Service difficulty report · Gas Generator · Airtrc AT802A

Difficulty date
March 19, 2007
Submitted
March 29, 2007
Operation
Air carrier
Aircraft
N805D
Make and model
Airtrc AT802A
Aircraft serial
902A0156
Engine
Pwa PT6A67A
Part
Gas Generator
Condition
Eroded
Location
Flange
Part time
1,800 hours
Stage of operation
NR
How discovered
9
Nature of condition
O
Precautionary procedure
O

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

What was found

AS THE HEAD BOLTS WERE BEING REMOVED FOR HSI. ONE NUT DETACHED FROM THE BOLT SHANK WITH THE THREAD INSIDE THE NUT. CLOSE INSPECTION OF THE ADJACENT BOLT REVEALED SEVERE EROSION (NOT CORROSION OR STRETCH DAMAGE) TO THE BOLT SHANK. IT WAS FURTHER NOTED AND PHOTOGRAPHED BY THE MFG REP THAT THE EXHAUST DUCT FLANGE AND GAS GENERATOR FLANGE IN THE BROKEN BOLT AREA HAD MATERIAL LOSS THAT WAS ALLOWING P3 AIR LOSS THAT MAYBE ATTRIBUTED TO THE HIGHER THAN NORMAL OIL TEMP INDICATION ON THE GROUND.. THE AIR LEAK IS VENTING ONTO THE SCAVENGE OIL TUBE COUPLING. MFG REP SAYS THAT THIS IS AN ISOLATED CASE AND IS NOT A SAFETY OF FLIGHT ISSUE AS THAT THERE ARE MANY MORE BOLTS THAT HOLD C-FLANGE TOGETHER. (K)