When departing or arriving from heliports or landing sites in the vicinity of airports especially within their CTR or ATZ, pilots filing flight plans using EuroFPL or other similar applications are advised to include in the remarks (RMK/) the supplementary information of their flight.
For a helicopter this can be added with the following format in ITEM 18 of ICAO flight plan form:
RMK/HELICOPTER SUPPLEMENTARY E.0230 P.002 R.E J.L A.RED C.PILOTNAME +306932XXXXXX
(Note that the / is replaced with a dot . or else the system will reject it).
This is because the supplementary information is not passed to the ATC of the airport if it is NOT set as origin or destination.
In Greece, although we address the correct AFTN messages for the flight, the ATC controlling the airspace of the landing site, usually wants to send again AFTN messages but misses supplementary information. Although this is not a common practice for Europe in order to overcome unnecessary communications we can use the above addition in remarks.
In some occasions we were told by ATC to add as departure the airport although the takeoff was outside the airport but within the CTR in order for them to receive the supplementary information. This is violating regulations and should not be accepted by the crews.
When not departing/arriving from airdromes with ICAO code, you should always use ZZZZ with the appropriate DEP/ or DEST/ in ITEM 18. OTHER INFORMATION like: DEST/KITHNOS 3726N02426E with any remarks under RMK/ required as mentioned above.
More information for correctly filing the ICAO flight plan: Instructions for ICAO flight plan form by EuroFPL (2400 downloads)