• Ice falls – aviation and atmospheric

    It is usually assumed that ice falling from the sky is aviation related, however ice falls from aircraft are considered to be relatively rare. In comparison to the 2.5 million flights a year in UK airspace, approximately 25 ice falls per year are reported to the CAA. Some of these instances may occur because ice which has naturally formed on an aircraft at higher altitudes breaks off as it descends into warmer air.

    Occasionally, there are reports of discoloured ice which may carry an odour. This could originate from a leak from a faulty seal on a hose socket which is used to load/unload liquid from the aircraft when on the ground. This is commonly known as 'blue ice'. It should be noted that all toilet waste is held within the aircraft and collected after landing by special vehicles during the preparation for the next flight.


    Falling ice which is clear and uncontaminated may not have originated from aviation activity. Indeed there have been reports of falling chunks of ice which date back to before the existence of aircraft. Research into the phenomena is ongoing by scientists across the world but is controversial.

    Research into large falling ice in Spain began in January 2000 after unexplained chunks of ice weighing several kilogrammes fell over the country during a 10 day period. The event was unusual in that the skies were reported as cloudless during that time. A working group was set up by a planetary geologist in Madrid who was collecting and researching extreme atmospheric events. The intention was to collect and analyse fallen ice to establish its composition. From the start of this research there have been many reports collated, including some from the UK, but the research has so far been inconclusive.

    The CAA’s role

    As the safety regulator for UK civil aviation, the CAA requires UK aircraft operators to minimise the risk of ice falls by performing regular maintenance to prevent leaks and take prompt corrective action if a defect is found.

    The CAA is unable to investigate the potential origin of an ice fall, but does record reports of this nature. Such reports should be directed to the Information Management Department at the email address below.

    These reports are then entered onto the CAA's Mandatory Occurrence Reporting system, which is the UK's national database for aviation safety incident records. This database contains aviation occurrence information which can be studied and analysed to assess safety implications and trends, and where possible initiate measures to reduce risks and enhance flight safety.

    The CAA has no liability for damage which may be caused as a result of an ice fall and a reporter should initially contact their insurance company in relation to any claim.

    Although the UK CAA is not responsible for the oversight of foreign aircraft which arrive and depart from our airports daily, inspections of foreign registered aircraft are undertaken on behalf of the Department for Transport.

    Reporting an ice fall

    To report an ice fall email us providing as much detail as possible about the event. Such details should include the time, location, damage to property, injuries to persons, and a description of the ice (including its approximate mass, colour and any odour). The reporter's name and telephone number should also be included. Associated photographs can be emailed as attachments.