American Airlines says a saddle clamp improperly installed on the foot of seat row legs on Boeing 757s is the “root cause” of why seats came loose on three flights.

The incidents, which resulted in two emergency landings, have prompted the carrier to inspect more 757s. “Originally, American planned to evaluate the seats on eight Boeing 757 airplanes, but out of an abundance of caution, the decision was made to proactively evaluate a total of 47 Boeing 757 airplanes that have the same model Main Cabin seats with a common locking mechanism.”

Huguley says the issue “does not seem to be tied to any one maintenance facility or one workgroup. The FAA is aware of our internal review and its findings, as well as the steps we are taking to proactively address the issue.