GA pilot reported inadvertently leaving the transponder code set from the previous flight. The pilot...

Attributes
ACN	1743554
Time
Date	202005
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Small Aircraft
Operating Under FAR Part	Part 91
Flight Phase	Parked
Route In Use	Direct
Flight Plan	None
Component
Aircraft Component	Transponder
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Private
Experience	Flight Crew Last 90 Days 8 Flight Crew Total 1800 Flight Crew Type 1600
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural Published Material / Policy

Narrative:

Landing after the second flight of the day; during shutdown noticed that transponder had been left on the previous flight's code assigned for flight following instead of having been set to XXXX which would have been appropriate for this flight conducted without flight following. The transponder is ads-B; so there was still a unique identifier. The flight originated at ZZZ shortly after xapm when the tower had shut early due to covid. I am used to getting a flight following code from ZZZ ground; but did not this time because of the closure. Had I been at a normally uncontrolled airport; I would have followed my checklist for electronics; but I am so used to getting codes at ZZZ that I did not pay proper attention to that portion of the preflight/runup. Compounding this is that the transponder is new and less familiar than the one I have flown with for years; which actually would indicate more attention is needed. Always run through full electronics checks on startup and shutdown!

Original NASA ASRS Text

Title: GA pilot reported inadvertently leaving the transponder code set from the previous flight. The pilot was accustomed to getting a code from the Tower; however the Tower had closed early due to COVID-19 hours and the pilot did not check the transponder.

Narrative: Landing after the second flight of the day; during shutdown noticed that transponder had been left on the previous flight's code assigned for flight following instead of having been set to XXXX which would have been appropriate for this flight conducted without flight following. The transponder is ADS-B; so there was still a unique identifier. The flight originated at ZZZ shortly after XApm when the Tower had shut early due to COVID. I am used to getting a flight following code from ZZZ ground; but did not this time because of the closure. Had I been at a normally uncontrolled airport; I would have followed my checklist for electronics; but I am so used to getting codes at ZZZ that I did not pay proper attention to that portion of the preflight/runup. Compounding this is that the transponder is new and less familiar than the one I have flown with for years; which actually would indicate more attention is needed. Always run through full electronics checks on startup and shutdown!

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.

GA pilot reported inadvertently leaving the transponder code set from the previous flight. The pilot was accustomed to getting a code from the tower; however the tower had closed early due to covid-19 hours and the pilot did not check the transponder.