diff --git a/airpower/aircraft.py b/airpower/aircraft.py
index d2739bb7..6b208d76 100644
--- a/airpower/aircraft.py
+++ b/airpower/aircraft.py
@@ -1,6 +1,7 @@
 import airpower.aircrafttype as apaircrafttype
 import airpower.altitude     as apaltitude
 import airpower.azimuth      as apazimuth
+import airpower.data         as apdata
 import airpower.draw         as apdraw
 import airpower.hex          as aphex
 import airpower.hexcode      as aphexcode
@@ -35,6 +36,8 @@ def __init__(self, name, aircrafttype, hexcode, azimuth, altitude, speed, config
     self._configuration = configuration
     self._flighttype    = "LVL"
     self._powersetting  = "N"
+    self._turnfp        = 0
+    self._bank          = None
     self._fpcarry       = 0
     self._apcarry       = 0
     self._aircrafttype  = apaircrafttype.aircrafttype(aircrafttype)
@@ -235,7 +238,7 @@ def _S(self, spbrfp):
 
     self._spbrap = -spbrfp / 0.5
 
-  def _TD(self, turndirection, turnrate):
+  def _TD(self, bank, turnrate):
 
     """
     Start a turn in the specified direction and rate.
@@ -243,7 +246,7 @@ def _TD(self, turndirection, turnrate):
     
     turnrates = ["EZ", "TT", "HT", "BT", "ET"]
     assert turnrate in turnrates
-    self._turndirection = turndirection
+    self._bank = bank
     self._turnrate = turnrate
 
   def _TL(self, facingchange):
@@ -252,9 +255,17 @@ def _TL(self, facingchange):
     Turn left.
     """
 
-    if self._turnrate == None:
-      # Implicitly declare a turn rate of EZ.
-      self._TD("L", "EZ")
+    if self._bank == "R":
+      self._turnfp -= 1
+    minturnrate = apdata.determineturnrate(self._altitudeband, self._speed, self._turnfp, facingchange)
+    if minturnrate == None:
+      raise ValueError("attempt to turn faster than the maximum turn rate.")
+
+    self._turnfp = 0
+    self._bank = "L"
+
+    # Implicitly declare turn rates.
+    self._turnrate = minturnrate
 
     if self._maxturnrate == None:
       self._maxturnrate = self._turnrate
@@ -288,9 +299,17 @@ def _TR(self, facingchange):
     Turn right.
     """
 
-    if self._turnrate == None:
-      # Implicitly declare a turn rate of EZ.
-      self._TD("L", "EZ")
+    if self._bank == "L":
+      self._turnfp -= 1
+    minturnrate = apdata.determineturnrate(self._altitudeband, self._speed, self._turnfp, facingchange)
+    if minturnrate == None:
+      raise ValueError("attempt to turn faster than the maximum turn rate.")
+
+    self._turnfp = 0
+    self._bank = "R"
+
+    # Implicitly declare turn rates.
+    self._turnrate = minturnrate
 
     if self._maxturnrate == None:
       self._maxturnrate = self._turnrate
@@ -421,6 +440,8 @@ def _doaction(self, action):
       self._vfp += 1
     else:
       raise ValueError("action %s does not begin with H, D, or C." % action)
+      
+    self._turnfp += 1
 
     lastx = self._x
     lasty = self._y
diff --git a/airpower/data.py b/airpower/data.py
new file mode 100644
index 00000000..0b36062f
--- /dev/null
+++ b/airpower/data.py
@@ -0,0 +1,77 @@
+def turnrequirement(altitudeband, speed, rate):
+
+  """
+  Determine the turn requirement accoring to the Air Power Integrated Turn 
+  Charts.
+  """
+
+  speed = int(speed)
+  if speed < 8:
+    ispeed = speed - 1
+  elif speed < 10:
+    ispeed = 7
+  elif speed < 12:
+    ispeed = 8
+  elif speed < 14:
+    ispeed = 9
+  else:
+    ispeed = 10
+  
+  irate = ["EZ", "TT", "HT", "BT", "ET"].index(rate)
+
+  if altitudeband == "LO" or altitudeband == "ML":
+    raw = [
+      [ 60,  1,  2,  3,  4,  6,  8, 10, 12, 14, 16, 20, ],
+      [ 90, 60,  1,  2,  3,  4,  5,  6,  8, 19, 12, 14, ],
+      [  0, 90, 60,  1,  2,  2,  3,  4,  6,  8, 10, 12, ],
+      [  0,  0, 90, 60,  1,  1,  2,  3,  4,  6,  8, 10, ],
+      [  0,  0,  0, 60, 60,  1,  1,  2,  3,  4,  6,  8, ],
+    ][irate][ispeed]
+  elif altitudeband == "MH":
+    raw = [
+      [  1,  2,  3,  4,  6,  8, 10, 12, 14, 16, 18, 22, ],
+      [ 60,  1,  2,  3,  4,  6,  7,  8, 10, 12, 14, 18, ],
+      [  0, 60,  1,  2,  3,  4,  5,  6,  8, 10, 12, 14, ],
+      [  0,  0, 60,  1,  2,  2,  3,  4,  6,  7, 10, 11, ],
+      [  0,  0,  0, 60,  1,  1,  2,  2,  4,  5,  7,  9, ],
+    ][irate][ispeed]
+  elif altitudeband == "HI":
+    raw = [
+      [  2,  3,  4,  6,  8, 10, 12, 14, 16, 18, 20, 24, ],
+      [  1,  2,  3,  4,  5,  6,  8, 10, 12, 14, 16, 20, ],
+      [  0,  1,  2,  3,  4,  5,  6,  8,  9, 10, 13, 16, ],
+      [  0,  0,  1,  2,  3,  3,  4,  6,  7,  8, 10, 12, ],
+      [  0,  0,  0,  1,  2,  2,  3,  4,  5,  6,  8, 10, ],
+    ][irate][ispeed]
+  elif altitudeband == "EH" or "UH":
+    raw = [
+      [  3,  6,  8, 10, 12, 14, 16, 18, 20, 22, 24, 28, ],
+      [  0,  4,  6,  8, 10, 12, 13, 14, 16, 18, 21, 24, ],
+      [  0,  0,  4,  6,  7,  8, 10, 11, 13, 15, 18, 21, ],
+      [  0,  0,  0,  4,  5,  6,  7,  8, 10, 12, 14, 18, ],
+      [  0,  0,  0,  0,  4,  5,  6,  7,  9, 10, 12, 14, ],
+    ][irate][ispeed]
+    if altitudebane == "UH" and raw != 0:
+      raw += 2
+  
+  if raw == 0:
+    return None
+  else:
+    return raw
+
+def determineturnrate(altitudeband, speed, fp, facingchange):
+
+  """
+  Return the minimum turn rate capable of a turn of the given facing change 
+  after expending the given number of FPs. If no turn rate is capable, return 
+  None.
+  """
+
+  for rate in ["EZ", "TT", "HT", "BT", "ET"]:
+    requirement = turnrequirement(altitudeband, speed, rate)
+    if requirement == None:
+      return None
+    if facingchange > 30 and facingchange <= requirement:
+      return rate
+    if fp >= requirement:
+      return rate