BEIJING — In June 2012, China reveled in a major scientific achievement: The nation's first manned deep-sea submersible, the Jiaolong, had dived more than 4.3 miles into the Mariana Trench in the Pacific Ocean. The feat, state-run media said, put China among the elite ranks of such deep-sea-faring countries as the U.S., France and Japan.
Equipped with sonar equipment and two mechanical arms that can lift as much as 220 pounds, the submersible is just the kind of vehicle that might prove useful in the search for missing Malaysia Airlines Flight 370, which investigators now believe is resting 2.8 miles beneath the surface of the Indian Ocean. Of the jet's 239 passengers and crew members, 153 were Chinese.
But while China has launched itself into the search effort with gusto — it focused its satellites to search for debris, scrambled ships and dispatched airplanes — the effort has thrown an awkward light on the gap between the country's high-tech aspirations and its limitations.
China hasn't offered the Jiaolong and the Australia-based search team hasn't asked, leaving the lead role to a U.S.-built robot sub, the Bluefin-21.
"We are frustrated that we have this great vehicle and it's not being deployed on this important mission," said Cui Weicheng, who helped design the Jiaolong and was aboard the vessel on several missions.
Then again, Cui acknowledged, Chinese officials might be worried about getting the submersible to the search area. Its mother ship, the Facing the Red Sun No. 9, built in 1978, has had engine problems and is unreliable.
"On its last mission, from June to September 2013, the mother ship broke down many times," Cui said. "It needed many repairs.... I think that's why the Chinese government may be hesitating to send it."
Forty days into the quest to locate the Boeing 777, it's been American, Australian and British equipment and vessels that have turned up what investigators have called the most promising leads. Meanwhile, officials in other countries have chafed about China getting out over its skis, rushing to release technical findings that proved to be false leads.
"We cannot deny that the United States has much more advanced technology in this regard," said Xu Guangyu, a retired military officer who is a consultant with the Beijing-based China Arms Control and Disarmament Assn. "The U.S. satellite system is much better, as is their ability to analyze very complicated data. These are things that we have to learn from the United States."
Last week, the state-run China Daily newspaper ran a rather frank front-page article headlined "Tech Gap Exposed in Search Mission; Experts Say More Development Needed in Nation's Advanced Maritime Equipment."
A few days earlier, China had grabbed headlines — and caught Australian search coordinators off guard — when state-run CCTV announced that China's Haixun 01 search vessel might have picked up acoustic transmissions from the jet's data recorders. It was the first report of any such "pings."
But questions quickly arose when photos showed searchers using a commercially available $16,000 hand-held device, made in the United States, dangled over the side of the boat. An Australian navy ship, meanwhile, towed a deep-water pinger locater lent by the U.S. military.
Little more was said about the purported pings until this week, when Angus Houston, the retired Australian air chief marshal who has been coordinating the search efforts from Perth, said the Chinese data had been "analyzed and discounted as a credible transmission." He said investigators were relying on four other detections made by the American pinger locater.
Though Houston tried to minimize the awkwardness of the Chinese disclosure, other governments have bluntly admonished Beijing.
Malaysia's acting transportation minister, Hishammuddin Hussein, rebuked it for wasting time by posting satellite imagery purporting to show debris over the South China Sea, along the aircraft's intended flight path. The photos, he said, had been released by "mistake."
China ought to be familiar with such "nontraditional security" missions. In the last decade, its military has practiced similar operations during exercises with foreign militaries and governments, said Dennis Blasko, a former U.S. Army attache to China and author of "The Chinese Army Today."
"This gives them a chance to implement that type of training in a real-world situation," Blasko said.
But the search has exposed a lack of trust not only in China's information, but in its intentions.
India, for instance, refused a request last month for China to send four warships to join the search around the Andaman Islands.
"China has been sniffing around Indian waters for a long time. Delhi was naturally suspicious of that request," said C. Raja Mohan, an Indian academic who has written widely about Sino-Indian maritime rivalry.
In China, where the search has received wall-to-wall media attention, the public is eager to see the country make a breakthrough contribution. Asked about it Monday, Foreign Ministry spokeswoman Hua Chunying said that China was "going full steam ahead with the search operation."
As speculation ran high last week that China might dispatch the Jiaolong, named for a fabled sea dragon, authorities posted a statement on the submersible's long-dormant Sina Weibo microblog account, apologizing for not keeping the account up to date. It explained that the team lacked the staffing to share fresh information.
Internet users met the message with disappointment and derision.
"To be honest, we don't really care if you actually write posts on Weibo," one commenter said. "We care about whether you can appear in the ocean southwest of Australia."
Said another, "We need a dragon that can dive into the ocean, not a worm that can only bluff."
Tommy Yang of The Times' Beijing bureau contributed to this report.