# Presentation: 224094

## SWA Flight 1248Landing Performance Issues 

- Kevin J. Renze, Ph.D.
- Aircraft Performance Group Chairman

*Office of Research and Engineering*** **

## Landing Performance Study

- Goals:
- Quantify runway surface conditions
- Determine airplane stopping capability
- Basis:
- FDR data from five SWA aircraft
- Boeing 737-700 engineering simulation
- Method:
- Determine airplane braking coefficient
- Calculate stopping margin for various
- 	stopping scenarios

## Runway Surface Conditions

**Runway Surface Conditions**

## Runway Surface Conditions

**Runway Surface Conditions**

## Runway Surface Conditions

**Runway Surface Conditions**

## Runway Surface Conditions

**Runway Surface Conditions**

## Runway Surface Conditions

**Runway Surface Conditions**

## Runway Surface Conditions

**Runway Surface Conditions**

## Runway Surface Conditions

**Runway Surface Conditions**

## Stopping Margin Study

- Specify deceleration configuration
- Ground spoilers (per accident)
- Wheel brakes (per accident)
- Reverse thrust (varied)
- Thrust reverser deployment timing
- Target reverse thrust setting
- Target reverser stowage speeds
- Compare stopping margin

## Airplane Stopping Capability

| Reverse Thrust Configuration | Stopping Margin (feet) | Conclusion/ Runway Exit Speed (knots) |
| --- | --- | --- |
| SWA practice [target 80/60 stow]  | -1310 | Overrun (44) |

## Airplane Stopping Capability

| Reverse Thrust Configuration | Stopping Margin (feet) | Conclusion/ Runway Exit Speed (knots) |
| --- | --- | --- |
| SWA practice [target 80/60 stow]  | -1310 | Overrun (44) |
| Flight 1248 [accident conditions] | -790 | Overrun (50) |

## Airplane Stopping Capability

| Reverse Thrust Configuration | Stopping Margin (feet) | Conclusion/ Runway Exit Speed (knots) |
| --- | --- | --- |
| SWA practice [target 80/60 stow]  | -1310 | Overrun (44) |
| Flight 1248 [accident conditions] | -790 | Overrun (50) |
| OPC/Boeing [target 60/30 stow] | -410 | Overrun (25) |

## Airplane Stopping Capability

| Reverse Thrust Configuration | Stopping Margin (feet) | Conclusion/ Runway Exit Speed (knots) |
| --- | --- | --- |
| SWA practice [target 80/60 stow]  | -1310 | Overrun (44) |
| Flight 1248 [accident conditions] | -790 | Overrun (50) |
| OPC/Boeing [target 60/30 stow] | -410 | Overrun (25) |
| Maximum reverse thrust        [maintained to a complete stop] | 230 | Stop |

## Airplane Stopping Capability

| Reverse Thrust Configuration | Stopping Margin (feet) | Conclusion/ Runway Exit Speed (knots) |
| --- | --- | --- |
| SWA practice [target 80/60 stow]  | -1310 | Overrun (44) |
| Flight 1248 [accident conditions] | -790 | Overrun (50) |
| OPC/Boeing [target 60/30 stow] | -410 | Overrun (25) |
| Maximum reverse thrust        [maintained to a complete stop] | 230 | Stop |
| Flight 1248 [accident conditions, except with a headwind] | 550 | Stop |

## Conclusions

- Airplane had sufficient performance capability to stop
- Timely selection, setting, and sustained use of reverse thrust were all critical
- Maximum safety margin was about 4%
- FAA advocates a minimum acceptable safety margin of 15%

## Conclusions

- Arrival assessment policy consistent with “layers of safety” philosophy
- Operators must assess actual arrival conditions; incorporate adequate margin
- Historic challenge to quantify runway surface conditions and trends remains

## Slide 18