GM3 NCO.OP.110 Aerodrome operating minima – aeroplanes and helicopters

CAA ORS9 Decision No. 47

Text in magenta in force from 30 October 2025

CRITERIA FOR ESTABLISHING RVR/CMV

  1. In order to qualify for the lowest allowable values of RVR/CMV specified in Table 3.A, the instrument approach should meet at least the following facility requirements and associated conditions:

    1. Instrument approaches with designated vertical profile up to and including 4.5° for Category A and B aeroplanes, or 3.77° for Category C and D aeroplanes, where the facilities are:

      1. instrument landing system (ILS)/microwave landing system (MLS)/GBAS landing system (GLS)/precision approach radar (PAR); or

      2. approach procedure with vertical guidance (APV); and where the final approach track is offset by not more than 15° for Category A and B aeroplanes or by not more than 5° for Category C and D aeroplanes.

    2. Instrument approach operations flown using the CDFA technique with a nominal vertical profile, up to and including 4.5° for Category A and B aeroplanes, or 3.77° for Category C and D aeroplanes, where the facilities are non-directional beacon (NDB), NDB/distance measuring equipment (DME), VHF omnidirectional radio range (VOR), VOR/DME, localiser (LOC), LOC/DME, VHF direction finder (VDF), surveillance radar approach (SRA) or global navigation satellite system (GNSS)/lateral navigation (LNAV), with a final approach segment of at least 3 NM, which also fulfil the following criteria:

      1. the final approach track is offset by not more than 15° for Category A and B aeroplanes or by not more than 5° for Category C and D aeroplanes;

      2. the final approach fix (FAF) or another appropriate fix where descent is initiated is available, or distance to threshold (THR) is available by flight management system (FMS)/area navigation (NDB/DME) or DME; and

      3. the missed approach point (MAPt) is determined by timing, the distance from FAF to THR is ≤ 8 NM.

    3. Instrument approaches where the facilities are NDB, NDB/DME, VOR, VOR/DME, LOC, LOC/DME, VDF, SRA or GNSS/LNAV, not fulfilling the criteria in (a)(2), or with an minimum descent height (MDH) ≥ 1 200 ft.

  2. The missed approach operation, after an approach operation has been flown using the CDFA technique, should be executed when reaching the decision height/altitude (DH/A) or the MAPt, whichever occurs first. The lateral part of the missed approach procedure should be flown via the MAPt unless otherwise stated on the approach chart.

The text below will replace the text above on 30 October 2025:

MEANS TO DETERMINE THE REQUIRED RVR BASED ON DH AND LIGHTING FACILITIES

  1. The values in Table 2 are derived from the formula below:

    RVR (m) = [(DH/MDH (ft) x 0.3048)/tanα] — length of approach lights (m),

    where α is the calculation angle, being a default value of 3.00° increasing in steps of 0.10° for each 10 ft of DH or MDH up to 260 ft, then increasing in steps of 0.10° for each 20 ft of DH or MDH up to 3.77° and then remaining constant. A lower RVR limit of 550 m and an upper RVR limit of 2 400 m has been applied to the table.”

  2. The lighting system classes in Table 2 have the meaning specified in Table 6.