By Victoria Bryan

MIAMI (Reuters) - Pilot screening and mental health measures aimed at preventing a recurrence of the Germanwings crash are rife with complications that will make them tough to implement, airline industry executives said this week.

International Air Transport Association (IATA) Director General Tony Tyler called the crash, in which the co-pilot locked the captain out of the cockpit and steered the plane into the French Alps, a "deliberate and horrible act by one of our own."

Prosecutors have found evidence the co-pilot, who had suffered from severe depression, had researched suicide methods and concealed an illness from his employer, sparking a debate on pilot screening and the relationship between aero medical doctors and licensing authorities.

The industry and authorities in the United States and Europe are now debating doctor-patient confidentiality, pilot screenings and medical check-ups, but it will be some time before progress is made.

"The psychological testing and mental state of pilots, it gets more difficult the more you get into it," Lufthansa Chief Executive Carsten Spohr said during a panel session at the meeting in Miami. Lufthansa owns Germanwings.

He has suggested random psychological tests, but said there might never be a foolproof response.

IATA's Tyler said any measures must not stigmatize mental health problems and that pilots had to be helped in a supportive way.

"If you penalize people with these problems, they will not declare them and may go under the radar and that's the last thing you want," he said.

The U.S.-based Civil Aviation Medical Association (CAMA) said random psychological tests and psychiatric screening had been discussed following the crash, but that it was difficult to regulate spontaneous irrational behavior.

"As medical examiners, we always attempt to keep a pulse on both the physical and mental makeup of every pilot we evaluate. This recent tragedy reaffirms the need to scrutinize the pilots we assess and be constantly vigilant of atypical behavior," said Dr. Clayton Cowl, President-Elect of the CAMA.

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Malaysia Airlines CEO Christoph Mueller suggested that other pilots and crew could help with keeping an eye out for any problems.

"There's a limitation of what medical doctors can detect and consequently report," Mueller said. "It needs to be the community where people know each other."

Spohr added that it was important to differentiate between depression and other mental health issues.

"Depression is a common disease and doesn't cause people to do what our pilot has done," he added.

(Reporting by Victoria Bryan; Editing by Christian Plumb)