Boeing Co. (BA) faces a new airworthiness directive requiring inspections on certain 737-8, 737-9, and 737-8200 aircraft due to cracking concerns, the Federal Aviation Administration said Thursday.

The regulator mandated the evaluations after discovering cracks in the bear strap near the front galley door that could compromise the structural integrity of the planes.

Boeing must inspect the exterior skin for existing repairs and perform detailed and high-frequency eddy current inspections for cracking. If damage is found, affected aircraft must be repaired before returning to service, the Federal Aviation Administration said.

The safety rule takes effect Sept. 10, for an estimated 471 domestically registered Boeing aircraft, the regulator said.