Rockwell International S-2R N8421V accident near Howard, South Dakota

Probable cause

A fractured fabricated aluminum oil line, which resulted in oil exhaustion followed by a forced landing.

NTSB analysis

The engine had recently been installed under a supplemental type certificate and had accrued 2 hours flight time before the accident. The pilot said that he took off on the test flight and adjusted the throttle and propeller control for climb. He noticed low oil pressure and a loss of propeller pitch control. In his attempt to return to the airport, the airplane started to settle and lose altitude. He made a forced landing in a rough pasture. The right wing struck terrain, which damaged the spar, and the airplane nosed down. Postaccident examination revealed a fractured aluminum line where it attached to the propeller governor, resulting in a loss of oil and oil pressure. Only two quarts of oil remained in the crankcase. The fractured line had been fabricated during the engine installation. Maintenance personnel said they should have installed more Adel clamps to secure the line and minimize vibrations.

Text from the NTSB. Open the NTSB docket for CEN12LA357 for the full record.