Three Tesla Motors employees were killed in Palo Alto on Wednesday when their small plane struck power lines following takeoff. The National Transportation Safety Board is currently investigating the plane crash, but have not revealed any findings yet.

This is second fatal private aviation accident involving power lines this year.

In early January, a helicopter carrying three scientists and a pilot crashed into unmarked power lines in California, causing a fire on the craft that killed all four. The Federal Aviation Administration places the responsibility of placing lights and markers on power lines with the companies that own them, but does not require it.

At this time, unmarked power lines are not believed to have been a factor in Wednesday's fatal plane crash.

Instead, area pilots believe that mechanical failure or pilot error is more likely. Foggy weather may have also contributed to the collision, which ended in a fiery plane crash in the middle of a residential area.

Despite falling debris and the fact that parts of the plane hit several houses and other structures, no one on the ground seems to have been injured. Authorities are waiting to confirm this until all the debris has been cleared, but all residents in the immediate crash area appear to be accounted for.

Authorities are also withholding the identities of the plane's occupants until the families have been notified.

The plane crash comes at a rough time for Tesla Motors. The electric car company, which is currently trying to raise funding, was planning its initial public offering and gearing up for the release of a new model.

Related Resources: