Narrative:

The aircraft had a write-up for inoperative pitch trim which was cleared prior to departure by re-racking a computer and testing controls. About 2.5 hours into flight at FL340 and mach .85 the autoplt limit annunciated and aircraft began to climb. I disconnected the autoplt but had no trim or control yoke movement in pitch. Trim was intermittent and aircraft stayed level, although we declared an emergency to protect our airspace. The other pilot flew as I worked the checklist with the flight engineer. A phone patch to company maintenance personnel was established. As we read the notes on the checklist we became convinced that the stabilizer was probably stuck. These notes indicated that pulling the pitch disconnect would be of little or no use. The note did not contradict the checklist or indicate not to pull the disconnect as called for. On initial occurrence of the problem the yoke seemed to break free momentarily when pushed forward. It took quite a lot of force to do (maybe 25 pounds) and I was reluctant to do it again and upset the aircraft at high altitude and mach. This along with not knowing that the pitch disconnect handle could be re-inserted after pulling plus the note on the checklist and our becoming convinced of a jammed stabilizer caused us to not follow the subsequent checklist items in as timely a manner as we might. The checklist called for pulling the pitch disconnect. As the aircraft descended it became more difficult to pitch up using the wing engines. I used the spoilers as the aircraft was speeding up and used wing engines to change pitch attitude. We then attempted to break the yoke free with aft pressure, which illuminated two stabilizer push lights. We pushed these thereby disabling two hydraulic systems in the first officer's pitch control path. 'Pull pitch disconnect' was annunciated. We did this and regained control of the aircraft through the captain's yoke. We landed without problem. Better understanding of the system and checklist execution would have resulted in a solution to the problem more quickly. Callback conversation with reporter revealed the following information: the reporter stated the autoplt was the first alert with the autoplt limit warning and when disconnected the airplane climbed. The reporter said all three methods of pitch control, pitch trim switches on the control yoke, autoplt and mechanical pitch trim wheels on either side of the pedestal had failed. The reporter stated an emergency was declared to clear airspace and pitch trim was maintained with wing engines and flight spoilers. The reporter stated, finally with aft yoke pressure, which illuminated the two stabilizer 'push' lights, they then pushed these, disconnecting two hydraulic inputs to the stabilizer. The reporter said stabilizer control was regained through the captain's yoke. The reporter stated on the ground a technician entered the stabilizer compartment and found blue ice covering the stabilizer components. The reporter said it was discovered that a lavatory leak was allowing blue water to follow a control cable and pass through the pressure dome through a fair lead grommet that was defective.

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Original NASA ASRS Text

Title: A LOCKHEED L-1011 AT FL340 DECLARED AN EMER DUE TO LOSS OF PITCH CTL. NO STABILIZER TRIM OR CTL YOKE MOVEMENT IN PITCH.

Narrative: THE ACFT HAD A WRITE-UP FOR INOP PITCH TRIM WHICH WAS CLEARED PRIOR TO DEP BY RE-RACKING A COMPUTER AND TESTING CTLS. ABOUT 2.5 HRS INTO FLT AT FL340 AND MACH .85 THE AUTOPLT LIMIT ANNUNCIATED AND ACFT BEGAN TO CLB. I DISCONNECTED THE AUTOPLT BUT HAD NO TRIM OR CTL YOKE MOVEMENT IN PITCH. TRIM WAS INTERMITTENT AND ACFT STAYED LEVEL, ALTHOUGH WE DECLARED AN EMER TO PROTECT OUR AIRSPACE. THE OTHER PLT FLEW AS I WORKED THE CHECKLIST WITH THE FE. A PHONE PATCH TO COMPANY MAINT PERSONNEL WAS ESTABLISHED. AS WE READ THE NOTES ON THE CHECKLIST WE BECAME CONVINCED THAT THE STABILIZER WAS PROBABLY STUCK. THESE NOTES INDICATED THAT PULLING THE PITCH DISCONNECT WOULD BE OF LITTLE OR NO USE. THE NOTE DID NOT CONTRADICT THE CHECKLIST OR INDICATE NOT TO PULL THE DISCONNECT AS CALLED FOR. ON INITIAL OCCURRENCE OF THE PROB THE YOKE SEEMED TO BREAK FREE MOMENTARILY WHEN PUSHED FORWARD. IT TOOK QUITE A LOT OF FORCE TO DO (MAYBE 25 LBS) AND I WAS RELUCTANT TO DO IT AGAIN AND UPSET THE ACFT AT HIGH ALT AND MACH. THIS ALONG WITH NOT KNOWING THAT THE PITCH DISCONNECT HANDLE COULD BE RE-INSERTED AFTER PULLING PLUS THE NOTE ON THE CHECKLIST AND OUR BECOMING CONVINCED OF A JAMMED STAB CAUSED US TO NOT FOLLOW THE SUBSEQUENT CHECKLIST ITEMS IN AS TIMELY A MANNER AS WE MIGHT. THE CHECKLIST CALLED FOR PULLING THE PITCH DISCONNECT. AS THE ACFT DESCENDED IT BECAME MORE DIFFICULT TO PITCH UP USING THE WING ENGS. I USED THE SPOILERS AS THE ACFT WAS SPEEDING UP AND USED WING ENGS TO CHANGE PITCH ATTITUDE. WE THEN ATTEMPTED TO BREAK THE YOKE FREE WITH AFT PRESSURE, WHICH ILLUMINATED TWO STABILIZER PUSH LIGHTS. WE PUSHED THESE THEREBY DISABLING TWO HYDRAULIC SYSTEMS IN THE FO'S PITCH CTL PATH. 'PULL PITCH DISCONNECT' WAS ANNUNCIATED. WE DID THIS AND REGAINED CTL OF THE ACFT THROUGH THE CAPT'S YOKE. WE LANDED WITHOUT PROB. BETTER UNDERSTANDING OF THE SYSTEM AND CHECKLIST EXECUTION WOULD HAVE RESULTED IN A SOLUTION TO THE PROB MORE QUICKLY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE AUTOPLT WAS THE FIRST ALERT WITH THE AUTOPLT LIMIT WARNING AND WHEN DISCONNECTED THE AIRPLANE CLBED. THE RPTR SAID ALL THREE METHODS OF PITCH CTL, PITCH TRIM SWITCHES ON THE CTL YOKE, AUTOPLT AND MECHANICAL PITCH TRIM WHEELS ON EITHER SIDE OF THE PEDESTAL HAD FAILED. THE RPTR STATED AN EMER WAS DECLARED TO CLEAR AIRSPACE AND PITCH TRIM WAS MAINTAINED WITH WING ENGS AND FLT SPOILERS. THE RPTR STATED, FINALLY WITH AFT YOKE PRESSURE, WHICH ILLUMINATED THE TWO STABILIZER 'PUSH' LIGHTS, THEY THEN PUSHED THESE, DISCONNECTING TWO HYDRAULIC INPUTS TO THE STABILIZER. THE RPTR SAID STABILIZER CTL WAS REGAINED THROUGH THE CAPT'S YOKE. THE RPTR STATED ON THE GND A TECHNICIAN ENTERED THE STABILIZER COMPARTMENT AND FOUND BLUE ICE COVERING THE STABILIZER COMPONENTS. THE RPTR SAID IT WAS DISCOVERED THAT A LAVATORY LEAK WAS ALLOWING BLUE WATER TO FOLLOW A CTL CABLE AND PASS THROUGH THE PRESSURE DOME THROUGH A FAIR LEAD GROMMET THAT WAS DEFECTIVE.

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.