There are more than 236 FAA-certified aircraft repair stations in Texas, according to the FAA's Web site. News 8 has learned that hundreds of the mechanics working in those shops do not speak English and are unable to read repair manuals for today's sophisticated aircraft.

"There are people [where I work] who do not know how to read a maintenance manual as they are spelled out, because they don't have a clue," said one certified aircraft mechanic who works at a Texas aircraft repair station. He wished to remain anonymous to protect his employment.

News 8 discovered that mechanics at one licensing center in San Antonio were being tested in Spanish as late as last fall. The FAA ultimately shut the facility down.

Supervisors in Texas repair stations say they are supposed to oversee the repairs of dozens of untrained mechanics who can't read the manuals and can't write down the work they've done.

But the FAA does not require every person working at a repair station to be a certified A&P. One certified A&P can sign off on the work of dozens of uncertified mechanics.

That creates a huge problem, another certified mechanic told News 8. "I need an interpreter to talk to these people," he said. "They can't read the manuals, they can't write, and I have so many working for me I can't be sure of the work they've done."

To be sure of proper quality, the supervisor has to either re-do the work himself or take the chance that no mistakes have been made. There is a push to get work out the door and planes back in the air. But when he signs his name to certify the repair for flight, he is legally responsible for it.