diff --git a/openap/gen.py b/openap/gen.py
index a000b7c..8b20743 100644
--- a/openap/gen.py
+++ b/openap/gen.py
@@ -80,6 +80,8 @@ def climb(self, **kwargs) -> pd.DataFrame:
             cas_const_cl: Constant CAS for climb (kt).
             mach_const_cl: Constant Mach for climb.
             alt_cr: Target cruise altitude (ft).
+            airport_elevation: Airport elevation (ft).
+
             random: Generate trajectory with random parameters. Defaults to False.
 
         Returns:
@@ -119,6 +121,11 @@ def climb(self, **kwargs) -> pd.DataFrame:
                 / aero.ft,
             )
 
+            airport_elevation = kwargs.get(
+                "airport_elevation",
+                0
+            )
+
             vs_pre_constcas = self.rng.uniform(
                 self.wrap.climb_vs_pre_concas()["minimum"],
                 self.wrap.climb_vs_pre_concas()["maximum"],
@@ -147,6 +154,11 @@ def climb(self, **kwargs) -> pd.DataFrame:
             alt_cr = kwargs.get(
                 "alt_cr", self.wrap.cruise_alt()["default"] * 1000 / aero.ft
             )
+
+            airport_elevation = kwargs.get(
+                "airport_elevation",
+                0
+            ) * aero.ft
             vs_pre_constcas = self.wrap.climb_vs_pre_concas()["default"]
             vs_constcas = self.wrap.climb_vs_concas()["default"]
             vs_constmach = self.wrap.climb_vs_conmach()["default"]
@@ -164,7 +176,7 @@ def climb(self, **kwargs) -> pd.DataFrame:
         # intitial conditions
         t = 0
         tcr = 0
-        h = 0
+        h = airport_elevation
         s = 0
         v = 0
         vs = 0
@@ -181,7 +193,7 @@ def climb(self, **kwargs) -> pd.DataFrame:
                 v = v + a_tof * dt
                 vs = 0
                 seg = "TO"
-            elif h < 1500 * aero.ft:
+            elif h < airport_elevation + 1500 * aero.ft:
                 v = v + a * dt
                 if aero.tas2cas(v, h) >= vcas_const:
                     v = aero.cas2tas(vcas_const, h)
@@ -237,11 +249,13 @@ def climb(self, **kwargs) -> pd.DataFrame:
     def descent(self, **kwargs) -> pd.DataFrame:
         """Generate descent trajectory based on WRAP model.
 
+
         Keyword Args:
             dt: Time step in seconds. Defaults to 1.
             cas_const_de: Constant CAS for descent (kt).
             mach_const_de: Constant Mach for descent.
             alt_cr: Top of descent altitude (ft).
+            arr_airport_elevation (float): airport elevation(ft).
             random: Generate trajectory with random parameters. Defaults to False.
             withcr: Include a short cruise segment of 60 seconds. Defaults to True.
 
@@ -284,6 +298,11 @@ def descent(self, **kwargs) -> pd.DataFrame:
                 / aero.kts,
             )
 
+            arr_airport_elevation = kwargs.get(
+                "arr_airport_elevation",
+                0
+            ) * aero.ft
+
             vs_constmach = self.rng.uniform(
                 self.wrap.descent_vs_conmach()["minimum"],
                 self.wrap.descent_vs_conmach()["maximum"],
@@ -309,6 +328,12 @@ def descent(self, **kwargs) -> pd.DataFrame:
             alt_cr = kwargs.get(
                 "alt_cr", self.wrap.cruise_alt()["default"] * 1000 / aero.ft
             )
+            
+            arr_airport_elevation = kwargs.get(
+                "arr_airport_elevation",
+                0
+            ) * aero.ft
+            
             vs_constmach = self.wrap.descent_vs_conmach()["default"]
             vs_constcas = self.wrap.descent_vs_concas()["default"]
             vs_post_constcas = self.wrap.descent_vs_post_concas()["default"]
@@ -350,18 +375,18 @@ def descent(self, **kwargs) -> pd.DataFrame:
                 v = aero.cas2tas(vcas_const, h)
                 vs = vs_constcas
                 seg = "CAS"
-            elif h > 1000 * aero.ft:
+            elif h > arr_airport_elevation + 1000 * aero.ft:
                 v = v + a * dt
                 if aero.tas2cas(v, h) < v_app:
                     v = aero.cas2tas(v_app, h)
                 vs = vs_post_constcas
                 seg = "POST-CAS"
-            elif h > 0:
+            elif h > arr_airport_elevation:
                 v = v_app
                 vs = vs_fa
                 seg = "FA"
             else:
-                h = 0
+                h = arr_airport_elevation
                 vs = 0
                 v = v + a_lnd * dt
                 seg = "LD"
@@ -492,7 +517,7 @@ def cruise(self, **kwargs) -> pd.DataFrame:
 
     def complete(self, **kwargs) -> pd.DataFrame:
         """Generate a complete trajectory based on WRAP model.
-
+        
         Keyword Args:
             dt: Time step in seconds. Defaults to 1.
             cas_const_cl: Constant CAS for climb (kt).
@@ -502,6 +527,8 @@ def complete(self, **kwargs) -> pd.DataFrame:
             range_cr: Cruise range (km).
             alt_cr: Target cruise altitude (ft).
             mach_cr: Cruise Mach number.
+            airport_elevation (float): Airport elevation (ft).
+            arr_airport_elevation(float): Arrival airport elevation(ft).
             random: Generate trajectory with random parameters. Defaults to False.
 
         Returns: