Plane hits trees after inadvertent encounter with IMC

The pilot reported that, after the sky cleared, he departed the airport following another airplane as a flight of two.

During the flight, they approached a ridge with no significant turbulence or issues. He added that they were suddenly in instrument meteorological conditions (IMC), and the lead airplane disappeared.

He immediately changed course 10° to the left, and as he transitioned to instrument flying, the airplane encountered a downdraft.

Shortly after, the windscreen “filled with trees,” which he estimated were less than a 100 feet away. He pitched the nose up to dissipate energy, and the airplane hit trees and terrain in Carrabassett Valley, Maine. 

The airplane sustained substantial damage to both wings. No one was injured in the crash.

The pilot reported there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation.

The nearest official weather reporting station, which was 16 miles southwest of the accident site, reported, about the time of the accident, 10 miles visibility, temperature 70°F, dew point 66°F, a broken layer at 2,700 feet, a second broken layer at 3,200 feet, and an overcast layer at 4,100 feet.

Although these were marginal visual flight rules conditions, given the mountainous terrain, the pilot should have expected that the mountain peaks may become obscured, and with a 4° temperature/dew point spread that visibility conditions could change rapidly.

The pilot said he should have flown his original flight plan, which was at a lower altitude so that he could have avoided unexpected and unpredicted winds and entering IMC.

Probable cause: The pilot’s improper decision to initiate the flight in marginal visual flight rules over mountainous terrain, which resulted in an inadvertent encounter with instrument meteorological and downdraft conditions and the subsequent controlled flight into trees and terrain.

NTSB Identification: GAA18CA538

This September 2018 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.