On 24 March, 1945, the western Allies launched Operation Plunder Varsity, aimed at crossing the River Rhine, the last natural barrier protecting the western flank of Hitler's Germany.
And yet, for the glider-borne elements of the Allied airborne - particularly the British - this picture is misleading, if not entirely inaccurate. For them, Varsity was a challenging and costly venture and the glider forces were landed far more successfully in Holland in September 1944 than in Germany in March 1945. The apparent success in Varsity stemmed not from highly accurate and concentrated airborne delivery but from the fact that the operation plan was far less ambitious and demanding than the Market Garden plan.
So what went wrong? In an earlier blog, I discussed a number of issues, including aircrew inexperience (many aircrew had only recently been transferred from the RAF ‘pool’ to the Glider Pilot Regiment), an over-complex landing plan, poor visibility, which was substantially self-generated by the Allies, and heavy German flak. More broadly, it is possible to argue that, by focusing on the supposed lessons of Arnhem, the Allies ignored some of the other key lessons identified after earlier airborne operations. This blog considers the flak issue in more detail and owes much to another report by the 21st Army Group Operational Research Section, although by no means entirely concurring with the views of its author.
The planning stages of Varsity found the Allies back in the situation they had faced in the previous summer: 6th Airborne Division had been withdrawn from the line after the Normandy campaign and rebuilt; the American airborne corps had been enlarged by the arrival of the 17th Airborne Division. The question therefore arose, how should these troops be employed?
Market Garden had illustrated the potential difficulties and dangers involved in using airborne forces to support major river crossings. Montgomery’s offensive, Operation Plunder, did not target bridges, in any case, but relied on Second Army to achieve an assault river crossing. Furthermore, after Arnhem, the Allies concluded that they must establish a foothold on the Rhine’s eastern bank before an airborne landing there, to ensure that the airborne forces were not cut off.
So what role could the airborne play? Potentially, they could attack German defences east of the Rhine to assist Second Army’s advance. Moreover, another river, the Issel, lay just a few miles beyond the Rhine, and the capture of its bridges intact would certainly be useful. Nevertheless, by comparison with the Rhine, the Issel was a puny obstacle that Allied ground forces (with an overwhelming advantage in terms of numbers, fire support and engineering equipment) could easily have bridged without undue delay. A sober appraisal of the situation might well have cast serious doubt on the need for airborne support, or at least airborne support on anything like the scale ultimately committed, and it is hard to avoid the conclusion that Varsity was something of a job-creation scheme. The flak story must be considered in this context.
Early in the war, airborne operations benefited from the surprise factor: airborne warfare was new and revolutionary. By March 1945, this advantage had substantially been exhausted and it is therefore not surprising to learn that the Germans were anticipating an airborne landing in the exact area where Varsity was mounted. Apart from deploying anti-glider obstacles - so-called Rommel’s asparagus - they were strengthening their flak defences in the area right up to the day Varsity was launched. Prisoner debriefs afterwards confirmed that the airborne landing was expected at the time and place that it occurred, and a marked German map also suggested that some leakage of information had taken place.
The number of German flak guns of all calibres deployed throughout the Varsity area was daunting. On the eve of the operation, Second Army assessed that there were some 608 flak positions containing 899 light guns and 186 heavy guns, although subsequent investigation on the ground suggested that half these positions were unoccupied on the day of the operation. Had all units been at full strength, there would have been 562 flak guns in the Varsity area, 78 heavy and 484 light. As many of the light guns incorporated triple or quadruple barrels, the number of barrels that might have fired on the Allied airborne armada was not far short of one thousand, and Allied intelligence estimates, exaggerated as they were, would have implied an even higher total. Earlier in the war, a flak threat of this magnitude might well have dissuaded the Allies from attempting an airborne assault. However, as we have seen, by March 1945, they had to find a use for their airborne reserve.
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| A map of German flak positions included in the ORS report, also showing the Varsity DZs and LZs. |
In airborne operations during the Second World War, the threat of flak could be addressed in three ways. Two of these involved evasion, and the first means of evasion was delivery by night, although we should note that the Allied airborne did not operate at night in Sicily or Normandy to evade flak. Rather, the airborne timetable was dictated. by the dawn amphibious landings. Darkness certainly reduced the vulnerability of troop carriers, gliders and their tugs, but it imposed other penalties. Night-time landings tended to be inaccurate, and the airborne forces were often widely dispersed. Moreover, even when they landed accurately, the airborne faced far greater challenges with orientation, assembly and unloading at night than during the day. This caused significant delays in the execution of operations that were almost always time-sensitive and sometimes time-critical.
The alternative was geographical evasion - routing and landing airborne troops away from known flak concentrations. Given its scale and the inherent vulnerability of transport aircraft in daylight, the Market Garden airlift was in many ways a triumph of evasive routing, but flak evasion contributed to the decision to land the airborne troops some distance from their objectives, complicating their task on the ground.
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| A typical three-pit German flak position on the bank of the Rhine. |
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| A far more elaborate defensive system, including flak pits, set further back from the river. |
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| Extensive flak defences near the American LZs. |
Medium bombers
The 21st Army Group ORS recorded that twelve positions were attacked by Allied medium bombers of 2 Group (RAF) and IX Bombardment Division (USAAF) on the morning of 24 March. Their munitions comprised 260 lb fragmentation bombs, clusters of 20 lb fragmentation bombs and 500 lb bombs. While the 260 lb bombs were dropped accurately and damaged buildings and equipment associated with one flak battery, no guns were hit. The targets were too small, relative to the typical bomb patterns. Although an average of 500 bombs was dropped on each battery, only one landed in a gun pit, which was unoccupied at the time. The 20 lb fragmentation bombs were likewise accurately released, but the high concentrations of bombs in the target areas were not sufficiently dense to achieve many hits on gun pits. The flak gunners sustained a number of casualties but not enough to reduce the effective ground-to-air firepower.
In summary, the medium bombers achieved little effect by direct destruction. However, the ORS argued that they might have achieved some temporary morale effect. Although the German gunners had orders not to open fire before the airborne operation began for fear of disclosing their positions, they disregarded these instructions and actually damaged 58 of the 336 medium bombers involved.
Artillery
Between 0930 and 0959 hrs on 24 March, some 24,000 artillery rounds (440 tons) were fired at 95 flak positions in the Varsity area. The amount of fire with which the targets were engaged varied from 16 to 1,000 rounds with an average of 242 rounds per target. It was subsequently concluded that 39 of the targeted positions were unoccupied when Varsity was launched; 23 more positions that had never been occupied were also targeted. The barrage was cut short due to the early arrival of the first Dakotas over the DZs.
Very little physical damage was inflicted by the artillery. Again, some morale effect was suggested by the fact that there was a delay before troops who took cover during the artillery barrage manned their guns, and this may have reduced the volume of fire during the opening stage of the airborne landings. Prisoners also reported that several 20 mm guns had been jammed by the dust the shelling raised. Nevertheless, it should also be remembered that the artillery barrage complicated the airborne (particularly the glider) task, for dust and smoke generated by the Allied guns contributed to reduced visibility in the landing areas, which caused many paratroops and gliders to come down well off-target.
Fighter-Bombers
Second Tactical Air Force had four wings of Typhoons permanently employed in a counter-flak role. Between them, they kept an average of 37 aircraft over the operational area in the first four hours of the landings, beginning half an hour before the initiation of the airborne assault. Periodically, more than 60 aircraft were present.
The Typhoons were armed with either rockets or cluster bombs in addition to their 20 mm cannons. Each flight was given an area of operation and instructions to dive down and attack any flak position seen to be firing; if no such fire was observed, there was always a prearranged target known to be a flak position, which was to be attacked before aircraft returned to base. The Typhoons were also directed to execute a large-scale ground strafing attack before the first airborne landings, but this did not occur because the Dakotas arrived early.
The British glider tugs were flying at 2,500 ft at the time of release and were due to climb to much greater heights for the return journey, so the Typhoons had to remain at about 4,000 ft to maintain observation. Thick ground haze along with smoke and dust from the ongoing battle and the smoke screen generated to conceal the Rhine crossing conspired to prevent 70 per cent of the Typhoon pilots from seeing any guns firing. Poor visibility also hampered the task of those pilots that executed attacks on flak positions.
After Varsity, the 21st Army Group ORS could not find all the flak positions reportedly attacked by the Typhoons, but, of those inspected, just one had sustained a direct rocket hit, which destroyed a 37 mm light gun. Two multi-barrel light guns were damaged by strafing. A Typhoon strike on a 105 mm gun position had set off fires around the guns without damaging them, and a 20 lb fragmentation munition from one of the cluster bombs had killed an 88 mm gun crew without damaging the gun itself.
Once more, the ORS suggested that both rockets and cluster bombs probably achieved some temporary morale impact. However, multiple attacks would have been necessary to sustain this effect, and they were rarely carried out. Quite apart from the visibility problem, many observed batteries were not targeted because they were sited in the area of the DZs and LZs, which the Typhoons were not allowed to attack, and some batteries east of the autobahn were also sited too close to advancing Allied ground forces for air strikes to be executed without a significant risk of fratricide.
The mere presence of the Typhoons did not apparently exercise much effect on the German gunners either. Prisoners reported that they were rarely seen, almost certainly because of the prevailing poor visibility and the height at which they were flying. The noise of Dakota and other aircraft engines at lower altitudes would have drowned out the sound of the Typhoon Sabres, and the sight of descending gliders loaded with airborne troops understandably distracted the flak gunners from the less direct threat of rocket attack.
Assault by Airborne Troops
After the first half hour of the airborne landings, there was a progressive decline in the number of aircraft and gliders hit by flak, suggesting a marked reduction of firepower. In a number of cases, the ORS found that gliders had landed within 50 yards of anti-aircraft guns and, although some were burnt-out wrecks, others were undamaged. Debriefing reports provided an explanation: on hitting the ground, air-landing troops had prioritised the elimination of nearby flak batteries before unloading and proceeding to their RV points. Between 10 and 15 batteries were dealt with in this way - an appreciable proportion of the batteries in the immediate vicinity of the dropping and landing zones. The destruction of flak positions by the airborne troops exceeded that caused by the artillery and air forces combined.
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| Many Horsas landed almost on top of German flak batteries. |
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| Horsas next to a flak battery at Haminkeln. |
The interrogation of German flak gunners reinforced this conclusion. Far from being the old men and boys so often encountered among German ground forces by this stage of the war, the 36 men interrogated were aged between 20 and 30, and the ORS found that 18 had ‘excellent morale, far higher than infantry and other prisoners captured in the battle area’. They ‘seemed pleased to have done the Allies some harm’. There was little indication that air or artillery attack had exerted much effect on them, but the airborne assault had generated fear and amazement.
Prisoners from 15 positions outside the Artillery Zone were interrogated - i.e., gunners from positions that might have been subjected to air strikes. In 10 cases, the men said that they had been attacked by fighter-bombers, and five of these attacks occurred after they had fired their guns - presumably in response. The prisoners claimed to have fired back at the fighters. It thus seems that the Typhoons exerted at least some effect by drawing fire. In four of the five positions that reported no Typhoon attack, the guns had not fired during the operation because the airborne formations were out of range. The flak batteries inside the Artillery Zone evidently inflicted the most damage.
Effects of the Flak
Gliders
The main victims of flak in Operation Varsity were the gliders, with the British Horsas and Hamilcars incurring more losses and damage than the American Wacos. In many cases, the same guns that targeted them while in flight continued firing when the gliders landed; the guns were reportedly well sited for a dual role. The ORS admitted that its figures for damage and loss were much too low because only some 1200 out of 1400 glider reports were available, and it was feared that the remaining 200 could be accounted for by damaged or destroyed gliders, a high proportion of which were British.
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| A wrecked Horsa at Haminkeln railway station. |
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| Another crashed Horsa on one of the Varsity LZs. |
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| Allied air reconnaissance photographed this burning Horsa on 24 March 1945. |
The number of seriously damaged gliders reported was 153 and those not unloaded or the unloading of which was delayed for considerable periods amounted to 173. The causes were:
A. Crash landing due to flak damage.
B. Fires due to flak or mortar.
C. Crews being pinned down by artillery, mortar or sniper fire in the landing zone.
The ORS suggested that a secondary effect of the flak was the disorganisation caused by damage to towing planes. Stricken aircraft severed glider tow ropes as they plunged to earth; at least 20 gliders had to cast off when their tow planes were hit. ‘The result of such occurrences contributed to the fact that numerous gliders landed some distance from their appointed LZs and were separated from others.’ In other words, the flak played a major part in the widespread dispersal of the landings, and while some gliders certainly landed away from their appointed LZs, many did not actually land in an LZ at all. The glider landings were far less accurate and concentrated than the Market Garden landings or even the main British glider landings in Normandy. And while losses among the British gliders were higher than among the American, dispersal severely impacted on the Americans because their Wacos were not large enough to accommodate jeeps and artillery guns as a single load. Consequently, there were many instances of guns arriving with no jeeps to tow them.
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| A plot of the British glider landings; only around 280 of the 405 gliders landed in this area or could be identified by the OR teams. |
Why did the British airborne lose more gliders than the Americans? It was planned that British gliders would be released at 2,500 ft and the American gliders at 700 ft. In fact, the American gliders were released at widely varying heights, but the higher they were released, the more likely they were to be hit.
41.6 per cent of American gliders released below 1,000 ft were hit by flak.
44.1 per cent released between 1,000 and 1,500 ft were hit by flak.
50.5 per cent released between 1,500 and 2,000 ft were hit by flak.
69.4 per cent released over 2,000 ft were hit by flak.
By contrast, all the British gliders were released above 2,500 ft and 59.5 per cent were hit by flak.
Out of 853 US gliders for which reports were available (American gliders were double-towed two gliders per tug), 381 were damaged, 82 seriously - involving some loss of control. Out of 272 British gliders for which reports were available (out of a total of 405 that reached the battle area - 133 unaccounted for), 160 were damaged, or 58.8 per cent - 60 seriously. At LZ O, 36 out of 46 sustained damage, 20 being seriously damaged. To reach LZ O, gliders had to fly within range of many more guns than gliders heading for the other LZs. At LZ U, 44 out of 66 sustained damage.
Apart from incurring heavier losses because they were released at higher altitude, British gliders proved more vulnerable to incendiary bullets than American gliders. The wooden structure of the Horsas and Hamilcars was enough to stop incendiary bullets, whereas they often passed harmlessly through the Waco’s fabric skin.
The 21st Army Group ORS admitted that the loss of glider-borne equipment was serious, but suggested that the losses sustained by the glider pilots and their passengers, were ‘not sufficient to affect the course of the battle’. Again, this chiefly reflects the fact that the Varsity objectives were not particularly challenging or vitally important. Individual tactical failures could be absorbed in a way that would not have been possible in every battle plan - Market Garden being an obvious example. Varsity was not dependent on ‘moving parts’ - interlinked and interdependent objectives - in the way that Market Garden was.
The ORS assessment can in any case be challenged in at least one case. While the rail and river bridges between Hamminkeln and Ringenberg were key objectives for 6 Air-landing Brigade and were captured by the 2nd Battalion Oxfordshire and Buckinghamshire Light Infantry - the heroes of Pegasus Bridge - they faced a determined counter-attack from tanks and supporting infantry during the early hours of the 25th. In their depleted state, the 2nd Ox and Bucks were unable to hold the bridge and obtained permission from divisional headquarters to destroy it. It was duly blown at 0240 hours. In the context of the overall Allied plan, the loss of this single bridge was unimportant. In the context of an operation like Market Garden, it could well have been decisive. Air imagery shows that the road bridge over the Issel south of Hamminkeln - another British glider force objective - was not intact by 25 March either.
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| The bridge over the Issel north of Haminkeln (right of the railway bridge) was demolished on the night of 24/25 March. |
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| The Issel bridge south of Haminkeln, also largely destroyed by 25 March 1945. |
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| Further south, only a few Wacos landed near this bridge (one of which came down in the river), but there is no sign of prepared defences in the area. |
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| One of numerous Horsas that abandoned the landing plan in favour of a safe landing - anywhere. |
From the ORS account and other sources, we may conclude that the gliders drew fire away from the troop carriers and glider tugs. No aircraft were hit before dropping their paratroops and few sustained damage before releasing their gliders. Out of 1,587 aircraft, 357 were damaged and 53 lost. Altogether, 316 anti-flak sorties, involving 92 attacks on gun positions, were flown by Typhoons of 83 and 84 Groups during the operation. Two aircraft were lost and seven damaged; additionally one Tempest and four Typhoons were lost which were not attacking gun positions, although their loss was due to flak.
Airborne Casualties
The ORS recorded that during the first 24 hours of the operation there were 744 casualties in total from among the British and American glider troops. This was 19.5 per cent of the 3,800 troops. It is unclear whether these figures are complete, and the British proportion was concealed in the total. It was certainly higher than the American proportion, and it is interesting that the ORS chose to present the figures in this way.
Comparable figures for British glider pilots killed, wounded and missing were recorded by the ORS as 250 or 28.5 per cent. However, this figure was based on the total number of aircrew (880) that would have arrived in the battle area had 35 sorties not been aborted. The aborts reduce the total to 810, increasing the percentage to 30.9. The Americans sustained a glider pilot casualty rate of 10 per cent.
The ORS stated that, although some of these casualties were caused by small arms and mortar fire, the majority were attributable to light or heavy flak used in anti-aircraft or ground roles. British glider troops suffered twice as many casualties as British paratroops, and approximately 30 per cent of their casualties are said to have occurred in the air or immediately after landing. Yet other sources (including official sources) are less restrained and underpinned the assessment of the British glider landings made in my earlier blog on this subject:
The majority of glider-borne cargoes were destroyed or damaged or could not be recovered and deployed in battle, and 27 per cent of the glider pilots became casualties. The casualty rate sustained by 6 Air Landing Brigade in Operation Varsity totalled approximately 40 per cent, most of the losses being incurred during the actual landings;[1] the 2nd Oxfordshire and Buckinghamshire Light Infantry lost half their strength in a period of about 20 minutes.[2] After a recovery effort extending over several days, the final equipment losses included 46 per cent of 6th Airborne Division's jeeps, 44 per cent of their trailers, 44 per cent of their carriers, half their light tanks, 29 per cent of their 75mm Howitzers, half their 25 pounders, 56 per cent of their 17 pounder anti-tank guns, 29 per cent of their 6 pounder anti-tank guns and 56 per cent of their Dodge 3/4 ton weapon carriers.[3]
Conclusion
The ORS concluded that the Allies’ flak suppression efforts contributed little to Varsity’s success. Flak was not appreciably damaged by artillery or air attack, and the resulting losses of gliders, personnel and equipment were substantial. The higher the gliders were released, the more damage they suffered. Some morale effect was achieved by Typhoon ground attack, but the only marked reduction in flak intensity occurred when airborne troops captured the gun positions.
Hence, while suppression might have provided a solution to the flak problem in early airborne operations against weak and unprepared adversaries, its utility against stronger opponents anticipating an airborne assault was very limited. The air weapons of the World War II period lacked the necessary precision; the artillery was no better. We might speculate that some kind of specific small-scale airborne action might have been mounted to clear flak before the main force arrived, but this would have introduced more complexity into plans that were better kept simple. In the absence of effective suppression measures, and, given the inaccuracy of night landings and the associated problems of assembly and unloading in darkness, the only practical alternative was geographical evasion.
Finally, from a purely historical perspective, the subject of this blog should remind us of the realities of Operaton Varsity, which differ considerably from some of the more optimistic accounts contained in popular histories. The reality is that the Allied airborne were dispatched in broad daylight to an area where the Germans were thought to have deployed more than 1,000 flak guns. Earlier in the war, such an intelligence assessment would either have caused the operation to be drastically changed or cancelled altogether. However, by 1945, the need to find a use for the Allied airborne reserve was enough to override such objections as might have been raised, and the Allies convinced themselves that artillery and air power could deal with the problem. The consequences of this mistaken assumption were reflected in the heavy casualties sustained by the British glider pilots and the air-landing troops.
1. Howard N. Cole, On Wings of Healing: The Story of The Airborne Medical Services, 1940-1960 (William Blackwood, Edinburgh, 1963), p. 166.
2. UK National Archives, WO 171/4320, 6 Air Landing Brigade Headquarters War Diary, 24 March 1944.
3. Colonel TBH Otway, Airborne Forces (War Office Official monograph, 1951), pp. 318.
