Narrative:

Flying from tlh to bct we had climbed to 25000 through rain. After level flight at 25000 for awhile with altitude hold engaged on autoplt the aircraft slowly climbed to approximately 100 ft or so above selected altitude. Altitude hold button was disengaged to correct the altitude level. Aircraft went into a very sudden steep dive requiring much back pressure on control yoke. ZJX was immediately called requesting lower altitude as the electric and manual trim were both inoperative and the aircraft was in a very steep descent. It appeared to us the trim was in an almost full down position and frozen. We were unable to maintain level flight. Our first call to ZJX was blocked by another aircraft. We were then advised by the center we were below our assigned altitude. We explained our situation and we were cleared to a lower level. There was no traffic conflict. We descended to 17000 ft which was below the freezing level where we regained trim control and were able to level off. We then in clear air climbed back up to 19000 and continued to but, we checked with factory maintenance and our own staff of mechanics. All drain holes were to be checked and cleaned if necessary and all elevator and trim lube areas to be checked and svced with the proper lube.

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Original NASA ASRS Text

Title: LOSS OF ACFT CTL ACCOUNT FROZEN ELEVATOR AND OR HORIZ STABILIZER. ELECTRIC TRIM AND MANUAL INOP.

Narrative: FLYING FROM TLH TO BCT WE HAD CLBED TO 25000 THROUGH RAIN. AFTER LEVEL FLT AT 25000 FOR AWHILE WITH ALT HOLD ENGAGED ON AUTOPLT THE ACFT SLOWLY CLBED TO APPROX 100 FT OR SO ABOVE SELECTED ALT. ALT HOLD BUTTON WAS DISENGAGED TO CORRECT THE ALT LEVEL. ACFT WENT INTO A VERY SUDDEN STEEP DIVE REQUIRING MUCH BACK PRESSURE ON CTL YOKE. ZJX WAS IMMEDIATELY CALLED REQUESTING LOWER ALT AS THE ELECTRIC AND MANUAL TRIM WERE BOTH INOP AND THE ACFT WAS IN A VERY STEEP DSCNT. IT APPEARED TO US THE TRIM WAS IN AN ALMOST FULL DOWN POS AND FROZEN. WE WERE UNABLE TO MAINTAIN LEVEL FLT. OUR FIRST CALL TO ZJX WAS BLOCKED BY ANOTHER ACFT. WE WERE THEN ADVISED BY THE CENTER WE WERE BELOW OUR ASSIGNED ALT. WE EXPLAINED OUR SITUATION AND WE WERE CLRED TO A LOWER LEVEL. THERE WAS NO TFC CONFLICT. WE DSNDED TO 17000 FT WHICH WAS BELOW THE FREEZING LEVEL WHERE WE REGAINED TRIM CTL AND WERE ABLE TO LEVEL OFF. WE THEN IN CLR AIR CLBED BACK UP TO 19000 AND CONTINUED TO BUT, WE CHKED WITH FACTORY MAINT AND OUR OWN STAFF OF MECHS. ALL DRAIN HOLES WERE TO BE CHKED AND CLEANED IF NECESSARY AND ALL ELEVATOR AND TRIM LUBE AREAS TO BE CHKED AND SVCED WITH THE PROPER LUBE.

Data retrieved from NASA's ASRS site as of July 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.