Quantitative Volcanic Ash. QVA forecasts provide higher resolution information on the location of ash in the atmosphere than the traditional volcanic ash advisory (VAA) products and unlike the VAA, also include ash concentration information. QVA also offers operators the opportunity to move away from the traditional ‘discernible ash’- based criteria for avoiding ash and instead use certified engine susceptibility volcanic ash exposure thresholds for flight route planning and inflight replanning. Operators with approval and procedures/practices will be able to use QVA information to fly more efficient routes while maintaining safety in accordance with their safety management program.