diff --git a/roles/preflight/defaults/main.yml b/roles/preflight/defaults/main.yml
index db10a6b..a0b9ac4 100644
--- a/roles/preflight/defaults/main.yml
+++ b/roles/preflight/defaults/main.yml
@@ -1,2 +1,5 @@
 ---
-# preflight default variables
+min_free_disk_percent: 20
+max_load_multiplier: 2
+change_freeze: false
+host_reboot_required: false
diff --git a/roles/preflight/tasks/main.yml b/roles/preflight/tasks/main.yml
index 872eb0d..963278b 100644
--- a/roles/preflight/tasks/main.yml
+++ b/roles/preflight/tasks/main.yml
@@ -1,6 +1,81 @@
 ---
-# preflight tasks
-# Implementation to follow
-- name: Placeholder
+- name: Check change freeze
+  ansible.builtin.assert:
+    that:
+      - change_freeze == false
+    fail_msg: "FROZEN: {{ inventory_hostname }} is under a change freeze. Aborting."
+    success_msg: "Change freeze check passed"
+
+- name: Check disk space on critical mountpoints
+  ansible.builtin.shell: |
+    df {{ item }} --output=pcent | tail -1 | tr -d ' %'
+  register: disk_usage
+  changed_when: false
+  loop:
+    - /
+    - /var
+    - /boot
+  ignore_errors: true
+
+- name: Assert disk space is sufficient
+  ansible.builtin.assert:
+    that:
+      - item.stdout | int < (100 - min_free_disk_percent)
+    fail_msg: "DISK: {{ item.item }} is {{ item.stdout }}% full — minimum {{ min_free_disk_percent }}% free required"
+    success_msg: "Disk OK: {{ item.item }} is {{ item.stdout }}% used"
+  loop: "{{ disk_usage.results }}"
+  when: item.rc == 0
+
+- name: Get load average
+  ansible.builtin.shell: |
+    cat /proc/loadavg | awk '{print $3}'
+  register: load_avg
+  changed_when: false
+
+- name: Get CPU count
+  ansible.builtin.shell: |
+    nproc
+  register: cpu_count
+  changed_when: false
+
+- name: Assert load average is acceptable
+  ansible.builtin.assert:
+    that:
+      - load_avg.stdout | float < (cpu_count.stdout | int * max_load_multiplier)
+    fail_msg: "LOAD: 15min load average {{ load_avg.stdout }} exceeds threshold ({{ cpu_count.stdout }} CPUs x {{ max_load_multiplier }})"
+    success_msg: "Load average OK: {{ load_avg.stdout }} ({{ cpu_count.stdout }} CPUs)"
+
+- name: Check for pending reboot (Debian/Ubuntu)
+  ansible.builtin.stat:
+    path: /var/run/reboot-required
+  register: reboot_required
+  when: ansible_os_family == "Debian"
+
+- name: Warn if reboot is pending
   ansible.builtin.debug:
-    msg: "preflight role - tasks to be implemented"
+    msg: "WARNING: {{ inventory_hostname }} has a pending reboot. Patching will proceed but reboot required afterwards."
+  when:
+    - ansible_os_family == "Debian"
+    - reboot_required.stat.exists
+
+- name: Set reboot_required fact (Debian)
+  ansible.builtin.set_fact:
+    host_reboot_required: "{{ reboot_required.stat.exists | default(false) }}"
+  when: ansible_os_family == "Debian"
+
+- name: Check for pending reboot (RHEL/CentOS)
+  ansible.builtin.shell: |
+    needs-restarting -r
+  register: rhel_reboot_check
+  changed_when: false
+  failed_when: false
+  when: ansible_os_family == "RedHat"
+
+- name: Set reboot_required fact (RHEL)
+  ansible.builtin.set_fact:
+    host_reboot_required: "{{ rhel_reboot_check.rc == 1 }}"
+  when: ansible_os_family == "RedHat"
+
+- name: Preflight complete
+  ansible.builtin.debug:
+    msg: "Preflight passed for {{ inventory_hostname }} — proceeding with maintenance"