Pilot Debrief

Smyth SIDEWINDER near Tucumcari, NM — 2019-09-14

Final reportWPR19LA273
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Date
2019-09-14
Location
Tucumcari, NM, USA
Aircraft
Smyth SIDEWINDER
Registration
N492AC
Category
Airplane
Highest injury
None
Fatalities
0
Phase of flight
Cruise

Probable cause

The in-flight separation of a section of a propeller blade due to a fatigue crack, which resulted in a forced landing.

NTSB narrative

The pilot reported that during cruise flight, the engine momentarily started to run rough before he heard a loud bang followed by a separation of a portion of the propeller blade. The pilot shut the engine down and performed a forced landing to open desert terrain, during which the airplane impacted vegetation, resulting in substantial damage to the left wing. Postaccident examination of the propeller blade revealed a chordwise fracture across the propeller about 12 inches from the hub. The fracture origin area exhibited a small pit, consistent with progressive crack growth from a flat fracture surface in the area identified as the origin. The pit was likely initiated by corrosion, as it exhibited evidence of chlorine-containing salts. No maintenance logbooks were located for the propeller, and its total time in service and most recent inspection were not determined.

Analysis

Primary failure mode
Mechanical failure
First missed decision gate
Inspecting the propeller for fatigue and corrosion before the flight.

NTSB coding

Evidence available

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

Docket documents3

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