function shipFixedShotdown(shipObj, fleetObj, formationModifier, K = 1, onCombinedFleetNum = 0) {
		var floor = specialFloor(shipObj);
		var adjustedAA = shipAdjustedAntiAir(shipObj);
		return Math.floor(
			(floor(adjustedAA) + Math.floor(
				Array.isArray(fleetObj) ? fleetCombinedAdjustedAntiAir(fleetObj.main, fleetObj.escort, formationModifier) :
					fleetAdjustedAntiAir(fleetObj, formationModifier) )
			) * K / 10 * getCombinedFleetModifier(onCombinedFleetNum)
			// according KC vita calculations, `/ 10` should be `* 0.25 * 0.8 / 2`, abyssal uses 0.75 instead of 0.8
		);
	}
@return {number} an integer indicating how many planes will be shotdown.
@param {Object} shipObj - instance of KC3Ship
@param {Object} fleetObj - instance(s) of KC3Fleet,
       if combined fleet requested, should pass nested object: {main: mainFleetObj, escort: escortFleetObj}.
@param {number} formationModifier - formation modifier, see #getFormationModifiers
@param {number} K - AACI modifier, default to 1
@param {number} onCombinedFleetNum - if ship on combined fleet, pass her fleet number (1 or 2), otherwise 0.