One in five air traffic controllers recently employed by the Federal Aviation Administration was washed out before the end of their training, said a government report released on Friday.

The FAA has been taking the number of newly hired controllers, who did not complete their training, too lightly because of the blemishes in their methodology, the inspector general of Transportation Department said.

The inspector general said 22 percent of the new controllers who were hired within the new methodology were not able to complete their training last year. In 2008, 31 percent of the controllers did not finish their training. But, it was only 10 percent less two years ago.

The aviation agency formerly predicted less attrition rate for hired controllers in 2009. However, what is important to FAA now is to measure the attrition rate of newly hired controllers and to understand why trainees drop out of the program.

Right now, the FAA is finding it difficult to hire 11,000 new controllers by 2019 in order to fill in the retiring employees. Controllers are obliged to retire as they reach the age of 56 and most of the controllers today have started reaching the retirement age.

Laura Brown, spokeswoman of the agency, said FAA currently has 15,700 controllers. It has started using the new methodology and has agreed with the findings of the inspector general.

For the past two weeks, two FAA controllers were involved in high-profile suspensions. Since then, FAA’s controllers are under careful observation and inspection. The two incidents involving the controllers are currently under investigation by the National Transportation Safety Board.