good evening!
I was making a flightplan for a flight to EHHV and found this NOTAM
WEF 1102150900 TIL 1102151600
TEMPORARY SPECIAL RULES ZONE 'VELUWE' ACTIVATED FOR EXERCISE
'CHALLENGE' AREA: 520725N0054349E - 520800N0054000E -
521300N0053400E - 521400N0053800E - 522500N0054100E -
523500N0055000E - 523000N0055800E - 522755N0055734E -
IN A CIRCLE LINE WITH CENTERPOINT 522203N0055530E
WITH RADIUS 6NM CLOCKWISE TO 521604N0055505E - 521136N0055409E ALONG
EHDL CTR BACK TO 520725N0054349E BTN GND/3000FT AMSL
AREA PROHIBITED FOR NON PARTICIPATING ACFT UNLESS APV
BY DUTCHMIL ATCC.
LOWER LIMIT: GND UPPER LIMIT: 3000FT AMSL : NOTAM EH/M0204/11
maybe some helicopter training such a op EHHV a while ago?!
Gr DJ