Aircraft Accident Investigation – Study Guide
Purpose: Understand rules, definitions, findings, causes, recommendations, and the organizations
involved in accident investigations.
Main Goal: Improve aviation safety and prevent recurrence of accidents, not assign blame or liability.
Key Definitions
ICAO Aircraft Accident: Occurs between boarding and disembarkation if:
- A person is fatally or seriously injured from being in, in contact with, or exposed to jet blast of the
aircraft (exceptions: natural/self-inflicted causes, stowaways).
- The aircraft sustains structural damage or failure requiring major repair/replacement (exceptions:
isolated engine/propeller damage, dents, tires, fairings).
- The aircraft is missing or inaccessible.
Serious Injury (ICAO): Hospitalization >48 hrs within 7 days, bone fractures (except fingers/toes/nose),
severe lacerations, internal organ damage, 2nd/3rd degree burns, >5% burns, exposure to infectious
substances or radiation.
NTSB Substantial Damage: Similar to ICAO, excludes engine-only failures, minor dents, skin
punctures, tires, brakes, wingtips.
NTSB Serious Injury: Same as ICAO; Fatal Injury = death within 30 days.
Civil vs Public Aircraft: Civil = all non-public aircraft. Public = government-operated aircraft (law
enforcement, firefighting, research). Military aircraft = public.
Findings, Causes, and Recommendations
Findings: Statements of significant events/conditions in chronological order. Include both causal and
non-causal factors.
Causes: No single cause – accidents result from multiple factors. ICAO defines causes as actions,
omissions, events, or conditions leading to an accident.
Types of Causes:
- Proximate Cause: Immediate trigger (e.g., 'pilot error').
- Root Cause: Explains why failure occurred, often correctable (e.g., 'inadequate training').
- Descriptive Causes: Describe what happened.
- Explanatory Causes: Explain why it happened.
USAF Definition: A cause is any act, omission, condition, or circumstance that if corrected would likely
have prevented/mitigated the mishap.
Recommendations: Aim to prevent recurrence by correcting deficiencies. Should be practical,
objective-focused, and prioritized by effectiveness.
Example of Prioritization: System-wide issues (engine/transmitter reliability) > inspection of tires > local
hazard like a single runway obstruction.
Key Players in Investigations
Purpose: Understand rules, definitions, findings, causes, recommendations, and the organizations
involved in accident investigations.
Main Goal: Improve aviation safety and prevent recurrence of accidents, not assign blame or liability.
Key Definitions
ICAO Aircraft Accident: Occurs between boarding and disembarkation if:
- A person is fatally or seriously injured from being in, in contact with, or exposed to jet blast of the
aircraft (exceptions: natural/self-inflicted causes, stowaways).
- The aircraft sustains structural damage or failure requiring major repair/replacement (exceptions:
isolated engine/propeller damage, dents, tires, fairings).
- The aircraft is missing or inaccessible.
Serious Injury (ICAO): Hospitalization >48 hrs within 7 days, bone fractures (except fingers/toes/nose),
severe lacerations, internal organ damage, 2nd/3rd degree burns, >5% burns, exposure to infectious
substances or radiation.
NTSB Substantial Damage: Similar to ICAO, excludes engine-only failures, minor dents, skin
punctures, tires, brakes, wingtips.
NTSB Serious Injury: Same as ICAO; Fatal Injury = death within 30 days.
Civil vs Public Aircraft: Civil = all non-public aircraft. Public = government-operated aircraft (law
enforcement, firefighting, research). Military aircraft = public.
Findings, Causes, and Recommendations
Findings: Statements of significant events/conditions in chronological order. Include both causal and
non-causal factors.
Causes: No single cause – accidents result from multiple factors. ICAO defines causes as actions,
omissions, events, or conditions leading to an accident.
Types of Causes:
- Proximate Cause: Immediate trigger (e.g., 'pilot error').
- Root Cause: Explains why failure occurred, often correctable (e.g., 'inadequate training').
- Descriptive Causes: Describe what happened.
- Explanatory Causes: Explain why it happened.
USAF Definition: A cause is any act, omission, condition, or circumstance that if corrected would likely
have prevented/mitigated the mishap.
Recommendations: Aim to prevent recurrence by correcting deficiencies. Should be practical,
objective-focused, and prioritized by effectiveness.
Example of Prioritization: System-wide issues (engine/transmitter reliability) > inspection of tires > local
hazard like a single runway obstruction.
Key Players in Investigations
