By Peggy Senzarino, Mason City Globe Gazette

MASON CITY — Icing may have caused the crash of a Mercy Medical Center-North Iowa helicopter on Jan. 2, according to a preliminary report from the National Transportation Safety Board.

Flight nurse Shelly Lair-Langenbau, 44, Hanlontown; paramedic Russell Piehl, 48, Forest City, and pilot Gene Grell, 53, a Med-Trans employee, were killed when the Mercy Air Med helicopter crashed north of Ventura on its way to pick up a patient in Emmetsburg.

The preliminary report includes comments from a private pilot at the Mason City Municipal Airport and a witness who heard the helicopter moments before it crashed. Both witnesses describe the weather conditions at the time of the accident.

“A pilot located at the Mason City airport reported that he saw the helicopter fly overhead and estimated its altitude as 300 feet above ground level. He was leaving the airport at that time and noted there was a glaze of ice on his car. He added that the roads were icy as he drove out of the airport and onto Highway 18,” according to the report.

The pilot commented he had flown into Mason City at 6:30 p.m. and encountered some light ice.

A second witness said he was working in his garage when he heard the helicopter. He stated that the sound of the helicopter changed as if it was turning, followed by what he described as a “thump” and then everything was quiet.

“He subsequently responded to the accident with the Ventura Fire Department. He reported that there was a coating of ice on his truck windshield that the wipers would not clear. He decided to drive another car to the fire station because it had been parked in the garage. While responding to the accident site with the fire department, as the fire truck he was on was waiting to cross Highway 18, they observed a Clear Lake police car, also responding to the accident, slide through the intersection. They informed dispatch to advise following units to expect slick road conditions. He noted that there was a haze in the air, which was evident when looking toward a street light; however, he did not recall any precipitation at the time,” the report states.

The flight originated from Mercy Medical Center-North Iowa, Mason City, about 8:49 p.m. Jan. 2, with an intended destination of the Palo Alto County Hospital in Emmetsburg.

The report describes the crash site one mile north of Highway 18 along Balsam Avenue.

Debris stretched for about 100 feet towards the west-southwest. The helicopter was fragmented, and the cockpit and cabin areas were compromised. The main wreckage consisted of the main rotor blades, transmission, engine, portions of the fuselage, and the tail boom. The tail rotor had separated from the tail boom and was located about 80 feet east-northeast of the main wreckage, the report stated.

The landing skids had separated from the fuselage. The left skid was located at the initial impact point with the right skid located about 35 feet west of the main wreckage.

Pilot Grell held an airline transport pilot certificate with helicopter and single-engine airplane ratings.

His airplane rating was limited to private pilot privileges. Grell was issued a second class airman medical certificate on April 17, 2012, with a limitation for corrective lenses. His most recent regulatory check ride was completed on Sept. 29, 2012, about the time of his initial employment with the Med-Trans. At that time, Grell reported having accumulated a total flight time of 2,808 hours, with 2,720 hours in helicopters.

The helicopter, a Bell model 407, was registered to Suntrust Equipment Leasing & Finance Corp. and operated by Med-Trans Corp.

The NTSB’s preliminary report is subject to change. There is no word on when a final report will be released.