The US FAA announced on Thursday that flights cancellations caused by volcanic ash during April will not affect slot assignments at two major US gateways.
The FAA says it "will grant relief from the use-or-lose requirements for all carriers operating scheduled flights at JFK and EWR to or from points in Europe during the period from April 14 through 26, 2010."
The ruling is in response to a request made by Continental Airlines, which has an international gateway at Newark, in May.
The carrier argued that cancellations should be exempt due to the ash created by the eruption of Iceland's Eyjafjallajökul volcano in April.
Currently, carriers must utilize slots at least eighty percent of the time, or they will be withdrawn.
The agency believes that allowing slots to go unused 20% of the time accounts for "routine" cancellations. The FAA concluded that ash-related cancellations are "unusual circumstances" that justify a "limited waiver of the minimum slot usage."
In addition, the FAA ruled that it will "grant similar relief on an individual carrier basis" to airlines that face cancellations due to ash through 30 October.
Carriers must contact the FAA Slot Administration Office to receive a waiver.