On August 15, 1999, a Cessna 337 (registration N99MH) was involved in an aviation accident near Edgewood, NM. Investigators recorded the probable cause as: Breakage of the safety wire that secured the propeller control cable to the support bracket. Factors were the inability of the pilot to feather the propeller or change propeller rpm, and rough, uneven, and unsuitable terrain on which to make a forced landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
During climbout after takeoff, the rear engine lost partial power to 1,700 rpm. The pilot initially turned to return but instead landed in an open field. Investigation found a broken safety wire that prevented propeller pitch adjustment.
Accident Description
During the climbout phase after takeoff, the rear engine experienced a partial loss of power, with engine speed dropping to 1,700 rpm. The pilot initiated a turn to return to the departure airpark but then changed his mind, deciding instead to maintain control of the aircraft by executing a landing in a rough and uneven open field.
Postaccident Examination
A postaccident examination of the aircraft revealed that the safety wire securing the propeller control cable to its support bracket had fractured. This failure allowed the cable housing to flex within the engine compartment. According to the examination, the safety wire broke when the pilot reduced engine rpm to climb power. The breakage prevented the pilot from feathering or changing the rear propeller pitch settings.