Hi All, I've never got this, obviously to do with Instrument Approaches, What are they and when do we use RADIO? When do we use BARO? Does it tell me on an ILS Plate? I would really appreciate a simple explanation, Many Thanks, Tristan

RADIO is ONLY used for ILS Cat II/III.If on the approach plate says RA (radio altitude) in the section where decision heights are shown then this is an indication that radio must be used.

Thankyou! Very much appreciated!!

The RADIO is using the radio altimeter for minimums. The BARO is using the barometric altimeter for minimums.

BARO=Altitude, RADIO=Height. A Height is a RADIO messured distance from the airplane to the ground below you. An Altitude is a barometric messured altitude from the airplane and down to sealevel reffering to a local QNH/US barometrci setting (forget the term). So if the appraoch chart is reffering to a Decision Altitude, you then set the figure using the BARO and using the local QNH/US baro setting.If the approach chart is reffering to a Decision Height, you set that figure using the RADIO setting.Many approach charts refer to both Altitude and Height, where the Height is often in brackets(). See the Copenhagen (EKCH) chart for ILS CATI+II+III to RWY 22L, linked below. The chart is reffering to OCA (H), which is the Obstacle Clearence Altitude (Height) - the level to wich you can descent on your current CAT appr. without having visual reference to the ground; in other words: If you reach the OCA (H), and do not have visual reference - G/A.http://www.slv.dk/Do..._II_III)_en.pdf Hope this cleared things up for you... Mas