India has deployed attack helicopters to a disputed region in the Himalayan mountains.

But India isn’t sending its new U.S.-made AH-64E Apache s, arguably the most lethal attack helicopter in the world. Instead, India has dispatched an Indian-designed helicopter that the Indian military considers more suitable for operating at high altitudes.

Two Light Combat Helicopters, or LCH, have been dispatched to the Ladakh region, where Indian and Chinese troops engaged in border clashes in June. The Indian military has so far ordered 30 LCHs, from Indian aviation firm HAL.

“LCH is a potent weapon platform because of its state-of-the-art systems and highly accurate weapons that are capable of hitting any type of target by day or night,” said a HAL news release. “The other features of LCH include its ability to operate in the complete ‘Area of Responsibility’ (AOR) and altitudes. It has capability to carry adequate weapon load at high altitudes under varied conditions. All these characteristics make it most suitable for hot and high altitude operations.”

What’s interesting is that India has another attack helicopter: the U.S. AH-64E Apache, arguably the most advanced attack helicopter in the world. India recently took delivery of the last of 22 Apaches, part of a $3 billion deal signed in 2015 that also included 17 CH-47 Chinook helicopters (the Trump administration recently agreed to deliver another six AH-64Es).

The Apache is an impressive and combat-proven flying machine, with its Hellfire anti-tank missiles and Longbow fire control radar. The Indian AH-64E Guardian version features a more powerful engine, better data networking and improved composite rotor blades. Compared to the LCH, the Apache is faster, has more engine power and carries far more weapons, though the LCH has longer range (here’s a comparison between the LCH and the older AH-64D model).

However, high altitudes are challenging for rotary-wing aircraft. For example, U.S. Apache pilots operating over mountainous Afghanistan in 2002, flying as high as 12,500 feet above sea level and in temperatures ranging from 5 degrees to 122 degrees Fahrenheit, had to take extra precautions. “Performance planning was a critical part of each mission,” wrote one pilot. “Each mission required performance planning for altitudes, temperatures, and gross weights that were much higher than we normally operate.”

The Ladakh plateau of the Himalayan mountains, where China and India both claim territory, is 10,000 feet or more above sea level. For armored vehicles, the climate and terrain are so inhospitable that Indian tanks deployed there require special lubricants and must constantly run their engines to avoid freezing.

But the LCH has demonstrated an ability to operate in these conditions. In 2015, an LCH conducted several test landings on the Siachen glacier on Ladahk, at altitudes up to 15,800 feet while carrying a modest 500-kilogram (1,102 pound) load.  

While the AH-64E can fly at altitudes up to 20,000 feet, Indian commentators argue that the LCH is more suitable for the Himalayas. “While the Apaches would do well in the plains, they would have limitations operating in the upper reaches of the Himalayas,” wrote one former Indian Air Force commander. “During the Kargil War of 1999, there was a need felt for armed attack helicopters capable of operating at high altitude. That’s where the LCH fits in. It has successfully been tested in altitudes over 13,000 feet and was the first attack helicopter to land at the forward landing base in Siachen.”

But there is a price to be paid for high-altitude performance. The most striking difference between the AH-64 and the LCH is in their armament. The Apache is a flying arsenal that packs a 30-millimeter cannon and up to 16 Hellfire missiles and Hydra 70-millimeter unguided rockets. The LCH is more lightly armed with a lighter 20-millimeter cannon and up to four missiles or rockets. “The Indian LCHs, which are currently equipped with 70mm rockets and chin-mounted cannons, do not yet have anti-tank and air-to-air missiles,” noted the Times of India.

Against armor on open ground, India’s Apaches would devastate Chinese and Pakistani tanks. But in the Himalayas, where terrain and climate conspire to limit troop deployments, a flying arsenal probably isn’t needed. Just an armed helicopter that can fly above the mountains.

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