Suspected Unapproved Parts Details
On July 25, 2013, an inadvertent feather event occurred shortly after takeoff on a DeHavilland DHC-8-100 series aircraft. Flight data records indicated that the #1 PCU was closed during takeoff when a beta condition did not exist. Examination of the subject PCU revealed that the beta light assembly was installed incorrectly, deforming the switch case. The deformed case interfered with the free action of the switch’s internal mechanism, causing the switch to intermittently remain closed as the propeller transitioned above the ground handling range during takeoff. This condition resulted in a propeller over-torque when the aircraft’s beta backup system became active and commanded the propeller to feather while the engine was in a high-power condition.
The basic propeller control unit is widely used for UTC Aerospace (Hamilton Sundstrand/Hamilton Standard). Because there may be detailed variations for different aircraft and propeller models, owner/operators should verify specific components installed on their aircraft or in inventory. The list of propellers and aircraft that use PCUs include (but are not limited to): Hamilton Standard Models 14RF-9, 14RF-19, 14RF-21, and 14RF-23; 247F-1; 14SF-5, 14SF-7, 14SF-11, 14SFL11, 14SF-15, 14SF-17, 14SF-19, 14SF-23; and 6/5500/F propellers installed on Embraer EMB-120 and EMB-120RT; SAAB-SCANIA SF340B; Aerospatiale ATR42-100, ATR42-300, ATR42-320, ATR72, ATR72-210; DeHavilland DHC-8-100 series, DHC-8-300; Construcciones Aeronauticas SA (CASA) CN-235 and CN-235-100; Canadair CL215T and CL415; and British Aerospace ATP airplanes. These airplanes are all twin engine installations.
Initial discovery of the issue for the date range of 2010-2013 for 401 specific parts that PPI notified the owner/operators of the issue and it communicates this to all owners and operators to make them aware of this safety matter.
