The Chinese-made Y12e aircraft is unable to operate with a full load from the country’s airfields due to temperature restrictions, Nepal Airlines Corporation (NAC) said in its performance analysis report submitted to the Tourism Ministry.

The 17-seater plane, which Nepal received as a gift from the northern neighbour, flies well in very cold weather, with performance falling with a rise in temperature and altitude. For example, the Y12e can fly from Kathmandu to Khanidanda at full capacity when the temperature is 0 degrees Celsius. At 14 degrees Celsius, the plane can carry only 12 passengers; and at 30 degrees Celsius, the allowable cabin load drops to a mere six passengers.

Likewise, the performance report showed that on the Nepalgunj-Jumla sector, the aircraft can fly at its optimum capacity when the temperature is 0 degrees Celsius, and when the temperature rises to 18 degrees and 30 degrees, the cabin load decreases to 14 and 7 passengers respectively.

The Y12e is totally unsuitable for the Pokhara-Manang sector, according to the report. The allowable cabin load is seven passengers at 0 degrees, two passengers at 10 degrees, one passenger at 12 degrees and zero passengers at 14 degrees Celsius respectively.

The aircraft can fly with 12 passengers in all weather conditions from Biratnagar to Taplejung. Likewise, on the Jomsom-Pokhara route, it can fly with 16 passengers in all weather conditions; but on the return flight, the passenger load has to be reduced to 14, the report showed.  

From Lukla to Kathmandu, the Y12e can carry 16 passengers in all weather conditions; but from Kathmandu to Lukla, the number has to be reduced to 13. The report has mentioned that the cargo load has to be slashed significantly as well. “The report has clearly stated that the aircraft cannot fly at its optimum capacity when the temperature rises, or during sunny days. It is ironic that the other aircraft in Nepal are affected by visibility, haze and fog when the temperature drops; but this plane performs best when it is cold,” said a ministry official.  

The Y12e aircraft doesn’t perform well in thin air, and on a hot day, it would require a very long runway to take off, officials said. “This affects the output of the engines, thereby requiring a longer runway and reducing climb performance,” officials said. “As a result, the number of passengers and the cargo load is reduced when the temperature is high.”

China has gifted a Y12e and an MA60 aircraft to NAC as part of a deal for six Chinese aircraft—two MA60 and four Y12e. The MA60 and Y12e aircraft currently in operation in Nepal are flying with a load restriction.

Following widespread criticism of the performance of these planes, a delegation consisting of technicians and bureaucrats are currently in China to take a closer look at the aircraft being made for NAC. The team is led by Suresh Acharya, joint secretary of the Tourism Ministry, and includes two engineers and a pilot from NAC and a representative from the Civil Aviation Authority of Nepal.

The national flag carrier had said that the planes could not carry a full load of passengers on Nepali routes, about which they had not been told in advance. Although the Y12e aircraft is designed to fly over remote terrain, it has a regulatory limit, which means the manufacturer has not issued a certificate allowing it to fly to airstrips with a slope of more than 2 degrees.

Before visiting China, the officials had said they would compare the findings with the performance chart issued by the aircraft manufacturer. They will then make their recommendation to the government whether or not to procure the remaining aircraft.