[MilCom] Flight Check 87

[clifford.web]

hi guys

can anybody help me out here.

there is a USAF aircraft doing patterns around RAF Mildenhall using the callsign of Flight Check 87.
can anybody help me out and give me an id of what this aircraft may be??
if it departed from the USA, do you think it would have used this callsign enroute to Europe?
i beleive the final destination of this aircraft is ETAR later today.

any help appreciated.

Cliff