# Presentation: 864886

## Safety Study

- Risk Factors Associated with Weather-Related General Aviation Accidents

## Aviation Safety - Regional Staff

- Kurt Anderson
- Jill Andrews
- David Bowling
- John Brannen
- Nicole Charnon
- Tealeye Cornejo
- Steve Demko
- Debra Eckrote
- Todd Fox
- Catherine Gagne
- Mitch Gallo
- Bob Gretz

- Bob Hancock
- Dennis Hogenson
- Clint Johnson
- Patrick Jones
- Alex Lemishko
- Larry Lewis
- Tom Little
- Ed Malinowski
- Steve McCreary
- Frank McGill
- Van McKenny
- Tim Monville
- George Petterson

- Howard Plagens
- Wayne Pollack
- Arnold Scott
- Jim Silliman
- Corky Smith
- Tim Sorensen
- Jim Struhsaker
- Pam Sullivan
- Butch Wilson
- Leah Yeager
- Al Yurman

- Jeff Guzzetti, Deputy Director Regional Operations

## Staff

- Meteorology
- Jim Skeen
- Greg Salottolo
- Kevin Petty
- Don Eick
- Air Traffic Control
- Barbara Zimmermann
- Bill English
- Scott Dunham

- Communication Center
- Grant Bell
- John Taylor
- Brian Huddleston
- Grady Goodman
- Dan Maas
- Chris Mason
- Richard Chancellor
- Malcolm Brown
- Randy Rodriguez
- Russell Sottile

- Study Managers
- Loren Groff
- Jana Price

- Editor
- Sally Bennett

## Background

## General Aviation (GA)

- Operations conducted under 14 CFR Part 91
-  Does not include air carrier, air taxi, or air tour operations
- 1,614 GA accidents in 2004 represented 94% of all U.S. civil aviation accidents

## General Aviation (GA) Accidents in IMC

## GA Accidents that Result in Fatality

## Previous Safety Board Studies

- 1968: Weather-involved accidents in 1966
- 1974: Fatal weather-involved accidents over a 9-year period
- 1976:  Nonfatal weather-involved accidents over an 11-year period
- 1989: VFR-into-IMC accidents over a 5-year period

## Previous Safety Board Recommendations

- Collection and dissemination of weather information
- Pilot training and operations
- Air traffic control

## Study Method and Procedures

## Weather-related Accidents

- Defined as: “Accidents that occur in weather conditions characterized by instrument meteorological conditions (IMC) or poor visibility.”

## Case Control Methodology

- Epidemiological approach frequently used in public health research
- Used to identify factors that increase a pilot’s risk of being involved in a weather-related GA accident
**Cases**: weather-related GA accidents
**Controls**: “nonaccident” GA flights that occurred under similar circumstances

## Selection of Study Variables

- Variable selection was guided by:
- Previous research findings
- Investigator expertise
- Practical constraints
- Variables included information about pilots, flights, and aircraft

## Accident Inclusion Criteria

- GA airplane operation and
- IMC or marginal VMC at the time and location of the accident
- Other accidents potentially involving lack of visual reference

## Study Procedure

- Data collection: August 2003 – April 2004
- Regional ASIs notified study managers if accidents met study inclusion criteria
- Staff monitored FAA daily accident reports
- Study managers identified and collected data from matching nonaccident flights

## Matching Nonaccident Flights

- Weather conditions
- Location (within 30 miles)
- Time (within 30 minutes)
- Rules of flight
- Number of engines
- Engine type

## Identifying Nonaccident Pilots

| Flight Plan | 
Method |
| --- | --- |
| IFR | Flight tracking software used to obtain registration numbers of matching flights |

## Slide 18

## accident aircraft

## accident aircraft

- potential control aircraft

## Identifying Nonaccident Pilots

| Flight Plan | 
Method |
| --- | --- |
| IFR | Flight tracking software used to obtain registration numbers of matching flights |
| VFR or None | FBOs and airports within 30 miles of accident and along route of flight were contacted to identify matching flights and pilots |

## Data Gathering

- Accident flights
- Regional accident investigations
- Supplemental data form
- Nonaccident flights
- Study managers interviewed pilots
- 100% of pilots contacted participated
- Most interviews conducted within 72 hours of accident flight

## Additional Study Data

- Previous aviation accidents, incidents, and violations
- FAA knowledge and practical test records
- Forecast and actual weather conditions

## Statistical Results

## 72 Study Accidents

## 72 Study Accidents

## Study Groups

- 72 accidents, representative of all weather-related GA accidents

- 135 matching nonaccident flights

## Individual Comparisons

- Chi-square (2) tests used to measure group differences
- Comparisons included
- Pilot information
- Aircraft and flight information

## Pilot-Related Variables

- Instrument rating
- Pilot certification level
- Total flight hours
- Age at accident
- Years as pilot
- Age at initial certification
- FAA knowledge and practical test performance
- Accident/incident history

## Aircraft and Flight-Related Variables

- Aircraft ownership
- Purpose of flight
- Planned flight length

## Significant Differences

- Instrument rating
- Pilot certification level
- Age at accident
- Age at initial certification
- FAA test performance
- Accident/incident history
- Aircraft ownership and purpose of flight
- Planned flight length

## Logistic Regression

- Binary logistic regression used to predict accident involvement
- Also provides estimates of relative risk

## Logistic Regression Model

- Instrument rating
- Pilot flight hours
- Age at first certificate
- Aircraft ownership
- Prior accident or incident

- Highest pilot certification
- Practical test pass rate
- Purpose of flight
- Planned flight length

## Logistic Regression Model

|  | Wald | Sig. |
| --- | --- | --- |
| Instrument rating | 9.55 | .002 |
| Pilot flight hours | 1.06 | .788  |
| Age at first certificate | 13.52 | .004 |
| Aircraft ownership | 2.55 | .279 |
| Prior accident or incident | 4.76 | .029 |
| Highest pilot certification | .389 | .533 |
| Practical test pass rate | 1.86 | .173 |
| Purpose of flight | 2.06 | .152 |
| Planned flight length | 7.87 | .049 |

- 2 = 57.45, *p* < .001

## Logistic Regression Model

|  | Wald | Sig. |
| --- | --- | --- |
| Instrument rating | 9.55 | .002 |
| Pilot flight hours | 1.06 | .788  |
| Age at first certificate | 13.52 | .004 |
| Aircraft ownership | 2.55 | .279 |
| Prior accident or incident | 4.76 | .029 |
| Highest pilot certification | .389 | .533 |
| Practical test pass rate | 1.86 | .173 |
| Purpose of flight | 2.06 | .152 |
| Planned flight length | 7.87 | .049 |

- 2 = 57.45, *p* < .001

## Analysis of Results

## Issue Areas

- Pilot training and proficiency differences
- Testing, accident, and incident history
- Weather briefing sources and methods

## Analysis of Results

- Pilot Training and Proficiency Differences

## Pilot Differences

- Pilots who learned to fly prior to age 25 at lowest risk

## Age at Initial Certification

## Pilot Differences

- Differences not likely the result of age-related effects

- Pilots who learned to fly prior to age 25 at lowest risk
- Accident risk 3.4x to 4.8x greater for other pilots

## Highest Pilot Certification Level

## Instrument Rating

## Pilot Differences 

- Pilots who learned to fly prior to age 25 at lowest risk
- Nonaccident pilots had higher levels of certificate and rating

## Purpose of Flight

## Aircraft Ownership

## Pilot Differences 

- Pilots who learned to fly prior to age 25 at lowest risk
- Nonaccident pilots had higher levels of certificate and rating
- Nonaccident flights were more likely to be conducting paid operations
- Career pilots subject to more training and oversight

## Initial Requirements

- All levels of pilot certificate require specific weather knowledge training
- All certificate levels above private require demonstration of instrument flight performance

## Recurrent Requirements

- Instrument flight proficiency required for instrument-rated pilots
- Flight review currently required for all pilots
- Every 24 months
- 1 hour flight/1 hour ground instruction
- General knowledge, rules, procedures

## Maintaining Proficiency

- 	Periodic training and evaluation help maintain and improve knowledge and skills

## Analysis of Results

- Testing, Accident and Incident History

## Test Performance and Accident Risk

- FAA knowledge and practical tests required for certification
- Cumulative pass-rates developed using private, commercial and instrument tests
- “High” pass rate: ≥70%
- “Low” pass rate: <70%

## Knowledge Test Performance

## Practical Test Performance

## Test Performance and Accident Risk

- Analysis linked high test failure rates to accident involvement
- Currently there are no failure limits on knowledge or practical tests

## Air Sunshine Accident July 13, 2003

- Over 15-year period, pilot failed 9 practical tests
- Recommendation A-05-02
- Study whether existing system for post-failure remediation is adequate
- Based on study, establish failure limits as necessary

## FAA Knowledge Tests

- Applicants who miss all weather questions may still pass test
- No minimum requirements within knowledge areas

## Accident/Incident History

- Previous research has linked prior accidents to future accident risk
- Accident/incident history data obtained from FAA

## Pilot Accident/Incident History

## Accident/Incident History

- Accident/incident history associated with 3.1x greater accident risk
- Average of 1 in 330 active pilots in U.S. involved in accident annually
- Most pilots survive and continue to fly after the event
- Existing records could be used to identify pilots at heightened risk

## Analysis of Results

- Weather Briefing Sources and Methods

## Pilots’ Use of Preflight Weather

- Accident pilots
- Investigators checked documented briefings or interviewed surviving pilots
- Nonaccident pilots
- Study managers interviewed pilots, usually within 72 hours of flight

## Pilots Who Obtained Preflight Weather Information

**Pilots Who Obtained Preflight Weather Information**

## Pilots Who Obtained Documented Preflight Weather Information

**Pilots Who Obtained Documented Preflight Weather Information**

## Weather Information Sources Used by Nonaccident Pilots

## Majority of accident and nonaccident pilots used flight service (FSS)
Nonaccident pilots reported supplementing FSS briefings with Internet or other services
Graphical images 
Interactive tools

- Nonaccident pilots reported supplementing FSS briefings with Internet or other services
- Graphical images
- Interactive tools

**Weather Information Sources Used by Nonaccident Pilots**

## Flight Service Stations

- February 2005: FAA announced new operator for FSS system
- Transition to new operation: late 2005
- Opportunity to consider incorporating additional information in briefings

## Slide 68

## FAA Guidance to GA Pilots on Weather Information

- Guidance in FAA advisory circular limited to FSS and DUATS

## “The AWC Homepage ‘Standard Briefing’ is intended as a tool to help pilots better visualize weather and weather-related hazards.  It is not intended as a substitute for a weather briefing obtained from a Flight Service Station (1-800-WXBRIEF).”

- “The AWC Homepage ‘Standard Briefing’ is intended as a tool to help pilots better visualize weather and weather-related hazards.  It is not intended as a substitute for a weather briefing obtained from a Flight Service Station (1-800-WXBRIEF).”

## Slide 71