Uncommanded Loss of Control – Pitch
Approximately 8 miles from the final approach fix, on the [airport] approach, the pilot flying commanded flaps 15. I selected flaps 15 and observed the flap indicator move to the selected position. The autopilot was engaged and trimmed in response to the flap and horizontal stabilizer configuration change. The PF commanded gear down. I put the gear handle down and gear extension was normal. I observed the trim wheel moving to the nose down stop while the nose started to pitch up. The PF disconnected the autopilot and had to use above normal force to stop the pitch up rotation. The PF attempted to trim out the force but found the trim at the nose down limit. He asked for my for assistance pushing the control wheel forward to counteract the pitch up force.
We discontinued the approach to runway 23, retracted the landing gear, and continued to fly over the top of the airport toward the shoreline at 1700 ft. The PF commanded flaps 7, I selected flaps 7 and observed the flap indicator move to the selected position. I tried my electric trim and it was normal. The PF transferred controls to me and I selected flaps zero. The flaps moved to the selected position. The pitch up force lessened. I selected flaps 7, the flaps moved to the selected position. The pitch up force was less and I worked to trim out the remaining control forces.
As I worked to maintain level and trim out control force the STAB MISCOMPARE annunciator illuminated due to my speed being over 210 Kts. I reduced thrust and the annunciator went out. The pitch up force continued to lessen to the point where I was able to trim the force out and had neutral control feel. I transferred the controls to the Left Seat Pilot and he agreed that the control force was normal with flaps 7. We decided todo a flaps 7 landing at SRQ runway 14. We accomplished the checklist.
The touchdown and rollout was normal. Thrust Reverser and Speed Break function was normal. Normal breaking was applied and we exited the runway at C5 and taxied to Atlantic Aviation. We left the flaps and trim set as they were for landing. No damage or fluid leaks were found during post flight.
ERC Acceptance & Closing Notes:
- OE flight. Excellent response by the crew.
- Technicians sent out to inspect the aircraft on the ground, no issues were found.
- Horizontal stabilizer has been serviced as a precaution.
Key Takeaways
Pilots should be reminded to always monitor the aircraft’s response closely during critical configuration changes. Ensure that any change in flap settings is cross-checked with proper trim adjustments and automation responses. Be prepared to promptly revert to a safe configuration or discontinue the approach should abnormalities emerge.
Diversion Due to Mechanical Issue – Pitch and Roll Trim
While operating a repositioning leg from (airport) in aircraft (tail number) at approximately (time), we experienced control issues involving both the pitch and roll trim systems. During a descent from approximately FL280, the aircraft entered an uncommanded nose-down attitude that exceeded the parameters of a normal descent profile. This uncommanded pitch change resulted in the autopilot disconnecting without pilot input.
Significant nose-up control pressure was required to counter the attitude, and both pilots were needed on the controls to regain stability. Once the aircraft was under control, we pulled the Pitch Trim circuit breaker and attempted to reset the autopilot. Upon re-engagement, the autopilot initially functioned but soon commanded an uncommanded nose-up attitude, again requiring both pilots to manually counter the input and regain control.
Given the uncertainty surrounding the aircrafts trim and autopilot systems, and in the interest of safety, we elected to to divert to (airport) rather than continue to our destination of (airport). ATC inquired whether we had the aircraft under control, which we confirmed, although we remained concerned about the potential for recurring control issues. ATC subsequently declared an emergency on our behalf, and we proceed to land at (airport) without further incident.
ERC Acceptance & Closing Notes:
- Autopilot issue caused a pitching issue.
- The crew properly wrote up the issues. Autopilot servo has been replaced.
- ERC feels crew responded appropriately.
Key Takeaways:
The crew’s decisive actions to disconnect automation, isolate the faulty system (via circuit breaker), and divert to a nearby airport highlight critical priorities: maintain control, diagnose the problem, and never hesitate to divert when aircraft reliability is uncertain. Always treat abnormal automation behavior as potentially escalating and be prepared to revert to manual flight and declare an emergency if needed.
Communications Issue – Uncontrolled Airport
We were departing from an uncontrolled field with a high volume of arriving and departing special event air traffic. Departure clearance void times were being issued in 3-minute increments. Arriving aircraft were being pressured to cancel their IFR flight plans by flight crew on the ground as soon as they checked in on the Unicom frequency. There was continuous unprofessional radio chatter by the flight crew waiting to takeoff which blocked radio position reports from arriving inbound aircraft. It was apparent that there was a high level of frustration by many of the flight crew due to a 3:30 wait time to depart which was being transmitted over the Unicom frequency. Many of the aircraft shut down their engines multiple times to conserve fuel.
When we were number one to depart, we noted an inbound aircraft four miles from the airport. We were given a departure clearance from ATC. We made visual contact with the inbound aircraft and determined there was sufficient separation to depart safely. As we lifted off the inbound aircraft called missed approach. During the post flight discussion this was the determination of what occurred. As the weather had slightly improved aircraft were cancelling their IFR clearances farther out than we observed earlier. ATC was issuing takeoff clearances to aircraft on the ground with 3-minute void times while the inbound aircraft were still in the air. The excessive unnecessary radio chatter made it difficult to hear the arriving aircraft’s position reports and type of aircraft inbound. The following recommendations were made to improve safety during high volume air traffic events.
Due to the lack of ATC departure and arrival control as well as lack of direction on the ground at an uncontrolled airport we will only utilize controlled airports where the departures and radio communications are under direct and complete control of the FAA.
Additional consideration will be made to operate to airports outside the ring of high-volume event traffic in the future. It was discussed that landing at an airport further away from the event with much less air traffic would actually save the passengers time due to the extremely long wait times to depart.
ERC Acceptance & Closing Notes:
- Sole source event.
FAA recommendation is to call hotline at the local FSDO to address issue during these types of events. - Safety Takeaway:
Key Takeaways:
High traffic volumes at uncontrolled airports, especially during special events, can create unsafe conditions when clear communication and coordination break down. In this case, excessive and unprofessional radio chatter, pressure on inbound aircraft to cancel IFR early, and tight departure void times contributed to reduced situational awareness. This highlights the importance of disciplined radio use, thorough traffic scanning, and using caution when operating under minimal ATC oversight.
Aircraft System/Equipment Malfunction – Flaps
We departed [airport] with no issues and on approach into [airport] and clear visual based on the meteorological conditions which was over 10 miles, we were cleared for a visual and on base leg at 1500ft, we selected flaps to 30 degrees and landing gear came down, I saw a caution on number 1 EICAS and saw that flap had failed and looked down to the flap position indication and saw that it had failed at 24 degrees. I informed my SIC who was the pilot flying on the left seat. We knew right away that [airport] wouldn’t be adequate for our landing and decided to head to our filed alternate which was [airport].
We informed the controller and my SIC took over the radios whilst I run the checklist for this, abnormally I heard then ATC said you can’t go to [airport] except [if] you are an Emergency aircraft – which we declared that we were. We had this same Flap issue couple of days going to [airport] when it failed at 3 degrees and on landing it moved to 4 degrees and this was written up and the aircraft was RTS with a reset of this system. After this reset, we (crew) had been discussing about our destination airport and runway length and considering a recovery airfield in case we are going to a short field if per chance this flap failed again.
On hearing the ATC saying we can’t land in [airport] due TFR, we looked at the situation and felt it’s better to proceed to [airport] because we were closer to [airport] as we aren’t sure if the flap was going to move to another position and hence it’s better to declare emergency and land as soon as possible whilst still trying to run the checklist for this system. Thereafter, further vectors were given whilst I went through the Checklist to set us up for approach into [airport].
We landed with no issues and taxied to [FBO] and fire trucks followed us and after packing, they asked if all was well with us and Pax and they took my details and company details and drove back to their posts.
ERC Acceptance & Closing Notes:
- Non sole source event due to declared emergency.
- Crew appropriately elected to divert to alternate.
- PIC debriefed on decision to select PBI as alternate.
- POI has been notified.
Key Takeaways:
Always evaluate runway requirements in advance, never hesitate to declare an emergency when safety is in question, and treat recurring system anomalies with increased caution.
