Under what conditions may class D airspace be entered with a radio failure?

Question

Question PPL(A) - Private Pilot License - Communication

QuizVDS · Accepted Answer

Approval has been granted before

QuizVDS · Answer

There are other aircraft in the aerodrome circuit

QuizVDS · Answer

It ist the aerodrome of departure

QuizVDS · Answer

It is the destination aerodrome

Id 75 - PPL(A) EN - Under what conditions may class D airspace be entered with a radio failure?