The drone's test flight lasted for 96 minutes before it crashed on landing. The company mentioned the drone's structural failure in a post about the test flight, but not that the NTSB was investigating the accident. Facebook's drone accident highlighted some of the recent challenges tech firms face as they try to deliver the internet to developing countries.

The NASB (National Aviation Safety Board) is conducting an investigation following the incident.

The drone is part of a project to bring internet access to remote locales. No casualties occurred, but the accident is the latest in a series of snags to Facebook's mission to increase worldwide connectivity. 

Earlier this year, an explosion destroyed one of the social media giant's satellites that were supposed to broaden internet service in and around Africa. According to Bloomberg reports, the company has also faced political resistance to the idea in India. 

The high-altitude drone, which has a wingspan wider than a Boeing Co. 737 and is powered by four electric engines, suffered a "structural failure" as it was coming in for a landing, according to an undisclosed investigation by the National Transportation Safety Board.

"We were happy with the successful first test flight and were able to verify several performance models and components including aerodynamics, batteries, control systems and crew training, with no major unexpected results," the company said in an e-mailed statement.

737, is made of ultra-light carbon-fiber and designed to eventually be solar powered, enabling it to remain airborne for long periods of time. It is one of a number of Facebook initiatives aimed at overcoming logistical hurdles to internet access. 

Zuckerberg wrote about the drone's first flight in a Facebook posting.

"We gathered lots of data about our models and the aircraft structure -- and after two years of development, it was emotional to see Aquila actually get off the ground."

When the drone is fully functional, it will be able to deliver data 10 times faster internet speed than at present.

The NTSB has not yet explained what it think caused the most recent accident.