Use of altitude-encoding transponder is mandatory at Malmi
Due to the proximity of Helsinki-Vantaa’s airspace, Helsinki-Malmi’s airspace is a TMZ and RMZ where the use of an altitude-encoding transponder (C or S mode) and radio is mandatory.
It is very important that your transponder is switched to the ALT position so that it encodes pressure altitude information. Please remember that simply switching the transponder on is not enough, it must be set to the ALT position.
Filing a flight plan also remains good airmanship, even though flying in uncontrolled airspace.