Dash 8-100
Flight Crew Air Transport Pilot (ATP)
Time Pressure; Troubleshooting; Confusion; Workload
Aircraft Equipment Problem Critical
Flight Crew Landed in Emergency Condition; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Returned To Departure Airport; General Flight Cancelled / Delayed; General Maintenance Action; General Declared Emergency
Aircraft
I first became aware that the aircraft wasn't trimmed properly after v1 and prior to vr; the aircraft seemed to want to lift off at an airspeed less than vr; I held very little pressure on the yoke to keep the aircraft on the runway until vr. At vr I rotated the aircraft and moved the manual trim forward to reduce the forward pressure that was required for a neutral feel on the yoke. At this time the pressure was very light and not concerning. The pilot not flying brought up the gear and we continued a normal departure off runway heading to 4000 ft. After the gear and flaps were up I noticed very little forward pressure required while climbing at the command bars roughly a go-around setting. We were then switched to departure were they gave us a couple of headings before eventually assigning a climb to 8;000 feet and direct ZZZ VOR. At that time I engaged the autopilot with setting of rnav and vertical speed climb of 1;000 fpm the aircraft began the turn and lowered the nose as a cruise climb began. Once becoming level at 8;000 feet the pilot not flying and I noticed the pitch mis-trim message on the ID-802 panel. At that time I noticed the manual trim was full forward so I grabbed the yoke and disengaged the autopilot. Once disengaged the aircraft tried to climb sharply. I then applied forward pressure roughly a medium pressure. If left uncorrected a stall would have occurred. I notified the pilot not flying of our condition and reduced the power to flight idle; while at the same time I armed the standby elevator trim and tried to lower the nose with no movement on the manual trim or with the feel in the yoke. I then directed the pilot not flying to declare an emergency and that we are returning back to the airport. The pilot not flying declared the emergency with TRACON and notified the flight attendant along with the passengers. At the same time I slowed the aircraft to 160 knots which reduced the forward pressure required a little and began taking vectors for the approach. Once the pilot not flying was back on frequency I directed him to take out the non-normal emergency checklist. We went through the loss of manual trim first which I had already tried earlier. Next we agreed that we may have to do a zero flap landing so we quickly reviewed that checklist writing down approach speeds and noting special considerations. At that time we were on the base leg to join the localizer. We talked about flaps and decided that flaps may help the condition so once on the localizer tracking inbound we put in 5 degrees of flaps to see if conditions improved and they did; the forward pressure required reduced. After that we went to 10 degrees of flaps and the pressure went from a forward pressure to a slightly aft pressure but mostly neutral. We continued the approach at 10 degrees of flaps to the runway. Once on the ground we cleared the runway and taxied to the gate. Notified operations and company.
Trim was set for takeoff. Controls were checked with no abnormal feel during the control check on the Before Takeoff checklist. Aircraft climbed normal with the exception of slightly more nose down trim than normal. Upon level off the Mistrim (NOSE DN) message was displayed on the 800 panel . The pilot flying disconnected the autopilot and had to exert unusually high nose down forces to maintain level flight. The trim wheel was set full nose down and the Yoke had to be held full forward. Power was then reduced which helped reduce the forward pressure it took to maintain altitude. Crew declared an emergency and began a return to the airport. An announcement was made to the passengers and airport operations was called. Crew tried using the STBY elevator trim which had no effect on the flight controls. Crew also briefed a flapless landing and accessed the abnormal flap landing checklist in the event the use of flaps produced an undesirable effect during the approach. The flight continued with the yoke full forward to a normal landing. Aircraft was taxied to the gate. Dispatch and then maintenance were notified. Crew had flown this Aircraft 4 legs earlier with a notable abnormalities.
A DHC-8-100 crew discovered that they required full nose down trim to maintain level flight at 8;000 feet. They declared an emergency; completed QRH procedures and returned to departure airport.