In April 2010, Icelandic volcano Eyjafjallajökull erupted. The resulting ash plume caused over 95,000 flights to be canceled. The economic impact attributed to the volcano was estimated at $1.7 billion in losses. All due to the microscopic particulates that make up the ash cloud; the fine, abrasive particles erode metal, clog fuel systems, and pose a danger to all leading edges of an aircraft.
As a result of this natural disaster, aircraft manufacturers were forced to define specific limits on how much ash is considered acceptable for a jet engine to ingest without damage.
The National Aviation Association: (NAA) in conjunction with engine manufacturers, set new guidelines which allowed aircraft to fly where levels of volcanic ash are between .2 and 4 milligrams per cubic meter of air space. These levels were declared by governments, aircraft manufacturers, and airlines not to have safety implications if appropriate maintenance and ash inspection procedures were followed. Airspace in which the ash density exceeds this limit is categorized as a no fly zone. How then are airlines, traffic controllers, and aviation authorities to accurately establish ashfall advisories for future scenarios without compromising passenger safety? Read More.