United itself grounded 24 of its Boeing 777s ahead of a Federal Aviation Administration order for increased safety inspections for the type of engine involved, which uses a unique hollow fan blade. 

 

Two blades on the United jet were fractured, the National Transportation Safety Board (NTSB) said.

 

By Monday, other airlines also were grounding their 777s.

 

United says services will not be impacted by the grounding because it has spare aircraft capacity due to Covid.