A medical helicopter involved in a fatal crash in a north-side neighborhood that killed three people last week fell 600 feet in eight seconds before it hit the ground, according to a preliminary report from the National Transportation Safety Board.

The LifeNet helicopter lost radar contact about 140 feet above ground and a quarter-mile before it crashed outside of a home on North Park Avenue near East Glenn Street on July 28, the report states.

Pilot Alex Kelley, 61, paramedic Brenda French, 28, and flight nurse Parker Summons, 41, died in the crash.

The AS350 B3 Eurocopter was flying from Marana to Douglas.

According to the report, witnesses reported seeing the helicopter fly in a southeast direction when it started to descend rapidly.

Witnesses also told investigators the helicopter made some unusual sounds, including rapid intermittent popping noises.

The sounds were followed by quietness as the helicopter descended.

The helicopter's flight trajectory became vertical as it fell, but the aircraft was level when it hit the ground, the report states.

Memorial service

A public memorial service is scheduled for Friday to honor the three LifeNet crew members killed in last week's helicopter crash in Tucson. It will be held at 10 a.m. at the Calvary Chapel's East Campus, 8725 E. Speedway.

Contact reporter Jamar Younger at jyounger@azstarnet.com or call 573-4115.