> ## Documentation Index
> Fetch the complete documentation index at: https://www.narev.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Preliminary preflight — part 1

> Preliminary preflight — part 1: conditions, actions and checks for the Boeing 737-800.

Use this procedure when its prerequisites apply. Confirm each required aircraft state before acknowledging the corresponding checklist item.

## General

Complete the preliminary, CDU, captain and first-officer procedures in the applicable ground configuration. Retain the side-specific requirements. A captain instrument or control does not satisfy an independent first-officer or standby check.

Use the assigned detailed panel procedures for Set, Check, Test and Pass requirements. Observe the specified result and restore the required operating configuration after each actual cockpit test. Do not operate a system merely because its control appears in the reference list.

Complete loading, performance preparation and the required equipment checks before progressing to the dependent departure procedures. Where an item requires an external inspection or crew adjustment, retain the assigned verification or explicit scenario exclusion.

### 1. Battery switch — **Guard closed**

Verify the battery-switch guard is closed. Verify guard position independently of battery-switch position.

> **Checks and evidence**
>
> **Expected response:** Guard closed
>
> **Verification:** Confirm the guard itself through an approved observation path; inspect battery position separately.

### 2. GPU or APU — **On bus**

Connect the assigned GPU or APU electrical source to the bus. Verify the selected source is supplying the bus.

> **Checks and evidence**
>
> **Expected response:** On bus
>
> **Verification:** Require source availability and on-bus evidence for the chosen source.

### 3. IRS mode selector — **Off, then nav**

Move each applicable IRS mode selector OFF, then NAV. Verify the ordered selector change and the required position/alignment indications.

> **Checks and evidence**
>
> **Expected response:** OFF, then NAV
>
> **Verification:** Require both applicable selector positions and, when NAV is required, the approved alignment/position-initialization checks.

### 4. Voice recorder — **As needed**

Set the voice recorder as required for the installed equipment and assigned operation.

> **Checks and evidence**
>
> **Expected response:** As needed
>
> **Verification:** Use a configuration record and the recorder state where fitted.

### 5. Flight deck access — **Guard closed**

Verify the flight-deck-access guard is closed. Door position does not establish guard position.

> **Checks and evidence**
>
> **Expected response:** Guard closed
>
> **Verification:** Observe the required guard state independently of door state.

### 6. Emergency equipment — **Check**

Check the emergency equipment required by the assigned simulator scenario. Retain the equipment-check evidence or authorized exclusion.

> **Checks and evidence**
>
> **Expected response:** Check
>
> **Verification:** Record the actual evidence or the explicit scenario-level exclusion.

### 7. ELT light/switch — **Guard closed**

Verify the ELT light/switch guard is closed. Do not activate the ELT to satisfy this check.

> **Checks and evidence**
>
> **Expected response:** Guard closed
>
> **Verification:** Observe guard closure and any required ELT indication.

### 8. PSEU light — **Extinguished**

Verify the PSEU light is extinguished, using a valid powered indication.

> **Checks and evidence**
>
> **Expected response:** Extinguished
>
> **Verification:** A specific PSEU indication, not absence of MASTER CAUTION.

### 9. GPS light — **Extinguished**

Verify the GPS light is extinguished. A displayed position estimate is not the required annunciator.

> **Checks and evidence**
>
> **Expected response:** Extinguished
>
> **Verification:** A specific valid GPS-annunciator observation.

## Continue after this procedure

Continue to [Preliminary preflight — part 2](https://www.narev.ai/docs/irl-gym/aircraft/procedures/preliminary-preflight-2.md). The checklist adds no condition between these parts; the next part’s individual step conditions still apply.


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