KUALA LUMPUR, Sept 15 — The Air Accident Investigation Bureau’s preliminary report released today on the Beechcraft Model 390 Premier 1 crash last month has found no evidence of incapacitation or physiological factors that affected the flight crew's performance.

The flight crew of the plane that crashed in Bandar Elmina near Shah Alam, Selangor consisted of two pilots: Shahrul Kamal Roslan, 41, and his second-in-command Heikal Aras Abdul Azim, 44.

"Both pilots held valid medical certificates from the Federal Aviation Administration and the Civil Aviation Authority of Malaysia,” the bureau, which comes under the Ministry of Transport, said in the preliminary report.

The bureau said in the report that both pilot Shahrul and his second-in-command Heikal had a First Class Medical Certificate from the Federal Aviation Administration.

While the medical cert noted a limitation stating that both pilots must use corrective lenses to meet vision standards at all required distances, a thorough review and supporting documentation found that Shahrul and Heikal had no significant medical concerns.

The designated medical examiner who conducted physical examinations of both pilots also identified no significant conditions.

"Based on available history and physical examinations, pilot-in-command and second-in-command had no known medical conditions that could pose significant hazards to flight safety,” it said.

The early report also stated that Shahrul had rested sufficiently the night before the plane departed from Langkawi.

However, the report did not release a transcript of the final 30 minutes of the cockpit voice recording (CVR), even though it was successful in retrieving data from the recorder on board.

"Initial analysis of the recovered CVR recording has provided critical leads to uncovering the cause of the accident, with a focus on the aircraft flight control systems.

"Results from the pending inspection and examination of the related aircraft parts and components at the National Transport Safety Board and Original Equipment Manufacturer laboratories are necessary to provide collaborative and conclusive evidence in establishing the cause of the accident,” it said.

In an accompanying statement, the Transport Ministry emphasised that the preliminary report represents an early discovery and is considered reliable as at the time of its release.

"It must be regarded as tentative and is subject to alteration or correction if additional evidence becomes available,” it added.

The ministry said that the final report of the ongoing investigation will be finalised by August 2024, allowing for a 12-month period to complete the document after the accident.

The Beechcraft 390 Premier 1 aircraft flying from Langkawi in Kedah to Subang Jaya crashed onto the Guthrie Highway at about 2.50pm on August 17, killing all eight people on board, including Pahang state executive councillor Datuk Seri Johari Harun.

The aircraft was destroyed following the ground impact and subsequent fire.

An e-hailing driver and a p-hailing rider on the highway were also killed.