Airlines relying on HF communications to keep in contact with their aircraft are in for a bumpy ride. With sunspot activity increasing as we reach the current 11-year peak (predicted to be next year) HF is going to become increasingly unreliable. Over the past few weeks intense solar flares have caused widespread HF radio blackouts, and it is going to get worse. The problem comes when masses of particles are ejected from the sun's surface. The increase in flares is linked to the increase in sunspots, although the physics is nott completely understood.
PARTICLES
The particles stream towards earth and are funnelled towards the poles by the earth's magnetic field, where they cause massive ionisation. This blacks out HF radio, sometimes for hours, although people in extreme northern or southern latitudes may get to see aurora. The blackouts do not affect VHF, UHF or satellite communications, hence the industry's desire to move away from HF. But HF is still used, especially on transatlantic links, so air-to-ground communication could remain difficult for some time.
Source: Flight Daily News
