MD80 flight crew; after three legs of questionable flight control characteristics; decided to have maintenance look for a potential mechanical issue.
Synopsis
MD80 flight crew; after three legs of questionable flight control characteristics; decided to have maintenance look for a potential mechanical issue.
Narrative
I wrote up aircraft with a flight control issue on this flight. It was the third flight of the day for this cockpit crew and upon landing (First Officer's leg) I decided that this aircraft needed to be looked at by maintenance. Something was not right with its flying capability. The first leg was the First Officer's and I noticed he complained with the aircraft's trim. He flew and we had a jumpseat rider. The First Officer worked the trim a lot in climb and landing configuration. The landing on the first leg was not one of his best and he usually makes nice landings. But now I feel the aircraft has an issue; not the First Officer. I flew the next leg; and I noticed on takeoff the trim was not right; very nose heavy. I made a comment. The aircraft pitch did not want to move smoothly and did require a lot of trim. At times I had to trim to move the elevator to move it smoothly; versus jerky. Then it just seemed to be a badly BENT aircraft; like many you see on the line. At cruise on autopilot; it seemed to be fine. On approach; I had to trim the jet for every pitch or aileron movement! It took a lot of trim; and the ailerons seemed to want to roll off at low speed. Still I was not sure it was anything but a bent up aircraft. It did not have the 'NORMAL FEEL' but it was not a safety issue I felt at the time. We chatted about the trim and effort and I told First Officer it was different in pitch and roll on landing configuration. The next leg was First Officer's again. On takeoff; he said the trim was wrong again! And it felt very nose heavy. Now we had two takeoffs to compare. Usually loads is right on the takeoff trim; so I knew it was not loads. First Officer struggled in the climb with the trim again; but in cruise it trimmed out and was ok on the autopilot. During the landing; again he complained about the excessive amount of trim; and as he went into the flare; I saw him use a whole bunch of left aileron to keep the wings level. It was not normal; and that is when I decided he had a control problem. It was not 'JUST A FEELING' but something I could compare and see. I wrote the aircraft up for control issues. I did discuss it with the outbound Captain; maintenance and my First Officer. The possibility of sending a bad aircraft back out with revenue was not one I was willing to make. It was time for maintenance to look the aircraft over. I did not attempt to check it out at any time; or try to carry the write-up to our final destination. I was unsure until the two takeoffs and the excessive aileron on the last landing. It might have been very small or a large issue; but it was time to have maintenance take a look. The aircraft did not have the normal feel; even as many are bent but this one was more so. It just took the three flights to make sure the write-up was the correct one vs. just complaining about a 'BENT' aircraft.
Second reporter narrative
Captain and I flew aircraft for 3 legs. I flew 2 of the 3 legs that day. On the first leg; the pitch trim on rotation seemed to be nose heavy. It seemed that the load may have been slightly off as it took more than normal force to rotate and fly the aircraft. On landing; the aircraft handled more like a tail heavy load with some lateral instability. I attributed this to the weather condition. Captain few the next leg and he noticed on takeoff the trim was not even close! He mentioned it to me that the aircraft in pitch seemed to not want to move smoothly and did require a lot of trim. At times; both of us had to trim the pitch to get the elevator to move smoothly; but it did not seem to be anything more than a bad BENT aircraft! At cruise it handled normally; in trim and with autopilot on. On approach; Captain had to trim the aircraft for each pitch and aileron movement. It took a lot of trim to get the aircraft to where he wanted it. He did make a nice landing but it was a handful; and the ailerons seemed to want to roll as the aircraft was slowed. Upon landing the left wing seemed to lift after touchdown; but again I thought it might have been the weather. We chatted about the trim and the effort and I did say it felt different. The final leg; on takeoff; I said the trim was not correct; so now I had 2 takeoffs with what we felt was the wrong trim. This was not something normal; as load control usually gets it right. I also complained of the heavy pitch and the trim needed to place the aircraft where I needed it. It did respond; but it was not that standard feeling? Once again at altitude it felt somewhat normal on autopilot. On landing; again I had to work a lot of trim to keep it where I wanted; and in the landing flare I had a bunch of aileron (almost full left aileron) into the left wing as I flared. The jumpseat rider mentioned that I had about 70% throw of the ailerons on landing. This was far different from my first landing as there was no wind or weather to blame for this amount of control input. The Captain decided then that this now confirmed the aircraft had a problem versus just a feeling? We decided to make the write up; and discussed it with the outgoing Captain and local maintenance. I feel that if we hadn't had multiple legs on this aircraft; we would not have noticed the unique flight characteristics of aircraft.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.