20VOR in I.F.R. — periodic checking

20 VOR in I.F.R. — periodic checking

20.1This clause applies only for the following navigation system of an Australian aircraft for which the holder of the certificate of registration has elected to use the CASA maintenance schedule: a VOR system installed in an aircraft equipped for flight under the I.F.R.

20.2Check and ensure that each of the following requirements is the case:

(a) based on tests made on a representative number of radials, the deviation indicator must centre when the omni bearing selector (OBS) is within 3 degrees of the selected radial;

(b) the deflection sensitivity must be such that a 5 dot left and a 5 dot right deflection must be obtained when the OBS is varied 10 degrees ± 2 degrees from the on‑course setting, and the indications must be of the correct sense;

(c) where installed, the radio magnetic indicator (RMI) reading must be within 4 degrees of the selected radial;

(d) the TO-FROM indicator must continue to show TO or FROM as originally selected when the OBS is rotated by ± 45 degrees from the selected radial;

(e) the flag must remain concealed during each of the tests mentioned in paragraphs (a) to (d), however, when the signal input level is reduced so as to cause the deviation indicator deflection to fall by 2 dots, the flag must be at least partly visible.

Note 1 A simulator may be used for the checking mentioned in paragraphs 20.2 (a) to (e).

Note 2 The sensitivities referred to in this subclause are related to a “standard” 5 dot-0-5 dot, 150 microamperes-0-150 microamperes indicator. Proportional deflections apply to other than “standard” indicators.

20.3The checks mentioned in this clause must be carried out each time a periodic inspection is carried out in accordance with paragraphs 2.4 and 2.5 in Part 2 of Schedule 5 of CAR.