diff --git a/.github/workflows/test_benchmarks.yml b/.github/workflows/test_benchmarks.yml
index bc2a5dce3..5b18b2c2c 100644
--- a/.github/workflows/test_benchmarks.yml
+++ b/.github/workflows/test_benchmarks.yml
@@ -18,7 +18,7 @@ on:
 jobs:
 
   latest_benchmarks:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     timeout-minutes: 90
 
     steps:
diff --git a/.github/workflows/test_docs.yml b/.github/workflows/test_docs.yml
index 31977627d..287fc9510 100644
--- a/.github/workflows/test_docs.yml
+++ b/.github/workflows/test_docs.yml
@@ -18,7 +18,7 @@ on:
 jobs:
 
   latest_docs:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     timeout-minutes: 90
 
     steps:
diff --git a/.github/workflows/test_workflow.yml b/.github/workflows/test_workflow.yml
index 7f028d92d..ce705719b 100644
--- a/.github/workflows/test_workflow.yml
+++ b/.github/workflows/test_workflow.yml
@@ -18,7 +18,7 @@ jobs:
 
   pre_commit:
     # run pre-commit checks
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     steps:
     - uses: actions/checkout@v4
@@ -28,7 +28,7 @@ jobs:
     - uses: pre-commit/action@v3.0.1
 
   test_ubuntu:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/test_workflow_dev_deps.yml b/.github/workflows/test_workflow_dev_deps.yml
index 92daf1528..fed5ad912 100644
--- a/.github/workflows/test_workflow_dev_deps.yml
+++ b/.github/workflows/test_workflow_dev_deps.yml
@@ -14,7 +14,7 @@ on:
 jobs:
 
   test_ubuntu:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
     strategy:
       fail-fast: false
       matrix:
diff --git a/.github/workflows/test_workflow_no_dev_install.yml b/.github/workflows/test_workflow_no_dev_install.yml
index dd8f1f67e..d58ffea15 100644
--- a/.github/workflows/test_workflow_no_dev_install.yml
+++ b/.github/workflows/test_workflow_no_dev_install.yml
@@ -17,7 +17,7 @@ on:
 jobs:
 
   test_ubuntu_no_dev_install:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-22.04
 
     timeout-minutes: 90
 
diff --git a/aviary/utils/preprocessors.py b/aviary/utils/preprocessors.py
index 070f20de3..bf555c8d0 100644
--- a/aviary/utils/preprocessors.py
+++ b/aviary/utils/preprocessors.py
@@ -400,21 +400,6 @@ def preprocess_propulsion(aviary_options: AviaryValues, engine_models: list = No
     aviary_options.set_val(Aircraft.Engine.NUM_WING_ENGINES, num_wing_engines_all)
     aviary_options.set_val(Aircraft.Engine.NUM_FUSELAGE_ENGINES, num_fuse_engines_all)
 
-    # Update nacelle-related variables in aero to be sized to the number of
-    # engine types.
-    if num_engine_type > 1:
-
-        keys = [
-            Aircraft.Nacelle.LAMINAR_FLOW_LOWER,
-            Aircraft.Nacelle.LAMINAR_FLOW_UPPER
-        ]
-
-        for var in keys:
-            try:
-                aviary_options.get_val(var)
-            except KeyError:
-                aviary_options.set_val(var, np.zeros(num_engine_type))
-
     if Mission.Summary.FUEL_FLOW_SCALER not in aviary_options:
         aviary_options.set_val(Mission.Summary.FUEL_FLOW_SCALER, 1.0)