B767-300 and 300 ER
Flight Crew Last 90 Days 125; Flight Crew Total 9000; Flight Crew Type 2000
Aircraft Equipment Problem Less Severe
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Aircraft
We experienced an abnormal pitch control anomaly after takeoff. As pilot not flying; I completed pilot not flying duties. The Captain continued to fly the aircraft to 6;000 FT MSL at which time he asked me to fly the aircraft and establish an opinion as to the performance and whether we should continue on with the flight. Positive transfer of controls was made and I flew the aircraft to approximately 14;000 FT. Based on my experience; the pitch control felt very sluggish and slow to respond to inputs. The Captain and I agreed in which we decided to return to the airport of departure. An Emergency was declared and priority handling was provided by ATC. We landed the aircraft with no problems or events. Good CRM was applied.    Prior to engine start during the Before Start Checklist; (below the line) the Captain was performing the flight control check and noticed the pitch and elevator check seemed very mushy and not the normal feel he was used to. He asked me to do the check as well. Since the first officer doesn't normally do this check; I could only base my observation on limited experience for this scenario. The controls seemed mushy but not overly noticeable. All indications were normal and no EICAS messages appeared. So we didn't feel there were any reasons to ground the aircraft.
During the flight control check I thought the elevator felt 'mushy'; but the indices showed full authority was available. I asked my First Officer to exercise the elevator. His impression was in agreement that there was something 'mushy' in the feel of the elevator. Full elevator travel was available; so we elected to take the aircraft. There were no EICAS or status messages regarding flight controls. At rotation the aircraft felt 'mushy' in pitch control. After the aircraft was cleaned up I transferred control to my First Officer for his input and he agreed that something was not correct with the pitch system. I again took control of the aircraft and expressed to my First Officer that I thought we should return as we didn't know what was wrong with the pitch system and that we were heading into mountainous terrain. My First Officer concurred and informed ATC of our desire to return due to a pitch control anomaly; declared an emergency; requested CFR; and notification to our Dispatcher. I flew about a 15 mile; hand flown; stable; final with another elevator feel and authority confirmation check about 5 miles out by both me and my First Officer. The flare for touchdown was 'mushy' also; but a normal geometry touchdown and roll out was accomplished and the aircraft was taxied to ramp with CFR following. Brake temperatures never exceeded 2's. After a brief discussion with CFR; I called our Dispatcher and relayed the events leading up to the emergency declaration and air turn back. I am surprised there is no maintenance check; or indication to the crew of the anomaly via EICAS or Status messages. Maintenance investigation confirmed that the inner spring of a dual spring in the elevator feel system had failed which yielded the 'mushy' feel in the pitch system of the aircraft.
B767-300 flight crew reports a 'mushy' feeling elevator during a flight control check prior to departure; but with full elevator movement available the crew elects to depart. Once airborne the same mushy feeling prompts the crew to return. Maintenance discovers a broken inner spring in the elevator feel system to be the cause.