The crash of @Official_PIA flight #PK8303 in Pakistan, like every other air crash, will be investigated as per standards and recommended practices laid down in Annexe 13 of the Chicago Convention, 1944.
This thread details some of the processes key to an air crash investigation

The purpose of an investigation into air accidents is not to proportion liability of anyone but to find out the cause that led to the crash and prevent it from happening in the future.

All member states of The International Civil Aviation Organization ( @icao ) are expected to adhere to SARPS (Standard and Recommended Practices) provided by the aviation body. These are however “recommendatory” in nature as the title suggests.

Four states can participate in any accident investigation. They are, the State where the crash has occurred, the State of the Operator, the State of Registration of the aircraft and the State of the Manufacturer.

The #A320 AP-BLD involved in this accident was registered in Pakistan to the nations flag carrier and crashed within the country. Hence, the only other party involved in this investigation will be the European Union i.e. the State of Manufacturer.

Annexe 13 of the #ChicagoConvention, 1944, expects the State where the crash (read, Pakistan) to comply with any requests made by the State of Manufacturer (read, European Union).

Despite the above, #Pakistan, where the accident has occurred, has every right to disallow any State from taking part in an ongoing investigation.

Compensation for air crashes depends largely on the route operated by the aircraft. Local consumer laws apply if the aircraft was being operated on a domestic route which was the case with PK 8303.

In case of an International flight, compensation shall be governed either by the #MontrealConvention or the #WarsawConvention.

Finally, a preliminary investigation report has to be sent within thirty days of the accident to @icao and all interested parties. The Final report should be submitted preferably within one year of the crash.