Service difficulty report · Engine · Pilats PC1247

Difficulty date
April 17, 2025
Submitted
April 24, 2025
Operation
General aviation
Aircraft
N476SS
Make and model
Pilats PC1247
Aircraft serial
696
Aircraft time
12,862 hours, 13,050 cycles
Engine
Pwa PT6A67
Engine time
11,988 hours, 11,977 cycles
Part
Engine
Condition
Damaged
Location
Zone 400
Part time
11,988 cycles
Stage of operation
CR
How discovered
B
Nature of condition
B
Precautionary procedure
B

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

What was found

TOOK 15 MINUTES TO CLIMB TO 17,000 AND WERE LEVEL FOR APPROXIMATELY 25 MINUTES WHEN A RAPID SERIES OF BLAST NOISES CAME FROM THE ENGINE ACCOMPANIED BY LARGE AMOUNTS OF SPARKS CONTINUOUSLY EMANATING OUT OF THE EXHAUST. OUR POWER SETTING WERE LIKELY 1.5PSI TO 2PSI BELOW MAX TORQUE, AS THIS IS GENERALLY WHERE I LIKE TO SET THE POWER. OUR ITT’S WERE WELL WITHIN THE NORMAL RANGE (LIKELY AROUND 710) AND OUR NG’S WERE NORMAL ALSO. THESE SPECIFIC NUMBERS CAN BE PULLED. THERE WERE NO INDICATIONS THAT THE SURGES OR STALLS (WHICHEVER THEY WERE) AFFECTED THE ENGINE INDICATIONS, THOUGH I REDUCED POWER QUICKLY AFTER THE EVENT TO GET IT TO STOP. THE SEPARATOR WAS CLOSED IN VMC CONDITIONS. I REDUCED POWER IN HOPING TO FIND A SWEET SPOT WHERE THE BLASTS WERE NOT OCCURRING AND PULLED THE PCL BACK TO HAVE THE NG IN THE SINGLE DIGIT RANGE. THIS HAD THE EFFECT THAT I WAS LOOKING FOR WITH A CESSATION OF THE SURGES AND SPARKS FOR THE MOST PART. ANY POWER INPUTS THEREAFTER ON OUR WAY TO THE NEAREST AIRPORT BROUGHT BACK THE SURGES AND SPARKS. I FELT AS IF I COULD GET AN INCREASE IN POWER FROM THE ENGINE, AND DID SO A FEW TIMES, BUT THE SPARKING AND SURGE/STALLS INCREASED AS WELL. THE SPARKS ALSO CONTINUED INTERMITTENTLY ON THE WAY TO THE AIRPORT, BUT NOT AS MANY AS WHEN EVENT INITIALLY STARTED. AROUND 5 MILES AWAY FROM THE AIRPORT WE DID START TO SMELL SMOKE, BUT NOT THAT WAS VISIBLE NOR SEEMED TO BE WORKING ITS WAY INTO THE COCKPIT TO ANY SIGNIFICANT DEGREE. THIS SMELL WAS BRIEF AND DISSIPATED QUICKLY. I INTENTIONALLY KEPT THE AIRCRAFT HIGH ON THE WAY TO OUR KAVP TO BETTER ENSURE MAKING THE AIRPORT IF THE ENGINE WERE TO QUIT. WE WERE SET UP FOR THE ILS AND VECTORED TO LOSE ALTITUDE. WE BROKE OUT OF AN OVERCAST LAYER WHICH MAY HAVE BEEN 2500 TO 3500’. I CALLED FOR THE GEAR AND FLAPS WHEN WE WERE MAYBE ¼ OF A MILE FROM THE RUNWAY TO ENSURE WE WOULD MAKE IT. I DID NOT USE BETA OR REVERSE AND WE ROLLED OUT NEAR THE FAR END OF THE RUNWAY.