Allegiant Air allegedly operated a McDonnell Douglas MD-88 on more than two dozen flights after improper engine maintenance, according to the U.S. Federal Aviation Administration (FAA), which has proposed that the carrier pay a civil penalty of $715,438. In a statement issued Wednesday, the FAA said that Allegiant had asked the agency in October 2017 if it could deactivate an MD-80's automatic reverse thrust system when the engine's exhaust gas temperature was above normal limits. The FAA's response, delivered two months later, was that "deactivating that system would be improper unless the system caused the excess temperature, because the temperature exceedance could have other causes." On April 13, 2018, the exhaust gas temperature exceeded normal limits during an Allegiant MD-88's takeoff from Roanoke, Virginia, for Orlando, Florida, the FAA said.