Sao Paulo, Brazil ? A radar failure over the Amazon forced Brazil to turn back or ground a string of international flights Saturday, deepening a national aviation crisis just hours after the president unveiled safety measures prompted by the country’s deadliest air disaster.

Further shaking Brazilians’ confidence, authorities said they had mistaken a piece of the fuselage from Tuesday’s accident for the flight recorder and sent it to a laboratory for analysis.

The radar outage from 11:15 p.m. Friday to 2:30 a.m. Saturday, caused by an electrical problem, forced numerous planes heading to Brazil from the U.S. to return to their points of origin and make unscheduled landings at airports from Puerto Rico to Chile.

Eight of the 17 planes flying in the coverage area of the radar system were rerouted, and some airlines canceled flights bound for Brazil.

While the nation has had chronic problems with delays and cancellations on domestic flights over the past 10 months, the radar outage was the first time that international flights have been severely affected.

“This is total chaos here. I have never seen anything like it and it makes me feel very unsafe,” said Eli Rocha, 52, of Oklahoma City, who was trying board a flight to Dallas on Saturday at Sao Paulo’s international airport.

The flight was crowded with weary Americans arriving on other delayed or diverted flights.

The confusion followed a nationally televised speech by President Luiz Inacio Lula da Silva, who tried to calm the nation Friday night by announcing new safety measures and saying authorities will build a new airport in Sao Paulo, where an Airbus A320 operated by TAM Airlines crashed, killing 191 people.

Silva said aviation officials will limit the number of flights and restrict the weight of planes traveling into Congonhas airport and that the location of the new airport will be chosen within 90 days.