  Quantum metrology allows for a huge boost in the precision of parameters
estimation. However, it seems to be extremely sensitive on the noise. Bound
entangled states are states with large amount of noise what makes them unusable
for almost all quantum informational tasks. Here we provide a counterintuitive
example of a family of bound entangled states which can be used in quantum
enhanced metrology. We show that these states give advantage as big as
maximally entangled states and asymptotically reach the Heisenberg limit.
Moreover, entanglement of the applied states is very weak which is reflected by
its so called unlockability poperty. Finally, we find instances where behaviour
of Quantum Fisher Information reports presence of bound entanglement while a
well-known class of strong correlation Bell inequality does not. The question
rises of whether (and if so, then to what degree) violation of local realism is
required for the sub-shot noise precision in quantum metrology.
