Service difficulty report · Spur Gear · Dhav DHC8311

Difficulty date
August 26, 2013
Submitted
September 14, 2015
Operation
General aviation
Make and model
Dhav DHC8311
Engine
Pwa PW123
Part
Spur Gear
Part number
310831601
Condition
Cracked
Location
Reduction Gb
Part time
13,206 hours
Stage of operation
IN
How discovered
9
Nature of condition
O
Precautionary procedure
K

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

What was found

(CAN) AT DISASSEMBLY OF THE RGB MODULE, FOR A LIGHT O/H DUE TO MIO (METAL IN OIL), 3 CRACKS WERE NOTED IN THE 2ND STAGE SPUR GEARSHAFT WALL, PN 3108316-01, SN RWA27A159. THE CRACKS ARE ORIGINATING FROM THE NR 15 BEARING MATING FACE AND PROPAGATING FORWARD. THE CRACKS ARE APPROXIMATELY 1.0", 2.5" AND 3.0" IN LENGTH. THE 1.0" AND 2.5" CRACKS ARE ADJACENT TO EACH OTHER APPROXIMATELY 0.060" APART. THERE IS MATERIAL BREAKOUT AT THE TOOLING SLOT CORNER. THE SEPARATED PIECE OF MATERIAL WAS PICKED BY MAGNETIC CHIP DETECTOR IN-FIELD. THE MISSING PIECE IS APPROXIMATELY 0.060" WIDE, 0.100" LONG AND 0.050" DEEP. THE OEM HAS BEEN NOTIFIED REGARDING THIS FINDING AND THE INFORMATION IS BEING REVIEWED BY SERVICE ENGINEERING INVESTIGATION GROUP. THE OCCURANCE DATE OF THE MIO INCIDENT IS UNKNOWN AT THIS TIME.THE OCCURENCE DATE RECORDED ABOVE IS THE FILING DATE.