Pilot Moved The Throttle Control Lever Forward And Heard A “Pop” Sound Come From The Engine

Aviation Investigation Final Report
Location: Kapolei, Hawaii Accident Number: ANC24LA005
Date & Time: December 4, 2023, 12:50 Local Registration: N691YW
Aircraft: Diamond Aircraft Ind Inc DA40 Aircraft Damage: Substantial
Defining Event: Loss of engine power (partial) Injuries: 1 Serious, 1 Minor
Flight Conducted Under: Part 91: General aviation - Flight test

Analysis: While enroute the pilot moved the throttle control lever forward and heard a “pop” sound come from the engine, followed by a rumbling noise and an airplane vibration. The pilot pulled the throttle back to its original position in an attempt to stop the rumbling and vibrations and turned the airplane back toward the runway for an emergency landing.

Engine power was not restored, and the airplane began to lose altitude, so the pilot performed a forced landing, which resulted in substantial damage to the fuselage and both wings. Postaccident examination revealed that baffling from the exhaust muffler had broken loose, blocking about 3/4 of the opening. The blocked exhaust reduced the volumetric efficiency of the engine cylinders, resulting in the partial loss of engine power.

Probable Cause and Findings: The National Transportation Safety Board determines the probable cause(s) of this accident to be -- A partial loss of engine power due to lose baffling from the muffler, which resulted in an obstruction of the exhaust system.

FMI: www.ntsb.gov