The introduction of retracting undercarriages in the Thirties added another task for the AID, in testing their actuation. Seen here is the port undercarriage unit of a Bristol Blenheim.

Camouflage and markings were also a matter for AID checking: not just the disruptive pattern, but the detailed stencilled markings, in black or white to contrast with the background, giving assembly numbers and doping scheme - Cellon X in the case of fifth production Bristol Blenheim I K7037, seen in this view.

The right-hand-drive cockpit of a Vickers Vimy was functional and ugly, with few “dials” - the engine instruments were on the inboard sides of the nacelles.
Control cables were checked for strength as well as for correct operation, and were tagged as evidence of inspection.

"Vickers-Vimys" for China: A batch of Vickers-Vimy-Commercial machines in various stages of erecting at the Weybridge works of Messrs. Vickers, Ltd.
Vickers Vernon Is ready for pre-covering inspection of their fuselages at Weybridge. The AID was responsible for inspecting both military and civil aircraft from 1919 to 1937.

Interior view of a Vernon showing stretcher (top) and troop seats. AID checks ensured that all airframe attachments were secured against vibration.