SDR 96ZZZX4323

Service difficulty report · Lock

Difficulty date
July 1, 1996
Submitted
March 26, 2000
Operation
General aviation
Engine
Pwa JT12A8
Part
Lock
Part number
536210
Condition
Missing
Location
3rd Stage Disk
Part time
322 hours
Stage of operation
IN
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

INTERNAL BLADE RUBBING, BINDING, AND LOCKING UP. AN INDUCTION TEST RUN WAS PEFORMED ON 6-20-96. DURING THE TEST, VIBRATION OF 3.8 MIL AT 75 PERCENT WAS NOTED. (3.2 MIL IS MAXIMUM ALLOWABLE). ENGINE WAS DISASSEMBLED AS NECESSARY TO ACCESS COMPRESSOR ASSY. COMPRESSOR WAS DISASSEMBLED TO ELEVATE RUBBING CONDITION. P/N 536203, 3RD STAGE COMPRESSOR BLADE WAS FOUND LOOSE IN THE BLADE SLOT OF 3RD STAGE DISK. BLADE HAD MOVED AFT MAKING CONTACT WITH COMPRESSOR STATOR, P/N 385503, DAMAGING EVERY VANE. BLADE LOCK COULD NOT BE FOUND AND SUSPECT IT MAY HAVE FAILED AND EXITED ENGINE ALLOWING BLADE TO WORK LOOSE. NO OBVIOUS DAMAGE FROM LOCK WAS NOTED. CAUSE OF LOCK FAILURE IS UNKNOWN AT THIS TIME. ONE EACH P/N 536