Following the grounding of all 32 of the suspect 777s in operation in Japan, the FAA ordered immediate or “stepped up” inspection of 24 airplanes at UAL.
The practice remains controversial and what's permitted is still unclear, though the FAA issued guidance on this subject a year ago, according to the GAO.
The company will offer its hybrid-electric retrofits to operators of existing aircraft such as the Twin Otter and Grand Caravan, as well as for new models.