New Delhi: The Aircraft Accident Investigation Bureau (AAIB) said on Friday it is still analysing evidence collected as part of its ongoing probe into the crash of an Air India aircraft in June last year which killed 260 people.AAIB, tasked with investigating the crash, also didn't provide any recommendation for the aircraft manufacturer Boeing, indicating that there was no evidence yet to question the safety of the 787 Dreamliner aircraft.The final report, AAIB said, will be issued after completion of the remaining investigative activities and required review processes under international aviation norms.The International Civil Aviation Organisation (ICAO) recommends that the country conducting an aircraft accident investigation should publish a report within a year, but if it's not possible to do so, an interim statement should be released annually, on each anniversary of the occurrence, detailing the progress of the investigation and any safety issues raised."Significant progress has been made in the examination and analysis of aircraft systems, flight recorder data, engine-related components, maintenance and operational records, and other evidence relevant to the investigation," AAIB said. Additional technical evaluations and specialist examinations, wherever considered necessary, will be undertaken to ensure that all findings and conclusions are supported by verified evidence and sound scientific analysis, it added.John Cox, a former airline pilot and chief executive of Safety Operating Systems, which provides consulting services on accident investigations, said AAIB was right to delay the final report if it felt it needed more examination."It is completely in their purview to decide when to release the report," he said. "The investigators would want to back the report with strong evidence so that it stands every scrutiny when published."A preliminary report issued last year said seconds after take-off, the fuel control switches on both engines briefly moved from 'run' to 'cut off', severing fuel supply and causing a loss of power.