a device similar to a VASI (visual approach slope indicator) used for fixed-wing aircraft
unit showing four signals: “above slope”, “on slope”, “slightly below” and “below” for the pilot based on the approach angle of the helicopter, mõõteseade, mis näitab nelja signaali: "kalde kohal", "nõlval", "veidi allpool" ja "allpool", mis põhinevad kopteri lähenemisnurgal
HAPI . EKI terminibaas Esterm. Институт эстонского языка, Сынавееб 2026. https://sonaveeb.ee/search/unif//esterm/HAPI/1/est (01.07.2026)
