Piper PA-32-260 N3618W accident near Grantsville, Maryland

Probable cause

The pilot’s decision to continue the flight into an area of moderate to heavy icing conditions, which resulted in a degradation of airplane performance and subsequent loss of control.

NTSB analysis

During cruise flight above 10,000 ft mean sea level (msl) in instrument meteorological conditions (IMC), the pilot noted the airplane’s airspeed slowing and the autopilot pitching the airplane up in order to maintain altitude. After he disconnected the autopilot, the pilot had difficulty maintaining pitch control. The pilot suspected that the airplane was accumulating ice but did not see any on the wings or windscreen. A performance study using automatic dependent surveillance-broadcast (ADS-B) data indicated that the airplane descended and slowed until there was a sudden loss of lift near the airplane’s stall speed, which was consistent with an aerodynamic stall. The pilot lowered the nose, and the airplane gained airspeed while continuing to descend.

About 3 minutes 30 seconds later, the airplane experienced a second sudden loss of lift at a much lower lift coefficient and higher airspeed. This second loss of lift was consistent with an accumulation of ice on the wing, which increased drag and reduced the amount of lift the wing could produce before a stall. The airplane recovered briefly before drag again began to increase. Drag continued to gradually increase until the flight descended below ADS-B coverage. According to the pilot, the airplane descended out of the clouds into heavy rain. The pilot performed a forced landing to a road. During the landing the airplane impacted trees and terrain, resulting in substantial damage to the fuselage, wings, and empennage.

Based on surface weather observations, upper air sounding data, and satellite weather imagery, clouds were likely present in the accident area from 3,300 ft msl (about 400 ft above ground level) through 13,000 ft msl. In areas with precipitation, which the flight encountered, clouds likely persisted from 13,000 ft msl to near the surface. Moderate or greater icing conditions were indicated from near 6,000 ft msl through 9,500 ft msl, but icing conditions likely persisted through 13,000 ft msl near the cloud tops. Further, supercooled liquid droplets (SLD) conditions were likely present in the icing encountered by the flight. The flight was likely in IMC below 13,000 ft msl with moderate or greater icing conditions and SLD.

The pilot’s reports that the airplane was underperforming, unable to climb, and that the autopilot was increasing pitch to maintain altitude were consistent with ice accumulation degrading handling. The second loss of lift event occurred at a high lift coefficient, high angle of attack, and at an airspeed lower than the airplane’s stall speed. The ice accumulation on the airplane likely made it difficult for the pilot to control airspeed and attitude, which resulted in a loss of control.

Based on the ForeFlight weather briefing information that the pilot received, he should have been aware of the potential for icing conditions on the accident flight. His decision to continue the flight in an airplane not equipped for flight into known into icing conditions resulted in the accident.

Text from the NTSB. Open the NTSB docket for ERA22LA191 for the full record.