Nepal's only international and largest airport cannot handle wide-body aircraft due to its weak runway, a recent study conducted by a Spanish company said.

Ayesa Ingenieria, the firm assigned to study on the status of runway at Tribhuvan International Airport (TIA) concluded that the runway of the airport is unable to carry wide-body aircraft 'due to its aging asphalt foundation and turmoil caused to the upper surface after the landing of the heavy jets.'

Following the repeated cracks appeared in the TIA's runaway especially during the rainy season, the Nepali government had assigned the Spanish company to study the condition of the runaway last year.

Frequent occurrences of cracks on the 3,050 meter long runway have affected a number of flights prompting either to divert or delay the landing of hundreds of aircraft since 2011.

"Damage in the lower asphalt surface layers is reflected quickly in the upper surface resulting in cracks and other sorts of damages," the report states.

The company submitted the partial report to the Civil Aviation Authority of Nepal (CAAN), Nepal's aviation regulatory body, on Thursday while it said that the full report will be submitted in the coming week.

Due to the repeated cracks appeared in the runaway, the TIA management in 2013 has already asked all airlines operators to switch for narrow-body crafts if they are to operate in Nepal.

The runway handles 250 planes, local and international at an average day while it handles around 400 planes a day during the peak season, from September to November.

The runway at TIA was constructed in 1967 and upgraded in 1975. The runway constructed targeting to handle Boeing 757 currently serves airplanes like airbus and Boeing 777 which has also aggravated the situation.

The study report has recommended that the lower layers of the runway be dug up and the foundation be repaved by removing damaged asphalt layers and substituting them with a new base and surface courses.

"The runway was designed for DC-10 airplane but the operation of huge crafts including Boeing 777 made the runway weaker before the expected time, "Narayan Singh, deputy chief of Air Transport Capacity Enhancement Project conducted by CAAN told Xinhua.