U.S. loosens rules for Lockheed F-35, allows faster flight, tighter curves
July 29, 2014 at 18:00 PM EDT
WASHINGTON, July 29 (Reuters) - U.S. authorities have loosened some flight restrictions on Lockheed Martin Corp's F-35 fighter jets, allowing pilots to fly faster and take tighter curves, as military officials investigate a massive engine failure that grounded the entire fleet of warplanes for over three weeks.