Accident Details
Probable Cause and Findings
Maintenance personnel’s improper installation of the muffler attachment hardware, which resulted in the muffler separating in flight, thermal damage that interrupted the magnetos’ function, and the subsequent total loss of engine power.
Aircraft Information
Registered Owner (Current)
Analysis
On September 30, 2018, about 1121 central daylight time, a Cirrus SR22 airplane, N818GM, impacted terrain following a total loss of engine power near Addison Airport (ADS), Dallas, Texas. The pilot and flight instructor were not injured, and the airplane was substantially damaged. The airplane was registered to and operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91 as an instructional flight. Day visual meteorological conditions prevailed for the flight, which departed ADS about 1115, with a destination of Waco Regional Airport (ACT), Waco, Texas.
While on departure climbing through 2,800 ft mean sea level, the pilot and flight instructor noticed multiple avionics malfunctions and turned back toward ADS. During this turn, the engine lost total power and indications of a fire were noticed. When the flight instructor and pilot recognized the airplane was not within gliding distance of ADS or a suitable forced landing area, the pilot initiated the Cirrus Airframe Parachute System (CAPS). The airplane descended under parachute into a parking lot and the main spar was damaged. Accident site examination revealed a hole near the lower right engine cowling from a burn through.
Examination at the recovery facility revealed two of the three sets of hardware were missing from the muffler attach point. The remaining bolt, washers, spring and castellated nut remained attached, but no cotter pin was installed. Without the muffler attachment hardware, the exhaust collector was free to rotate. The hole in the lower right engine cowling was consistent with escaping hot exhaust gas.
Various components in the right forward side of the firewall were thermally damaged. Numerous white areas consistent with electrical arcing were present, including both magneto p-leads shorted against the metal engine mount frame. Although both magneto p-leads were shorted, the two magnetos were not damaged. After the magneto p-leads were disconnected, the magnetos produced sparks at all ignition leads when the engine was manually rotated.
During a pre-buy inspection of the airplane, a report prepared by the maintenance provider listed issues discovered and corrective actions performed. Two of the entries were "#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 to replace the cylinder o-ring, dated three days prior to the accident, required removal and reinstallation of the muffler.
Data Source
Data provided by the National Transportation Safety Board (NTSB). For more information on this event, visit the NTSB Records Search website. NTSB# CEN18LA392