Robotic Inspection of Jet Fuel Tanks Saves Money,
Increases Safety
By Paul Proctor

adjustable depending on computer capacity.  Maverick can take up to 150,000 datapoints in a day, versus 200 or so by a single human inspector, Hartsell said.  Software is being fine-tuned to improve sensor coverage and eliminate blind spots.  New survey patterns are being devised to avoid potential tether entanglement around structural supports.
   Robotic inspection avoids the expense and downtime of draining and cleaning tanks for inspection and disposal of related fumes.  It also minimizes risk to humans by keeping in-tank manhours to a minimum.  There is no need to shift petroleum products to backup tanks during inspection.  Overall savings will likely be "substantial," according to Hartsell.  Estimates range up to 80 percent less than a comparable manual inspection.  That adds up to between $30,000 to $500,000 a tank, Hartsell said.
   Maverick was developed in cooperation with the U.S. Department of Energy's Idaho National Engineering and Environmental Laboratory.  Preliminary operational trials have been performed in aviation storage fuel tanks at Atlanta's Hartsfield International Airport. In October, Maverick was tested in Johnson Space Center's 6.5 million gallon neutral buoyancy tank to improve tether management using NASA's space-related umbilical cord expertise.

   Solex Robotics Systems, Idaho Falls, Idaho, created Maverick, a rugged tank floor robot that allows in-service inspection of aboveground aviation fuel tanks for mandated corrosion and structural integrity checks. 
   The submersible robot is remote controlled and travels on tank floors using traction wheels.  Its instrumentation payload includes a sonar-like "pinger" and multi-channel ultrasonic sensor array that continuously maps and correlates the surface condition and thickness of the tank's welded metal floor.  There are also position tracking sensors and an onboard video system that records inspections.
Maverick is connected to a "base

station" trailer/transporter by a floating tether, which also aids in retrieval of the robot from the tank.
   Maverick is purged and pressurized with an inert gas before it is lowered into the tank.  A monitoring system tracks pressurization and stops operations if there is a problem, according to Don Hartsell, president of Solex.  Data from Maverick's integrated transducer array is presented in real time and can be displayed in various formats.  A final report is issued to the tank owner for documentation.
   Sensor frequency can be varied to best match conditions.  Up to now,
Sampling has been set at once every inch, but it is infinitely