What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Pilot stated that during cruse flight at 3500 feet aircraft began to vibrate / shutter and he could not maintain altitude. Pilot felt that the vibration /shutter was from the left side of aircraft. Pilot feathered the left engine but the vibration/shutter didn't stop, the pilot applied full throttle to the right engine, aircraft still would not maintain altitude.
As the FAA filed it
PILOT STATED THAT DURING CRUSE FLIGHT AT 3500 FEET AIRCRAFT BEGAN TO VIBRATE / SHUTTER AND HE COULD NOT MAINTAIN ALTITUDE. PILOT FELT THAT THE VIBRATION /SHUTTER WAS FROM THE LEFT SIDE OF AIRCRAFT. PILOT FEATHERED THE LEFT ENGINE BUT THE VIBRATION/SHUTTER DIDN'T STOP, THE PILOT APPLIED FULL THROTTLE TO THE RIGHT ENGINE, AIRCRAFT STILL WOULD NOT MAINTAIN ALTITUDE.
NTSB investigation
The NTSB’s investigation of this event, with its probable cause and findings. Matched to this report by N-number and date.