Tower controller reported a runway incursion involving a citation and a uav.

Narrative:

I was in the local control position. Aircraft Y was in the VFR traffic pattern doing touch and goes/low approaches. Aircraft X was inbound on a visual approach to runway 23L. Aircraft Y was issued a go around due to runway separation on a prior aircraft not involved in this event. On the go aircraft Y was given right closed traffic and told to extend his download. Aircraft Y declared minimum fuel at this time. Traffic to follow on aircraft X was given to aircraft Y to follow. Aircraft X was on a 3 or 4 mile final at this time. Aircraft Y flew a mile downwind and then declared emergency fuel. Aircraft X was in a critical phase of flight short final and I allowed him to land but advised him minimal time on the runway and that the aircraft behind him must land. Aircraft Y was told to follow aircraft X and cleared to land. Aircraft Y turned directly behind aircraft X. Aircraft X was given another expedite request off of the runway. Aircraft X was turning off at the A4 intersection as aircraft Y crossed the landing threshold. The time from the declaration of minimum fuel to emergency fuel was very short. The traffic to follow would not require aircraft Y any undue delay. Had emergency fuel been called earlier then the citation could have been sent around before his critical phase of flight; allowing the then priority emergency aircraft a clean runway.

Original NASA ASRS Text

Title: Tower Controller reported a runway incursion involving a Citation and a UAV.

Narrative: I was in the Local Control position. Aircraft Y was in the VFR traffic pattern doing touch and goes/low approaches. Aircraft X was inbound on a visual approach to Runway 23L. Aircraft Y was issued a go around due to runway separation on a prior aircraft not involved in this event. On the go Aircraft Y was given right closed traffic and told to extend his download. Aircraft Y declared minimum fuel at this time. Traffic to follow on Aircraft X was given to Aircraft Y to follow. Aircraft X was on a 3 or 4 mile final at this time. Aircraft Y flew a mile downwind and then declared emergency fuel. Aircraft X was in a critical phase of flight short final and I allowed him to land but advised him minimal time on the runway and that the aircraft behind him must land. Aircraft Y was told to follow Aircraft X and cleared to land. Aircraft Y turned directly behind Aircraft X. Aircraft X was given another expedite request off of the runway. Aircraft X was turning off at the A4 intersection as Aircraft Y crossed the landing threshold. The time from the declaration of minimum fuel to emergency fuel was very short. The traffic to follow would not require Aircraft Y any undue delay. Had emergency fuel been called earlier then the citation could have been sent around before his critical phase of flight; allowing the then priority emergency aircraft a clean runway.

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.

Attributes
ACN	1685967
Time
Date	201909
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Aircraft 1
Make Model Name	British Aerospace Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Landing
Route In Use	Visual Approach
Flight Plan	IFR
Aircraft 2
Make Model Name	Cessna Citation Undifferentiated or Other Model
Operating Under FAR Part	Part 91
Flight Phase	Final Approach
Route In Use	None
Flight Plan	VFR
Person 1
Function	Local
Qualification	Air Traffic Control Developmental
Events
Anomaly	ATC Issue All Types Conflict Airborne Conflict Ground Incursion Runway Inflight Event / Encounter Fuel Issue