Douglas DC-3C accident at Miles City, Montana, 12 Mar 1964

Accident narrative

On March 12, 1964, Frontier Airlines Flight 32, a Douglas DC-3C, crashed and burned during an instrument approach to the Miles City Airport in Montana. The accident occurred at approximately 2050 mountain standard time in wet snow, strong gusty winds, and near-freezing temperatures. All five occupants—three crew members and two passengers—were killed, and the aircraft was destroyed.

**The flight**

Flight 32 was a regularly scheduled service from Billings to Sidney, Montana, with intermediate stops planned at Miles City and Glendive. The crew consisted of Captain Kenneth C. Huber, First Officer Daniel H. Gough, and Stewardess Dorothy Ruth Reif. Both pilots were highly experienced; Captain Huber had 1°,335 total flying hours, including 12,830 in DC-3s, and First Officer Gough had 2,539 hours, with 1,355 in DC-3s.

Before departing Billings, the captain received a weather briefing indicating an approaching cold front. He was advised to expect gusty west to northwest winds, turbulence, at least moderate icing, and possible squalls in the Miles City area, with ceilings and visibility expected to be lower than the terminal forecast.

The aircraft departed Billings at 2001 on an Instrument Flight Rules (IFR) clearance to the Miles City VOR at 7,000 feet. Its gross weight and center of gravity were within prescribed limits.

**The approach**

En route, the Great Falls Air Route Traffic Control Center (ARTCC) relayed updated weather observations to the flight. At 2033, ARTCC transmitted a special 2030 observation for Miles City: an indefinite ceiling of 400 feet, sky obscured, visibility one mile, moderate snow showers, and surface winds from 300 degrees at 20 knots with peak gusts to 30 knots. ARTCC then cleared Flight 32 for an approach to the Miles City Airport.

At 2045, the flight reported to the Miles City Flight Service Station (FSS) that it was over the VOR starting the approach. The crew also contacted the Frontier Airlines station agent, who provided the wind conditions, confirmed there was no local traffic, and offered to have the runway rudder lock ready. The flight advised they would be on the ground in three minutes.

At 2048, Flight 32 reported to the FSS that it was over the VOR inbound. The FSS advised that the wind favored Runway 30, and the flight replied, "we'll plan three zero." This was the final radio contact. In none of the transmissions did the crew mention any operational distress or weather difficulties.

At approximately 2050, the aircraft struck the ground about 1-1/2 miles northeast of the VOR, 9,900 feet short of the approach end of Runway 4.

**What the investigation found**

The aircraft crashed on a 22-degree upslope at an elevation of 2,610 feet, slightly below the airport elevation of 2,628 feet. At impact, the DC-3 was in a slight nose-up and left wing-down attitude, with the landing gear down and wing flaps extended one-quarter. The aircraft disintegrated over a distance of 600 feet and was destroyed by fire.

Investigators found no evidence of any operational defect or malfunction in the airframe, systems, or powerplants prior to impact. Maintenance records were current. The Miles City VOR was flight-tested by the FAA and found to be operating normally. Propeller slash marks indicated a ground speed at impact of 137 knots, which under the existing winds equated to an indicated airspeed of approximately 134 knots.

Witnesses near the VOR site and the airport reported poor visibility, heavy wet snow, and gusty winds. A technician at the VOR facility saw a DC-3 pass overhead toward the airport at 2048, about 1,000 feet above the ground. He stated the aircraft appeared and sounded normal, and he could see the airport's rotating beacon 3-1/2 miles away. Another witness, an experienced pilot located a mile southeast of the airport, heard an unusually loud airplane noise for five to eight seconds that ended abruptly at 2050.

Because there was no evidence of mechanical failure, the Board evaluated two plausible possibilities for the unexplained descent below the minimum altitude:

First, the Board considered that the crew might have established visual contact with the ground or the airport beacon while near the VOR. It is possible that, while attempting to maintain visual reference, the pilots continued an unmonitored descent below the clouds. The high impact speed with gear and flaps extended suggested that power was added late in a rapid descent. However, the Board concluded the evidence could not support a definitive finding that the crew committed a gross departure from proper piloting techniques.

Second, the Board evaluated airframe icing. Weather conditions were conducive to moderate to heavy icing and severe turbulence, which could have impaired airspeed and altitude control. However, the aircraft's de-icing system was presumed operational, and the impact speed of 134 knots indicated airspeed was sufficient to counteract severe icing. Furthermore, the Board noted that if airspeed and altitude control had become critical, the crew would not normally have extended the landing gear and flaps, or they would have immediately retracted them. Thus, there was insufficient evidence to definitively cite icing.

**Probable cause**

The Board determines that the probable cause of this accident was "the descent below obstructing terrain, for reasons undeterminable, during an instrument approach in adverse weather conditions."