The US Federal Aviation Administration (FAA) has finally approved Amazon's request to begin testing out its Prime Air drone delivery service, eight months after Amazon asked the regulator for approval.

According to the experimental airworthiness certificate issued to Amazon, the unmanned aerial vehicles (UAV) must be flown at a maximum height of 400 feet and must remain within the line of sight of the pilot.

This ties in with the proposed new rules for commercial helicopter drones announced by the FAA on 15 February.

The terms of the certificate also require Amazon to provide monthly data to the FAA, which includes the number of flights conducted, the pilot duty time per flight, any unusual hardware or software malfunctions, any deviations from air traffic controllers' instructions, and any unintended loss of communication links.

Dreaming of a teleportation delivery service

Amazon has been pushing its Prime Air delivery service dreams since December 2013, when the firm showed off a video of its prototype UAV.

And even in February when it seemed like all hope was lost since the FAA proposed regulations that would prevent UAVs being used to fly long distances out of the line of sight of the pilot, Amazon decided it would continue to test out its services in other countries.

The reason that Amazon is so keen on drone deliveries is that they like the idea of being able to get products delivered to customers at a lightning-fast speed, almost like teleportation.

"I have three kids, and once when my wife was on a business trip one of the little ones woke up in the middle of the night screaming for a pacifier, which I couldn't find," Amazon Prime Air's vice president Gur Kimchi said in an interview to Popular Science on 19 February.

"I got lucky and found the pacifier. But the better solution was for the pacifier to come to me. I imagine myself pulling out my phone, pushing a button, and 30 minutes later the pacifier shows up."

One-hour delivery services are already on their way

For now, Amazon is slowing trialling Prime Now – one-hour delivery services in the US, and is now offering speedy deliveries in New York City, Miami and Baltimore.

The service runs from 8am to 10pm, seven days a week and deliveries cost $8 (£5.42).

The service is only available in certain post code areas for certain common household items like paper towels, toys, batteries and shampoo.

Amazon might be able to trial its drone delivery service without the line of sight requirement, but it will have to be in countries where there is no legislation preventing it.

Australia, Germany and China are currently quite open to having UAV delivery services and are happy to grant companies permission to run tests.

The UK is another big potential market, but on 5 March, the House of Lords released its proposed drone regulations, which follow a similar line to the FAA's rules and list a maximum piloting range of 500m and mandate that a UAV cannot come within 50m of people.