Federal authorities are seeking changes in aviation rules that would guarantee an extra hour of daily rest for commercial pilots.

The proposal would give pilots at least nine hours of down time between work days compared to the current eight hours, and reduce a pilot’s maximum shift to 15 hours. Exhausted pilots would also have the right to decline a work assignment without penalty.

According to the Federal Aviation Administration, pilots would also get at least 30 consecutive hours of time off on a weekly basis, a 25 percent increase over the current rules.

Transportation Secretary Ray LaHood and  Federal Aviation Administrator Randy Babbitt announced the proposed regulations at a press conference Friday. “This proposal is a significant enhancement for aviation safety,” LaHood said. “Both pilots and passengers will benefit from these proposed rules that will continue to ensure the safety of our nation’s air transportation system.”

The role of a fatigued pilot in the fatal crash of Colgan Air Flight 3407 in February 2009 helped spur the proposed changes, according to ABC news. The flight crashed into a house in Buffalo, N.Y., killing all 49 people on board and one person on the ground. The National Transportation Safety Board has been recommending stricter rules on pilot rest since the early 1990s, based in part on expert opinion holding that fatigue can affect individual performance in a manner similar to alcohol.

The FAA will take public comments through November 13, and expects to put the new requirements into effect by August 1, 2011.