ST. PAUL (AP) — The Minnesota National Guard says mechanical failure and human error led to the crash of a Black Hawk helicopter that killed three Guard members last December.

The Guard released a summary on Wednesday that said the crew was conducting a maximum power check on the number one engine near St. Cloud. That engine failed during the check, and the number two engine was in the idle setting, causing a dual engine-out condition.

The summary also says the maintenance test pilot failed to respond to a critical situation during the routine maintenance test flight.

The summary did not include names of any of the positions listed.