NASHVILLE (AP) - A small plane crash that killed four members of a Kansas family while narrowly missing a Nashville, Tennessee, YMCA during peak afternoon hours was caused by the pilot's failure to maintain airspeed after an engine lost power.

An investigation of the Feb. 3, 2014, crash by the National Transportation Safety Board says ice accumulation on the airframe also contributed to the accident.

Killed in the crash were Glenn and Elaine Mull, their daughter Amy Harter, and their granddaughter Samantha Harter.

Glenn Mull, the pilot, was the owner of Mull Farms and Feeding in Pawnee Rock.

The family was traveling from the Great Bend Municipal Airport to attend the National Cattlemen's Beef Association Trade Show.

Their Gulfstream 690C was too damaged for investigators to determine why one of the engines lost power.