B737-700 captain reported a visual illusion on the runway due to discolored asphalt.

Attributes
ACN	1685981
Time
Date	201909
Place
Locale Reference	TNCA.Airport
State Reference	FO
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Final Approach Landing
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
Experience	Flight Crew Last 90 Days 240 Flight Crew Type 10000
Events
Anomaly	Inflight Event / Encounter Other / Unknown

Narrative:

Runway 11 at aua has the visual illusion of a vehicle on the runway at midfield. As we passed through 1;000 feet on final approach to aua; the pilot flying said to me 'I think that there might be a vehicle on the runway'. I could immediately observe a dark; vehicle-sized object clearly contrasted on the concrete runway surface in the first third of the runway. I asked tower to verify a clear runway. The tower controller complied and offered that we were cleared to perform a go-around; if we deemed that to be necessary. As we got within 200 feet of touchdown; I focused hard and could discern that it was; in fact; a patch of asphalt (or paint) on the concrete surface. As we entered the flare; it was totally obviously not a vehicle or any threatening object.

Original NASA ASRS Text

Title: B737-700 Captain reported a visual illusion on the runway due to discolored asphalt.

Narrative: Runway 11 at AUA has the visual illusion of a vehicle on the runway at midfield. As we passed through 1;000 feet on final approach to AUA; the Pilot Flying said to me 'I think that there might be a vehicle on the runway'. I could immediately observe a dark; vehicle-sized object clearly contrasted on the concrete runway surface in the first third of the runway. I asked Tower to verify a clear runway. The Tower Controller complied and offered that we were cleared to perform a go-around; if we deemed that to be necessary. As we got within 200 feet of touchdown; I focused hard and could discern that it was; in fact; a patch of asphalt (or paint) on the concrete surface. As we entered the flare; it was totally obviously NOT a vehicle or any threatening object.

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.