a low-level strike. The crews were told - through informational films - that the defenders would be largely Romanian pilots and there were only 80 heavy AA guns and 160 smaller ones arranged for night time attacks and operated by indifferent Romanian gun crews. This was wishful thinking - in reality there were four times the heavy artillery and many German gun crews.
The bombers to be used were each fitted with a (releasable) fuel tank in their bombbay to increase their fuel capacity to 3,100 US gallons (12,000 L) at the cost of some of the bombload. The Norden bombsights were replaced with low-level bombsights and the lead B-24s - which were expected to suppress the enemy defences - were also fitted with two nose mounted .50-cal (12.5 mm) machine guns, which were operated by the pilot. The dorsal turrets of the lead aircraft were modified to be able to fire to the front as well. The aircraft of the 389th had their ventral ball turrets removed to move weight balance forward and so improve fuel economy.
To put 156 aircraft over the target, the planners had determined that 186 aircraft would need to start the mission. There were problems with keeping aircraft operational due to the effect of the desert environment on the engines, compounded with lack of spare engines. RAF workshops took on the overhaul of engines for the Ninth Air Force.
The ordnance carried by the bombers consisted of 500 lb (230 kg) and 1,000 lb (450 kg) high-explosive bombs, supplemented by incendiary bombs. All were armed with delayed action fuses varying in time from 45 seconds to six hours.
Originally the operation was to consist of 154 bombers, but the final number reached 178, with a total of 1,751 aircrew, one of the largest commitments of American heavy bombers and crewmen up to that time. The planes were to fly from airfields near Benghazi, Libya. They were to cross the Mediterranean and the Adriatic Sea, pass near the island of Corfu, cross over the Pindus Mountains in Albania, cross southern Yugoslavia, enter southwestern Romania, and turn east toward Ploiești. Reaching Ploiești, they were to locate predetermined checkpoints, approach their targets from the north, and strike all targets simultaneously. The five main refineries of Ploiești were designated as targets White 1-5, while the Creditul Minier refinery in Brazi was designated target Blue, and Steaua Română in Câmpina was designated target Red.
For political reasons, the Allied planners decided to avoid the city of Ploiești itself so that it would not be bombed by accident.
Order of battle
Ninth and Eighth Air Force
- Ninth Air Force, General Uzal G. Ent,
- 98th Bombardment Group (Heavy) ("Pyramiders"), Col. John R. Kane
- 343rd Bombardment Squadron
- 344th Bombardment Squadron
- 345th Bombardment Squadron
- 376th Bombardment Group (Heavy) ("Liberandos"), Col. Keith K. Compton
- 512th Bombardment Squadron
- 513th Bombardment Squadron
- 514th Bombardment Squadron
- 515th Bombardment Squadron
- Eighth Air Force
- 44th Bombardment Group (Heavy) ("Flying Eight Balls"), Col. Leon W. Johnson
- 66th Bombardment Squadron
- 67th Bombardment Squadron
- 68th Bombardment Squadron
- 506th Bombardment Squadron
- 93rd Bombardment Group (Heavy) ("Flying Circus"), Lt.Col. Addison Baker, Maj. John L. Jerstad
- 328th Bombardment Squadron
- 329th Bombardment Squadron
- 330th Bombardment Squadron
- 409th Bombardment Squadron
- 389th Bombardment Group (Heavy) ("Sky Scorpions"), Col. Jack W. Wood, 2nd Lt. Lloyd Herbert Hughes
- 564th Bombardment Squadron
- 565th Bombardment Squadron
- 566th Bombardment Squadron
- 567th Bombardment Squadron
Romanian and German
- Luftflotte 4 – Jagdfliegerführer Rumänien Otopeni
- IV./Nachtjagdgeschwader 6 – Ziliștea, with Bf 110
- 10./NJG6 – Otopeni
- 12./NJG6 (Escadrila 51 Vânătoare de Noapte) – Otopeni
- I./Jagdgeschwader 4 – Mizil, with Bf 109
- 1./JG4
- 2./JG4
- 3./JG4
- 4./JG4 (Escadrila 53 Vânătoare)
- Flotila 2 Vânătoare Pipera
- Grupul 6 Vânătoare – Pipera, with IAR 80
- Escadrila 61 Vânătoare
- Escadrila 62 Vânătoare
- Flotila 3 Vânătoare
- Grupul 4 Vânătoare
- Escadrila 45 Vânătoare – Târgșor, with IAR 80
Tidal Wave
The day before the operation, Tedder, Brereton and Ent toured the camps speaking encouragement to the crews and emphasising the importance of the mission. Tedder said "It's a hard dangerous mission. It will take all your famous American courage and resourcefulness".
On the morning of 1 August 1943, starting around 04:00 the five groups comprising the strike force took off from their home airfields around Benghazi. Large amounts of dust kicked up during takeoff caused limited visibility and strained engines already carrying the burden of large bomb loads and additional fuel. These conditions contributed to the loss of one aircraft, Kickapoo, during takeoff, but 177 of the planned 178 aircraft departed safely. The number of aircraft in each group were 376th - 28, 93rd - 37 , 98th - 46, 44th - 37, 389th - 29. The transit of the Mediterranean was at between 2,000 and 4,000 ft (610 and 1,220 m).
Into the Balkans
The formation reached the Adriatic Sea without further incident. However as they reached Corfu instead of climbing to 10,000 ft (3,000 m) on signal with the rest, aircraft #28, Wongo Wongo of the 376th Bombardment Group (the lead ship of the lead group, numbering about 40 B-24s) piloted by Lt. Brian Flavelle, began to fly erratically before spiralling into the sea due to an unexplained malfunction and exploding. Lt. Guy Iovine—a friend of Flavelle who was piloting aircraft #23 Desert Lilly—descended from the formation to look for survivors, narrowly missing another aircraft Brewery Wagon. No survivors were seen, and due to the additional weight of fuel, Iovine was unable to regain altitude to rejoin the formation and resume course to Ploiești and turned back to base.
The resulting confusion was compounded by the inability to regain cohesion due to orders to maintain strict radio silence. Ten other aircrews returned to friendly airfields after the incident, and the remaining aircraft faced the 9,000 ft (2,700 m) climb over the Pindus mountains, which were shrouded in cloud cover. Although all five groups made the climb around 11,000 ft (3,400 m), the 376th and 93rd, using high power settings, pulled ahead of the trailing formations, causing variations in speed and time which disrupted the synchronization of the group attacks deemed so important by Smart. The weather conditions contributed to the formations spreading and losing sight of each other - nearing the Danube the two leading groups flew over the cloud cover, the following three choosing to go under it. Mission leaders deemed these concerns to be less important than maintaining security through radio silence. Although the Americans' orders would have allowed them to break radio silence to rebuild their formations, the strike proceeded without correction, and this proved costly. The 98th having lost sight of the leading groups, thought it had ended up ahead and flew to the west to allow what it thought was the 93rd to take the lead until it recognised the error and took the lead of the three again.
While in flight towards Bulgaria, the bomber formations were detected by German radar. The bombers were also spotted by Bulgarian Avia B-534s, which took off to protect Sofia.