A crack in a cockpit window was found on a Boeing 737 aircraft over the weekend after the plane was airborne.
All Nippon Airways said on Monday that airline crew noticed the crack on one of the six cockpit windows about 40 minutes into the flight.
The plane immediately returned to Sapporo-New Chitose Airport, where it landed safely. The plane was set to travel to Toyama airport, further inland in Japan.
The Japanese airline said no injuries were reported for the 65 passengers and crew members.
“The crack was not something that affected the flight’s control or pressurization,” a spokesperson for the airline said, per Reuters.
The cause of the break is currently under investigation.
This is the second major incident for Boeing this month after an Alaska Airlines flight was forced to emergency land when an emergency panel blew out mid-flight.
Related: Plane Takes Off With Broken Windows, Makes Emergency Landing
The plane models, however, are different. The aircraft involved in the Alaska Airlines fiasco was a Boeing 737 Max 9, which has now been indefinitely grounded by the Federal Aviation Agency.
Boeing was down over 17.6% in just a one-month period as of Monday morning.
