Sailors assigned to aircraft carriers will now get mandated amounts of rest time each day thanks to a policy change by Naval Air Forces.

Recent reforms to the NATOPS General Flight and Operating Instructions Manual mean that non-aviation personnel will be guaranteed eight hours of uninterrupted sleep daily.

They also will no longer be regularly scheduled for more than 18 hours of continuous duty, according to the command.

If a mission or job requires such a long stint, sailors will be afforded at least 15 hours of off time before resuming their duties.

While sleep regulations already exist for the aviation crews, the new policy reflects fears about fatigue dogging the surface force. Concerns about the lack of rest for those sailors were highlighted by official probes in the wake of the deadly collisions last year involving the guided-missile destroyers Fitzgerald and John S. McCain.

Military investigators noted that crew fatigue hikes the risk of accidents.

Naval Air Forces spokesman Cmdr. Ron Flanders said that the new regulations for sailors assigned to flattops reflect the findings in those investigations.

The surface force has since implemented guidance — not formalized policies — that aim to ensure crews are getting rest periods that more closely align with the human body’s natural Circadian rhythm.

Watches, safety and duties in general suffer when sailors are tired, according to a Naval Air Forces blog post announcing the policy change.

“Remaining in an alert status, standing watch, performing collateral duties, and other disruptions to a Sailor’s circadian rhythm and sleep periods during high tempo operations can create the conditions for catastrophic mishaps,” the blog post states. “Accident rates for nearly every activity increase after 18 hours of wakefulness, and this fatigue creates the conditions for poor judgement and preventable mistakes.”