Date: 202109
Local time of day: 1201-1800
Location: DEN.Tower, CO
Aircraft: No Aircraft
Reporter organization: Government
Reporter function: Supervisor / CIC
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness; Workload; Communication Breakdown; Distraction; Fatigue
Second reporter function: Local
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: Other at beginning of shift
Result: Air Traffic Control Provided Assistance; Air Traffic Control Separated Traffic
Contributing factors: Company Policy; Environment - Non Weather Related; Human Factors
Primary problem: Company Policy

Narrative: Short staffing shift:We had a total of 4 CPC's until XA:00 local; then down to 3.  We were in a staffing trigger; however the rate was way too high.The agreed rate by NATCA and Management with said staffing should be a 38 AAR [Airport Acceptance Rate]; instead; we started the shift with 114 (unrestricted) and then down to a 76 at 3 CPC's.Everyone felt unsafe: the CPC's; the TMC; the OS.  We brought this to the attention of everyone involved.  The ATM; the District; Center; TRACON; and Command Center.  We all agreed to lower the rate to a 48 later in the night since the 114 and 76 rate already had aircraft in the air for the time.  The 48 rate was implemented; the Center; TRACON and Command Center were all on board.  Then the NOM [National Operations Manager; (at the Command Center)] and the District Manager talked; and brought us back up to the 76.The ATM said keep the CPC's on position as long as necessary. I asked the question; what is unsafe?  6 hours on position?  He said if need be.Overall; we did have many controllers on over 2 hours; 1 CPC stayed on position for 3.5 hours working LC.  1.	Were you; or the employees you were supervising; working too many aircraft? Yes 2.	Were you; or the employees you were supervising; responsible for too much airspace? Yes 3.	Were you; or the employees you were supervising; unable to provide additional services (e.g.; solicitation of PIREP's; issuance of depicted weather; issuance of traffic advisories)? No weather that night; however; would have been much worse if there had been. 4.	Was the volume and/or complexity of traffic managed to allow for a safe operation? No 5.	Were positions de-combined in a timely manner? No 6.	Were you; or the employees you were supervising; able to staff properly?  No; to safely run the operation; Management and NATCA locally believe we should have a minimum of 7 positions open.  9 would be ideal (I.e. 4 LC's; 2 GC; CD; 2 CC).... We ran the shift with only 4 open; many over two hours.  7.	Did the lack of staffing cause you to be fatigued (e.g.; increased time on position or increased volume)? Yes 8.	Did you have enough people to run the shift with the volume and/or complexity of traffic? No; our staffing guidelines require 10; we had 3 CPC's. 9.	Were Traffic Management Initiative(s) implemented to address the volume and/or complexity of traffic? No; we were denied. 10.   Was a Staffing Trigger Form filled out? Yes 11.	Was there proper shift management and/or planning to address the volume and/or complexity of traffic during special events (e.g.; weather events; Super Bowl; NASCAR; Final Four; airshows)? We tried; we were overrun.We have had many reports of similar events. We have filed hotlines on similar events.  Nothing has changed.


Second narrative: At the beginning of the shift we started with 4 CPC's which latter declined to 3. During my second session I worked over two hours with a 30 minute break. On my third session because of staffing I was required to work for 3 hours and 20 minutes. During the latter part of the session around 2 hours I became fatigued and tried. I was working all the locals on the west side of the airport and because of staffing I had to work all the grounds also for most of the three hour session. Having to continuously scan all taxiways for taxing aircraft while safely watching aircraft landing on three runways became difficult at times working for that long. This has been a constant problem for most of the year. More Staffing is the number one cause for concern. The facility needs more bodies training as soon as possible with only having half of the CPC's required to work safely.


Synopsis: Three DEN Tower personnel reported short staffing and asking for the Airport Acceptance Rate to be lowered.