Service difficulty report · Safety Switch · Beech 1900D

Difficulty date
April 12, 2019
Submitted
August 17, 2020
Operation
General aviation
Make and model
Beech 1900D
Aircraft time
18,183 hours
Part
Safety Switch
Part number
444EN496
Condition
Unserviceable
Location
Mlg
Part time
150 hours
Stage of operation
NR
How discovered
O
Nature of condition
F
Precautionary procedure
O

As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.

What was found

(CAN) THIS GEAR SAFETY SWITCH (SQUAT SWITCH) HAS MULTIPLE SWITCH THROWS THAT CONTROL MULTIPLE SYSTEMS. ONE SWITCH THROW THAT CONTROLS THE OPERATION OF THE GROUND FINE SOLENOIDS SHORTED INTERNALLY WHICH MAKE THE GROUND FINE SOLENOID SYSTEM ALWAYS BEHAVE LIKE IT IS IN GROUND MODE EVEN WHEN THE AIRCRAFT IS IN THE AIR. AS A RESULT WHEN THE AIRCRAFT WAS IN THE FLARE FOR LANDING AND THE POWER LEVER WERE RETARDED TO FLIGHT IDLE THE PROPELLER BLADE ANGLE WENT TO FINE AND CAUSED THE AIRCRAFT TO LOSE MORE AIRSPEED THAN INTENDED. THE GROUND FINE SOLENOIDS ARE THERE TO MAKE THE PROP BLADE ANGLE FINER FOR GROUND OPERATIONS AND ARE ACTUATED THROUGH THE RH GEAR SAFETY SWITCH. WE INSTALLED A NEW RH GEAR SAFETY SWITCH WITH THE SAME PART NUMBER AND THE DEFECT WAS RECTIFIED. THE DEFECTIVE SWITCH WAS RELATIVELY NEW WITH ONLY 150.9 HOURS ON IS SINCE INSTALL. (TC# 20190417007)

More about the Beech 1900D