6 questions on this topic, recalled by candidates after DGCA sittings between 2021 and 2026. Together they were asked 10 times; the most repeated come first. Pick a year to see only what was asked that year.
A. Halo
A halo proves the cloud is made of ice crystals, which carry negligible icing risk. A corona or iridescence means supercooled water droplets - an icing cloud.
C. Cirrostratus
Halos form in thin ice-crystal cloud, typically cirrostratus. A halo in the sky often means a warm front is approaching.
B. Ice crystals
A halo is light refracted by ice crystals, giving a ring of about 22 degrees around the sun or moon, red on the inside.
B. Altostratus
A corona is a small coloured ring around the sun or moon made by diffraction through thin water-droplet cloud - altostratus or altocumulus. Cirrostratus (ice) gives a halo instead.
A. Southern Hemisphere
Australis means southern: the Southern Lights, seen in high southern latitudes. The Aurora Borealis is the Northern Lights.
B. Altocumulus (AC)
A corona is a small coloured ring close around the sun or moon, made by diffraction through WATER droplets - so the cloud is altocumulus or altostratus and carries an icing risk. A halo is the large ring made by ice crystals.
Our independent check found that more than one option can be argued for, as worded in the recall. The key gives the answer most references support.
These are candidates' recollections, not official DGCA papers: wording can differ from the paper as set. Every answer was checked against the DGCA CARs, AIP India, ICAO documents or worked calculation (independent check completed 17 Oct 2026). Spotted a mistake? Tell us and we will check it against the source.