Pilot Debrief

CIRRUS DESIGN CORP SR22 near Winokur, GA — 2024-03-16

Final reportERA24LA141
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Date
2024-03-16
Location
Winokur, GA, USA
Aircraft
CIRRUS DESIGN CORP SR22
Registration
N469GB
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Climb

Probable cause

A total loss of engine power due to the unseating and subsequent failure of the No. 4 piston connection rod bushing.

NTSB narrative

About 30 minutes into the flight, without warning, the airplane’s engine made a “loud noise” and stopped producing power. This was immediately followed by oil spraying onto the windscreen. Unable to divert to the closest airport due to distance and with no suitable places to land, the pilot deployed the whole airframe parachute system. The airplane came to rest between several trees and the airframe was substantially damaged. The pilot and passenger egressed the airplane without injury. Postaccident examination of the engine revealed a hole in the crown of the engine crankcase near the Nos. 3 and 4 cylinders. Further examination revealed the No. 4 piston connecting rod detached, with pieces found in the crankcase and oil sump. Additionally, the connecting rod bushings on all of the remaining piston connecting rods showed various signs of migration out of their respective locations; all bushings showed signs of chips and damage. Given these findings, it is likely that the bushings unseated themselves and migrated outward, resulting in imbalance, vibration, and the eventual failure of the No. 4 bushing and the subsequent total loss of engine power. A critical service bulletin (CSB) existed for the bushings that included augmented oil change procedures and inspections; however, the CSB was not adhered to, nor was it required to be due to the nature of the operation. The mechanic who had been maintaining the airplane assumed the procedures he was adhering to were sufficient, as they included routine oil changes at more frequent than recommended intervals, examination of the oil filter internal element, and having a laboratory analyze the engine’s used oil for the previous 14 months. The accident occurred 15 hours after the most recent oil change and the oil analysis report. Additionally, communications between the laboratory and mechanic, had indicated no substantive anomalies or other concerns indicating an imminent failure.

Analysis

Primary failure mode
Engine power loss
First missed decision gate
Mechanic should have followed the critical service bulletin for bushing inspection.

NTSB coding

Evidence available

  • Photos
  • 9 docket documents
View NTSB final reportView NTSB docket

Docket documents9

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