And the band droned on

A bill introduced this week by Arizona senators John McCain and Jeff Flake seeks to put the brakes on plans to expand the use of surveillance drones along the U.S./Mexico border. Questions have been raised about safety and the purpose of missions being flown by the Department of Homeland Security's current fleet of nine Reaper drones, supplied by San Diego's General Atomics.

The border security agency originally deployed ten of the unmanned aerial vehicles. One crashed off the coast of San Diego after a generator failure during a flight launched from Sierra Vista, Arizona.

According to a report from the Tucson Sentinel, the proposed Unmanned Aircraft System Improvement Act of 2015 would stop the department from purchasing any more drones until it can document that it has "successfully operated its current fleet."

A December 2014 report indicates that the existing drones have been in the air for only 20 percent of the hours anticipated. Despite that, the program is still experiencing cost overruns.

Questions also exist regarding the legitimacy of the stated purpose of border security. Reports indicate that hundreds of missions have been flown in support of other law-enforcement agencies.

The new bill would require Homeland Security to report annually to Congress for the next five years, detailing the number of flight hours required to provide border surveillance as well as the amount of time planned for support of other agencies.

The agency has been pushing to expand its fleet for some time, signing an agreement to purchase an additional 14 units in 2012 despite a lack of funding and defined need. Homeland Security says it just wants to add a single drone to replace the one it ditched in the Pacific Ocean.