He is concerned the pressure tests will find other leaks in the seabed around the well.
Searchers reported seeing a large shadow on the seabed, suggesting the crashed jet has been located.
This device, looking rather like a bloated torpedo, is equipped with lights and cameras that scan the seabed for debris.
Each 6000kg sculpture is lowered to the seabed where it is drilled into the substrate to lessen the effects of turbulent weather.
The blowout preventer sits near the seabed and is the crew's last line of defense against what happened on April 20.