RAF Maintenance

by R E Hautier
British Air Ministry

When fighting airplanes are scarce, efficient maintenance is necessary to keep them in the air.

Fighting and training aircraft of the Royal Air Force are backed by a two-fold maintenance organization with wide ramifications. The system is elastic, and capable of great expansion: it has been designed with an eye to the conditions of modern warfare. It has two sides, RAF and civil.

On the RAF side, in the field and at home, servicing is done in every squadron and larger repairs in the service-manned repair depots, while supply of replacements whether of engines and instruments or components is done by equipment depots. On the civil side is a newly created civilian repair organization, a widespread system with roots in all branches of industry. It is controlled by Lord Nuffield and its job is to do overhauls and repairs over and above those done by the service.

Maintenance Command

The Maintenance Command of the Royal Air Force controls the main system of storage, distribution and upkeep of Britain's air-fighting equipment, from factory to squadron or flying school. This is a recent organization, evolved to meet the problems produced by the great expansion of the RAF It is designed to relieve the Operational and Training Commands of the problems of supply and repair services; and to concentrate all maintenance units into one comprehensive organization.

Although part of a uniformed service, the Maintenance Command is planned and run on the lines of big industry. Wherever any specialized problems of storage, distribution or maintenance was known to have been solved in civil industry, the RAF went to the industrial experts for advice on handling its service counterpart. Railway managers, patrol, the automobile association, executives of big commercial undertakings, all helped in designing the framework of the maintenance system of the modern RAF.

In structure the Command resembles four groups of businesses, each with a separate function, all under the control of a holding company. One group handles equipment; one aircraft and engines; another ammunition and fuel; and the fourth repair and salvage. Control is largely decentralized, all administrative details being left to the separate groups and their subsidiary organizations. Only matters of broad policy are handled at the top.

The function of the groups is to receive and store, and then to distribute to the operational and training units serviceable articles of equipment of all kinds — everything that goes to keep the aircraft in the air as efficient fighting or training machines. Once an item, whether an aircraft or a spanner, reaches a unit, that unit is responsible for keeping it going. Maintenance Command supplies everything needed for routine maintenance and minor repair — petrol, ammunition, fabric, metal, dopes, etc. When airframes, engines and accessory equipment need major overhaul or repair they go back to the Maintenance Command. They may go on to civilian workshops of the civil maintenance organization.

First Maintenance Problems Are at the Squadrons

Usage, and wear and tear of aircraft takes place in the operational and training units. These are the fighter (pursuit), bomber and reconnaissance squadrons, and the flying and armament training schools. And it is at these units that the first impact of maintenance demands is felt.

The Royal Air Force with units on a front stretching from the Arctic to the tropics, operates under a wide variation of climatic and other conditions. But in the interests of simplicity, and the interchangeability of personnel, a system of aircraft maintenance has been devised for squadrons which is largely, though not absolutely, standardized.

Standard periods between inspections of aircraft and engines are laid down, generally in terms of flying hours. Under certain conditions, as, for example, where limited flying takes place, or in climates where corrosion is rapid, there is an alternative system based on time limits irrespective of hours flown.

Even under full war conditions the inspection and servicing of British operational aircraft follows a strict routine. Every time a fighter returns from patrol, or a bomber from a raid, the "between flight" inspection is made. Tanks are refueled and, if the pilot reports that he has been in action, the structure is examined for bullet holes and ammunition is replaced. E

ach day, whether it has been in action or not, every operational aircraft undergoes the "daily inspection”. Riggers, litters, wireless mechanics and armorers go over their parts of the airplane and give it the "OK" before turning it over to the flying crew. This inspection ensures that every serviceable aircraft of a British operational squadron is always ready to go into immediate action.

After a given number of hours' flying — the exact time depends on the type — the "first periodical inspection" is made. This job calls for two or more hours work from the ground engineers — unbuttoning cowlings and generally looking around. A further spell of flying is followed by the rather more comprehensive "second periodical inspection", when everything that moves on the aircraft comes under examination. Finally, there is a standard "life" for each type of aircraft and engine, at the end of which it is sent away for complete overhaul.

Squadron Headquarters Servicing Party

In the operational squadrons of the RAF part of the routine servicing is done in the "flights" (or divisions of the squadron), part at squadron headquarters by a servicing party of fitters and other specialists under a skilled engineer officer. Between-flight and daily inspections, and a proportion of other routine inspections are the job of the flights. Work beyond the capacity of the flights, or which requires a higher degree of technical skill, is handled by the headquarters servicing party. This includes light repairs, and the more important and lengthy routine inspections. Damaged units which are estimated to require more than a certain number of man-hours to repair are handed over to one of the repair shops of the repair and salvage group of Maintenance Command.

Maintenance in the Field

The maintenance of units of the British Air Forces in France and other theaters of war is organized on lines similar to those at home. Repair and salvage units go with the expeditionary force; backed, in the major theaters of war, by fully equipped repair depots. These units comprise a headquarters, and a number of repair and salvage sections, some of which are mobile. They are competent to repair aircraft in situ and fly them back to their squadrons; or to dismantle them and hand over the components to the repair organization behind. The repair and salvage unit can also assist the operational squadrons with servicing work beyond their normal capacity.

The fact that British operational aircraft, both at home and abroad, have been serviced and maintained in the open through months of the most severe winter weather and have always been ready for service, is an indication of the efficiency of the RAF maintenance engineers.


Another feature of modern warfare — the need for mobility — has a particular reaction on the maintenance. problems of an air squadron in the field. The accessory equipment of RAF units such as electric engine starters, refueling tankers, light workshops, engine dismantling tackle, oxygen plants are all highly mobile. An entire squadron, and all its gear, can move with its own mechanical transport in a matter of hours. This degree of mobility is in the tradition of the Royal Air Force in the last German war. It is recorded of No 32 Fighter Squadron that "on the 21st July, 1918, the Squadron was attached to the 9th Wing, and was moved to Vert Galand. The aircraft left for their new station within 30 minutes of the order for this move being received.

Specialization of Maintenance Personnel

Parallel with the standardized system of maintenance schedules for aircraft, simplification has also been introduced into the technical trades of the Royal Air Force. Broadly, there are three recognized groups of skilled craftsmen. Each group is employed, and paid, according to their degree of skill.

Supervisory and expert workshop personnel, qualified to work on either airframes or engines, or on instruments, radio and armament from the first group. In the Squadrons specialists of this sort are generally kept in the headquarters servicing party. Many more are employed in the bigger service workshops behind the squadrons. Two other groups of tradesmen, less highly skilled, provide personnel for flight servicing work and for routine operations.

Maintenance of Trainer Aircraft

Flying training schools, having less need of mobility, have carried specialized employment of personnel further than is possible with operational squadrons. Here the flights (or subdivisions of the flying part of the school) have no responsibility for maintenance of the training aircraft other than for the daily, and between-flight inspections. All other maintenance work is carried out by a specialized servicing flight which is the equivalent of the squadron headquarters servicing party.

RAF flying schools are generally equipped to carry out rather more extensive repairs than is an operational squadron. Their workshop and handling capacity varies somewhat as between one school and another. And the extent to which overhauls and repairs may be undertaken by training schools, without recourse to the workshops of the repair group, is also dependent on the amount of work arising. That, in its turn, is largely determined by the amount of flying being done.

Aircraft Repairs in Situ

An increasing proportion of the major repairs undertaken by the RAF maintenance organization are now being done in situ by mobile working parties. These parties are supplied either from the service-manned depots of the Maintenance Command, or from civilian repair works by arrangement with the civilian repair organization. Sometimes the work will be limited to an emergency patch-up job sufficient to enable the aircraft to be flown home for further repair, or in less serious cases the whole repair is done on the spot. Repair in situ is particularly useful for dealing with large, bomber type aircraft which are difficult to move by road or other than air transport.

Major Overhauls
Air Frames and Engines

Crashed airframes and engines which can advantageously be repaired, and airframes and engines due for a major periodic overhaul, in most cases go back to the constructors or to some selected firm with proper facilities for doing the work.

The Nuffield Scheme

Quick repair of the large quantities of air equipment — airframes, engines, and accessory items — was foreseen as one of the principal problems of full-scale air war. Engineering capacity formerly engaged in satisfying peacetime requirements has now been turned over to repairing the equipment of the Royal Air Force.

Lord Nuffield, founder of Morris Motors, was appointed Director-General of Maintenance under the Air Ministry soon after the war started. His special task is organizing and developing this organization. Like a number of other leaders of industry who are now assisting the Government, he works without salary. The civil repair organization comprises many industrial units, with suitable floor space and machinery. Spread throughout Britain, but coordinated to work as a whole, they provide against the possibility of knockout air attack.

Service Manned Repair Depots

Parallel with the civil repair organization are a number of service-manned repair depots. They have the dual function of handling maintenance work of an urgent character for which capacity may not be immediately available in the civil repair shops; and of affording training for service personnel destined to man the mobile repair sections operating in the field.

Storage Units

Storage units of different kinds are required to receive equipment from the manufacturer, hold it until it is needed by units, and issue it when the time comes. The vast quantity of equipment now available for the RAF has involved the construction of many new units of this kind. Previous ideas as to storage were overhauled and these new units were organized on entirely new lines. The organization has been tested by exercises in peace; it is now standing the test of war.

Methods of distribution as well as of storage were also re-examined and modified to suit the varying needs of units at all the different stations of the Royal Air Force as well as those on the fighting fronts — one of which is the United Kingdom itself.

This article was originally published in the July, 1940, issue of Aviation magazine, vol 39, no 7, pp 42-43, 102.
The original article includes 2 photos.
Photos credited to British Combine, Wide World.