The Federal Aviation Administration is temporarily grounding flights of the 737 Max 9 aircraft after a piece of the plane became detached from the aircraft in the middle of an Alaska Airlines flight this week.
The incident happened on Friday. The Alaska Airlines flight was forced to land abruptly in Portland, Oregon.
The piece that came loose left a huge hole in the plane.
The National Transportation Safety Board is also investigating.
All 737-max-9 aircraft must remain grounded until emergency inspections are carried out.
This affects about 170 aircraft.
Operations of this model had previously been stopped due to other safety concerns.
