Air Fronts: Theaters of Operation - ETO -  AP 156: Battle of Britain - 2. Maintenance

THE BATTLE OF BRITAIN. Air Ministry Pamphlet 156; Issued by the Department of the Air Member for Training, August 1943

MACHINERY OF OPERATION

II. Maintenance

It was not only in the air that a battle was being fought, another one was taking place all the time on the ground - the battle of Maintenance. Airmen at R.A.F. stations had a constant struggle, often under difficult conditions, to keep their aircraft ready not only to fly but to fight; flying schools had to compete with shortages in instructors and material and yet train more pilots in less time; depots and storage units had, by hook or by crook, to ensure that replacement aircraft were always available and that, so far as was humanly possible, no aircraft was ever kept on the ground for want of spares; landing grounds and communications had to be restored in the shortest possible time when damaged by enemy bombing.

Supply of Pilots

The most serious factor in maintaining the effective strength of the Fighter Command was the supply of pilots. These were required not only for replacing casualties but also for relief of those who were tired. By the end of the evacuation from Dunkirk there were only three day fighter squadrons left which had not been engaged in continental fighting, squadrons had only partially recovered from the effects of the fighting in France, and were neither fresh nor up to full establishment when the fighting began over Great Britain.

Relief of Squadrons

During the first phases of the Battle of Britain squadrons would normally be kept in the active areas until they were no longer capable of putting nine aircraft up into the air, when they would be relieved. The most satisfactory method of relief was by moving complete units. This was done at first but later on, owing to the difficulties of transport, the relief had to be limited to flying personnel and aircraft crews, the rest of the personnel being retained at the original sector station. The disadvantage of this was that most of the officers and men were strange to each other. The period during which squadrons remained in the active areas varied greatly. It was also found that the heaviest casualties usually occurred in newly arrived squadrons because they were not familiar with the latest methods of air fighting.

New System Adopted

The pilot situation caused much anxiety in August and by the beginning of September had become so serious that a special system was introduced to tide over the emergency. Under this, squadrons were grouped into three categories:

Category A. Squadrons in No. 11 Group and on its immediate flanks which were bearing the brunt of the fighting.

Category B. A few squadrons maintained at operational strength to be available as immediate reliefs should this be unavoidable.

Category C. Remaining squadrons, which were stripped of the majority of their operational pilots for the benefit of the A squadrons and devoted their energies to training new pilots from the Operational Training Units (O.T.Us) or from other commands.

The A squadrons were stabilized and were not to be relieved except under very special circumstances. They were kept up to establishment mainly from the C squadrons.

The C squadrons were not fit to meet German fighters, but were capable of defending their sectors against unescorted bombers.

Signals from stations stating their requirements in pilots and aircraft would be sent in at 2200 hours daily, and every endeavour was made to ensure that reinforcements should arrive by 1200 hours the following day.

Help from other Commands

Every effort was made to meet the pilot deficiency. Coastal Command transferred some of their best fighter pilots; the numbers for training at fighter O.T.Us were increased by transfers from Bomber Command and, during August and September by some 60 pilots from the Army Co-operation squadrons. The Fleet Air Arm also loaned 51 fighter pilots to Fighter Command during the battle. Some of the pilots transferred from the Army Co-operation squadrons carried out their first operational patrol within a fortnight of their volunteering to join the Fighter Command.

Training Command

On 27 May 1940 the original Training Command had been divided into two, Flying Training and Technical Training. Owing largely to lack of available resources at that time the programme of flying training was in no way flexible, consequently when the need for fighter pilots rapidly increased there was no method of varying the training so as to increase the supply. There were only three O.T.Us in Fighter Command - their capacity was insufficient to meet demands and, to accentuate the shortage, the supply of fighter pilots from the Service Flying Training Schools (S.F.T.Ss) was insufficient to meet the intake requirements of the fighter O.T.Us.

The need for additional fighter pilots was fully realized by the Flying Training Command. As early as June the A.O.C.-in-C. had issued an instruction ending as follows: `It must be realized that our main contribution to the defence of this country is the maximum training output up to the required standards, and that some risks in local defence must be faced in order to meet the main responsibility.' Again at a conference at the end of July 1940, he stated in reference to the battle: `Reinforcements are of course vital, and it is the duty of Flying Training Command to, furnish reinforcements in the form of pilots.' All possible steps were taken to effect this; pilots qualified for accelerated training were 'creamed off' from Advanced Training squadrons of the S.F.T.Ss and made available for early postings to the O.T.Us. During September the intake at eleven S.F.T.Ss was increased by 25 per cent. and the length of the S.F.T.S. courses was progressively reduced. Again towards the end of September, the length of the courses at six of the Elementary Flying Training Schools was reduced and the intake at the E.F.T.Ss increased by 25 per cent.

The greatest contribution made by the Flying Training Command to the Battle of Britain lay in the thoroughness of the system of instruction. This ensured that when a pilot reached his O.T.U. and got to his operational aircraft he would very soon acquire complete mastery and control of it under all conditions and would also be able to shoot straight.

The small number of aircraft crashes in fighter squadrons due to errors of pilots during the Battle of Britain is also a tribute to the thoroughness of their training. Over half the aircraft casualties were analysed and of these only 4 per cent. were classified as due to errors of pilots. By way of comparison it may be noted that during 1918 in France the proportion was 24 per cent.

Training Command would also have co-operated in the event of attempted invasion by participation in a scheme for making operational use of all possible aircraft in emergency. There were various stages in this scheme, from the absorption of Bomber Operational Training Units into the striking forces of their Command to the employment of light aircraft used at E.F.T.Ss. The great majority of the aircraft so obtained were to be placed under the operational control of the A.O.C.-in-C. Bomber Command, who had power to delegate to subordinates as necessary. The aircraft would move complete with maintenance crews.

The grand total of aircraft which could thus be made available ran well into four figures, if those temporarily unserviceable or on major inspections are included. Training would naturally have been at a standstill had the scheme been brought into operation.

Servicing and Maintenance Crews

The great majority of the ground personnel who served during the Battle of Britain had either completed or had started their training in the original Training Command.

At the start of the war this Command had to meet a big commitment, for which its existing resources were quite inadequate. New schools were under construction but did not open till late in 1940. Methods had therefore to be improvised; amongst them were:

(a) Making the fullest use of the limited training equipment by ensuring a regular flow of weekly entrants, succeeding each other in weekly phases of training;

(b) Reduction of the length of all courses;

(c) Using Technical Institutes as supplementary schools of instruction;

(d) Using billets and requisitioned garages and other buildings at Morecambe and Blackpool to form new schools.

These makeshift schools and mass production methods meant that risks were being run, but the effect of the changes was minimized because tradesmen in the pre-war Air Force were of first-class quality and formed a nucleus which could be rapidly expanded in war-time.

Quick Servicing and its Value

After aircraft had landed from a patrol or flight, during the Battle of Britain, it was very important to have them turned round, i.e. ready for action again as soon as possible. Apart from the fact that the fighters had, on many days, to take off at very short intervals or at least come to readiness, there was always the danger of enemy aircraft sneaking in and catching our fighters whilst they were unready for action.

Quick servicing was largely a matter of teamwork and was developed into a fine art - refuelling, re-arming, checking over the engine, including its oil and glycol, replacing oxygen cylinders and testing the R/T set, would all go on simultaneously and rapidly but also thoroughly. Good drill enabled the crews to carry out their work without impeding each other. The Tannoy broadcasting system was used to assist. Station commanders or their controller in the Sector operations rooms knew when their squadrons were returning and used to broadcast to the dispersal area on the airfield some warning message such as No. X squadron servicing party stand by; the squadron will be landing in ten minutes'. This enabled each servicing crew, petrol tankers and so forth to be ready and waiting in the right places to receive the aircraft as they taxied in. It is recorded that on many occasions all the aircraft of a squadron formation were replenished with fuel and ammunition and got ready for another battle in eight to ten minutes after landing. Servicing parties had not only to deal with aircraft of their own station, but also with those from other airfields landing after a fight.

Maintenance and Repairs

Regular maintenance and repair work was carried out by day and by night. It was soon found that pooling of all the maintenance personnel on a station (other than the servicing parties) was necessary, since the amount of repair required varied considerbly: one squadron might go through the day with little or no damage; another might have got into a tough spot and have most of their aircraft unserviceable. The station Engineer Officer would therefore detail from the pool a proportion for the maintenance and repair of each squadron's aircraft, in accordance with the work required to get them serviceable again. This combined maximum output with economy in man power and was made standard practice.

Most of the maintenance work on the signals equipment of aircraft had to be carried out at night by the light of torches. The greatest trouble arose through damp, and extreme care was necessary to keep R/T equipment dry in rain or dew. Occasionally defective equipment had to be removed from aircraft, taken to the nearest power point and a hot-air blower used. Charging accumulators at dispersal points was somewhat difficult at first owing to lack of mobile charging plant, and small petrol-electric sets were used and run 24 hours daily in the endeavour to keep abreast of requirements. R.A.F. Signals personnel also installed and maintained field cables to dispersed flights and laid field cables each night from the flare path to the watch office or control tower. There was excellent co-operation between the signals staff and the aircraft fitters.

Small portable tents were provided which could be erected over the centre portion of the aircraft, but much of the maintenance had to be done in the open, sometimes in bad weather; dispersal of aircraft not only to satellite landing grounds but over wide areas at each of them, combined with insufficient transport, increased the labour required to complete any job; the damage done to the station organization by enemy bombing and the black-out added to the problems.

Value of the part played by Ground Crews

Every mechanic realized that on his skill and thoroughness depended not only the pilot's success in the next fight, but his life; the pilots knew this and their complete confidence in their aircraft and the men who maintained them was no small factor in the high morale which made such a great contribution to victory in the Battle of Britain. And the maintenance crews felt, and rightly so, that they shared in their pilot's triumphs, which were gained largely because many individuals, each skilled in his own particular line, worked together as one team.

During the heavy fighting of 15 September one of the Polish squadrons had only four aircraft serviceable by the evening; the others had suffered all sorts of damage: control surfaces shot away, radiators smashed, control cables cut, wings riddled by bullets, and even propellers hit. It was expected that the enemy would return in force next day and the mechanics realized how much depended on them. They worked all night, and by dawn on the 16th, twelve fighters were ready to take off.

The mechanics may not be much in the public eye, but a splendid spirit prevailed through them all; they triumphed over all difficulties and the R.A.F. realizes now much was due to their efficiency and devotion.

Encouragement of the Team Spirit

Everything was done to foster the team spirit. Station commanders would visit the personnel at work at all hours of the night and give them a word of encouragement. Every evening a broadcast would be given of the work done by each squadron, announcing the number of enemy aircraft brought down and decorations awarded, with words of praise for the maintenance staff who made the results possible. The facilities afforded by the Tannoy system were of great value in pulling the whole station together and did much to make everyone feel that his or her job was an important factor in the whole work of the team.

Keeping Balloons Flying

Balloon personnel did not lag behind in their determination to keep their weapon in the air whatever happened. Here is an example: On 24 September a site forming part of the balloon barrage at Southampton lost its balloon in a gale. They were preparing to inflate a new one when an air raid started, just before 1330 hours. An unexploded bomb fell near the balloon site; it was decided to evacuate this and a new site was prepared. At 1824 a second attack started, 8 U.X.Bs falling near the new site, which was also abandoned. Work on the third site was started on 25 September and a new balloon was flying at 1530. About 24 hours later, i.e. on 26 September at 1620, the balloon then flying at 4,500 feet was shot down. Bombs fell close to the site, the gas trailer was thrown into the air, all bottles were scattered, but none exploded and there were no casualties to personnel. The cable was salvaged as soon as the raid was over. Bottles were collected, and a new balloon was flying by 2030 hours using the damaged winch. This was changed the next day.

Maintenance Command and Supply of Material

Lord Beaverbrook was appointed to the Ministry of Aircraft Production in May 1940, and his drive and energy produced a great spurt in the output of aircraft and of urgently needed equipment. Whatever may have been the effect later, for instance, on the supply of spare parts, it was this spurt that ensured the supply of fighters, especially of Spitfires, being sufficient to replace wastage during the Battle of Britain. The aircraft firms co-operated wholeheartedly and, as an example of this, the work done by the firm of de Havilland in connection with the constant speed airscrew is given on page 35.

The pre-war estimates of aircraft wastage during the periods of maximum activity were exceeded, but not by much; consequently the basis on which the maintenance organization was planned approximated to the actual requirements. The events in France and at Dunkirk had strained the maintenance units to the limit, so that the whole Maintenance Command had been trained to meet emergencies before the Battle of Britain started and certain modifications in procedure had been introduced. For instance, it was ruled that in urgent cases expenditure could he incurred without previous sanction. The full support of the Air Ministry was given to this procedure, almost revolutionary by pre-war standards. Civilian workers, as well as the R.A.F., all realized the need for special efforts and worked at full pressure.

The maintenance organization did far more than supply spare parts, it dealt with new aircraft, salvage and repairs. Every fighter aircraft used in the Battle of Britain passed through one of the Aircraft Storage Units (A.S.Us) where it was fitted with various parts of its equipment, including guns, sights, and most of the R/T.

Replacement of Aircraft

Losses amounting to as much as 50 per cent. in individual squadrons were replaced before 12 noon on the following day. It speaks highly both for the maintenance organization and for the aircraft factories that in no period of the Battle of Britain was there a deficiency of aircraft needed to make good the wastage in squadrons. The reserves went down, and for some time the issues of aircraft considerably exceeded the receipts, but the Aircraft Storage Units never actually ran out of single-seater fighters complete and ready for issue. The lowest figure was on the 13 September after which the resources again rose steadily. During the first part of the Battle of Britain aircraft were allotted to squadrons, but in the later stages they had to be allotted to stations, because squadrons were moving so quickly. In most cases the aircraft were flown from the factories to A.S.Us by ferry pilots of the Air Transport Auxiliary and from the A.S.Us to squadrons by pilots of a Service Ferry pool. During August the total number in and out of A.S.Us amounted to nearly 4,000 aircraft, and for a short period operational pilots had to be used to help out the ferry pilots.

It is doubtful whether the supply of aircraft could have been maintained at the rate required without the very thorough system of repair. Of the total number of aircraft issued during the Battle of Britain to fighter squadrons, exclusive of the fly-in repairs of under 24 hours, 35 per cent were repaired and only 65 per cent. new, and of the total struck off the strength of the squadrons, exclusive of missing aircraft, 61 per cent. were eventually repaired and 39 per cent. reduced to produce or spares.

The organization for aircraft repair developed during the early stages of the battle. Up till April 1940 the routine for the repair of aircraft was the same as during peace, i.e. a damaged aircraft was assessed either as :

i Repairable by the Unit,

ii Repairable by a contractor or R.A.F. repair depot, or

iii Recommended for reduction to spares and produce.

The weakness of this scheme became obvious during the fighting in France. Airfields became overloaded with unserviceable aircraft, which frequently did not require a large amount of work to make them serviceable. The stations concerned did everything possible to carry out repairs, but were unable to cope with the volume of work. A modification was therefore introduced. The assistance of contractors was brought in to work on those aircraft which could be repaired on the site; others which were severely damaged were dismantled and moved by road either to a contractor's works or to an R.A.F. repair depot. It soon became clear that should the enemy begin bombing our airfields this scheme might result in further and serious damage to aircraft unless they were removed from forward airfields as soon as possible. A further change was therefore introduced and came into force on 27 May 1940. Aircraft were divided into three categories:

iv Those capable of rapid repair at the station and with station facilities,

v Those beyond station repair but fit to be flown to an R.A.F. or civil repair depot,

vi Those unfit to be flown.

Repairs under Category (iv) were limited to those that could be carried out within the next 24 to 36 hours. Any aircraft which could not be repaired within this time were treated as under class (vi). Class (v) consisted of aircraft which were safe to fly straight in a lightly loaded condition. They were known as `fly-in' repairs. If an aircraft, after delivery at a repair depot, was found to be repairable within 24 hours, the pilot could wait for it and fly it back. Aircraft under class (vi) were removed by road for repair or for reduction to spares and produce. Although under this system some aircraft, which only required comparatively small repairs, had to be placed in class (vi), it was rightly considered that the extra work involved in dismantling and reassembling, including the risk of extra damage during that process, was more than compensated for by the benefit of clearing airfields and the avoidance of further damage by enemy bombing. No accident was recorded due to the fly-in system. The Ministry of Aircraft Production co-operated wholeheartedly in this scheme.

Most of the Hurricane aircraft were repaired at Henlow, and during the intense periods that station worked up to 20 fly-in repairs per week whilst the pilot waited, in addition to major repairs of 12 per week. The speed record for changing both main planes which included fitting 8 guns and filling up with ammunition was 1 hour 55 minutes. Another good job of work carried out at Henlow was the conversion of Browning guns from Mk. II to Mk. II Star, the latter giving an increased rate of fire. On an average 300 of these guns were converted each week from May to November 1940.

Supply of Spares

Originally depots holding stores and spare parts had been specialized; for instance, one would deal with all engine spares, another with airframe parts, and so on. This system had great administrative convenience and allowed of some economy in man-power, but it entailed the obvious danger that the whole stock of some particular type of spare parts might be destroyed by a successful bombing attack, so the alternative of universal equipment depots was introduced. Under this system each depot held a relatively small number of every type of spare part and equipment, so that in the event of any one of them being bombed, only a portion of the total stock would be destroyed and the other depots would be able to supply all the needs of the squadrons. During the Battle of Britain this method was also extended to each depot, stocks being divided amongst widely separated sites, each of which held its proportion of the most vital types of spares. This subdivision was abandoned later, since complications of paperwork caused too much delay in making issues, and the danger from enemy air attack had been reduced.

Special steps were taken to prevent any aircraft being kept on the ground for want of spares if this could possibly be done. The special code letters A.O.G. meaning aircraft on ground were used to indicate special urgency. Spare parts were obtained from the Salvage Sections. A black list was kept up, showing what spares were in short supply and special efforts were made to ensure that these would be available with the minimum of delay; for instance, they were the first to be dealt with at the depots when received from contractors. Apart from this there was the organization known as the Master Provisioning Offices. These were located at equipment depots and each office dealt with its own particular types of equipment or spares. Should one universal equipment depot be unable to supply one of their squadrons, the M.P.O. was notified, and this office would arrange for another depot to supply what was required, or else get it direct from the makers, who would send the parts direct to the squadron demanding. Needless to say, all demands were dealt with throughout the 24 hours.

Salvage

The salvage organization was also an important factor. Eight salvage units were organized before the battle started, manned mostly by service personnel. All crashes were reported to the headquarters of the group which controlled these units and the engineer officer attached to each salvage unit had to decide whether any particular aircraft was (a) repairable on the spot and then being capable of being flown away, (b) repairable at con-tractors' works, or (c) fit only for reduction to produce and spares. The salvage units were also responsible for clearing operational aerodromes of crashed aircraft. The importance of their work increased during the battle because station personnel were so hard worked that they were sometimes unable to deal even with comparatively minor repairs. Salvage units also dealt with enemy aircraft after they had been examined by technical intelligence officers.

Another group in the Maintenance Command was responsible for the supply of petrol, ammunition and bombs. The pre-war estimate of expenditure of small arms ammunition was fairly accurate; some types of ammunition were short during the battle, but the total requirements were always available in one type or another.

Very little damage was caused either to storage or to repair units by enemy air attack; during the battle only two aircraft had to be written off by Maintenance Command from this cause.

Maintenance of Airfields

Attacks on our airfields were naturally anticipated, and steps taken to meet them. The number of A.A. guns was quite insufficient to meet the urgent needs of the whole country, and only a few were available for the direct defence of the more important airfields. R.A.F. detachments were organized with Lewis guns and some hundreds of 20 mm. cannon not required immediately for use in aircraft; they formed a mitigation but not a remedy.

The Army could only provide small numbers of troops for the protection of airfields against parachute or ground attack, but on 15 June 1940 instructions were issued to Technical Training Command for the training of 30,000 men for the defence of R.A.F. stations. This was started at Blackpool on 19 June, and by the end of July the full number was out at station. Armoured vehicles were extemporized.

`Stand-by' operations rooms had been constructed some distance from sector headquarters; they were small and had not been provided with the full scale of land telephone lines, but though some loss of efficiency resulted from their use, they proved very valuable makeshifts. Aircraft were widely dispersed and a certain degree of protection afforded by aircraft pens. Shelter trenches were provided for the personnel.

Preparations were also made by Fighter Command Head-quarters for dealing with the problem of feeding the personnel on a station in the event of the kitchen and dining-rooms being completely demolished and no alternative immediately available. Two mobile columns were formed, one to serve stations south-east of the River Thames, and the other to serve those north-east of the Thames. Each could feed 2,000 men and was entirely self-contained, not only with cooking facilities but with plates, knives and forks and washing-up arrangements. The columns could move at short notice. Actually they were never required.

The Works and Buildings Directorate had formed a repair organization, but station commanders realized from the start that it was also their duty to make all preparations within their power, since in the event of heavy bombing of several airfields, rapid repair would be a large-scale job calling for the services of every available man and woman on the station affected.

Works Repair Depots

On most stations was located a small Works and Buildings detachment whose duty it was to fill in bomb holes and repair damage. Behind this nucleus Works Repair Depots were formed; they were manned by civilian workmen and had a varying strength of 50 to 200. They had their own transport for their men and held reserves of equipment including bull-dozers, mobile excavators, mobile generating plants and pumps for petrol and water, as well as piping, timber and power cables. These depots were located so that any R.A.F. Station could be reached by one of them within two hours. The men carried out ordinary maintenance work on stations, but were always available for emergencies; they lived in the neighbourhood and the drivers were always on duty ready to fetch men should they be suddenly required. The policy for these depots was not to make any permanent repairs but to get things going in the shortest possible time; for example, runways if damaged were not repaired in ferro-concrete, but holes were filled up with hard core and given a tarmac cover. During the Battle of Britain some 800 cubic yards of hard core was kept on each of the southern airfields for repairs to the landing area and special reports had to be rendered if bomb craters in that area were not filled up within the 24 hours. The men took pride in getting their job done and remaining on it day and night until the work was finished. In addition, on some air-fields parties from General Construction Companies of the Royal Engineers were lent to the Air Ministry and employed on certain R.A.F. stations, but they were gradually withdrawn in the later stages of the battle when the Army again had employment for them. These R.E. units had little or no equipment but formed a very useful reserve of man-power.

Arrangements on Stations

The following is typical of the steps taken by station commanders:-

(a) All station personnel not engaged in essential control, servicing or maintenance of aircraft, or the A.A. defence of the station, were organized into works companies to assist in repair work; shovels were collected and stored at various points, under lock and key.

(b) Arrangements were made with local district councils for immediate call on all their Diesel tractors.

(c) Arrangements were made with local sand and gravel pit companies for each to supply, at short notice, a number of lorry-loads of sand and gravel in tip-up lorries, and special `right-of-way' road permits were granted to them. The tip-up lorries were invaluable where speed of repair was so important.

(d) Arrangements were made with Army troops in the neighbourhood for one or more companies to come to the assistance of the R.A.F. complete with shovels.

(e) Two complete sets of landing-lane markers and landing tees were made and kept under lock and key. These were for use in the event of the airfield being damaged by enemy bombing, at a time when our squadrons were in the air and fighting other enemy formations. The first thing necessary after such an attack was for someone to go up into the air to see if a landing-lane, 50 yards wide and reasonably straight, could be defined amongst the craters. This took a minute or two, and then markers were laid out 50 yards apart on both sides of the lane, and our squadrons could land again in another ten or fifteen minutes' time.

In addition to their important task of re-arming aircraft, the armament staff were normally responsible for manning R.A.F. A.A. posts also, although without specialist training, for dealing with unexploded bombs, under the supervision of the armament officer. U.X.Bs on the landing ground were removed at once, others railed off.

The W.A,A.F. personnel earned unstinted praise for their coolness during enemy air attack and the way they carried on their duties.

Repair of Telecommunications

The land-line telephone communications and teleprinter system for the R.A.F. was installed and maintained by the General Post Office. The personnel did magnificent work during the Battle of Britain in the repair of communications after enemy bombing, they worked night and day and no job was too difficult for them. They carried out their duties quietly and inspired every confidence. Often the Royal Corps of Signals took on the work of making temporary repairs to the communication system inside a station, thus leaving the Post Office staff free to deal with external circuits. The Engineering Department of the G.P.O. had set up a special organization before the war to deal with wartime emergencies and G.P.O. liaison officers had been appointed to various R.A.F. commands or group headquarters. At certain operational stations the continuous attendance of maintenance staff had been arranged.