The Swedish system was introduced after WWI and is still in use. Each aircraft type is assigned a series of function letters and a number. If an aircraft had multiple functions, more than one letter can be used. For example, the JAS 39 is designed to combine fighter, attack and reconaissance roles in a single airframe. The first letters has the highest priority.
When subtypes of one aircraft have different roles, they also have different function letters. For example, the fighter version (with a secondary attack) role of the Saab 337 Viggen is the JA 37; but the attack version (with a secondary fighter role) is the AJ 37.



A = Attack

B = Bomb

Fpl = Flygplan (aeroplane; used for multirole light aircraft)

Hkp = Helikopter

J = Jakt (fighter)

S = Spaning (reconnaissance)

SF = Spaning foto (photographic reconnaissance)

SH = Spaning havs?vervakning (maritime reconnaissance)

Sk = Skol (trainer)

T = Torped (torpedo bomber) (obsolete)

Tp = Transport