Citation Excel (C560XL)
Situational Awareness
Aircraft Equipment Problem Critical; Deviation - Altitude Excursion From Assigned Altitude; Inflight Event / Encounter Unstabilized Approach
General None Reported / Taken
Aircraft; Human Factors
Maintenance test flight.Crew requested to perform a functional test flight on the aircraft after several maintenance events; to include a declared emergency following gear issues; and failure of both engines to run due to lack of ignition & fuel flow on both #1 & #2 engines in separate events.The maintenance test flight was again attempted to be bypassed by departments at the office; as the ERTS (Expected Return To Service) placed on the jet was consistently followed in a short time by live legs; or early morning trips without a maintenance flight being placed into the schedule. Maintenance Control seemed to understand the crew's needs and wants to perform a functional flight; but the schedule was never built to allow a jet (which had been down for about 3 weeks at this point for various issues) to be test flown.Preflight inspections and W&B (Weight and balance) calculations were completed prior to the crew taxiing out. The only odd indications crew had during taxi checks was a noted looseness on the TR (Thrust Reverser) levers which was not there previously. TR checks were normal otherwise; so crew took note of the situation and continued the taxi to the runway.Upon liftoff; I noted a strong pitch up in the nose; and difficulty in pushing the nose forward (down); using electric trim. I asked my Copilot to confirm the trim was moving; and they indicated it was; albeit slowly. Cleaning up gear and flaps returned the aircraft to a more normal feel in the controls and the crew verbalized a need to mention the trim movement when returning from the flight.The goal of the maintenance flight was to perform gear swings in order to confirm functionality of both the uplocks and 'down & locked' indications. I placed the plane on autopilot and continued to climb to 4000 feet; and attempted to avoid clouds building in the vicinity. Once we were clear; we slowed the jet to under 200 kts and tested the gear a few times. Once we were satisfied the gear was functioning properly; we informed ATC the purpose of our flight was complete and we were ready to head in. ATC gave us a left downwind vector for Runway XXR. Once established; and still on auto pilot; I requested flaps 7 at 4000 ft. and 195 kts. A few seconds after my copilot moved the flap lever; the jet began an extremely significant pitch up attitude and autopilot disengaged. I grabbed the yoke and began trying to pitch the nose down; and apply nosedown trim at the same time; with no movement sensed. My copilot noted the trim was full nose down already & not moving. I requested help in shoving the nose forward and we both began pushing forward with full strength. We were able to arrest the climb some; but not push the nose forward completely. I asked my copilot to take out the 7 degrees of flaps we had just selected. Within a second; the back pressure began easing on the yoke; and we were able to return to a normal attitude again - after having climbed about 1000 ft. My copilot noted the altitude change and I began descending back down to our assigned 4000 ft. and ATC was informed of our issue and that we were descending again to our assigned altitude. With the volatility of the flaps; the crew decided we would perform a no-flap landing & informed Tower we needed the longer runway due to our situation; and requested extra time to run our abnormal checklist. We referenced the QRH for a no flap landing; making our Ref (Reference) speeds and landing distance calculations to determine the 9000 ft. available on [Runway] XXL; (at a Ref speed of 122kts) would be sufficient for our situation. I requested gear down in order to help keep us slow; and we informed Tower we were ready to turn in for the approach.We informed Tower of our situation and the fact that we would be remaining slow on a several-mile (10+) final approach. Tower began moving traffic behind us to XXR in response; and requested that traffic further out begin to slow to their approach speeds due toour situation.There were scattered clouds; no precipitation and winds were 020 at 19 kts; we landed uneventfully with plenty of runway remaining. No mention was made of the altitude deviation made by the crew while fighting the pitch up attitude.Maintenance test flights should be conducted with any significant Maintenance event. There should not be any pushback for doing something that helps ensure safety to crew and passengers in favor of placing a revenue flight on the plane.Each time we flew; or attempted to fly; this aircraft we had significant Maintenance events. I recommend this particular aircraft; given it's notorious record of significant Maintenance events; receives a full inspection event be performed on the jet to help catch and prevent further serious issues; or possibly worse; in the future.
Captain reported severe pitch-up after flap extension and conducted no-flap landing.