Blue ice (precipitation)
Blue ice in the context of aviation is frozen sewage material leaked mid-flight from commercial aircraft lavatory waste systems, a biowaste mixture of human waste and liquid disinfectant that freezes at high altitude. The name comes from the blue color of the disinfectant. Airlines are not allowed to dump their waste tanks in mid-flight, and pilots have no mechanism by which to do so; however, leaks can occur.
Danger of ground impact
There were at least 27 documented incidents of blue ice impacts in the United States between 1979 and 2003. These incidents typically happen under airport landing paths as the mass warms sufficiently to detach from the plane during its descent. A rare incident of falling blue ice causing damage to the roof of a home was reported on October 20, 2006 in Chino, California. A similar incident was reported in Leicester, UK, in 2007.
In 1971, a chunk of ice from an aircraft tore a large hole in the roof of the Essex Street Chapel in Kensington, London, and was one trigger for the demolition of the building. In November 2011 a chunk of ice, the size of an orange, broke through the roof of a private house in Ratingen-Hösel, Germany.
In February 2013 a "football sized" ball of blue ice smashed through a conservatory roof in Clanfield, Hampshire causing around £10,000 worth of damage.
Danger to aircraft
Blue ice can also be dangerous to the aircraft itself; the National Transportation Safety Board has recorded three very similar incidents where waste from lavatories caused damage to the leaking aircraft. All involved Boeing 727s, and in all cases waste from a leaking lavatory hit one of the engines, mounted at the rear of the aircraft, causing a power loss. The flights made safe emergency landings with the two remaining engines. Nobody was injured. Only one report specifically mentions ice, while another mentions "soft body FOD" (foreign object damage), indicating that in this case the "blue fluid" was not frozen.
In popular culture
Blue ice became known to many people from the last 2003 episode of the HBO series Six Feet Under, in which a foot-sized chunk drops on an innocent bystander. A similar incident occurs in the 1996 television series Early Edition episode “Frostbite” when the main character saves a man from being crushed by a chunk of blue ice. It was also mentioned in The Big Bang Theory. This also happened in an episode of CSI: NY. The title of the 1992 film Blue Ice is a reference to the phenomenon. The 2001 film Joe Dirt finds the title character (played by David Spade) proudly displaying a large chunk of "blue ice" which he has mistaken for a meteorite, and the topic has also been covered on the TV show MANswers. Blue ice was also featured in an episode of the television show Mythbusters. Blue ice is a cause of death in season 4 of 1000 Ways to Die.
- Gumz, Jondi (February 12, 2003). "Another mysterious chunk of blue ice hits". Santa Cruz Sentinel. Retrieved 2007-01-04. "The Living in Everyday Earth Web site reports there have been at least 27 documented blue-ice incidents nationally in the past 24 years."[dead link]
- "Toilet ice rips hole in couple's roof". Fox News. Associated Press. October 21, 2006. Retrieved 2011-01-05.
- Frozen Pee Anyone? BBC
- Essex Church in Kensington 1887-1987: History of a Unitarian Cause p25, by Raymond Williams
-  BBC
- "April 30, 1974 Incident". NTSB. Retrieved 2011-04-16.
- "April 16, 1985 Incident". NTSB. Retrieved 2011-04-16.
- "January 04, 1990 Incident". NTSB. Retrieved 2011-04-16.
- Derek Elley (October 14, 1992). "Blue Ice Review". Variety. Retrieved 2009-03-26.
- Mark Belko (November 21, 2002). "The sky is falling? Uh, not exactly". Pittsburgh Post-Gazette. Retrieved 2007-01-04.
- "It's a bird, it's a plane, it's a block of ice?". Bay News 9.com. January 28, 2007.[dead link]
- "Frozen Jetliner Waste Smashes Into Home". United Press International. April 14, 2008.