The pilots of the Aeroflot-Nord jetliner that crashed during its approach to the Perm airport last month gave false information about their qualifications to fly, a top aviation safety investigator said Thursday.

The damning comments by Gennady Kurzenkov, head of the State Aviation Inspection Service, appeared to confirm suspicion that pilot error was to blame for the Sept. 14 crash, which killed all 88 people on board.

Kurzenkov said the pilots of the Boeing 737 had submitted false documents to the airline showing that they had passed preflight courses, Itar-Tass reported. He did not elaborate.

The flight attendants also had false documents saying they were qualified to fly on international flights, he said. The Aeroflot-Nord flight was a domestic flight from Moscow to Perm.

The crash was caused by "a lack of coordination by the crew and their insufficient preparation for flights," Kurzenkov said.

Aeroflot-Nord officials could not be reached for comment after office hours Thursday. The airline has previously denied that its pilots lacked the necessary experience.

Aeroflot-Nord is a subsidiary of state-owned Aeroflot. After the crash, Aeroflot banned all of its subsidiaries from using the airline's name and logo in an attempt to protect its reputation.

Transportation Minister Igor Levitin has said the 737 had no technical problems and that both of its engines were in proper order before the flight. He also said there had been no midair explosion.

Levitin's comments came after a crash investigator told Kommersant that the tragedy had been the result of pilot error due to inexperience.

The plane burst into a ball of fire at an altitude of about 1 kilometer, apparently after an engine caught fire, scattering debris across an area of 10 square kilometers. The plane was making a second attempt at landing in difficult weather conditions.