CAPT OF A CPR TURBOPROP TOOK OFF WITH ICE ON THE TAIL SECTION WHICH FROZE WHEN CLBING THROUGH A FREEZING OVCST CAUSING THE ELEVATORS TO STICK AND FREEZE UP; RESULTING IN LOSS OF ACFT PITCH CTL. THE ICE MELTED AFTER ATC ASSISTED THEM TO A LOWER AND WARMER ALT.
Synopsis
CAPT OF A CPR TURBOPROP TOOK OFF WITH ICE ON THE TAIL SECTION WHICH FROZE WHEN CLBING THROUGH A FREEZING OVCST CAUSING THE ELEVATORS TO STICK AND FREEZE UP; RESULTING IN LOSS OF ACFT PITCH CTL. THE ICE MELTED AFTER ATC ASSISTED THEM TO A LOWER AND WARMER ALT.
Narrative
LARGE HAILSTORM PASSED THROUGH AREA LEAVING A LARGE AMOUNT OF SLUSH ON ACFT. CAPT HAD IT BRUSHED OFF WINGS AND MOST OF BODY; BUT NOT THE TAIL; AS THERE WAS NO MEANS TO GET TO IT. I; PNF; TOLD CAPT (OUR BASE SAFETY REPRESENTATIVE) THAT COMPANY OPS REQUIRED A 'CLEAN' AIRPLANE FOR TKOF. HE RESPONDED 'YEAH' BUT THAT HE WASN'T CONCERNED ABOUT THE TAIL AND THAT THE SLUSH WOULD BLOW OFF ON TKOF AND THAT THE TAIL HAD A POSITIVE PRESSURE ON THE BOTTOM ANYWAY. I ALSO TOLD HIM WE NEEDED TO GET A LADDER OR SOMETHING TO DEICE THE AIRPLANE WHEN WE NEEDED TO. WELL; HE WAS RIGHT; IT BLEW OFF ON TKOF -- RIGHT INTO THE SPACE BTWN THE ELEVATOR AND HORIZ STABILIZER. AND AS WE CLBED THROUGH A THICK FREEZING OVCST IT FROZE AND WHEN IT CAME TO LEVEL OFF AT 9000 FT; THE PITCH CTL WAS FROZEN. THIS CAUSED THE AIRPLANE TO LURCH ABOUT 400 FT AT A TIME AS WE WERE AT TIMES ABLE TO GET SOME MOVEMENT. I IMMEDIATELY INFORMED ATC WE HAD A PITCH CTL PROB AND SUSPECTED THE ELEVATOR HAD FROZEN OVER. WE OBTAINED A CLRNC TO 5000 FT (WARMER TEMP) AND A DEV E OF COURSE TO MAINTAIN VFR CONDITIONS. APCHING 5000 FT; CTLS BECAME NORMAL. CAPT CALLED CHIEF PLT ON GND AND RPTED INCIDENT. CAPT MADE A REALLY BAD DECISION AS BOTH FAR PART 135 AND COMPANY OPS REQUIRE A CLEAN AIRPLANE FOR TKOF. CAPT DID NOT LISTEN TO FO'S CONCERNS OR ASK FOR HIS INPUT. FO WAS NOT ASSERTIVE ENOUGH (BUT WILL BE IN THE FUTURE). BOTH CREW MEMBERS ARE TRAINED IN CRM (WHICH WILL BE PRACTICED IN THE FUTURE). WE WERE LUCKY -- YOU WILL NEVER GET ANOTHER RPT LIKE THIS FROM ME!
Second reporter narrative
I WAS ABLE TO ARREST THE CLB SOMEWHAT WITH USE OF TRIM AND POWER; WHILE CONTINUING TO FREE UP CONTROLS.(ABOUT 15-20 SECS) THEN; ALL OF A SUDDEN IT LET LOOSE AND AN ABRUPT NOSE DOWN ALTITUDE RESULTED. THEN AS SOON AS THE FROZEN CTLS BECAME UNFROZEN AND NOSE DOWN ALTITUDE CORRECTED; THEY WOULD BEGIN TO FREEZE UP AGAIN! AND AGAIN; WITH SOME FORCE; IT WOULD LET LOOSE; CAUSING ANOTHER ABRUPT ALTITUDE CHANGE
NASA callback
THE RPTR STATED THE AIRPLANE WAS NOT DEICED WITH DEICING FLUID; BUT JUST SWEPT WITH BROOMS BY THE TECHNICIANS. THE RPTR SAID IT APPEARED TOO WARM FOR NEEDING DEICING FLUID AS MOST OF THE SNOW AND SLUSH WAS SLIDING OFF THE WINGS AND FUSELAGE. THE RPTR SAID THE TOP OF THE FUSELAGE WAS NOT ENTIRELY CLR OF SLUSH AND BELIEVES THIS IS WHAT CAUSED THE ELEVATOR ICING PROB. THE RPTR STATED MAINT INSPECTED THE ELEVATORS AFTER THE INCIDENT AND CONCLUDED SLUSH SLIDING OFF THE TOP OF THE FUSELAGE LODGED IN THE STABILIZER ELEVATOR GAP.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.