Captain reported fatigued resulted in a go around due to aircraft not being properly configured.

Attributes
ACN	1671030
Time
Date	201908
Local Time Of Day	1201-1800
Place
Locale Reference	DEN.Airport
State Reference	CO
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	Regional Jet 200 ER/LR (CRJ200)
Operating Under FAR Part	Part 121
Flight Phase	Initial Approach
Route In Use	Visual Approach
Flight Plan	IFR
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP) Flight Crew Instrument Flight Crew Multiengine
Events
Anomaly	Deviation - Procedural Published Material / Policy Inflight Event / Encounter Unstabilized Approach

Narrative:

Failed to fully configure aircraft. Both of us were focused on the aircraft in front of us; talking about the fact that he wasn't moving off the runway fast enough. Focused on that; we forgot to put gear down and complete configuration. Received the gear horn descending through 1;000 ft. With flaps 20. It took us a second or two to realize what just happened. I looked down and saw our altitude of 870 ft. And called for a go-around. Tower asked the reason and I replied that we weren't fully configured. They questioned us to make sure it wasn't their fault that we were too close but it wasn't their fault. Normal go-around followed by normal approach and landing. Just exhausted; I came off 2 full days off with decent sleep but only slept about 2 hours during the overnight. Eliminate stand-ups; the continuous duty-periods of them go completely against everything we know about fatigue; circadian rhythm; etc.

Original NASA ASRS Text

Title: Captain reported fatigued resulted in a go around due to aircraft not being properly configured.

Narrative: Failed to fully configure aircraft. Both of us were focused on the aircraft in front of us; talking about the fact that he wasn't moving off the runway fast enough. Focused on that; we forgot to put gear down and complete configuration. Received the gear horn descending through 1;000 ft. with flaps 20. It took us a second or two to realize what just happened. I looked down and saw our altitude of 870 ft. and called for a go-around. Tower asked the reason and I replied that we weren't fully configured. They questioned us to make sure it wasn't their fault that we were too close but it wasn't their fault. Normal go-around followed by normal approach and landing. Just exhausted; I came off 2 full days off with decent sleep but only slept about 2 hours during the overnight. Eliminate stand-ups; the continuous duty-periods of them go completely against everything we know about fatigue; circadian rhythm; etc.

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.