In the last decade, most of the big U.S. airlines have shifted major maintenance work to places like El Salvador, Mexico, and China, where few mechanics are F.A.A.-certified.
To inspect any foreign repair station, the F.A.A. first must obtain permission from the foreign government where the facility is located. Then, after a visa is granted, the U.S. must inform that government when the F.A.A. inspector will be coming. So much for the element of surprise—the very core of any inspection process.
Read more on vanityfair.com.