PARIS - The head of Air France-KLM said on Wednesday it was not unusual that a slew of messages sent shortly before one of its planes crashed last month had not triggered an immediate reaction among staff.

Pierre-Henri Gourgeon told newspaper Le Figaro that a technician had no reason to suspect the seriousness of the situation when he saw 24 automatic messages had been sent by the Airbus before it plunged into the Atlantic.

Other planes which fly and land without the slightest problem can send even more messages, he told the paper's Thursday edition in his first interview since 228 people perished on flight AF-447 from Rio de Janeiro to Paris.

The interview was published on the paper's website on Wednesday.

It was not unheard of to lose communication with planes as they crossed oceans and to detect them again later, he said.

More than six hours elapsed between the last contact between the Air France plane and the launch of an emergency alert, according to an earlier report by France's BEA air accident board.

Gourgeon confirmed frost may have been a factor in the accident given that the automatic messages sent pointed to inconsistencies with the plane's speed readings, but he added that this would not be enough to explain the cause of the crash.

Addressing criticism the airline took too long to get in touch with the families involved, he said the process had been complicated by incomplete passenger information.

Hopes of finding the plane's recorders, or black boxes, had not faded and locating them remained crucial, he said, adding that Air France would do its best to draw lessons from the accident.

The search for the black boxes using a nuclear submarine would continue until July 10. The recorders emit a signal for about 30 days.
After that, France would continue to probe the seabed with special machines, he said.

In the same interview, Gourgeon said Air France-KLM may resort to several measures at the end of the summer, including reduced working hours, for the first time in its history to deal with a slump in demand.

(Reporting by Tamora Vidaillet; Editing by Matthew Jones)