U.S. aviation safety investigators are looking into possible anomalies with air speed and altitude indicators on two Airbus A330 jetliners, officials said on Jun. 25.

The National Transportation Safety Board (NTSB), which is helping French and Brazilian authorities to determine if speed indicators factored in the crash of an Air France A330 on Jun. 1, said it is also investigating incidents involving a TAM Airlines flight from Miami to Sao Paulo in May and Northwest Airlines flight between Hong Kong and Tokyo on Jun. 23.

Both flights experienced a loss of primary speed and altitude information, the safety board said in a statement. Both planes landed without incident.