# Presentation: 926089

## Kevin J. Renze, Ph.D.

- Airplane Performance

## Elevator Control Authority Investigation

**FDR data from 84 previous flights operated with the accident airplane**
**Beechcraft 1900D simulation**

## Elevator Travel Range

## Elevator Travel Range

## Elevator Travel Range

## Elevator Travel Range

## Beechcraft 1900D Simulation

**Engineering models provided by RAC**
**Implemented in NTSB simulation tools **
**Validated against Beechcraft 1900D flight test data**

## Beechcraft 1900D Simulation Results

**Beechcraft 1900D Simulation Results**

- Takeoff Roll

- Rotation

- Climb

- SHIFT

## Flight 5481 Simulation Results

**The elevator was restricted to 8****o**** downward**
** ****9.5****o**** downward elevator was needed**
**7****o**** downward elevator needed if CG within limits**
**Balance is critical pitch control factor, not weight**

## Conclusions

**Maintenance changed the pitch control system**
**Elevator was restricted to about half its downward travel**
**FDR data analysis (7****o downward)**
**NTSB simulation   (8****o downward)**
**9.5****o**** downward elevator needed**
**7****o****    downward elevator needed if CG within limits**

## Kevin J. Renze, Ph.D.

- Airplane Performance

## Airplane Weight and Balance

**Air Midwest program**
**Component load buildup**
**Takeoff ground roll analysis**

##   Flight 5481 Weight and Balance

## Average Weight Comparison

|  | Air Midwest1 |  | FAA Guidance |  |
| --- | --- | --- | --- | --- |
| Component | Old (lb) | New (lb) | Old (lb) | Interim (lb) |
| Passenger and
carry-on bags/ personal items | 175 | 200 | 185 | 195 |
| Checked bag | 25 | 30 | 25 | 30 |
| Carry-on bag checked planeside | 25 | 20 | - | - |

- 1 Limited carry-on program

## Average Weight Comparison

|  | Air Midwest1 |  | FAA Guidance |  |
| --- | --- | --- | --- | --- |
| Component | Old (lb) | New (lb) | Old (lb) | Interim (lb) |
| Passenger and
carry-on bags/ personal items | 175 | 200 | 185 | 195 |
| Checked bag | 25 | 30 | 25 | 30 |
| Carry-on bag checked planeside | 25 | 20 | - | - |

- 1 Limited carry-on program

##   Improved Weight and Balance

## Weight and Balance Concerns

**Average Weight Error Sources **
**Understated average weights**
**Heavy bags**
**Variance in actual weight and weight distribution**
**Average weight programs need improvement **
**Actual weight and location data could eliminate these errors **

##  Pitch Control Assessment

|  | Center of Gravity | Elevator Travel |  | Pitch Control |
| --- | --- | --- | --- | --- |
| Pre D6 Flights | In Limits | Normal |  | Adequate |

##  Pitch Control Assessment

|  | Center of Gravity | Elevator Travel |  | Pitch Control |
| --- | --- | --- | --- | --- |
| Pre D6 Flights | In Limits | Normal |  | Adequate |
| 9 Post D6 Flights | In Limits | Restricted |  | Critical |

##  Pitch Control Assessment

|  | Center of Gravity | Elevator Travel |  | Pitch Control |
| --- | --- | --- | --- | --- |
| Pre D6 Flights | In Limits | Normal |  | Adequate |
| 9 Post D6 Flights | In Limits | Restricted |  | Critical |
| Accident Loading, Normal Elevator | Significantly Aft | Normal |  | Marginal |

##  Pitch Control Assessment

|  | Center of Gravity | Elevator Travel |  | Pitch Control |
| --- | --- | --- | --- | --- |
| Pre D6 Flights | In Limits | Normal |  | Adequate |
| 9 Post D6 Flights | In Limits | Restricted |  | Critical |
| Accident Loading, Normal Elevator | Significantly Aft | Normal |  | Marginal |
| Beech 1900C Homer, AK 1987 | Extremely Aft | Normal |  | Accident |

##  Pitch Control Assessment

|  | Center of Gravity | Elevator Travel |  | Pitch Control |
| --- | --- | --- | --- | --- |
| Pre D6 Flights | In Limits | Normal |  | Adequate |
| 9 Post D6 Flights | In Limits | Restricted |  | Critical |
| Accident Loading, Normal Elevator | Significantly Aft | Normal |  | Marginal |
| Beech 1900C Homer, AK 1987 | Extremely Aft | Normal |  | Accident |
| Flight 5481 | Significantly Aft | Restricted |  | Accident |

## Conclusions

**Air Midwest’s program did not detect the significantly aft CG**
**Unacceptable errors still exist in average weight programs and require improvements**
**Actual weight and location data could eliminate these errors**
**The significantly aft CG and restricted elevator resulted in a loss of pitch control**

## Kevin J. Renze, Ph.D.

- Airplane Performance