"A first reading shows that the pilot in the cockpit used the automatic pilot to put the airplane on a descent toward an altitude of 100 feet," the BEA investigation office said in a statement reported by Reuters.
"Then several times the pilot modified the automatic pilot settings to increase the speed of the airplane as it descended," it added.
The Airbus A320 operated by the budget carrier Germanwings, was en route to Düsseldorf, Germany, from Barcelona, Spain, on March 24 when it lost altitude rapidly and slammed into the French Alps, killing all 144 passengers and six crew members on board.