A crack was discovered in the cockpit window of a Boeing 737-800 aircraft mid-flight

• A Japanese domestic flight was forced to turn back after a crack was found in the cockpit window.
• A spokesperson for the airline said that crack was on the outermost of four window layers.
• Boeing's planes have been under scrutiny following the Alaska Airlines mid-flight blowout.

A Boeing 737-800 aircraft was forced to return to its departure airport mid-flight after a crack in the cockpit window was discovered, reports say.

The domestic All Nippon Airways Flight 1182 was heading from Sapporo-New Chitose airport to Toyama airport in Japan when the crack was discovered.

A spokesperson for All Nippon Airways confirmed in a statement to Business Insider that Flight 1182 "experienced a crack on one of the outermost of the four layers of the cockpit window."