For the second time in two months, two airplanes narrowly avoided a midair collision over Bush Intercontinental Airport in Houston on Thursday, reports the Daily Mail.

A Singapore Airlines 777 jumbo jet flew “within 200 feet vertically and about one-half mile horizontally – about the distance of eight foot ball fields – of a Delta Air Lines A320,” just before 7 p.m. Thursday, according to the Daily Mail. The incident occurred about 10 miles northeast of the Texas airport.

The Federal Aviation Administration requires aircraft to remain separated at least a half-mile vertically and three miles horizontally. The agency is investigating the incident, reported the Houston Chronicle.

“An air traffic controller noticed the deviation and issued traffic alerts and instructions to the pilots of both aircraft,” said Lynn Lunsford of the FAA on Saturday. “The FAA is still determining the closest proximity between the two flights.”

“As a result of a preliminary analysis of the event, the FAA has taken steps to ensure that all flight crews are aware of the top altitudes for standard departure routes,” added Lunsford.

In late May, the FAA began its investigation of a similar incident above Houston earlier that month. Two United Airlines passenger jets came within a mile of each other.
The aircraft were 0.87 miles apart horizontally and 400 feet vertically. The incident involving United Airlines Flights 601 and 437 occurred just after takeoff, about two miles southeast of the airport.

The mistake of an air traffic controller put one aircraft in the path of the other. The controller then issued instructions to separate the planes, officials said.

Audio from the control tower confirms that controllers asked Flight 437 to turn right immediately, while telling Flight 601 to stop its turn, stop its climb, stop its turn, reports the Daily Mail.