The United States appears ready to lift its 21-year-old arms embargo against China in the wake of President Obama's request on Saturday to ease restrictions on the sale of cargo aircraft to Beijing.

In an Oct 8 letter, Obama called on the House and Senate to lift the ban on C-130 cargo aircraft sales to China, emphasizing "the national interest of the United States" to terminate the suspensions.

Should the proposal pass in both Houses of Congress, this will signal the first time since 1989 that the US has exported arms to China.

Obama stressed in his letter that C-130 cargo aircraft are to be deployed in response to oil spills at sea. However, he did not specify a date or financial cost for an imminent export.

License requirements shall remain in place for these exports, and will require review and approval on an ongoing, case-by-case basis by US government officials.

The C-130 cargo aircraft - also known as the Lockheed C-130 Hercules - is a four-engine turboprop military transport aircraft designed and built in the 1950s. Capable of using unprepared runways for takeoffs and landings, the C-130 was originally designed as a troop, medical evacuation and cargo transport aircraft.

The aircraft have been widely used by NATO and coalition troops on the battlefields of Afghanistan and Iraq. The C-130 has so far been exported to more than 50 countries worldwide.

Washington has exported to China Black Hawk helicopters and other advanced armaments in the 1980s, but has also led Western countries in its restriction of high-tech weapons sales to Beijing since 1989.

It has also threatened to cease cooperation with the European Union, if the latter were to lift its arms sales ban, according to Zhao Xiaozhuo, senior colonel and expert on US military affairs at Beijing-based Academy of Military Science.

"Israel, for example, under the pressure of the US, even had to quit from a contract of selling early warning aircraft to China," said Zhao.

The US, he added, is reluctant to export arms to China out of fears that Beijing's growing military expenditures are making it a fast-evolving threat.

There is also an underlying fear in Washington, Zhao added, that China would simply use the core technologies to its advantage.

Zhai Dequan, the vice-secretary-general of the China Arms Control and Disarmament Association, said that though the C-130 has been put in use for decades of years, it still has been of vast use in various military actions and exercises.

"As a tactical transport, C-130 cargo aircraft serve for middle-ranged deliveries - that is, the distance is within the (battlefield) theater," said Zhao.

"Unlike fighters, a cargo aircraft requires less updated technology and depends more on durability, and the C-130 has been performing quite well in the past decades," said Zhao. "Therefore it is still of operational value in the US."

Analysts said the White House's motives have been fueled by the Obama administration's plan to balance trade with China while testing the waters to further restore strained military-to-military relations.

The US is particularly worried about its trade deficit with Beijing. Moreover, while Washington has been accusing China of using its surplus to create an imbalance in bilateral trade, Beijing has countered that the US government has been banning high-tech American exports to China - and, thus, partly fueling the trade imbalance.

Zhai noted, however, that arms sales are beneficial in boosting related industries and, in doing so, creating job growth.

Beyond that, he added, China has other - and at times more important - reasons to have such hardware at its disposal.

"During the Wenchuan earthquake in 2008, the US ignored China's urgent need for aircraft engines used for rescuing victims," said Zhen. "If it is free trade, then what is the rationale of the US not selling China such conventional and not-so-high-end weapons?"

The other concern is to cast a light on the resumption of stalled military exchanges between the two countries.

Most notably, Beijing had suspended military exchanges altogether in January after the Obama administration unveiled plans to officially sanction the sale of a $6.4 billion military package to Taiwan - an inalienable part of China.

More recently, China has voiced objections to US military exercises with Republic of Korea (ROK) in the Yellow Sea, part of renewed cooperation between Washington and Seoul.

"The US wanted very much to bring the Sino-US military exchange on track - the scheduled meeting between the two countries' defense ministers in Vietnam is clearly a sign of dtente," said Zhai. "Therefore, Obama's proposal can be seen as yet another friendly signal to China."

However "there is more that the US can do," he added. "Apart from the C-130, the US should export more advanced weaponry to China, to fully realize the normalization and transparency of military exchanges."