Accident Investigation

An accident is defined by its operational time window and by one of three outcomes: qualifying injury, substantial aircraft damage, or the aircraft becoming missing or inaccessible.

Operational time window

For a manned aircraft, the occurrence must be associated with operation from the time a person boards with the intention of flight until everyone has disembarked. For an unmanned aircraft, it runs from readiness to move for flight until it comes to rest at the end of flight and the primary propulsion system is shut down.

Three accident tests

1. Injury: a person is fatally or seriously injured through being in the aircraft, direct contact with any part including a detached part, or direct exposure to jet blast.
2. Damage: the aircraft sustains damage or structural failure that adversely affects structural strength, performance or flight characteristics and normally requires major repair or replacement.
3. Missing: the aircraft is missing or completely inaccessible. It is regarded as missing when the official search is terminated without locating the wreckage.

Exclusions

Injuries from natural causes, self-inflicted injuries, injuries inflicted by another person and injuries to a stowaway hidden outside areas normally available to passengers and crew are excluded from the accident injury test. Damage limited to one engine and its cowlings or accessories, propellers, wingtips, antennas, probes, tyres, brakes, wheels, fairings, panels, landing-gear doors, windscreens, small skin dents or punctures, minor rotor-blade damage and hail or bird-strike damage is excluded unless the wider accident definition is met.

Fatal injury

Bali's national definition treats an accident injury as fatal when it results in death within 30 days of the accident date. This time limit classifies the occurrence even if death is not immediate.

A serious incident nearly becomes an accident. The difference is the result, not necessarily the hazard or the failed defences.

Serious injury

Serious incident

A serious incident involves circumstances indicating a high probability of an accident. Examples include a near collision requiring avoidance, marginally avoided controlled flight into terrain, take-off or landing on a closed or engaged runway, gross performance failure, serious fire or smoke, emergency oxygen use by flight crew, uncontained engine failure, major structural or system failure, crew incapacitation, emergency fuel state, severe runway incursion, excursion, operations outside the approved envelope and failure of multiple mandatory redundant systems.

Incident and significant incident

An incident is an occurrence other than an accident, associated with aircraft operation, that affects or could affect operational safety. Bali's national examples include damage or injury outside the accident definition, forced or precautionary landing, landing in an unairworthy condition, unknown position and any jeopardy to aircraft, occupants, other persons or property. A significant incident is one where an accident or serious incident could have occurred if the risk had not been managed within safety margins.

Air traffic incident

An air traffic incident is a serious occurrence related to ATS, including AIRPROX or a serious difficulty caused by faulty procedure, non-compliance or failure of a ground facility.

Notification is urgent because evidence, rescue needs and international obligations begin immediately. Send known facts first and follow with corrections rather than waiting for a perfect report.

Who notifies and when

The pilot-in-command, or if killed or incapacitated the owner, operator, hirer or other person on whose behalf the pilot was in command, and any relevant person must notify as soon as reasonably practicable. Bali states that this must be no later than 24 hours after awareness of the accident or incident. The fastest available means is used.

Notification goes to AAIB and DGCA. For an occurrence in India, information also goes to the District Magistrate and the officer in charge of the nearest police station. The aerodrome operator, the ATS unit concerned and DGCA, where applicable, also submit notification to AAIB.

Content of the notification

Air traffic incident report

A pilot reports a major air traffic incident immediately on the appropriate frequency so facts can be established. After landing, the completed Air Traffic Incident Report is sent promptly and in any case within 24 hours by the quickest available means, confirming a radio report or initiating the report when immediate radio notification was not possible.

Annex 13 allocates investigation leadership by territory and gives technically connected States defined rights to participate without displacing the investigator in charge.

If an occurrence is in a non-contracting State that does not investigate, the State of Registry should endeavour to do so. If the State of Occurrence declines, the State of Registry or State of Operator may investigate by agreement. The State conducting the investigation retains control and may delegate all or part to another State by mutual arrangement.

Accredited representative

The States of Registry, Operator, Design and Manufacture are entitled to appoint accredited representatives. A State that provides requested information, facilities or experts may also appoint one. Advisers may assist the representative under the investigator's control.

State with fatalities or serious injuries

On request, a State whose citizens suffered fatalities or serious injuries may appoint an expert. That expert may visit the scene, access relevant factual information, participate in victim identification, assist with questioning its surviving citizens and receive the final report.

The 2017 Rules divide investigations between AAIB, DGCA and a formal investigation ordered by the Central Government.

AAIB investigation

AAIB classifies an occurrence as accident, serious incident or incident. All accidents are investigated by AAIB. AAIB also investigates a serious incident involving an aircraft over 2,250 kg maximum mass or a turbojet aeroplane, and it may take up another serious incident or incident when expedient. The Director General, AAIB appoints an Investigator-in-Charge and any additional investigators. The Investigator-in-Charge directs the technical inquiry and controls access to evidence.

DGCA investigation

DGCA investigates incidents and serious incidents not assigned to AAIB under the mass or turbojet criteria, unless AAIB takes over. An appointed Inspector of Accidents or authorised investigator obtains records, examines aircraft and equipment, interviews witnesses and reports findings under the applicable order.

Formal investigation

The Central Government may order a formal investigation into an occurrence involving an Indian-registered aircraft when expedient. It appoints a competent person or Court of Inquiry and may appoint assessors with legal, aeronautical, engineering or other specialist knowledge. A Committee of Inquiry may be used where an ordered multidisciplinary examination is required. AAIB facilitates the investigation and administrative work under the rules.

Perishable evidence can disappear in minutes. Rescue and public safety come first, but otherwise the site, records and recorded data remain under investigation control.

Custody of the wreckage

The Investigator-in-Charge has unhampered access to wreckage and all relevant material, including flight recorders and ATS records, and controls them so authorised personnel can examine them without delay. Aircraft, contents and wreckage are not removed or disturbed without AAIB authority.

Permitted urgent action

Authorised people may disturb wreckage when necessary to rescue persons or animals, prevent destruction by fire or another cause, remove danger or obstruction to the public or air navigation, or bring wreckage in water to safety. Goods may be removed under AAIB supervision. Passenger and crew baggage may be released after photography, weighing and recording under police, magistrate or AAIB supervision. Mail receives equivalent controlled treatment with postal authority involvement.

Flight recorders

Flight data, cockpit voice and airborne image recordings are secured, stopped from being overwritten and downloaded through a controlled process. Bali states that cockpit voice and airborne image recordings are not used in disciplinary, civil, administrative or criminal proceedings against employees, operational personnel or organisations. Annex 13 additionally protects sensitive investigation records from disclosure except through the applicable balancing test.

Other protected records

Protection extends to statements taken from persons, communications between participants, medical or private information, cockpit recordings and analysis, and draft opinions or recommendations. The purpose is to preserve candid safety evidence while still allowing release where the competent authority finds that the administration of justice outweighs the adverse safety effect.

A disciplined investigation converts physical evidence, recorded data and testimony into findings, contributing factors and preventive action.

From notification to analysis

1. Classify the occurrence and appoint the Investigator-in-Charge.
2. Notify the relevant States and ICAO when the mass or aircraft criterion applies.
3. Preserve perishable evidence, map the site and secure recorders and records.
4. Form specialist groups for operations, engineering, human factors, survival, weather, ATS and recorded data as needed.
5. Validate factual evidence, reconstruct the sequence and analyse technical and organisational factors.
6. Consult participating States on the draft report, consider comments and finalise conclusions and recommendations.

Preliminary and final information

Initial and preliminary information shares essential facts while investigation continues. The final report is issued with minimum delay in an ICAO working language and is made public. It normally contains factual information, analysis, conclusions, causes or contributing factors and safety recommendations. A recommendation addresses a safety deficiency; it is not a finding of blame and does not by itself presume liability.

Recipients and ICAO thresholds

The report goes to relevant States including Registry, Operator, Design and Manufacture, States that participated or whose citizens suffered fatal or serious injury, and other entitled recipients. Bali states that ICAO is notified of an accident or serious incident involving an aircraft over 2,250 kg maximum mass, while the final report is sent to ICAO for an aircraft over 5,700 kg.

ADREP

ADREP is ICAO's Accident and Incident Data Reporting system. States submit standardised occurrence data so ICAO can identify international trends, compare safety problems and support prevention. It complements the narrative report rather than replacing it.

Investigation reacts to an occurrence. A mature State safety system also learns from hazards and errors before they cause an accident.

Mandatory reporting

Operators, crew, maintenance organisations, aerodromes, ATS providers and other specified persons report occurrences required by Indian rules and civil aviation requirements. Mandatory systems ensure that known serious hazards such as loss of separation, fire, system failure, runway incursion, dangerous-goods event or flight-control difficulty reach the responsible authority.

Voluntary reporting

A voluntary system accepts safety information that may not meet a mandatory threshold. It captures weak signals, hazards, mistakes and procedural problems. Identity and sensitive information are protected according to the scheme so personnel are willing to report honestly.

Just culture

Just culture does not mean freedom from accountability. It means people are not punished for actions, omissions or decisions proportionate to their experience and training, while wilful misconduct, deliberate violations, gross negligence and destructive acts remain unacceptable. This balance supports the reporting and analysis principles of the State Safety Programme and Annex 19.

Closing the loop

Reports are assessed, de-identified where appropriate, analysed for trends and converted into risk controls. AAIB sends recommendations to DGCA or another responsible authority, monitors action and maintains a recommendations database. The addressee records acceptance or rejection, planned action, owner and target date. Effective action is verified rather than assumed.