The Aeronautical Inspectorate Division (AID) was originally established by the War Office, and then passed successively to the Ministry of Munitions (1917), the Air Ministry (1920), the Ministry of Aircraft Production (1940), the Ministry of Supply (1946), and the Ministry of Aviation (1959).
The need for an aircraft inspection department was first officially recognised in 1912, when the report of the Departmental Committee on Accidents to Monoplanes was published. The committee was charged with investigating certain accidents that had occurred to monoplanes and to make recommendations for the reduction of such risks.
The Aeronautical Inspection Department (AID) was formed in December 1913 for the purpose of inspecting aircraft and other supplies for the Royal Flying Corps (RFC). The department was immediately organised into two main technical branches dealing with the inspection of aeroplanes and engines respectively, each under the control of an Inspector. The headquarters of the department were temporarily established in a private house - "Ashdean", Alexandra Road, Farnborough Common for receipt of machines delivered by private contractors for final flight tests as laid down in their contracts. At that date the establishment staff totalled 28. The growth of work caused by the war, and the take-over of inspection for the Naval as well as the Military Aeronautical Service, had necessitated an increase in the establishment to 10,600 by Armistice in November 1918.
The scope of the inspection carried out by AID comprised not only aircraft but supplies of many other kinds utilized by the Flying Service, such as balloons, hangars, tents, machine tools, raw materials, fabrics and a variety of general equipment. In the inspection of these multifarious supplies almost every trade was dealt with, and some idea may be formed of the department's technical requirements when it is realized that detailed inspection was made of all materials, of the manufacturing process to which they were subjected, of the assembly of various parts into component units and of the erection of the aircraft, engines, etc.
The Headquarters organisation was divided into sections, each containing officers specialising in its particular branch of engineering or science. The external organisation was on a geographical basis, the country being divided into districts each under the control of a district officer responsible for the entire conduct of inspection throughout his territory.
By 1939 AID was an engineering organisation, mainly civilian, but in part RAF, whose prime purpose was to ensure that all RAF and RN equipment manufactured or repaired by contractors and by RAF maintenance units was constructed to approved designs and was fit and serviceable for issue to the users, the operational and training units of the RAF and RN.
For administrative and technical control the staff of AID was divided into six divisions, namely aircraft, armament, engines, aircraft equipment, materials and general stores, the members of each division being specialists in the appropriate technical work. In 1941 a seventh, Common Services Division was added dealing with administrative matters and supervision of female personnel. Also a Consultant on Radiological Inspection (CRI) was appointed to AID.
AID grew apace. The outbreak of the war saw DAI with director's status. In October 1941 the post was upgraded to Deputy Director General and in June 1943 further upgraded to Director General, with coincident regrading of other senior staff.
In 1955 AID assumed the inspection of guided weapons, and a Guided Weapons Division was formed. In 1957 the inspection of aircraft equipment was transferred by AID to the Electrical Inspection Directorate (EID).
The inspectorates of the Ministry of Supply were re-organised in 1958/1959 on a technique basis whereby the Electrical and Mechanical Inspection Department lost its responsibility for mechanical equipment to the Fighting Vehicles Inspection Department and acquired responsibility for electrical/electronic equipment of aircraft from the Aeronautical Inspection Department.
The new inspectorates were organised in an Inspection Division under a Director-General of Inspection (DGI) and this organisation continued with the transformation of the Ministry of Supply into the Ministry of Aviation in 1959; the division was responsible for the inspection of all equipment and supplies procured by the Ministry.
The Aeronautical Inspection Directorate at Chessington was responsible for the inspection of aircraft airframes and accessories, aircraft engines, including turbine, piston and rocket engines, as well as guided weapons and metallic and non-metallic materials used in aircraft; each function was organised under the control of a deputy director. The inspectorate also had its own laboratories at Harefield, Middx as well as regional offices around the country and superintending inspectors working with the largest aircraft suppliers.
The Electrical Inspection Directorate at Aquila, Bromley was specifically responsible for electrical and electronic equipment and supplies as well as atomic weapons; in these fields EID was regarded as the inspectorate of ultimate reference. Internally, it was divided into four main divisions: Atomic Weapons, Electronics, Engineering Services and Power and Instruments.
The other two inspectorates in the Division, the Inspectorate of Armaments at Woolwich and the Inspectorate of Fighting Vehicles and Mechanical Equipment at Kidbrooke were transferred to the War Office by 1962.
In 1967 the Inspection Division transferred to the Aviation Group of the Ministry of Technology.