HAA Operations and Strategy

Heavy Anti-Aircraft guns played a vital role in the defence of the island. Six men could operate these weapons with an effective ceiling of approximately 30,000 ft (just over 9km!), 14,000 ft more than the outdated 3” 20 cwt which served alongside it in Malta. The cartridge for the 3.7 inch gun (94 x 675mm R) would weigh just around 13kg and were most commonly fitted with timed fuzes such as no No. 199. The less common 4.5 inch guns could only be used on static mounts. Even so, firing a much heavier shell with a larger calibre, the gun could only supersede the early ammunition variants of 3.7 ” by 4,000 feet. This gun would most commonly use the No. 207 fuze for what was a 24.9 kg shell.  

The guns fired with a terrific bang, a flash and lots of smoke from the muzzle, followed by the clash of steel as the breechblock was opened, then a huge clang, as the large brass empty cartridge was forcefully ejected and hit the concrete floor, rolling noisily often helped out of the way by a kick from an ammunition number. -Maurice Agius, p. 98

Once fired, the brass shell casings would be collected, counted, and disposed of. It is a great mystery why so many shells still survive in Maltese households as flower vases, bespoke decor, candles, ashtrays and even door handles. One can speculate that there were no facilities to recycle and reuse the spent brass, so the soldiers had to either throw it away, gift, or barter it with the locals for much needed extra rations or supplies. One hint lies in Ellul Mercer’s account of the very first days of war. He notes that the local population started buying brass items to preempt a possible cash drain. This scenario materialised, but it could be one factor to add as to why the cartridges were so desirable, beyond being simply quaint home decor. 

Clearing spent casings and re-stocking ammunition after a raid, Malta.

The Royal Artillery (RA) and Royal Malta Artillery (RMA) would both man such guns. Both HAA and LAA were mounted on stationary or mobile platforms around the island and especially the vulnerable airfields and harbour area. The latter type could be moved around to confuse enemy reconnaissance. It would require a whole book, or at least a dedicated article on itself just to skim the top of the logistical effort both types of guns required to operate. Besides shipping the shells through submarine and mine infested waters with incessant air attacks, once they reached the island they had to be transported to often remote gun sites lacking proper road access with little to no fuel available. 

Ammunition would then have to be stored appropriately, safely and constantly ventilated to keep it operable. For example, before clockwork fuzes arrived, a putty was used to perfectly seal the fuzes of stored shells lest the gunpowder absorbs moisture. The shells were also to be sorted, marked according to their type, and documented to keep track of stocks. This would have also been the case for the spare parts and barrels which had to be continuously maintained and occasionally replaced by a qualified limber gunner. In addition, each gun had its own paperwork: the amount of shells fired and any maintenance carried out on it was carefully written down.

Unloading a 3.7 inch gun on the quays of Malta, Imperial War Museum

By June 1942 Malta had twelve 4.5”, eighty four 3.7”, sixteen 3”, one hundred and forty Bofors and several pom-pom guns (Rollo, p. 258). But the guns were only valuable if they could be fed ammunition. Suffice to say that in April of 1942 alone, over 72,053 HAA and 88,176 LAA shells were fired (Rollo, p. 274), from 220,000 and 166,000 for the year respectively (Agius. p. 131). Altogether, they would be responsible for 102 confirmed kills for the month, the highest ever recorded. At the same time, ammunition was increased from 16 (in March) to 60 rounds per gun each day for HAA and single shots for LAA. (Fraser, p. 146). In addition, owing to the lack of ammunition to handle fast and agile fighters, only bomber formations were targeted, and of those only ones that had yet to drop their payload.

The gunners improved their capabilities as war progressed. A special camera known as a ‘Kine-Theodolite’ could even document the shell’s trajectory. By recording a shell’s burst and acquiring the angle of elevation, the ‘kine’ or ‘cine-theodolite’ could calculate where the shot actually reached. This would allow the teams to review, adjust and calibrate their aim accordingly after their engagement (especially important during training), always improving their gunnery. However, the enemy introduced several techniques to counter accurate anti-aircraft fire such as flying in staggered formations, constantly changing course and altitude. Agius notes that German Ju88 bombers would enter a ‘shallow’ dive when they reached the coast. The gunners would input a lower altitude then the accurate reading from the height-finder to preempt such a trajectory. Similarly, if the plane’s  travelled along a zig-zag pattern (as the axis learned to do), the gunner would simply assume a straight trajectory since their target would re-enter its trajectory every so often anyway.

Firing at specific targets proved very hard, especially when dive bombers started their quick and steep descent. In the beginning of the war, guns were fired in salvoes (Agius, 2008). Later on they could operate in such a way as to cover large areas through ‘barrages’. These could be fired in the form of ‘chevron’ with alternating heights, especially against low flying aircraft. Against bomber formations the ‘Xmas barrage’, which started off just before Christmas in 1941, was most effective covering a wide area in the shape of an ‘X’ with debilitating shrapnel. They could also fire into a specific area or ‘box’ and at different heights, chopping up any aircraft that enters it. This was used with great effect over dense bombing areas such as the Grand Harbour (aided with a smoke-screen by 1942) but even above nearby gun sites or other pre-calculated heavily targeted areas. Some German sources do not give it as much credit as British sources do, even stating that the barrages could be easily out manoeuvred (by smaller fighters). However, it was certainly a great feat of engineering and gunnery. Maurice Agius recounts that:


Every HAA gun position had received instructions to work out the bearing, elevation and fuze at various heights to specified points in the sky, above parts of the Grand Harbour, Hal Far and Luqa Airfields (later extended to many other likely targets), so that, when attacked, the fire from all gun positions in range would form a box barrage.  (p. 21). 

Diagram of the box-barrage showing HAA batteries (named by their technical designations) and their organisation over the designated target

A dense flickering of bright flashes on the ground far below indicated that the heavy Flak had opened fire. We promptly executed several sharp turns to right and left in automatic response. A few seconds later the first Flak bursts smudged the sky ahead of us. Others followed in rapid succession until quite a thick curtain of small dirty grey clouds had formed in our path. The enemy were apparently putting up a box barrage, and it was at our exact altitude. – ‘Memoirs of a Stuka Pilot’, Helmut Mahlke.

The British heavy AA, eg., at La Valetta on Malta, where it was concentrated in particular strength, presented the intervening Stuka unit with 3 such barrages, which were staggered in altitude. The first barrage was located at about approach altitude, the second barrage just after the start of the dive about 500 to 800m lower (thus infront of the diving unit), the 3rd barrage was again about 1000m  lower than the second- Helmut Mahlke. ‘Methods of Attacking Naval Targets with Dive-Bombers’, as quoted in ‘Stuka: Doctrine of the German Dive-Bomber, by Berg and Kast, p. 213-214

We climbed out and inspected the damage. As a memento, I took a couple of souvenir snapshots of my Iolanthe in her present sorry state before she was taken off to have a new pair of wings fitted. It was far beyond the limited capabilities of our field workshops to repair the old ones. In addition to the huge jagged hole that the Flak shell had torn in the wing, our mechanics counted no fewer than 184 bullet holes in the machine. It was almost too much. The aircraft looked like a colander. But the sight of it would have boosted the confidence of any fledgling Stuka pilot. It showed that, if the tanks and radiator weren’t hit, the Ju 87 could withstand an incredible amount of punishment. – ‘Memoirs of a Stuka Pilot’, Helmut Mahlke, describing his JU 87 after a mission over Malta. 

If the gun site was about to be dive bombed, meaning a direct attack by aircraft such as Stuka bombers, the crews would not take cover. Every gun position would have machine guns mounted and manned to engage short-range, low flying targets. The heavy guns themselves, such as the 3-inch 20 cwt gun, could load shrapnel shells filled with steel bearings which ballistically acted exactly like a ‘shotgun’ round: expanding with distance creating a directable wall of projectiles. Unlike normal high-explosive and shrapnel shells, they had a predictable spread, perfect against low-flying aircraft. Agius further notes that ‘Shrapnel fuze 2’ was used for an approaching target and ‘Shrapnel fuze 4’ for a ‘receding’ one. This method required the guns to be shot independently and in different directions so as to create a ‘dome’ of cover. In-fact, apart from ‘firing at gun control’ this manoeuvre was also referred to as ‘porcupine’. 

Even if the guns miss, being on the receiving end of anti-aircraft guns was often enough to deter fighters and bombers from their course. The guns of Malta are possibly responsible for causing the famous ‘Mosta Miracle’ by forcing a German bomber to jettison his load and head back to Sicily. Therefore, there always remained the possibility that anti-aircraft guns would damage or even destroy a friendly aircraft with shrapnel, besides the possibility of directly engaging it through misidentification. This was not unheard of, on multiple accounts. Some would even develop identification signals such as lowering their landing gears much earlier. However, until developments in June 1942, the guns could not operate if fighters were in the air, and had limited ceilings or areas of operation.

By Nikolai Debono, on behalf of Battlefront Malta