A320 and safety valve operation
has anyone really observed the operation of safety valve in-flight?
In a hypothetical situation, if A320 climbs to say FL410, CPC would maintain cabin altitude max 8000ft, delta pressure would probably cross 8 psi and safety valve may open up at some higher value of delta pressure. ECAM would trigger only if safety valve remains open for a minute or more..
What could be the possible outside conditions in which delta pressure may exceed the threshold for safety valve to operate?