(Reuters) - The U.S. aviation regulator proposed on Sunday that people flying drones for commercial purposes obtain a special pilot certificate, stay away from bystanders and fly only during the day.

The long-awaited draft rule governing drones also limits speed to 100 miles per hour, the altitude of flight to 500 feet above ground level.

Industry experts said the Federal Aviation Administration's draft rule appeared to be relatively benign, lacking onerous pilot qualifications standards that could have severely restricted commercial flying of drones.

However, the rule was unlikely to help Amazon.com in its quest to deliver packages with unmanned drones, since its approach requires an FAA-certified small drone pilot to fly the aircraft and keep it line of sight at all times - factors not envisioned in the online retailer's plan.

The draft rule, nearly 10 years in the making, still must undergo public comment and revision before becoming final, a process expected to take at least a year.

(Reporting by Alwyn Scott; Editing by Mark Heinrich)