Student Adam Ostapenko, 20, of Duluth, Minnesota, and instructor Annette Klosterman, 22, of Seattle died when the twin-engine Piper Seminole crashed in a swampy area in central Minnesota on Oct. 23, 2007.

The two were on a routine training flight from St. Paul, Minn., to Grand Forks.

The NTSB`s probable cause report, dated Sunday, says the airplane hit at least one Canada goose. The NTSB says the collision “caused the airplane to be uncontrollable.”

NTSB says the night flight contributed to the crash because the pilots could not have seen the goose.