Parachute and Cable? Schermuly Not

Attack on Kenley, painting by Barry Weekley.
Copyright: Barry Weekley (
Bundesarchiv Bild 101I-342-0603-25, Belgien-Frankreich, Flugzeuge Dornier Do 17
The Luftwaffe raids RAF Kenley
Hurricane of 615 Squadron damaged on the airfield on 18 August 1940

How does a system, originally designed as a maritime rescue apparatus, end up on Fighter Command airfields in 1940?

In this instance, it becomes the Parachute and Cable, or PAC, system for airfield defence. Originally developed in the early twentieth century as a land based means of sending a rescue line to stranded ships on the coast, it was used by the Canadian Army in the First World War as a means of laying communication cables between trenches; it was then further developed by the Royal Aeronautical Establishment (RAE) at Farnborough as a defence for low level bombing attacks.

By February 1940, with the Phoney War in its sixth month, Fighter Command was looking to improve the local air defence capabilities for its airfields both at home and in France. Facing a shortage of Bofors anti-aircraft guns, the Air Ministry adopted the Parachute and Cable system for the RAF alongside the Royal Navy. The initial contract, for 500 units and 3000 rockets, directed the equipment to the Admiralty for use on trawlers, being used in coastal convoy escort amongst other duties. The RAF requirement was much greater; 5000 units and 10000 rockets, fulfilment of this began in February 1940. At a conference on 15 February 1940, it was proposed initial installations would be carried out at RAF Manston, RAF Wattisham and AMES Great Bromley (a Chain Home radar station). The system was described “as the Mark II P.A.C. Scheme and it is to be installed at all operational and R.D.F. stations. It consists of a rocket with parachute fitted on the top fired electrically by means of a cartridge out of a tube vertically into the air. The electric supply is from batteries. The rocket ascends to a height of 600 feet and as it rises unwinds a length of 1-ton cable (480) feet), with another parachute of equal size to the first attached to the end. This whole assembly floats to earth at a rate of 40 feet per second.” The system was to be installed at sites on the perimeter of an aerodrome in three rows, each row twenty feet apart and each rocket 60 feet from the next in the row. Even at this stage, concern was expressed over the siting of the rockets primarily so they did not damage the based aircraft or obstruct the airfield taxying tracks or dispersals. The conference agreed that the siting of the system must be done in agreement with the Station Commander. This concern remained within Fighter Command even after the system was being installed on its airfields, with Dowding commenting “…they must be sited on ground outside the aerodrome…” Dowding also requested attendance of the installation review at Manston with the RAE expert, Squadron Leader T H England, such were his concerns. However, he did insist that the PAC operators could not be drawn from the existing establishment of each airfield. He also requested 4 PAC installations per airfield.

By 12 April 1940, the plan was to have completed installation at Fighter Command airfields by the end of June, including those in France; with training commencing at RAE Exeter on 6 May each course lasting 3 or 4 days. However, on 30 April, following the German invasion, all PAC apparatus was diverted to Norway and all other installations were postponed.

After the German attack in the West on 10 May 1940, matters took another twist with PAC systems being installed at locations involved in aircraft manufacture. By 25 May, the Hawker works at Langley and the Supermarine site at Eastleigh had had their installations completed, with Gloucester, Brooklands, Derby, Crewe & Glasgow identified as the next manufacturer sites for installation. On 30 May, Kenley along with Manston (resiting), Hornchurch, North Weald, Biggin Hill, Tangmere and Debden had been identified for installation. However Kenley was only fifth in this list. As the situation on the Continent deteriorated and following the Dunkirk evacuation, on 21 June a further 27 airfields primarily on the east coast were added to the list of installation sites. The installation at Kenley and Croydon is confirmed as completed by 30 June.

As late as 2 July, Dowding registers “a formal complaint” about not being consulted on the PAC installation at his airfields. However, on 8 July this complaint is rebuffed, with Wing Commander England being told by Dowding personally on 9 March that “he did not wish to visit Manston or any other Stations under his command in order to see the siting of the PAC Scheme.” This stance was repeated in a telephone conversation around 18 April. From this point on, Dowding has more important matters on which to focus his attention. However, he delegates authority to the Fighter Command Armaments Officer which results in the requirement to resite some of the PAC installations.

As the system has now been installed at a number of sites, and with training of operators underway, instructions are issued on the airfield maintenance of the equipment and proficiency of its operators. Responsibility for the equipment on an airfield lies with the Armaments Officer who should conduct daily inspections of the Schermuly Rockets and ensure that the equipment must be suitably protected from the weather especially sockets and connections, “a temporary method of protection is to put the connections or sockets between a waterproof covering lined with paper and place between two boards and sandbags”. The operators are expected to perform the judging of height and aircraft recognition once a week. In the live environment, “Operators should therefore hold their fire until the aircraft have reached a point from which it will take them 3-5 seconds to reach the line of rockets (i.e. approximately 300-500 yards away). No hard and fast range can be laid down, because clearly the correct range will vary upon the speed and method of approach of the enemy aircraft.”

By the beginning of the Battle of Britain, 26 airfield and manufacturer sites have the PAC system installed with a further 22 scheduled. However, concerns about damage to aircraft on the ground still remain and a number of requests are made to resite the PAC to overcome this. A report from the RAE relayed to Dowding allays this fear “… a discharged rocket on reaching the ground, although hot, does not constitute a danger to aircraft on which it may alight. The weight of the discharged rocket is approximately 15lbs. And during firing trials at Exeter one of these rockets hit a Blenheim in the region of one of the engine nacelles without causing any damage to the aircraft.” As a result of this report the decision to resite PAC installations is rescinded at the end of July.

Due to the nature of the PAC system, weather conditions continue to play a large part in its operability. Methods to overcome this are often down to the ingenuity of local personnel, a 3 August report from Church Fenton, “Technical Difficulties. It was found that after rain, the connections became damp. This trouble has now been eliminated by covering all connections with waterproof, and fastening same at each end with rubber bands also by pegging the connections off the ground with Y pegs. The connections at the bayonet sockets have now been soldered and this has prevented any play between the connection and bayonet sockets which tended to cause short circuits.”

As the Battle of Britain intensified at the beginning of August, Kenley requested a PAC installation at Shoreham and Redhill. This request is repeated on 11 August when West Malling is added to the list of satellite airfields. Airfield defence became even more pressing after 12 August, when the Germans changed their tactics to attacks on airfields in the 11 Group area; their intention being to force Fighter Command to give up the south east as an operating area, a prelude to the gaining of air superiority by the Luftwaffe. After three days of attacks, culminating in a heavy raid on RAF Croydon on 15 August, there was a two day lull as the Germans planned a series of attacks on Biggin Hill, Kenley, Hornchurch and North Weald for 18 August. Even on this date, there was still some confusion within elements of Fighter Command as to what form of attack PAC was intended to combat, the Air Ministry pointing out that it was not suitable against dive bomber attacks. Ironically, this was the day when the system made its successful combat debut at Kenley.

The raid on Kenley was a three pronged attack led by Kampfgeschwader 76 (KG76) with high, medium and low elements. The high level element was intercepted in the Sevenoaks area by the Hurricanes of number 32 and Spitfires of number 64 squadron. Following shortly after, at low level, were 9 Dornier Do.17s of 9 Staffel, KG76. They crossed the coast near Beachy Head, but their progress was tracked closely by the Observer Corps who kept 11 Group HQ at RAF Uxbridge informed of their routing. The original German plan envisioned this low level formation as being the final element of the attack on Kenley, arriving as the defenders were starting to recover from the earlier raids, however 9 Staffel were now the lead element of the attack. The raiders approached the airfield from the south skimming over the tree tops, their bombs destroying three of the hangars and cratering the airfield. However, this line of approach suited the defenders on the northern boundary perfectly, as A.C. Knowles described in his report: “After a short interval we observed twin engine bombers flying over the hangars in our direction at about 50ft. They then dropped bombs on the hangars. Two bombers approached A Line of Rockets machine gunning the ground defences. When they were in range I set up No.1 A Line 17 Rockets and observed that the left wing of the leading aircraft caught one of the wires, he staggered slightly then straightened up, though in great difficulty, and appeared to go down in the valley. The second aircraft also went into the line of Rockets. My view was then obscured owing to the first plane dropping a bomb on a pile of cinders a few yards from my lines. I then proceeded to fire Nos 2 & 3 lines and obtained no results, on testing the lines I found that Nos 2 & 3 had been knocked out of action apparently due to the blast of the bomb. When the bombing died down I repaired the lines then proceeded back to the Post to await further action.” Accompanying Knowles that day and responsible for another Line of rockets was A.C.2 Roberts, his report echoing the experience of Knowles. Roberts concludes his report: “Shortly after the raid I accompanied Wing Commander England to the wreck of the Dornier 17 and he gave his opinion that there was evidence of cables being caught on the wing.” In a letter to HQ Fighter Command on 21 August, the Kenley Station commander commends the operators: “It is desired to record the excellent judgment and devotion to duty displayed by A.C. Knowles and A.C. Roberts who were responsible for operating the lines in question.” In the space of a few moments the PAC system had brought down one enemy aircraft and damaged two others; only four of the attackers returned to their base, none of them having escaped damage either from ground fire or by the Hurricanes of 111 Squadron operating from Croydon. It is interesting to note that Manston could have been the first station to deploy the system operationally on the same day against attacking Me.109s, but its operators were caught by surprise.

The effectiveness of the system at Kenley is due in no small part to the support of the Station Commander. Throughout 1940, the Air Ministry views the local commander as the key in getting what we now term “buy in” from its operators. A Kenley resident, as a boy, witnessed a demonstration of the system in a local park; describing it as looking like a series of tea chests with a tube on the corner. Actually seeing the system in operation was worth more than a training drill which stopped short of firing the rockets.

The events of 18 August at Kenley had demonstrated that, under the right circumstances, the Parachute and Cable system was an effective close range airfield defence weapon. However, the operators put themselves at great risk when deploying the weapon; as an Air Ministry note on 3 September demonstrates: “Recommends provision of shelters with overhead cover but with good all round field of view for PAC operators. Dugout accommodation affording complete cover but allowing no view of attacking aircraft must on no account be provided as this encourages operators to shelter at the critical moment when they should be operating the weapon. Operators can control the apparatus in a prone position at ground level and a low parapet of sand bags against blast effect and light overhead cover raised well above the parapet against falling debris should provide adequate physical and moral protection.”

By 11 September, the network of, and plans for, installation of the Parachute and Cable system ranged from Sullom Voe in Shetland to Manston in Kent and St Eval in Cornwall. A simple solution to short range airfield defence had had its worth recognised. Another recorded instance of the system occurred on 18 February 1941 when a Heinkel He.111, from Kampfgeschwader 53 (KG53) the Condor Legion, was brought down by the PAC at RAF Watton in Cambridgeshire where it ran the length of one of the lines of rockets, crashing near Ovington in Norfolk. The aircraft had been on a reconnaissance mission over the Humber and was returning to base in somewhat marginal conditions when it descended below the cloud base believing it was over friendly territory. All five crew survived and were taken prisoner.

A further derivative of the Schermuly system was used by U.S. Rangers to scale the cliffs when attacking Pointe du Hoc on D-Day.

The PAC system was a short-term, quick solution to a pressing need at the beginning of 1940 that of airfield defence. With a shortage of Bofors anti-aircraft guns, and their slow rate of production, close airfield defence was down to Vickers and Lewis machine guns. Neither of these weapons really carried an effective punch against attacking aircraft as they were operated singly or in pairs. The adoption of the PAC system filled a gap in airfield defence coverage using a simple solution. As evidenced earlier, the siting of the system was crucial and at Kenley this proved propitious and effective.


The National Archives, Kew

Kenley Revival Oral Histories

Battle of Britain, Alfred Price (Ian Allan 2010)

Action Stations Vol.1: Military Airfields of East Anglia, Michael J Bowyer (PSL 1979)

Think Defence (

Comments about this page

  • A very interesting and imformative article. i take pride in my knowledge and knew nothing about the system, thanks so much for the article. I am making an raf hurricane based at kenley and this sparked my interest. once again thanks for posting the article.

    By philip skinner (20/02/2021)
  • When Plymouth was under air attack, probably 1941, I was a prep-school boy evacuated from Essex to Bigadon House, Buckfastleigh in Devon. One night a PAC landed on and blew a hole in the corrugated iron roof of Farmer Smerdon’s barn at the top of Bigadon Lane, behind Bigadon House. It was a complete mystery at the time. The PAC system was not then known about. I think that still applies. This is, for me at least, a very interesting article.

    By Leslie Head (05/07/2019)

Add a comment about this page

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.