Germanwings pilot struggled at US school

The German pilot who deliberately flew his airliner into a mountainside last year struggled with learning to fly and failed a key test of his skills during training in the US, according FBI interviews with his flight instructors.

Andreas Lubitz was promoted anyway. But his training difficulties were one more "red flag" that should have caused Lufthansa and the airline's Arizona flight school to take a closer look and discover his history of depression, asserted attorneys representing families of crash victims.

Lubitz was a co-pilot for Germanwings, a regional airline owned by Lufthansa, when he locked Flight 9524's captain out of the cockpit and set the plane on a collision course with a mountain in the French Alps last year.

All 144 passengers and six crew members, including Lubitz, were killed.

One instructor, Juergen Theerkorn, described Lubitz as "not an ace pilot", and said he failed one flight test because of a "situational awareness issue".

In aviation, loss of situational awareness usually means a pilot becomes absorbed in something and loses track of what else is happening with the plane.

But while Lubitz struggled with training, he would achieve passing scores enabling him to continue the program, Nickell said.

The FBI conducted the interviews a week after the March 24, 2015, crash.

Summaries were only recently released by prosecutors in Germany, according to attorneys with Kriendler & Kriendler in New York, who are representing the families in a lawsuit against the flight school. The lawyers provided copies to The Associated Press.

Officials for Lufthansa and the flight school didn't immediately reply to requests for comment.

An investigation has revealed that Lubitz was being treated for a relapse of severe depression and suicidal tendencies but had hid the information from Germanwings.

Germany's strict patient privacy laws didn't allow doctors to share medical information with an employer without the patient's permission.