When an aviation or a marine occurrence mentioned in Paragraph 1 of Article 6 arises, the TTSB shall immediately forward a notification to the aviation or marine occurrence investigation authority of the state of registry, state of the operator, state of design, and state of manufacture. The TTSB, having considered the factual situation of such occurrence, may immediately forward an additional notification to the aviation or marine occurrence investigation authority of the State whose citizens have sustained death thereby.
When a railway or highway occurrence mentioned in Paragraph 1 of Article 6 arises, the TTSB may forward a notification to the occurrence investigation authority of the state of registry, state of operator, state of design, state of manufacture, and state whose citizens have sustained death thereby.

When a transportation occurrence mentioned in Paragraph 1 of Article 6 arises, the TTSB shall designate a safety investigator as the IIC, who shall assemble an Investigation Task Force and will be fully responsible for the conduction of the investigation. The IIC shall invite representatives from the authorities and organizations concerned and experts to participate in the investigation.
The Investigation Task Force shall dissolve immediately after the publication of the investigation report.

When a transportation occurrence mentioned in Paragraph 1 of Article 6 arises, the owner of mode, the operator of mode, ultra-light vehicle activity group, and authorities concerned shall dispatch their representatives to the site of the occurrence and provide assistance to the investigation operation as instructed by the Investigation Task Force.
When a transportation occurrence or alleged transportation occurrence arises, the operator of mode shall ensure that the data inside the data recorder are intact, not destroyed or overrode or lost by continuous recording. The data recorder shall not be reactivated until the TTSB has retrieved the data. If the data inside the recorder are incomplete, the operator shall pay the cost for data recovery.
When a transportation occurrence arises, all the authorities concerned shall fulfill their duties in accordance with the Disaster Prevention and Relief Act as a preliminary step, blockade the occurrence site, and inform the TTSB of the measures taken at the site.

Unless it is necessary to take measures for the purposes of rescuing lives and firefighting, the integrity of the occurrence site shall be preserved. Should the clearance of the occurrence site be considered necessary, it should be discussed between the management authority of the occurrence site and the TTSB, and prior approval from the IIC is obligatory for doing so.

As the necessary measures to conduct a transportation occurrence investigation, the TTSB may have the priority to control and handle the mode, wreckages, data recorder, and other data and objects that may have a bearing on the occurrence (hereinafter referred to as relevant data and objects of transportation occurrence.)

The competent authorities and/or organizations of the occurrence site, the owner of mode, and the operator of mode shall provide assistance to the TTSB in searching, transporting, placing, safeguarding, and securing the relevant data and objects of transportation occurrence.
Should there be any risk of displacement, losing, or perishing of the relevant data and objects of transportation occurrence, the TTSB and authorities and/or organizations concerned shall take the necessary measures to preserve them, including photographing, sketching, marking, and other necessary actions to record and to protect such data and objects.
Any person discovering relevant data and objects of transportation occurrence in public and/or private land or premises shall notify the TTSB or other authorities and/or organizations concerned immediately and shall not remove any of such data and objects. Upon receiving such notification, the TTSB shall enter such site with the authorities and/or organizations concerned. The IIC or any representatives designated by the IIC shall take full control over the verification of the data and objects as well as the handling thereof.

When a transportation occurrence arises in the water, the TTSB, having thoroughly evaluated the necessity of investigation and the feasibility of recovery, shall immediately commence the activities of locating, recovering, and transporting the mode, wreckages, and data recorder mentioned in Article 14.
When a transportation occurrence arises on land, the TTSB, having thoroughly evaluated the necessity of investigation, shall immediately commence the activities of searching, site-surveying, and transporting the mode, wreckages, and data recorder mentioned in Article14.
For the purposes of conducting investigation operations in the water and on land, mentioned in Paragraph 1 and Paragraph 2, the TTSB may request assistance from the authorities and/or organizations concerned, the owner of mode, the operator of mode, or ultra-light vehicle activity group who shall not evade, obstruct, or refuse to provide the required assistance without reasonable grounds.

When a transportation occurrence mentioned in Paragraph 1 of Article 6 arises, under the purpose and necessity of investigation, the TTSB Investigation Task Force may request the owner of mode, the operator of mode, supervisory authority, and other authorities concerned to provide the following information pertinent to the investigation within a specified duration:
1. Loading status and dispatch information of the mode.
2. Records of training and personal backgrounds, licenses, and other data of the operation personnel of mode that can be of assistance for the assessment of the occurrence.
3. Data and records related to the certification and maintenance of the mode.
4. Data related to weather and traffic control.
5. The medical records of the operator of mode due to the transportation occurrence and before, and the medical records of injured passengers due to the transportation occurrence.
6. Data related to airport/station/port, auxiliary equipment for operation, and navigation aid equipment.
7. Data related to search, rescue, and firefighting.
8. Data related to the inspection records by supervisory authority of the mode and the operator of mode.
9. Data related to the data recorder.
10. Other data relevant to the transportation occurrence.

When a transportation occurrence arises, mentioned in Paragraph 1 of Article 6, members of the TTSB Investigation Task Force may interview the relevant personnel. Those individuals shall not evade or refuse to be interviewed without reasonable grounds and shall provide a truthful representation consistent with the facts. The supervisor(s) and employer(s) of such interviewees shall not obstruct the conducting of the interview.

Unless regulated otherwise by other laws, the TTSB Investigation Task Force may entrust the prosecuting authorities or commission any qualified independent and professional domestic/foreign authorities or organizations to perform autopsy, detailed examinations, tests, and collection of other relevant information of the deceased operators and passengers to identify their cause of death and their status regarding the use of alcohol, drugs, or toxic substances.

The personnel involved in the transportation occurrence investigation shall commit to confidentiality and conduct the investigation following the IIC’s instruction.

Except for the spokesperson designated by the TTSB or the official website of the TTSB, no person who participates in the investigation nor the supervisor or employer of such person, shall in the course of the investigation disclose publicly any information related to the investigation of the transportation occurrence.

Except in case of necessity for the analysis in the investigation of a transportation occurrence, the TTSB shall not publish in the investigation report the following information:
1. The testimony and evidence acquired in the course of the investigation;
2. Communication records between persons involved in the operation of the mode;
3. Medical records of the persons involved in the operation of the mode;
4. Medical records or personal information of persons related to the transportation occurrence;
5. Transcripts of transportation recordings; and
6. Transcripts of recordings from traffic control units.
No voice recordings shall be released to the public.

If, in the course of an investigation, it becomes known to, or it is suspected by the TTSB, that an act of illegal interference with the operation of mode of transportation occurred, the TTSB shall immediately inform the responsible domestic and foreign authorities concerned and may provide assistance in terms of investigation to the competent authorities concerned for the part related to the transportation occurrence.