Narrative:

Hangar space north/a. It had snowed approximately 3', very wet and easily removable snow. Deicer requested several times, not immediately available. Obtained suitable brush for snow removal for wings and top of fuselage. Copilot sent for line man and they stood on top of fuel truck and cleaned entire top side of horizontal stabilizer. All surfaces clean, but wet--no visible ice/snow. The aircraft was cleaned to my satisfaction. It was no longer snowing & the surface temperature was 34 degrees. Passenger showed for departure. Final walkaround of aircraft was simply wet surfaces, & west/17 yrs flying experience, including chicago and new england winters, aircraft appeared in excellent condition. Airborne by XA15. Everything working normally. Climbing through 7000' MSL I was manually trimming the aircraft nose forward, & the pressure was not relieving at the control wheel. The trim wheel was moving freely and working, but it didn't appear to be moving the elevator. As I was requiring more nose down trim, had to apply tremendous pressure in order to keep nose down. Finally elevator unfroze. Aircraft immediately responded to new nose down trim I had input. I was still in climb to my assigned altitude, 15000'. The OAT was -3 degrees C. No sooner did I get aircraft retrimmed, started feeling pressure was working against me again, but in reverse. Told copilot, 'we have a potentially serious problem, request vectors back to burlington airport. While he was doing that, I was on the P/a to passenger advising them we had trim problem and were returning to btv. At this time pressure was once again so great, and informed first officer to declare an emergency and immediate vectors for an ILS into burlington. We were approximately 20 mi southeast of airport when had to turn back. I knew we had to get into warmer air and there was high terrain directly below. Burlington approach was exceptional and handling us and providing vectors for ILS runway 15. While first officer on radio, I disabled the electric trim switch and asked him to pull electric trim circuit breaker in case that might have anything to do with our problem. Then called for unscheduled trim emergency, descent and below landing checklists. Trip problem recurred 3 more times after disabling electric trim system. Descending through 3000' MSL aircraft was starting to respond normally once again. Runway was seen approximately 2 mi on final and an uneventful landing was made. Did a post inspection inside aircraft looking for moisture in the tail around trim actuator. Not enough found to cause any problems. Aircraft was hangared in btv till maintenance could check it the next a.M. All trim & elevator cables & associated pulleys were checked. All elevator hinges and moveable tail components were inspected, lubed and found airworthy. Maintenance release was issued and aircraft was test flown--everything functioning normally. Concluded slush from snowstorm entered hinge area openings/trim linkages. No obvious stress applied, & couldn't tell where actual freezing occurred. With elevator control lock installed, it is in full down position. This exposes hinge area to rain, sleet & snow. Brushing snow off front to back only complicates problem. When rain/snow freezes it expands, and this is where we feel our problems began. Elevator movement was restr because of this ice trapped in the elevator hinge assembly. Later I visited plant assembly line to get a closer look at the hinge. After leaving had better understanding of how ice could form and become trapped in this area. Then headed to airport to look at hinge assembly on our aircraft. Found a stress point behind 2ND hinge on the bottom. There is where ice had initially formed. No way can move in flight unless you are able to break it off with extreme force or flying into warmer air, as we did. Recommendations: 1) obtain proper deice, and on small transport even after this is done, look inside the hinge openings to assure the glycol has satisfactorily melted ice in the hinge openings and that no puddles of water remain in these openings. Remember, no drainage to assist in this. 2) if elevator freezes and cannot free it, make slight pitch adjustments using trim tab in reverse. It acts as a miniature elevator when your regular elevator is jammed. In my case I was trying to trim the nose down, and with my elevator jammed it was actually causing me to hold more pressure while I was trimming because it was acting like an elevator. I feel though with my pressure and the pressure the trim tab exerted on the elevator, I was able to free the elevator. 3) my suggestions to manufacturer is possible drainage holes in the elevator hinge assembly. Provide the owners and operators with deicing procedures and stress the importance of a proper deice in the pilots operating handbook--particularly in the small transport series. Maybe the control lock should lock the elevator in a neutral position, or slightly pitched down to prevent water from collecting. 4) most important, know your airplane! Consider all options if your airplane is subjected to adverse WX while sitting outside. Especially you t-tailed flyers out there, we are often at a disadvantage if a 14' ladder is not available. 5) I also feel that anyone who teaches ground school on an small transport should be educated on the possibility of ice formation in the elevator hinge assembly so it can be conveyed to initial or recurrent trnees.

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Original NASA ASRS Text

Title: SMT ELEVATOR JAMS DUE TO ICE. EMERGENCY DECLARED.

Narrative: HANGAR SPACE N/A. IT HAD SNOWED APPROX 3', VERY WET AND EASILY REMOVABLE SNOW. DEICER REQUESTED SEVERAL TIMES, NOT IMMEDIATELY AVAILABLE. OBTAINED SUITABLE BRUSH FOR SNOW REMOVAL FOR WINGS AND TOP OF FUSELAGE. COPLT SENT FOR LINE MAN AND THEY STOOD ON TOP OF FUEL TRUCK AND CLEANED ENTIRE TOP SIDE OF HORIZ STABILIZER. ALL SURFACES CLEAN, BUT WET--NO VISIBLE ICE/SNOW. THE ACFT WAS CLEANED TO MY SATISFACTION. IT WAS NO LONGER SNOWING & THE SURFACE TEMP WAS 34 DEGS. PAX SHOWED FOR DEP. FINAL WALKAROUND OF ACFT WAS SIMPLY WET SURFACES, & W/17 YRS FLYING EXPERIENCE, INCLUDING CHICAGO AND NEW ENGLAND WINTERS, ACFT APPEARED IN EXCELLENT CONDITION. AIRBORNE BY XA15. EVERYTHING WORKING NORMALLY. CLBING THROUGH 7000' MSL I WAS MANUALLY TRIMMING THE ACFT NOSE FORWARD, & THE PRESSURE WAS NOT RELIEVING AT THE CONTROL WHEEL. THE TRIM WHEEL WAS MOVING FREELY AND WORKING, BUT IT DIDN'T APPEAR TO BE MOVING THE ELEVATOR. AS I WAS REQUIRING MORE NOSE DOWN TRIM, HAD TO APPLY TREMENDOUS PRESSURE IN ORDER TO KEEP NOSE DOWN. FINALLY ELEVATOR UNFROZE. ACFT IMMEDIATELY RESPONDED TO NEW NOSE DOWN TRIM I HAD INPUT. I WAS STILL IN CLB TO MY ASSIGNED ALT, 15000'. THE OAT WAS -3 DEGS C. NO SOONER DID I GET ACFT RETRIMMED, STARTED FEELING PRESSURE WAS WORKING AGAINST ME AGAIN, BUT IN REVERSE. TOLD COPLT, 'WE HAVE A POTENTIALLY SERIOUS PROB, REQUEST VECTORS BACK TO BURLINGTON ARPT. WHILE HE WAS DOING THAT, I WAS ON THE P/A TO PAX ADVISING THEM WE HAD TRIM PROB AND WERE RETURNING TO BTV. AT THIS TIME PRESSURE WAS ONCE AGAIN SO GREAT, AND INFORMED F/O TO DECLARE AN EMER AND IMMEDIATE VECTORS FOR AN ILS INTO BURLINGTON. WE WERE APPROX 20 MI SE OF ARPT WHEN HAD TO TURN BACK. I KNEW WE HAD TO GET INTO WARMER AIR AND THERE WAS HIGH TERRAIN DIRECTLY BELOW. BURLINGTON APCH WAS EXCEPTIONAL AND HANDLING US AND PROVIDING VECTORS FOR ILS RWY 15. WHILE F/O ON RADIO, I DISABLED THE ELECTRIC TRIM SWITCH AND ASKED HIM TO PULL ELECTRIC TRIM CB IN CASE THAT MIGHT HAVE ANYTHING TO DO WITH OUR PROB. THEN CALLED FOR UNSCHEDULED TRIM EMER, DSCNT AND BELOW LNDG CHKLISTS. TRIP PROB RECURRED 3 MORE TIMES AFTER DISABLING ELECTRIC TRIM SYS. DSNDING THROUGH 3000' MSL ACFT WAS STARTING TO RESPOND NORMALLY ONCE AGAIN. RWY WAS SEEN APPROX 2 MI ON FINAL AND AN UNEVENTFUL LNDG WAS MADE. DID A POST INSPECTION INSIDE ACFT LOOKING FOR MOISTURE IN THE TAIL AROUND TRIM ACTUATOR. NOT ENOUGH FOUND TO CAUSE ANY PROBS. ACFT WAS HANGARED IN BTV TILL MAINT COULD CHK IT THE NEXT A.M. ALL TRIM & ELEVATOR CABLES & ASSOCIATED PULLEYS WERE CHKED. ALL ELEVATOR HINGES AND MOVEABLE TAIL COMPONENTS WERE INSPECTED, LUBED AND FOUND AIRWORTHY. MAINT RELEASE WAS ISSUED AND ACFT WAS TEST FLOWN--EVERYTHING FUNCTIONING NORMALLY. CONCLUDED SLUSH FROM SNOWSTORM ENTERED HINGE AREA OPENINGS/TRIM LINKAGES. NO OBVIOUS STRESS APPLIED, & COULDN'T TELL WHERE ACTUAL FREEZING OCCURRED. WITH ELEVATOR CONTROL LOCK INSTALLED, IT IS IN FULL DOWN POS. THIS EXPOSES HINGE AREA TO RAIN, SLEET & SNOW. BRUSHING SNOW OFF FRONT TO BACK ONLY COMPLICATES PROB. WHEN RAIN/SNOW FREEZES IT EXPANDS, AND THIS IS WHERE WE FEEL OUR PROBS BEGAN. ELEVATOR MOVEMENT WAS RESTR BECAUSE OF THIS ICE TRAPPED IN THE ELEVATOR HINGE ASSEMBLY. LATER I VISITED PLANT ASSEMBLY LINE TO GET A CLOSER LOOK AT THE HINGE. AFTER LEAVING HAD BETTER UNDERSTANDING OF HOW ICE COULD FORM AND BECOME TRAPPED IN THIS AREA. THEN HEADED TO ARPT TO LOOK AT HINGE ASSEMBLY ON OUR ACFT. FOUND A STRESS POINT BEHIND 2ND HINGE ON THE BOTTOM. THERE IS WHERE ICE HAD INITIALLY FORMED. NO WAY CAN MOVE IN FLT UNLESS YOU ARE ABLE TO BREAK IT OFF WITH EXTREME FORCE OR FLYING INTO WARMER AIR, AS WE DID. RECOMMENDATIONS: 1) OBTAIN PROPER DEICE, AND ON SMT EVEN AFTER THIS IS DONE, LOOK INSIDE THE HINGE OPENINGS TO ASSURE THE GLYCOL HAS SATISFACTORILY MELTED ICE IN THE HINGE OPENINGS AND THAT NO PUDDLES OF WATER REMAIN IN THESE OPENINGS. REMEMBER, NO DRAINAGE TO ASSIST IN THIS. 2) IF ELEVATOR FREEZES AND CANNOT FREE IT, MAKE SLIGHT PITCH ADJUSTMENTS USING TRIM TAB IN REVERSE. IT ACTS AS A MINIATURE ELEVATOR WHEN YOUR REGULAR ELEVATOR IS JAMMED. IN MY CASE I WAS TRYING TO TRIM THE NOSE DOWN, AND WITH MY ELEVATOR JAMMED IT WAS ACTUALLY CAUSING ME TO HOLD MORE PRESSURE WHILE I WAS TRIMMING BECAUSE IT WAS ACTING LIKE AN ELEVATOR. I FEEL THOUGH WITH MY PRESSURE AND THE PRESSURE THE TRIM TAB EXERTED ON THE ELEVATOR, I WAS ABLE TO FREE THE ELEVATOR. 3) MY SUGGESTIONS TO MANUFACTURER IS POSSIBLE DRAINAGE HOLES IN THE ELEVATOR HINGE ASSEMBLY. PROVIDE THE OWNERS AND OPERATORS WITH DEICING PROCS AND STRESS THE IMPORTANCE OF A PROPER DEICE IN THE PLTS OPERATING HANDBOOK--PARTICULARLY IN THE SMT SERIES. MAYBE THE CONTROL LOCK SHOULD LOCK THE ELEVATOR IN A NEUTRAL POS, OR SLIGHTLY PITCHED DOWN TO PREVENT WATER FROM COLLECTING. 4) MOST IMPORTANT, KNOW YOUR AIRPLANE! CONSIDER ALL OPTIONS IF YOUR AIRPLANE IS SUBJECTED TO ADVERSE WX WHILE SITTING OUTSIDE. ESPECIALLY YOU T-TAILED FLYERS OUT THERE, WE ARE OFTEN AT A DISADVANTAGE IF A 14' LADDER IS NOT AVAILABLE. 5) I ALSO FEEL THAT ANYONE WHO TEACHES GND SCHOOL ON AN SMT SHOULD BE EDUCATED ON THE POSSIBILITY OF ICE FORMATION IN THE ELEVATOR HINGE ASSEMBLY SO IT CAN BE CONVEYED TO INITIAL OR RECURRENT TRNEES.

Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.