Azrael - yes welcome to the thread - I'm sure you will prove very useful indeed.
Regarding this supposed '50m' clearance - that is not far away from a 'western' CatI limit of 200ft so would not be out of the question for an approach using an accurate GPS or RNav system. It should, however, be remembered that this will be a BARO minimum.
We do not know
a) What sort of approach they were flying
b) What the limits for that particular approach would be for the PAF TU
c) I'm not even sure that we have established the precise capability of the TU in this respect?