It's a bit complicated. In the 1st edition, the locations are a combination of
F – Front
B – Back
R – Right
L – Left
C – Centre
S – Suspension
LH – Lower Hull
G – Glacis
HR – Hull Rear
TF – Turret Front
TB – Turret Back
HS – Hull Side
TS – Turret Side
D -Deck
The letters after that are the internal components that can be hit from that angle
When you shot at a vehicle, you'd dice on a table for that angle of attack – so head-on, oblique, side, rear.
That would then give you an area hit composed of one or more of the above in combination, for instance, if shooting a the side you might get F:HS, meaning a hit on the hull side towards the front of the vehicle. You then check the damage chart for that location and it tells you the armour value and the order that components are damaged if the shot penetrates:
A – Ammo
E – Engine
F – Fuel
L – autoloader
M – Missile Launcher
R -Radio
S – stores (cargo)
W – Main Weapon
X – Gunners MG
N – Rangefinder
T – Tyre
C – Commander
D – Driver
G – Gunner
P – Passenger(s)
It made for a detailed, but slow, damage resolution system. 2nd edition simplified it greatly, reducing damage to just six locations – front, side and rear each for turret and hull – with a simple table for each.
ponders nirvana.