A Singapore Airlines plane had a near miss with another aircraft while leaving Houston on Thursday night, reports said.
According to NBC News, a Singapore Airlines flight took off shortly before 7 pm on Thursday from Houston's George Bush Intercontinental and the pilot did not level off when he reached 4,000 feet as required.
This resulted in the outbound plane being less than 2,000 feet (610 metres) away from a Delta Air Lines flight which was preparing to head into Houston for landing. The incident happened about 10 miles (16 km) north-east of the airport, the report said.
"The Federal Aviation Administration (FAA) is investigating a loss of required separation that occurred Thursday evening between two jetliners while in airspace controlled by the Houston Terminal Radar Approach Control," the Federal Aviation Administration (FAA) said in a statement.
"An air traffic controller noticed the deviation and issued traffic alerts and instructions to the pilots of both aircraft."
The FAA said it did not yet know exactly how close the two planes came.
"The FAA has taken steps to ensure that all flight crews are aware of the top altitudes for standard departure routes."