> ## 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.

# Engine start — part 1

> Engine start — 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

Start **engine 2**, then **engine 1**. Begin engine 1 start only after engine 2 is stable. Complete the applicable preceding procedures and establish the assigned start-readiness and air-supply conditions before selecting GRD.

### Start controls

**Caution:** The start lever controls fuel admission. `SET_THROTTLE` controls thrust levers and is not the control for start-lever IDLE.

At **25% N2**, move the associated start lever to IDLE. Observe the N2 condition during the current start; do not act from an old sample or use thrust-lever percentage as N2.

At **56% N2**, **verify** that the associated engine start switch has returned to OFF. Do not select `ENG1_START_OFF` or `ENG2_START_OFF` merely to satisfy this verification. N2 reaching 56% does not prove switch return or starter-valve closure.

Verify the associated **START VALVE OPEN** indication is extinguished, then announce starter cutout. Keep switch return, valve indication, cutout announcement and engine stability as separate requirements.

### Engine 2 stable

Before the engine 1 start sequence, verify engine 2 stable against the assigned criteria. The stable condition applies to the entire engine 1 start sequence, including the announcement and GRD selection, even where later item text does not repeat it. The checklist supplies no numerical stability band or dwell time.

### Completion and continuation

Continue through all three pages. The source transitions connect part 1 to part 2 and part 2 to part 3; they do not override an item condition. After part 3 and the applicable readiness checks are complete, select Before Taxi, [Before Taxi](https://www.narev.ai/docs/irl-gym/aircraft/procedures/before-taxi-1.md).

If required start indications or instructions are unavailable, do not advance through the normal sequence. Use the assigned supervisory or non-normal start procedure. This chapter does not specify hot-start, hung-start, no-lightoff, starter-limit or abnormal-start recovery actions.

### 1. Engine 2 start — **Note**

Start engine 2 first.

> **Checks and evidence**
>
> **Expected response:** None
>
> **Verification:** Acknowledge this note. Do not record it as a completed physical check.

### 2. Pack switches — **Off**

Set both pack switches OFF. Verify both switch positions before selecting engine 2 GRD.

> **Checks and evidence**
>
> **Expected response:** OFF
>
> **Verification:** Both pack switch positions indicate OFF.

### 3. Engine 2 start sequence — **Announce**

Announce engine 2 start through the assigned crew/ground communication channel before selecting GRD.

> **Checks and evidence**
>
> **Expected response:** Announce
>
> **Verification:** The engine 2 start announcement has been transmitted through the assigned channel.

### 4. Engine 2 start switch — **GRD**

Select engine 2 start switch GRD. Monitor the associated engine indications.

> **Checks and evidence**
>
> **Expected response:** GRD
>
> **Verification:** Engine 2 start switch is in GRD. N2 increase is verified by the following item.

### 5. Engine 2 N2 RPM increases — **Verify**

Observe successive valid engine 2 N2 indications. Verify increasing N2 before proceeding to the fuel-admission condition.

> **Checks and evidence**
>
> **Expected response:** Verify
>
> **Verification:** Engine 2 N2 indications show an increase during the current start.

### 6. Engine 2 at 25% N2: Engine 2 start lever — **Idle**

**Condition:** Engine 2 at 25% N2.

When engine 2 N2 reaches 25% during the current start, move engine 2 start lever to IDLE. Do not move the forward thrust lever to satisfy this item.

> **Checks and evidence**
>
> **When:** Engine 2 at 25% N2.
>
> **Expected response:** IDLE
>
> **Verification:** The 25% N2 condition is observed before fuel admission, and engine 2 start-lever IDLE is confirmed.

### 7. Engine 2 at 56% N2: Engine 2 start switch OFF — **Verify**

**Condition:** Engine 2 at 56% N2.

When engine 2 N2 reaches 56%, verify that engine 2 start switch has returned to OFF. This is a verification item; do not select OFF merely to obtain the required indication.

> **Checks and evidence**
>
> **When:** Engine 2 at 56% N2.
>
> **Expected response:** Verify
>
> **Verification:** The 56% N2 event and the engine 2 start-switch OFF indication are observed independently.

## Continue after this procedure

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


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