diff --git a/aman/types/PerformanceData.py b/aman/types/PerformanceData.py
index 149a7e9..87b0a4e 100644
--- a/aman/types/PerformanceData.py
+++ b/aman/types/PerformanceData.py
@@ -11,6 +11,16 @@ class PerformanceData:
         self.rodAboveFL100 = 0.0
         self.rodBelowFL100 = 2000.0
 
+    def ias(self, altitude, distance):
+        if 24000 >= altitude:
+            return self.speedAboveFL240
+        elif 10000 >= altitude:
+            return self.speedAboveFL100
+        elif 5 >= distance:
+            return self.speedApproach
+        else:
+            return 220
+
     def __str__(self):
         return 'ICAO: ' + self.icao + ', FL240: ' + str(self.rodAboveFL240) + '@' + str(self.speedAboveFL240) + \
                ', +FL100: ' + str(self.rodAboveFL100) + '@' + str(self.speedAboveFL100) + \