Date: 202101
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: Embraer Legacy 450/500
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Climb; Takeoff / Launch
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Aircraft component: Autothrottle/Speed Control
Component problem: Malfunctioning
Reporter organization: Corporate
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Flight Instructor; Flight Crew Instrument; Flight Crew Multiengine; Other RG Sport
Human factors: Distraction; Situational Awareness; Troubleshooting
Anomaly: Aircraft Equipment Problem Less Severe; Deviation - Altitude Overshoot; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Overcame Equipment Problem
Contributing factors: Aircraft; Human Factors; Environment - Non Weather Related
Primary problem: Human Factors

Narrative: Taking off in ZZZ an incident occurred where we blew through altitude and we [were] slow to follow our heading assignment.I was PM on this flight; and it was the second flight of the day on this trip.Pre-flight was normal and we loaded up our passengers ahead of schedule with no pressure to rush.Upon receiving our takeoff clearance for Runway XX in ZZZ we were assigned a heading of 230 and an altitude of 2;000 feet. I performed the before takeoff checks and the PF armed the AT and the lateral mode (roll mode.) (SOP from manufacturer for takeoff with a heading assignment is either to activate heading mode and then spin the heading to the assigned heading at 400 feet; alternatively you can input the heading but leave it in roll mode until 400 feet upon which you can activate heading mode. Neither of which is particularly helpful during a high workload environment).Takeoff procedure was initially normal; we lined up on the runway and proceeded with a rolling start. The PF set takeoff thrust; and I made my first call at 40 kts. Sometime between 40 kts and 80 kts the AT Disconnect sounded. PF elected to continue. We rotated normally and after the call for 'Gear Up' and the '400 feet' call the pilot asked for me to engage the AT again. I hit the AT button; and continued with my climb sequence checklist. (Speed 180; FLC; Flaps to 0 and After Takeoff Checklist.)Around the time I hit FLC Tower called us to switch to departure. At approximately the same time the AT again disconnected (without an aural alert). I called AT disconnect and reminded the PF that he had to manually control the throttles for speed. As I swapped frequencies the PF attempted to rearm the AT's and blew through our initial altitude. The AT's again disconnected immediately after hitting the button and I called ATC informing them that we had blown through our ALT by 200 feet and were descending back to intercept as well and the late initial turn to a heading of 230.ATC acknowledged and asked us to IDENT and to turn to a heading of 260.At this point the PF had manual speed control; I finally armed the correct lateral mode. (Heading set to 230) PF and I had a quick discussion and decided now that the workload was lower we could troubleshoot. We armed the AT one last time however this time it did not disconnect; and we proceeded with the flight normally.There were a few contributing factors that caused this error.Firstly; we are both new on this equipment and are still learning the correct procedures and cadence of the flight.Secondly; due to COVID we have not been flying as much as we normally do further extend the period of settling into the new aircraft.Third; we believe manufacturer's procedure for setting the lateral mode during a very high workload stage of flight 400 feet during the climb sequence further exasperated the situation. The AP/FD should be programmed so that when you are in T/O mode that it will hold roll to 400 feet then will initiate the turn to a heading and revert to LNAV to HDG mode.Finally; the most critical error I believe was the PF's throttle technique. He would arm the AT and then bring the throttled straight to the stops whereas manufacturer procedure is to bring the throttle levers to around 40% TLA and then let the AT's set takeoff thrust. I hadn't noticed it in previous flight; but I noticed it on this takeoff because the throttle levers moved much to quickly to takeoff power. I believe that this movement overrode the AT logic and if he accidentally moved the throttles past the detent even momentarily it may have caused the AT's to disconnect. Then for the rest of the T/O roll the throttles were possibly still slightly past the detent not allowing engagement until they were finally moved to a lower power setting whereupon we could finally engage the AT's. We discussed this discrepancy during the cruise portion of the flight and the PF will use the correct throttle technique going forward.




Synopsis: Embraer Legacy First Officer reported altitude and heading discrepancies and cited distraction from an AT disconnect as a contributing factor.