JAKARTA, Feb. 24 (Xinhua) -- Indonesian authorities begin to investigate a case when a passenger plane landed without lowering its front landing gear Monday evening, the country's transport ministry said here Tuesday.

    The Lion Air's McDonnell Douglas MD-90 jet on a domestic flight from Medan of North Sumatra could not lower its nose landing gear when it arrived at Batam island's Hang Nadim airport, near Singapore.

    All 156 passengers on board were safe, but nine people were in shock after the accident.

    "The plane failed to lower its nose gear as it was landing in Batam airport," the ministry spokesman Bambang Ervan told Xinhua, adding that the Indonesian Transportation Safety Board was probing the accident.

    "The board is investigating whether it was a human error or out of others causes," he said.

    Indonesia has struggled to improve air safety, expecting the European Union to lift its travel ban on Indonesia in March or July, said Ervan.

    European Union has forbidden 51 Indonesian airliners, including the country's leading carrier Garuda, from entering its territory since July 6 2007 following a rampant air accidents that killed more than 250 people. EU extended the ban in November last year in Brussels.

    With the help of the EU, Indonesia has made improvements on its flight safety standards.

    The country's parliament on Dec. 17 passed a new regulation on aviation with stricter safety standards. The new rules were hailed by the EU, Indonesian Transport Minister Jusman Syafii Djamal said.

    Air accidents in Indonesia plunged in recent years when compared with three years ago.

    Taking airplanes is a favorite transport mean in the sprawling archipelago country with over 230 million population.