PUTRAJAYA (THE STAR/ASIA NEWS NETWORK) - The helicopter that crashed in Semenyih last month, killing all on board including a key aide to Malaysian Prime Minister Najib Razak, may have experienced damage to its left horizontal stabiliser, located in its tail section, when it landed at a school field before the crash.

The preliminary report on the crash released on Thursday revealed that the left landing gear of the chopper had sunk nearly 20 inches into soft ground when it landed at Sekolah Rendah Ladang Kota Bahagia in Muadzam Shah to drop off a passenger.

"The left horizontal stabiliser on the tail section may have experienced damage when the helicopter tilted 13 degrees to the left when it landed. The chopper was stationery at the school field for about five to 10 minutes," Transport Minister Liow Tiong Lai told a press conference.

"It is suspected that because of the damage, the stabiliser may have fallen off mid-flight, causing the helicopter to plummet to ground," he said.

Datuk Seri Liow said the left stabiliser had yet to be found, and advised villagers living around the crash site to hand it over if it was found.

"The piece has yet to be found and it is important for us to determine the cause of the crash," he added.

The Eurocopter Dauphine 9M-IGB chopper was travelling from Pekan to Subang on Apr 4 when it crashed in a rubber plantation near Kampung Sungai Pening in Semenyih.

The six killed were Rompin MP Jamaluddin Jarjis, chief private secretary to the prime minister Azlin Alias, Kedah businessman Robert Tan, pilot Cliff Fournier, bodyguard Mohd Raskan Seran and a female passenger by the name of Ajdiana Baiziera.