PA28 wing loading 73 kg m2
Cessna 172 wing loading 64.4 kg m2
Cessna 150 wing loading 48.8 kg m2
Of course the figure uses the max take-off weight.
Now take a Cessna 172 at min. weight
e.g. one light pilot plus min fuel
empty wt 646kg
pilot 60kg + 25kg fuel
wing loading reduces to 45 kg m2.
Is this aircraft now deemed unsafe for Night/ IMC & IFR?