| Feature | Sierra Pattern | Echo Pattern | Delta Pattern |
| :--- | :--- | :--- | :--- |
| Vertical Profile | Level segment | Continuous idle descent | Climb segment |
| Thrust | Idle -> Thrust -> Idle | Idle | TOGA -> Thrust -> Idle |
| FMS Symbol | S | (no symbol, default) | E or D |
| Primary Use | Meet altitude constraints with energy loss | Fuel-efficient descent | Terrain/ATC climb requirement |
| Fuel Burn | Moderate (increased) | Minimum | High |
Assuming both engines have failed, windmill restart attempts (Procedure "A") have failed, and you are above FL 250.
Step 1: Establish Clean Configuration
Step 2: Target Speed
Step 3: Enter the Sierra Pattern
Step 4: The Energy Pump (The "S")
Step 5: Restart Attempts
The Sierra Pattern isn't just about engines; it's about survival systems.