Story highlights The branch issued a two-day temporary grounding of all T-45 Goshawks

More than 110 pilots refused to fly due to issues with the aircraft's oxygen system

(CNN) The US Navy has implemented a "safety pause" for its fleet of T-45 training jets, according to a US official, a move that comes just days after more than 100 instructional pilots refused to fly in protest of continuing issues with the aircraft's oxygen system.

The two-day temporary grounding of all T-45 Goshawks will give Navy officials time to assess the concerns related to the rising rate of "physiological episodes" affecting pilots.

Reported physiological episodes resulting in dizzyness or even blackouts have been caused by oxygen contamination, human factors -- including air sickness and vertigo, failure of the on-board oxygen generation system and the failure of other key systems -- according to testimony last week from Rear Adm. Michael Moran.

The number of physiological episodes affecting T-45 pilots per year has quadrupled since 2012 , according Moran, a troubling trend that has also been identified in Navy pilots who fly F-18s and EA-18G Growlers

But determining the root cause of the issue is complicated by the fact that more than one factor can be attributed to a single physiological event.

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