My W/NG workshop manual includes the usual lubrication chart which refers to 'task numbers' which are not referenced anywhere in the book. It's annotated 'TLC405A' and appears to be a military thing.
The task system envolved braking down maintenance tasks on a vehicle to daily, weekly and monthly priorities, you would check your engine oil every day but only grease your hubs every week so nothing was forgotten but nothing was over maintained.
Every driver carried publications with the correct tasks for the place and period and they would be entered into your AB412 or AB412m log book and signed off by a superior along with every half gallon of petrol and pint of oil issued and mile driven.
The paper work for this was enormous but had to be completed before any "B" or "A" (Armoured (AB413)) vehicle could be driven anywhere.
The 'Task Numbers' are in the Drivers/Riders handbooks.
Ah - I was confused. The task numbers are not mentioned in my 1940 version of Ariel's own instruction manual - but having looked at the club library I see they are in later versions.
Here is the first page of tasks from my W/NG Riders handbook. I've scanned all 8 pages which I've emailed to you Simon. If anyone else wants them, just email me. Ron
It was Lieut-Col. C.E. Bowden who came up with the idea of a task system for the military vehicles. Each driver / rider had to follow the tasks on this wheel: