The National Transportation Safety Board says that the pilots of Southwest Flight 345 had switched controls before crashing the plane's nose into a LaGuardia Airport runway last month. A spokeswoman said, "It's not unusual but we don't know enough about it yet to make a determination as to whether or not this particular one was unusual."

On July 22, the flight from Nashville landed roughly, nose first into the runway at Laguardia. The landing gear collapse and 16 people were injured. This is what the landing was like:

The NTSB said the plane itself seemed normal. The NY Times reports:

A plane’s captain and first officer generally take turns landing, one as the “pilot flying,” with his or her eyes toward the runway, and the other as the “pilot monitoring,” which includes watching the instruments.

The safety board said that the captain had extensive experience as a 737 captain, but had flown to La Guardia only once before. The first officer also had extensive experience in the 737, and had landed at La Guardia six times in 2013, the board said.

On July 22, however, planes were landing in an unusual configuration for La Guardia that required them to come in low.

Southwest says it is cooperating with the investigation.