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PRIMARY CODE: UNIDENTIFIED AERIAL PHENOMENON

Date: 19:49 05/20/2021

Paged: NO

Status: Closed

POD: DEN

Reporting Facility: ZDC

REMARKS

Mode C intruder alert observed by controller moving slowly to the NW 50 SE of RIC @ FL400. 2 aircraft at FL390 were queried. First aircraft reported an unidentified aerial phenomenon just above them at FL400 and second aircraft (some time later) saw contrails above them at FL400. HQ DEN requested CONR to look at replay. CONR observed primary target off the HPW031 at 12 NM. The unknown phenomenon was traveling NW bound at approximately FL400. HQ DEN asked AMOC for replay and negative results found. ZDC reported calls signs of two previous aircraft as SCX3036 and PPJ510.