Co-pilot of the Spanair MD-82 jetliner that crashed in Madrid on August 20 appears to be behind the accident according to press reports.

The reports quoted a preliminary report by a commission investigating the accident, which has been leaked to the media.

The plane crashed at the airport after take-off, killing 154 and injuring 18 people.

The information transmitted to the plane's black box originated in the computer of the 31-year-old co-pilot, who had more than 1,050 hours of experience flying similar planes, according to the daily El Pais.

It was not unusual for the captain and co-pilot to take turns during flights, sources of the aviation sector were quoted as saying.

The investigating commission has also found that the plane's wing flaps were not properly deployed, and that a warning system failed to alert the pilots of the problem because of an electrical failure, the report was earlier quoted as saying.

The pilots' association Copac took court action against those responsible for leaking the report to the press.

Around 3,000 people Wednesday attended a funeral mass for the victims in Las Palmas, capital of the Canary Islands, where 72 of the fatalities were from.

Most of the mourners did not fit inside the cathedral, which packed in 1,000 people, including Crown Prince Felipe and Prime Minister Jose Luis Rodriguez Zapatero.

A funeral mass of similar proportions was held in Madrid six days earlier in the presence of King Juan Carlos.