D Bru ,
Reason for not searching so near the LKP
I was always wondering why.
May be simple:
It seems because they tried to hear ULB as you mentioned.
After ULBīs batteries nominal endurance they abandoned "sites near LKP"
Quite logical but DELAYED THE INVESTIGATION.
It seems like an "strategy error" (procedural error)
Because area near LKP is small compared to areas of 1, 2 and 3 phases.
Easy to say now...