Date: 201901
Local time of day: 0001-0600
Location: ZZZ.Airport, US
Flight conditions: VMC
Aircraft: MD-83
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class C ZZZ
ATC / advisory: Tower ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy; Ground Event / Encounter Other / Unknown
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: A previous write up concerning a maintenance issue with the stabilizer trim had been signed off as repaired. I was flying the aircraft. The flight proceeded normally until established on final approach on a clear day with little wind. When slowing through 180 knots just after gear extension and flaps 40 degrees with the autopilot off; I noticed that the controls became heavy and the stabilizer trim 'warble' was not annunciating while I trimmed nose up. I looked down at the stab trim position indicator and noticed that it was not moving. I asked the first officer to try to use his trim. My directions were ambiguous as I started to struggle to keep the nose up. He very well may have trimmed in the nose down direction but neither of us knows for sure. As we continued slowing resulting in even more force on the controls to keep the nose up; I verbally directed the first officer to continue trimming. Just a moment later we both realized that the trim indicated way too nose down for our configuration and speed. At that point; I directed the First Officer to reverse the direction of his trimming. He did; but the stabilizer trim did not appear to move any in the nose up direction. I then tried using the 'suitcase handles' to get the trim to move nose up. The stabilizer trim again did not appear to move nose up. While struggling against the out of trim condition; I felt that the stabilizer trim momentarily reversed so that I need to hold the controls nose down. To be perfectly honest; I may have fooled myself; here and compounded the critical nature of the situation. Looking back; I may have noted that I was high on the flight path and pushed the nose over. The few seconds that I did this made the struggle to get the nose up earlier feel like the stabilizer out of trim had flipped to a nose down out of trim condition. I instantly remembered the jack screw failure accident of an MD-80 years ago at Alaska Airlines. I had initially determined that we would go around and run the checklist; but now I was convinced that if we did the aircraft would be uncontrollable. As long as we continued on our present somewhat stabilized approach; we might be able to get the aircraft safely on the ground. I was able to keep the aircraft headed for the runway aim point. I did my best to flair the aircraft; but ended up with the yoke all the way back at touchdown. The result was a hard landing. I quickly brought the aircraft to a halt on the runway. I considered the possibility of aircraft damage; but I was confident there was no critical structural damage and proceeded to the gate. As I taxied the aircraft; I checked the stabilizer trim and it worked completely normally from either yoke control switch and the 'suitcase handles.' No injuries were reported for passengers or crew. Exterior inspection by the crew revealed no obvious aircraft damage. A hard landing was reported in the aircraft log book along with the stabilizer trim malfunction. A report was made to dispatch and MOC and the voice recorder circuit breaker was pulled. Cause: I unwittingly let this get out of control first by vaguely instructing the First Officer to check his stab trim without specific instruction to which direction that I wanted him to trim and then directing him to continue trimming as the controls got ever heavier. The trim malfunction then trapped us in this out of trim condition. Suggestions: I really don't have any other than I need to be more specific in the manner that I direct action by the First Officer to avoid miscommunication.




Synopsis: MD83 Captain reported communication breakdown between flight crew resulted in a misdiagnoses of a flight control issue and a hard landing.