Narrative:

Cleared direct to zzzzz which is a fix on the RNAV xx with clearance to turn to 180 heading after crossing zzzzz. Descent issued by approach to 2;500 feet which crew acknowledged. The 180 heading was preset on the heading bug by pm (pilot monitoring). Night conditions prevailed and airport was not yet in sight; however; I was beginning to pick up airport beacon. As we approached zzzzz; while still in descent; I began making out the runway (xxr). As PF (pilot flying)/pm were visually confirming; the aircraft began a smart turn to the inbound course of the RNAV approach. This momentary startle effect caused me to reach up and select heading mode. The only thing I can think of is that I must have bumped the alt select knob and lowered it; as cdfa minimums of 1;250 feet got posted on the aad (automatic activation device). As PF/pm agreed runway was in sight and before we could inform approach; the aircraft had passed through 2;500 feet and we received a low alt alert from approach. I immediately disconnected autopilot and stopped descent. Approach verified we had the field in sight; which we confirmed; and then were cleared for the visual. I began the descent again and maintained profile till landing. At no time were any [ground proximity warning system] warnings encountered; and aircraft was configured and stable by all sops.I cannot confirm that I reset the aad device; however; it must have been bumped or turned initially when the smart turn began; because as I stated prior; the smart turn caught me off guard as we both were looking outside acquiring the runway visually. This was a beautiful night with VMC conditions; however the placement of the runway in surrounding lights and the fact that the initial fix and final approach fix legs are doglegs complicated visual orientation. I should have just asked for the approach off of zzzzz.

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Original NASA ASRS Text

Title: Citation 680 Captain reported receiving a low altitude alert from ATC on a night visual approach.

Narrative: Cleared direct to ZZZZZ which is a fix on the RNAV XX with clearance to turn to 180 heading after crossing ZZZZZ. Descent issued by Approach to 2;500 feet which crew acknowledged. The 180 heading was preset on the heading bug by PM (Pilot Monitoring). Night conditions prevailed and airport was not yet in sight; however; I was beginning to pick up airport beacon. As we approached ZZZZZ; while still in descent; I began making out the Runway (XXR). As PF (Pilot Flying)/PM were visually confirming; the aircraft began a smart turn to the inbound course of the RNAV approach. This momentary startle effect caused me to reach up and select HDG mode. The only thing I can think of is that I must have bumped the alt select knob and lowered it; as CDFA minimums of 1;250 feet got posted on the AAD (Automatic Activation Device). As PF/PM agreed runway was in sight and before we could inform Approach; the aircraft had passed through 2;500 feet and we received a low alt alert from Approach. I immediately disconnected autopilot and stopped descent. Approach verified we had the field in sight; which we confirmed; and then were cleared for the visual. I began the descent again and maintained profile till landing. At no time were any [Ground Proximity Warning System] warnings encountered; and aircraft was configured and stable by all SOPs.I cannot confirm that I reset the AAD device; however; it must have been bumped or turned initially when the smart turn began; because as I stated prior; the smart turn caught me off guard as we both were looking outside acquiring the runway visually. This was a beautiful night with VMC conditions; however the placement of the runway in surrounding lights and the fact that the Initial Fix and Final Approach Fix legs are doglegs complicated visual orientation. I should have just asked for the approach off of ZZZZZ.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.