Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 33; Flight Crew Total 10508; Flight Crew Type 100
Confusion; Human-Machine Interface
Deviation - Altitude Overshoot; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Unstabilized Approach
Flight Crew Overcame Equipment Problem
Human Factors
I was flying and cleared for RNAV; outside the final approach fix; inbound. The approach was stable and the autopilot engaged. As I was putting the gear down and continuing to gradually slow; Approach called and instructed me change to Tower frequency. I had preloaded the frequency in the standby position of the radio anticipating the change. This is when the trouble began.On an airplane in which I have thousands of hours (and still occasionally fly); the frequency switching button is on the right side of the thrust control and the TOGA switch is on the left side; allowing a pilot to perform either action without releasing the powerplant control during a busy phase of flight. On the airplane that is the subject of this account (which is made by the same manufacturer); the thrust controls have a TOGA button on both sides. There is no frequency switching button on the powerplant controls.When I was instructed to change to the Tower frequency; I automatically (by muscle memory perhaps) pressed the right side of the powerplant controls to make the frequency change; however; I instead initiated the avionics to go into go-around mode. Immediately realizing my mistake; I disconnected the autopilot to continue the approach manually. This was futile; as the avionics had already sequenced to the missed approach point and the flight director was still commanding a climb.Accepting that I had botched the approach with a simple button-push; I contacted Approach (whose frequency I was still on) reported a 'malfunction' and requested another attempt at the approach. I was given a vector to turn right and climb to three thousand. This is when the next sequence of trouble began (or continued).Written out; this situation seems to play out in a slow manner; but from the moment I mistakenly pressed the TOGA button; events happened very quickly. In go-around mode the auto-throttle is commanded to takeoff thrust. After I turned the autopilot off; the auto-throttles disconnected; but they remained at the last thrust lever angle and thrust setting (less than takeoff thrust; but more than necessary for the situation). The aircraft was rapidly accelerating. I had also lost track of the gear being down since that action coincided with the frequency change radio call from Approach. When I selected the gear to retract; I was below VLE of 250 knots; but I was above VLO (Retract) of 200 knots. The aircraft accelerated so quickly I did not recognize the exceedance. The overspeed warning sounded immediately as I actuated the gear. I pulled the power back and pitched up to slow down. While pitching up I climbed through the three thousand foot clearance by about three hundred feet.After I got the plane under control and descended to three thousand feet; I confirmed my heading; altitude; configuration; and the flight mode annunciator and reengaged the autopilot. The whole sequence lasted maybe 20-30 seconds. Shortly thereafter; Approach gave me another vector and a climb to three thousand five hundred feet to re-sequence for the approach. (The Controller made no mention of my altitude excursion.) The following approach and landing were uneventful.The proper response to the situation would have been to simply proceed with the missed approach without disconnecting the automation and conducting the appropriate procedures. In older avionics systems it would have been easy to continue manually; but in modern mode-based avionics a pilot needs to think like the avionics are designed. When the mode changes so must the pilot's thinking; even if the mode is in error. Before corrective action can be implemented; the pilot has to fully grasp what the plane is now doing and what proper actions (with regard to the present mode) need to be taken before rectifying the initial mistake.This situation is also a good example of why differences in similar models of aircraft; even in which a pilot is very familiar; can induce a cascade of errors.
Captain activated TOGA intending to activate frequency select; which resulted in an overspeed and altitude deviation.