Wednesday, November 30, 2011

Pakistan has developed smartest nuclear tactical devices

ISLAMABAD: Pakistan s nuclear programme has made some extraordinary progress by developing one of the world s smartest nuclear tactical devices, it has been learnt.According to a western diplomat, the former dictator and the then President General Pervez Musharraf, during one of his meetings with US officials, had deemed it proper to convey it to the Americans what Pakistan possessed and how the country s nuclear scientists had secured the defence of Pakistan.The diplomatic source said that New Delhi also knows what Pakistan has produced and what is really unmatched. The Indians got this source said and believed that Musharraf intentionally conveyed this to the Americans so that the country is not treated by the US like Afghanistan and Iraq Pakistan is neither a signatory to NPT nor CTBT, however, it has unilaterally decided to use its nuclear programme only as deterrence against any foreign aggression.After becoming the target of the Western capitals particularly Washington, which have been unleashing all sorts of propaganda against Pakistan s nuclear programme, Islamabad has developed one of the most credible and foolproof command and control systems for its nuclear programme. The US authorities have acknowledged the credibility and security of Pakistan s nukes.Wikipedia quotes a Washington-based science think tank as saying that Pakistan is increasing its capacity to produce plutonium at its Khushab nuclear facility. The website said that the estimated Pakistani nuclear weapons was probably in the neighbourhood of more than 200 by the end of 2009. It, however, adds that the actual size of Pakistan s nuclear stockpile is hard for experts to gauge owing to the extreme secrecy, which surrounds the programme. Pakistan s nuclear programme was started by Zulfikar Ali Bhutto while the country conducted its nuclear test on May 28, 1998 during Nawaz Sharif s tenure.

USMC F-35B Training Likely To Begin in Aug. 2012

The U.S. Marine Corps could start training new students to fly its F-35B short take-off vertical (STOVL) landing version of the Joint Strike Fighter (JSF) in August 2012, a senior Defense Department official said.
The DoD has opted to use an approach based on reducing risks prior to starting training operations at Eglin Air Force Base (AFB), Fla., current and former officials said. As such the Pentagon has not set a specific date to issue a military flight release. Instead, the start of training will be "event driven."
Currently "[The U.S. Air Force and Department of the Navy] are waiting for aircraft flight clearance for test pilot maturation flights," a senior DoD official said. Further, "both services are still trying to determine how many maturation hours are needed by test pilots before instructor pilots and then students can be trained."
But if everything goes as currently planned, the Marine Corps students will probably start flying their version of the Lightning II around August 2012.
"Looks like training for STOVL students may go around August of this coming year," the official said. "Once student training starts, it will include all modes including STOVL."
Originally, the STOVL training was projected to start around April 2012. Air Force pilots will likely start training in the F-35A conventional-takeoff version months before the Marines, as previously planned.
But before Marines or any other students take to the air, the F-35 will have to undertake initial maturation flights, using the jet's conventional takeoff and landing mode in the case of the STOVL aircraft. Once clearance is received, the F-35B will fly using all of its modes.
"Nobody wants to go too fast, but on the other hand nobody wants to go too slow," said former Marine Corps deputy commandant for aviation, retired Lt. Gen. George Trautman. "At the end of the day it's going to be informed subjectivity where the leadership decides what sorties need to be flown in the maturation phase. I trust their collective judgment."
Retired Marine Lt. Gen. Emerson Gardner, a former aviator and deputy director of the Pentagon's Cost Assessment and Program Evaluation (CAPE) office, agreed.
"This is a validation of the Marine Corps' event-driven process to achieving initial operating capability," he said. "Instead of identifying specific dates for levels of capability, they have identified which capabilities/levels of proficiency need to be demonstrated before moving to the next level and developed a stair step process to achieving it."
Trautman said that there is an ongoing debate about how many maturation hours the F-35 needs before operational pilots should start flying it.
"I'm actually hoping it doesn't take till August," he said. "There has been a dialogue going on about how many maturation hours are required."
The debate, which is taking place between engineers and other official at Naval Air Systems Command and the Air Force's Aeronautical System Center, stems from the fact the aircraft at Eglin are operational planes flown by fleet pilots, not instrumented like test aircraft at Edwards AFB, Calif., or Naval Air Station (NAS) Patuxent River, Md., Trautman said.
But when it happens, the start of training operations will be an important milestone for the F-35 program.
"Whenever it occurs, absolutely it's a huge deal," Trautman said. "We want to start flying the airplane, we want to start getting the training cadre, the instructor cadre, up to speed so we can start getting students through there."
The sooner the maturation requirements can be met, the sooner the Marines can get pilots through the training pipeline, he said. Getting a base of trained pilots would then allow the Marines to move on to spooling up the first operational F-35B squadron at the Marines' base in Yuma, Az.
"It's been slower in the past year than we would have hoped, but there is lots of indication that the pace is going to pick-up. As it picks up, and things continue to go well for the program, that's the path that they're on, to stand-up that first squadron in Yuma," Trautman said. "It's just the normal evolution of things and it's good to know we're moving in that direction."
Gardner agreed.
"The Corps has begun the transition of all of its aviation inventory over the past decade, from MV-22s to UH-1Ys to AH-1Zs and now to the F-35B. Based on that history, they have learned to be event-driven and not calendar driven," he said. "The fact that they are continuing to move down this path confirms their confidence in the capability and should hearten supporters of the program."

EDA To Set Up Pilot European Satellite Procurement Cell

BRUSSELS - National defense ministers from 26 of the European Union's 27 member states (Denmark has an opt-out) have granted the European Defence Agency (EDA) a budget of 30.5 million euros ($40.7 million) in 2012 and agreed the agency should set up a pilot European satellite communication procurement cell.
Despite a considerable amount of talk about the importance of EU member states pooling and sharing more military capabilities and the ongoing financial crisis, there was precious little agreement on concrete initiatives with specific timelines.
At a news conference Nov. 30, EDA Chief Executive Claude-France Arnould described satellite communications as a "key enabler of any operation," allowing "soldiers to communicate, ships to navigate, HQ to operate in theater."
The new procurement cell will involve six to eight member states including the U.K., said Arnould.
It will be up and running straight away. Currently, member states spend about 3 million to 5 million euros per year to acquire satellite communications bandwidth. Demand is growing, particularly with the widespread use of UAVs on the battlefield, which require substantial communications capacity to control and transmit data from sensors.
The pilot program is designed to prove that pooling demand will reduce both costs (10 percent estimate) and ensure better availability (security of supply and rapid access). Astrium has been selected as the broker for this activity following an open competition.
Arnould said air-to-air refueling was a "major capability shortfall, as shown again in Libya," and that the aim "is to improve operational output and cost effectiveness and to address the dependency on the U.S. of European air forces."
Speaking privately, an EU official said that a medium- and long-term aim is to convince EU member states to reduce the current nine refueling fleets down to four (A400M, C130J, Airbus 330 and B767) and not to buy outside those aircraft types.
Another option Arnould noted is for those member states that are not buying A400Ms to instead purchase kits or pods allowing them to refuel from the A400M.
She stressed that there were "no proposals on the table for common procurement of new equipment" and that "capability is not just about acquisition." Training helicopter pilots is one example of a capability that the EDA has been working on since 2009.
The other eight areas for further consideration include maritime surveillance networking (currently covering EU borders only but might be extended for expeditionary tactical operations such as the Atalanta counter-piracy operation); medical field hospitals; future military satellite communications; ISR; pilot training; European transport hubs; smart munitions (the Libya operation showed that EU member state stockpiles were insufficient and that there was an overdependence on the U.S.); and naval logistics and training (capabilities such as aircraft carriers could be made available at all times by synchronizing maintenance schedules on a multinational basis).
Arnould also stressed that the EDA is working to coordinate with NATO as "cooperation is not a beauty contest between NATO and the EDA." She said the EDA would continue work on pooling and sharing, with a more comprehensive agenda coming out in the spring, just before NATO unveils its so-called smart defense proposals at its Chicago summit.
The key question is whether EU member states will follow up with concrete proposals in the 10 pooling and sharing areas other than the satellite communications cell. Regardless of how many proposals the EDA comes up with, that appears to be in doubt.
Arnould said there was "clear momentum for moving forward" and "an important window of opportunity to improve European defense capabilities" but conceded that "cooperation is not a natural reflex" and that "there are concerns, in particular about sovereignty and autonomy."
EU defense ministers also approved an administrative cooperation agreement between the EDA and Switzerland, under which the two parties can work together on research and technology, and armaments cooperation. The framework agreement sets out procedures for mutual consultation as well as for Swiss participation in ad hoc EDA programs and projects.

Amendment Would Allow U.S.-U.K. F-35 Transfer

The U.S. Senate approved an amendment to the 2012 defense authorization bill that would allow the United States to exchange certain F-35 Joint Strike Fighter (JSF) aircraft with the United Kingdom.
Sen. Carl Levin, D-Mich., chairman of the Senate Armed Services Committee, sponsored the amendment, which was approved by unanimous consent Nov. 30.
The Senate has also voted to limit debate on the authorization bill to another 30 hours, giving the legislation a chance to make it out of the Senate. If passed, the Senate authorization bill will have to be resolved with the House version passed earlier this year before making its way to the president for his signature.
The Pentagon requested the JSF amendment in a June 14 letter from Elizabeth King, assistant secretary of defense for legislative affairs, to Vice President Joseph Biden, in his role as president of the Senate.
The JSF trade, which the Pentagon describes as "mutually beneficial" and "cost neutral," requires such a legislative amendment to be implemented.
According to King's letter, the United States would give the United Kingdom one of its carrier variants (F-35C) in exchange for a short takeoff and vertical landing (STOVL) version (F-35B).
The United Kingdom decided last year, as part of its Strategic Defense and Security Review, to stop buying the F-35B. Instead, the Royal Navy will only buy the F-35C, which is being designed for conventional takeoffs and landings on aircraft carriers.
The cost-savings measure resulted in the U.K. having an extra F-35B on its hands.
The United States, which is buying the F-35B for the Marine Corps and the F-35C for the Navy, was not scheduled to receive its F-35Bs until later. A third variant, the F-35A, is being developed for the Air Force.
Under the exchange, the United Kingdom would have to cover any costs required to upgrade its F-35B aircraft so that it would be identical to the version the U.S. had planned to buy, according to the letter. The United Kingdom would also be responsible for any unique requirements it has for the F-35C.
Under the plan, United States would get an F-35B two years earlier. This means $10 million in additional operations and maintenance costs for the Marine Corps in 2013 and 2014 due to increased flight hours, fuel, training costs, etc.
In January, former Defense Secretary Robert Gates put the F-35B portion of the JSF program on probation for two years, saying he had serious concerns about the aircraft's performance in tests.
"If we cannot fix this variant during this time frame and get it back on track in terms of performance, cost and schedule, then I believe it should be canceled," Gates said.
A separate amendment, also approved Nov. 30, requires Defense Secretary Leon Panetta to submit a report to Congress on the F-35B's probationary period.
Sen. John McCain, R-Ariz., sponsored this amendment, which was also approved by unanimous consent.

Switzerland Taps Saab's Gripen as F-5 Replacement

STOCKHOLM - Swedish defense group Saab AB said Nov. 30 it was "proud and delighted" over Switzerland's decision to purchase 22 of its Gripen fighter jets to replace its aging F-5 fleet.
"Given that Switzerland is known globally for applying (the) highest procurement standards and requesting state-of-the art technologies, Saab is both proud and delighted that Gripen has been chosen as the Swiss Air Force's future multirole fighter aircraft," Saab said in a statement.
The Swiss selection "confirms that Saab is a market-leader in the defense and security industry and that Gripen is a world-class fighter system that provides the best value for money", Saab CEO and president Haakan Buskhe said in the statement.
Gripen is already in service with the Swedish, Czech, Hungarian, South African and Thai air forces.
Saab saw its share price take off on the Stockholm stock exchange after the announcement. Saab closed up 11 percent at 120 kronor ($17.75) in an overall market that closed up 5.14 percent.

Eurocopter Joins Turkey's Light Helicopter Race

ANKARA - Top European helicopter maker Eurocopter announced Wednesday that it will seek to become Turkey's key foreign partner in a program, worth more than $1 billion, to design, develop and manufacture hundreds of light utility helicopters, both military and civilian.
"We want to partner with Turkey in one of their top programs. The light utility helicopter program is a key project," said Thomas Hein, Eurocopter's vice president for sales and customer relations in Europe.

Under two multibillion-dollar contracts, Turkish Aerospace Industries (TAI) is co-producing with Italy's AgustaWestland 59 T-129 attack helicopters and jointly is making with Sikorsky Aircraft more than 100 T-70 utility helicopters, with a single copter weighing about 10,000 kilograms. To meet its heavy-lift helicopter needs, Ankara earlier this year signed a nearly $400 million contract with Boeing to buy six CH-47 Chinook choppers.Light utility helicopters generally weigh between 4,500 and 5,500 kilograms. "We are developing our product range, and we would like to produce, with Turkey, a chopper from scratch," Hein said.
Therefore, light utility helicopters are the last major copter type Turkey wants to produce with a foreign company.
"In my personal view, all major helicopter producers in the world will seek this cooperation with Turkey," Hein said.
Formed in 1992 through the merger of the helicopter divisions of France's Aerospatiale and Germany's DASA, Eurocopter sold 20 AS 532 Cougar utility helicopters to Turkey's military and then co-produced with TAI 30 other Cougars. But since 2006, the company has been silent about major Turkish helicopter deals, and Wednesday's remarks by Hein, who is responsible for ties with Ankara, means Eurocopter is back in the Turkish market.
Although it mainly is a defense project, the light utility program also will manufacture many private and commercial copters. But the Undersecretariat for Defense Industries (SSM), Turkey's procurement agency, has not formally announced the program. The Turkish government is expected to select a foreign partner in 2013. As a result, the number of helicopters to be produced and the financial size of the program are not clear, although the cost is expected to exceed $1 billion.
Although Eurocopter has developed tens of helicopter types in several categories, SSM insists on the development of a new type, and Hein said Eurocopter is ready to produce a new light helicopter with Turkey.
Eurocopter is part of European defense giant EADS.

China Blasts U.S. Deployments to Australia

BEIJING - China criticized a U.S. decision to deploy up to 2,500 Marines to Australia on Nov. 30, calling it proof of a "Cold War mentality," in Beijing's strongest comments yet on the issue.
President Barack Obama announced earlier this month that the U.S. would station the Marines in the northern city of Darwin in what many have viewed as a bid to counterbalance China's growing might in Asia-Pacific.
"We believe that any consolidation or expansion of military alliances is a manifestation of a Cold War mentality," defense ministry spokesman Geng Yansheng said in a statement.
It "does not conform with the current trends of peace, development and cooperation and is not conducive to enhancing mutual trust and cooperation between countries in the region".
Chinese state media has accused the U.S. president of trying to win votes by using his diplomatic ambitions in Asia to detract from U.S. economic woes.
Obama made the announcement as part of a week-long tour of the Pacific - during which he also took in three summits - aimed at asserting the United States as a Pacific power.
The U.S. views with increasing concern China's growing assertiveness in Asia-Pacific on territorial disputes, as do many of the Asian powerhouse's neighbors.
But China maintains it has a policy of "peaceful development" with all countries.
Geng said he hoped "relevant parties will do more to help peace and stability in the Asia-Pacific region, rather than the opposite.

Brazil Boosts Navy, But Fleet's Age, Size a Concern

SAO PAULO - As it bids for great power status, Brazil is boosting its naval power in the South Atlantic with an ambitious submarine program to protect its huge deep-water oil reserves and project its growing influence.
BRAZIL'S AIRCRAFT CARRIER Sao Paulo is seen in the Atlantic Ocean near Rio de Janeiro. (Brazilian Navy via AFP)
The emerging powerhouse already boasts Latin America's largest navy, but its aging fleet, including the Sao Paulo aircraft carrier - formerly the French Navy's Foch - nine British-built frigates and five coastal diesel-electric submarines, is in urgent need of modernization.
"The fleet is currently inadequate to carry out its assigned missions" in the South Atlantic, an area Brasilia regards as of high strategic value, Nelson During, chief editor of Brazil's respected defense website DefesaNet, told AFP.
Under the National Defense Strategy unveiled in 2008, the navy was tasked with developing a force to protect the country's huge "sub-salt" oil reserves, the Amazon river basin and its 7,491 kilometers (4,655 miles) of coastline.
The oil fields, located off Brazil's southeast Atlantic coast beneath kilometers of ocean and bedrock, could contain more than 100 billion barrels of high-quality recoverable oil, according to official estimates.
In a speech to the Navy's top brass in June, President Dilma Rousseff stressed that the buildup, including the acquisition of the country's first nuclear-powered submarine, was a key "instrument of deterrence."
Earlier this month Adm. Luiz Umberto de Mendonca told a congressional panel that some $117 billion would be needed by 2030 to fund the buildup, including the acquisition of 20 conventional submarines, six nuclear-powered ones and the creation of a second fleet to be based on the northeastern coast.
But During said such plans were "totally unrealistic given the 26 percent cut in this year's 15 billion real ($8 billion dollar) defense budget," adding that the navy only gets a third of that.
"We don't have the money and defense is not a priority in Congress," During added. "There is a feeling that we are a large country at peace with the world, with no external conflicts."
Eric Wertheim, an analyst with the US Naval Institute in Annapolis, said that Brazil, with "a powerful economy and around 200 million people ... must be able to defend its deep-water oil fields and protect the Amazon region.
"The country (must) also be ready for an unpredictable future that might include demands like escorting merchant ships that are vulnerable to piracy attacks on the other side of the world," Wertheim, who edits the Naval Institute Guide to Combat Fleets of the World, told AFP.
The recent oil spill from a well operated by a U.S. energy firm off Rio de Janeiro state "showed how unprepared the navy was to deal with such emergencies," he said.
The centerpiece of the naval buildup is the ProSub program, under which France is to supply four diesel-electric submarines and help develop the non-nuclear components of Brazil's first nuclear-powered fast attack submarine.
Except for the first boat, expected to be ready around 2016, all submarines are being built, with French technology transfer, at the Itaguai naval base and shipyard near Rio.
Brazil already has the uranium enrichment technology required for producing nuclear fuel and wants to use it to power the submarine.
But During said that because of repeated delays, the $2.66 billion nuclear submarine was not expected to be completed before 2025.
In addition to its deterrence value, a nuclear sub would give Brazil "status" and add "credibility" to its ambition to become a permanent member of the U.N. Security Council, he added.
Brazil also "intends to show the flag" in the South Atlantic, in view of its growing trade ties with African countries across the ocean, particularly former Portuguese colonies such as Angola, During said.
Some Brazilian strategists argue that Brazil should become "the dominant naval power in the South Atlantic, without excluding others," he added.
Last year, former defense minister Nelson Jobim raised eyebrows when he described any expanded NATO presence in the South Atlantic as "inappropriate," and some Brazilian lawmakers expressed concern when the United States decided to reactivate its 4th Fleet in the area in 2008.
But During dismissed those comments "as rhetoric for domestic consumption."

Germany Lends Air-Defense Radar to Israel

TEL AVIV - Germany recently delivered a Patriot air defense radar to Israel as a cost-free loaner pending conclusion of a three- to four-year refurbishment in the United States of Israel's own AN/MPQ-53 radars for its PAC-2 force.
German, U.S. and Israeli sources confirmed the trilateral cooperation, aimed at filling potential gaps in Israeli air defense coverage while Israel Air Force radars are being serviced at Fort Sill, Okla.
The loaner radar provided by the German Bundeswehr arrived here in mid-October, shortly before the first of three Israeli Patriot radar sets was shipped to the United States for servicing. The German delivery marks an expansion of strategic cooperation with Israel, which received two full-up Patriot PAC-2 batteries from Luftwaffe stocks in 2003 in the run-up to the U.S.-led coalition war in Iraq.
Sources said it will take about a year to replace aging components of each radar, extend service life, and improve its ability to interoperate with U.S. European Command's Patriot batteries that participate in biannual U.S.-Israel exercises and could be rushed here for emergency deployment during wartime.
The refurbishment program is estimated at $15 million and will be funded through annual U.S. Foreign Military Financing (FMF) assistance to Israel. Israeli and German officials confirmed that the German loaner radar would remain here until the upgrade program is complete and all Israeli radars are redeployed and integrated with other elements of the Air Force's Air Defense Force.
"Germany has contributed to the air defense system of Israel since 2003 with the loan of two Patriot systems. Additional components are temporarily on loan to maintain the operational capability of the systems," said Lt. Col. Holger Neumann, a German MoD spokesman.
An Israel Air Force officer emphasized that the recently launched Patriot radar upgrade is more logistical in nature and is not aimed at converting Israel's PAC-2 air defense force to the PAC-3 ballistic missile intercepting configuration.
Israel has no plans to procure PAC-3 missile interceptors from Lockheed Martin, he said. Instead, the Air Defense Force is looking to deploy the David's Sling air and missile defense system now in development by Rafael and Raytheon.
Nevertheless, the Air Force officer said Israel "is looking very closely" at a so-called Config-3 program that would render its existing PAC-2 force more capable of operating with PAC-3 intercepting batteries.
No decision has been made on the estimated $60 million Config-3 program with Raytheon, producers of the Patriot radar, engagement control stations, launching units, and improved PAC-2 interceptor missiles.

Still-angry Pakistan Backs Out of Afghan Conference

ISLAMABAD - Pakistan decided Nov. 29 to boycott a key international conference on Afghanistan next month, ramping up its protest over lethal cross-border NATO air strikes that have plunged U.S. ties into deep crisis.
The decision was taken at a Pakistani cabinet meeting in the eastern city of Lahore, days after Islamabad confirmed it was mulling its attendance in the German city of Bonn, where Pakistan's participation was considered vital.
"The cabinet has decided not to attend the Bonn meeting," a government official told AFP on condition of anonymity.
The prime minister's office said the cabinet agreed that "unilateral action" such as the Nov. 26 strike in the tribal district of Mohmand and the May 2 killing of Osama bin Laden near the capital was "unacceptable."
U.S.-led investigators have been given until Dec. 23 to probe the attacks, threatening to prolong significantly Pakistan's blockade on NATO supplies into Afghanistan implemented in retaliation for the killings.
The U.S. military appointed Air Force Brig. Gen. Stephen Clark to lead the investigation into the attack.
The team, set to include a NATO representative, is yet to arrive in Afghanistan but an initial military assessment team went to the border at the weekend after the catastrophic strike that killed 24 Pakistani troops.
The Afghan and Pakistani governments are also being invited to take part.
There was no immediate reaction from Islamabad or Kabul, although some analysts voiced surprise that it will take as long as nearly four weeks.
A Western military official in Kabul said the schedule for the findings being delivered was "way quicker" than initially expected.
U.S.-Pakistani ties have been in free fall since a CIA contractor killed two Pakistanis in January, and the latest attack raises disturbing questions about the extent to which the two allies cooperate with each other.
Islamabad insists that the air strikes were unprovoked, but Afghan and Western officials have reportedly accused Pakistani forces of firing first.
"With the kind of technology available to the U.S. and NATO, it was expected they would be able to do it [the investigation] much earlier, not more than two weeks," Pakistani defence analyst Talat Masood told AFP.
In Pakistan, angry protests over the NATO strikes pushed into a fourth day, with 150 to 200 people demonstrating in Pakistani-administered Kashmir, setting fire to an American flag and an effigy of NATO chief Anders Fogh Rasmussen.
The crowd carried banners and shouted: "Those who befriend America are traitors" and "We are ready for jihad," an AFP reporter said.
Pakistan has vowed no more "business as usual" with the United States. In addition to shutting its Afghan border, it has ordered Americans to vacate an air base reportedly used by CIA drones and a review of the alliance.
Yet behind the rhetoric, Islamabad has little wriggle room, being dependent on U.S. aid dollars and fearful of the repercussions for regional security as American troops wind down their presence in Afghanistan in the coming years.
In an interview with CNN, Prime Minister Yousuf Raza Gilani stopped short of threatening to break the alliance altogether saying: "That can continue on mutual respect and mutual interest."
White House spokesman Jay Carney said U.S. President Barack Obama believed the latest incident was "a tragedy," and said Washington valued what he called an "important cooperative relationship that is also very complicated."
Last time Pakistan closed the border, in September 2010 after up to three soldiers were killed in a similar cross-border raid, it only reopened the route after the United States issued a full apology.
The U.S. military has insisted the war effort in Afghanistan would continue and has sought to minimize the disruption to regular supply lines.
Nearly half of all cargo bound for NATO-led troops runs through Pakistan.
About 140,000 foreign troops, including about 97,000 American forces, rely on supplies from the outside to fight the 10-year-old war in Afghanistan.
Yet so far, officials say there has been no sign that Islamabad would bar the U.S. aircraft from flying over Pakistan.

China's First Aircraft Carrier Starts Second Trial

BEIJING - China's first aircraft carrier began its second sea trial on Nov. 29 after undergoing refurbishments and testing, the government said, as tensions over maritime territorial disputes in the region ran high.
The 300-meter (990-foot) ship, a refitted former Soviet carrier called the Varyag, underwent five days of trials in August that sparked international concern about China's widening naval reach.
"China's aircraft carrier platform, after successfully completing its first sea trial in August, returned to the shipyard as planned for further refitting and testing," the defense ministry said in a brief statement.
"The work has been carried out and it set sail again on November 29 to carry out relevant scientific and research experiments."
Beijing only confirmed this year that it was revamping the old Soviet ship and has repeatedly insisted that the carrier poses no threat to its neighbors and will be used mainly for training and research purposes.
But the August sea trials were met with concern from regional powers including Japan and the United States, which called on Beijing to explain why it needs an aircraft carrier.
The Nov. 29 announcement comes against a background of heightened tensions over maritime disputes in the Asia-Pacific region, where China's growing assertiveness has put it on collision course with the United States.
President Barack Obama this month irritated Beijing with a drive to enhance the U.S. role as a regional power, positioning Marines in northern Australia and pushing for a potentially transformational trans-Pacific trade pact.
Beijing sees the initiatives as intruding into its own sphere of influence, with the dispute over the South China Sea putting the two major world powers' differences into stark focus.
China claims all of the strategic area, as does Taiwan, while four Southeast Asian countries declare ownership of parts of it, with Vietnam and the Philippines accusing Beijing's forces of increasing aggression there.
The region is a conduit for more than one-third of the world's seaborne trade and half its traffic in oil and gas, and major petroleum deposits are believed to lie below the seabed.
The announcement of the carrier's second sea trial comes after Beijing said last week it would conduct "routine" naval exercises in the Pacific Ocean before the end of November.
China reportedly bought the carrier's immense armored hull - with no engine, electrics or propeller - from Ukraine in 1998.
The PLA - the world's largest active military - is extremely secretive about its defense programs, which benefit from a huge and expanding military budget boosted by the nation's runaway economic growth.
Earlier this year, China announced military spending would rise 12.7 percent to 601.1 billion yuan ($91.7 billion) in 2011.

Russia Activates Missile Warning System Near EU

MOSCOW – Russia on Nov. 29 activated a radar warning system against incoming missiles in its exclave of Kaliningrad on the borders of the EU, in response to Western plans for a U.S. missile shield in Europe.
President Dmitry Medvedev announced that the Voronezh-DM station was moving on to immediate combat readiness, days after threatening to deploy missiles in Kaliningrad amid a growing dispute with the West.

Using rhetoric reminiscent of the Cold War, he added: "If this signal is not heard, we will deploy other methods of protection including the taking of tough countermeasures and the deployment of strike forces.""I expect that this step will be seen by our partners as the first signal of the readiness of our country to make an adequate response to the threats which the (Western) missile shield poses for our strategic nuclear forces," Medvedev said.
Medvedev said last week Russia was prepared to deploy Iskander missiles, which officials say have a range of up to 500 kilometres (310 miles), in the Kaliningrad exclave that borders EU members Poland and Lithuania.
Romania and Poland have agreed to host part of a revamped U.S. missile shield which Washington said is aimed solely at "rogue" states like Iran but Moscow believes would also target its own capability.
NATO member Turkey has decided to host an early warning radar at a military facility near Malatya in the southeast as part of the missile defence system.
Medvedev, who visited Kaliningrad to sign the decree on activating the station, said Russia needed to hear more than promises from the West to resolve the standoff.
"Verbal statements do not guarantee our interests. If other steps are made then of course we are ready to listen," Medvedev added in a statement quoted by Russian news agencies from Kaliningrad.
"We can no longer be content with verbal promises that the (U.S. missile shield) system is not aimed against Russia. These are empty statements and do not guarantee our security."
But he said that the activation of the Kaliningrad station "does not close the door for dialogue" with the United States on missile defense.
Kaliningrad is part of the former German East Prussia region that was annexed by the Soviet Union at the end of World War II and remains one of Moscow's prime territorial strategic assets.
The RIA Novosti news agency quoted Defense Minister Anatoly Serdyukov as saying that the station could keep track of 500 objects at a range of up to 6,000 kilometers.
The move comes in the run-up to legislative elections on Dec. 4, where Medvedev is leading the list of the ruling United Russia party amid an atmosphere of growing nationalism in Russia.
Medvedev has championed a reset of relations with the United States under President Barack Obama. But Prime Minister Vladimir Putin, who traditionally has a more prickly relationship with the West, is set to become president in 2012.
An analyst said the decision to activate the system was important but had to be seen in a domestic context.
"Data from this station will allow Russia's leadership to make a decision about a retaliatory nuclear strike, should such a hypothetical need arise," said Mikhail Khodaryonok, editor of journal "Aerospace Defence."
But he described the announcement as mainly "pre-election rhetoric" given that both the U.S. missile shield and the Russian system are defensive in nature.
"You would really need to have a vivid imagination to link it to the U.S. missile defense system."