Accident Overview
On September 30, 2018, at approximately 1121 central daylight time, a Cirrus SR22, registration N818GM, sustained substantial damage after impacting terrain near Addison Airport (ADS) in Dallas, Texas. The flight, an instructional mission under Title 14 Code of Federal Regulations Part 91, had departed ADS about 1115 en route to Waco Regional Airport (ACT). Day visual meteorological conditions prevailed.
Sequence of Events
While climbing through 2,800 ft mean sea level, the pilot and flight instructor observed multiple avionics malfunctions and initiated a turn back toward ADS. During the turn, the engine experienced a total loss of power, and indications of a fire were noticed. Recognizing that the airplane could not glide to ADS or a suitable forced landing area, the pilot activated the Cirrus Airframe Parachute System (CAPS). The airplane descended under parachute into a parking lot, damaging the main spar.
Examination Findings
Post-accident examination at the recovery facility revealed that two of three sets of hardware were missing from the muffler attach point. The remaining bolt, washers, spring, and castellated nut were still attached but lacked a cotter pin. Without the muffler attachment hardware, the exhaust collector was free to rotate. A hole in the lower right engine cowling was consistent with escaping hot exhaust gas.
Thermal damage was found on various components on the right forward side of the firewall. Numerous white areas consistent with electrical arcing were present, including both magneto p-leads shorted against the metal engine mount frame. Despite the shorted p-leads, the two magnetos were undamaged and produced sparks at all ignition leads when manually rotated after disconnecting the p-leads.
Pre-Buy Inspection History
During a pre-buy inspection of the airplane, a maintenance provider's report listed issues and corrective actions, including "#1-cylinder base o-ring is seeping" and "replaced #1-cylinder base o-ring P/N 641066 IAW TCM IO-550-N MN CH17-3." The work order for the cylinder o-ring replacement, dated three days before the accident, required removal and reinstallation of the muffler.