Pilots at Edwards Air Force Base (AFB), Calif., have started to test fly the F-35 Lightning II fighter at night, Lockheed Martin announced Jan.19.

Flown by company test pilot Mark Ward, aircraft AF-6, which is an F-35A conventional takeoff and landing variant, took off at 17:05 on the afternoon of Jan. 18 and landed a little after sunset. The jet flew for a little more than an hour.

The sortie consisted of basic straight-in approaches, Lockheed’s press release said.

Meanwhile, on the other side of the country at Eglin AFB, Fla., Marine Maj. Joseph “O.D.” Bachmann flew the 33rd Fighter Wing’s third F-35B to the seaside base on Jan. 19. The addition of the short takeoff vertical landing fighter brings the total number of F-35s at the Florida base to nine. Two B-models and six F-35As were delivered earlier.

U.S. Navy Document Plans Carrier Air Wings’ Future

The U.S. Navy’s carrier air wings of tomorrow will look very different from today’s, according to a new document produced by the sea services.

By 2032, the Navy’s fleet of F/A-18E/F Super Hornet fighters and new EA-18G Growler electronic attack jets will have begun to be replaced by new types, a new document called Naval Aviation Vision 2012 says.

The Navy will consider manned, unmanned and optionally manned aircraft to replace the long serving Rhino, as the F/A-18E/F is known to carrier deck crews. The Super Hornet will begin to reach the end of its service life around 2025 and must be replaced. The document says a competitive fly-off will be held at some point in the future.

The Super Hornet-derived EA-18G will also start being replaced by a new aircraft, but the document offers no further details.

Additionally, a new Unmanned Carrier Launched Surveillance and Strike (UCLASS) is to be integrated onto the carrier deck around 2018 — possibly with four to six planes embarked. The aircraft could make use of technologies developed by the X-47B program. The Navy document calls for “balanced survivability” so that the unmanned strike plane will be effective in “specified tactical situations.”

The F-35C will serve alongside these prospective aircraft.

But the Navy isn’t going to stop with replacing just its fixed-wing assets, as the document calls for the wholesale replacement of its helicopter fleet.

The MH-60 helicopter fleet will be supplanted by a new rotary-wing aircraft. The Fire Scout unmanned helicopter will also be replaced as will the MH-53E Sea Dragon counter-mine and heavy lift helicopter. In the case of the MH-53E, a replacement aircraft needs to be operational by 2026, the document says.

The Marines will get a Cargo Resupply Unmanned Aerial System (CRUAS) by 2032, and the service’s entire fleet of tactical remotely operated drones will be replaced. The Navy will continue to fly the Broad Area Maritime Surveillance version of the Global Hawk unmanned plane in 2032.

The training aircraft fleet will look similar to today’s, the document says. The T-6 and T-45C will soldier on, as will the TH-57 training helicopter. But the T-44 and TC-12B multi-engine turboprop trainers will be replaced with a new aircraft. The Marines’ C-20 and Navy’s C-26D and UC-12 fleets will also be replaced. As well, a new plane will take the place of the C-2 Greyhound carrier onboard delivery plane starting in 2026.

Nor has the Navy forgotten about its fleet of F-5 and F-16 aggressor aircraft. A replacement aggressor aircraft is envisioned for 2025, according to the document.

JSF may miss acceleration Goals

The F-35 Lightning II’s transonic acceleration may not meet the requirements originally set forth for the program, a top Lockheed Martin official said.

“Based on the original spec, all three of the airplanes are challenged by that spec,” said Tom Burbage, Lockheed’s program manager for the F-35. “The cross-sectional area of the airplane with the internal weapons bays is quite a bit bigger than the airplanes we’re replacing.”

The sharp rise in wave drag at speeds between Mach 0.8 and Mach 1.2 is one of the most challenging areas for engineers to conquer. And the F-35’s relatively large cross-sectional area means, that as a simple matter of physics, the jet can’t quite match its predecessors.

“We’re dealing with the laws of physics. You have an airplane that’s a certain size, you have a wing that’s a certain size, you have an engine that’s a certain size, and that basically determines your acceleration characteristics,” Burbage said. “I think the biggest question is: are the acceleration characteristics of the airplane operationally suitable?”

A recent report by the Defense Department’s top tester, J. Michael Gilmore, says that the Navy’s F-35C model aircraft, which has larger wing and tail surfaces, is not meeting requirements for acceleration.

The report doesn’t say whether the F-35A and F-35B have hit similar snags.

Richard Aboulafia, an analyst with the Teal Group, Fairfax, Va., said that the revelation was not particularly surprising.

“It’s a strike fighter,” Aboulafia said. “It’s not an interceptor; it’s not an F-22.”

Aboulafia said it was unclear whether additional engine power could boost acceleration in the difficult transonic regime. So far, doubts about the aircraft’s aerodynamic performance haven’t diminished Lockheed’s sales prospects, he said.

The F-35 transonic acceleration specifications were written based on clean-configuration F-16 Fighting Falcon and F/A-18 Hornet fighter, Burbage said.

But unlike the Hornet or the F-16, the F-35 has the same configuration unloaded as it does loaded with weapons and fuel, Burbage said. When an F/A-18 or F-16 is encumbered with weapons, pylons and fuel tanks, those jets are robbed of much of their performance.

“What is different is that this airplane has accelerational characteristics with a combat load that no other airplane has, because we carry a combat load internally,” Burbage said, the F-22 Raptor notwithstanding.

Even fully loaded, the F-35’s performance doesn’t change from its unencumbered configuration, he said.

In the high subsonic range between Mach 0.6 to Mach 0.9 where the majority of air combat occurs, the F-35’s acceleration is better than almost anything flying.

Thus far, Lockheed has not had issues with the plane’s acceleration, Burbage said. There are top level Key Performance Parameters from which lower level detailed engineering specification are derived and Lockheed’s job is to meet as many of those specifications as possible within the laws of physics, he said. Discussions are underway about if those original specifications are relevant given the jet’s acceleration in a combat configuration, Burbage added.

Air Force Lt. Col. Eric Smith, director of operations at the 58th Fighter Squadron at Eglin Air Force Base, Fla., and F-35 test pilot, said that flying the aircraft is a thrilling experience.

“I can’t even explain the adrenaline rush you get when you light the afterburner on that thing,” Smith said. “The acceleration is much better than an F-16.”

But the F-35’s aerodynamic performance is not what makes the jet special, Smith said. The F-35 powerful sensors and data-links and how that information is fused into a single coherent and easy to use display are what will make the jet an effective warplane.

Burbage added that while the F-35 is designed as a supersonic fighter, it’s not optimized for the extremely high supersonic speeds that the Raptor was designed to operate at.

“This is not a supercruising airplane like the F-22,” Burbage said.

Lockheed Touts Fix for F-35 Fuel Dump

Lockheed Martin has found a way to fix the F-35 Lightning II’s fuel dump system, eliminating a potential fire hazard, a top company official said.

“We expect to have that configuration change back in the test airplane early this year,” said Tom Burbage, Lockheed’s Joint Strike Fighter program manager. “The permanent modification that will go into all the production airplanes will be tested by the second quarter of this year.”

The current test aircraft fleet has an interim solution installed, Burbage said.

In conventional aircraft, fuel can be dumped through a mast that ejects the fluid away from the aircraft’s surfaces. But to keep the F-35 stealthy, the design pumped fuel out forcefully from a valve that is flush with the wing, Burbage said. This design allowed a portion of dumped fuel to move back toward the aircraft’s structure. On the Marine Corps’ F-35B version of the aircraft in particular, the fuel could flow too close to the roll-post ducts, part of the short-takeoff-and-vertical-landing system, and potentially ignite.

The problem came to light in a November report to acting Pentagon procurement czar Frank Kendall compiled by the Defense Department’s top operational tester, J. Michael Gilmore.

DoD Tester: Toxins Suspected in 2011 Raptor Grounding

A Jan. 13 report from the Pentagon's top tester said the U.S. Air Force grounded its F-22 Raptors last year "due to suspected contamination problems associated with the aircraft environmental control system and associated onboard oxygen generation system form later April through late September 2011."

A U.S. AIR Force F-22 Raptor prepares to land at Joint Base Elmendorf-Richardson, Alaska, on Nov. 16, two months after the service lifted its fleetwide grounding. (Staff Sgt. Sheila deVera / U.S. Air Force)

Complied by the Pentagon's chief operational tester J. Michael Gilmore, the review confirms Defense News' July 25, 2011, report that toxins entering the cockpit of the Raptor had caused more than a dozen incidents that resembled hypoxia.

Since the grounding was lifted in September, the Raptor has flown more than 6,000 times. More incidents have occurred, despite Air Force precautions that include installing charcoal-based filters and having pilots wear pulse-oximeters to alert them of problems.

"There have been approximately 90 events of interest and 15 are being investigated for potential physiological incidents -- 8 involving pilots and 7 involving aircraft maintenance personnel," said Air Force spokeswoman Jennifer Ferrau. "This translates to a 1.8 percent event rate since the return to flight in September."

The Air Force categorizes these occurrences into "events of interest" and "physiological incidents." An event of interest is an aircraft indication, system malfunction or a data point that has not caused symptoms of hypoxia, but is noteworthy for data collection and further analysis, Ferrau said.

"Any event involving hypoxia-like symptoms may be categorized by Air Force Instructions as a physiological incident following an investigation," she said.

A Scientific Advisory Board quick-look study ordered last year by Air Force secretary Michael Donley should be finalizing its report either in late January or early February.

Sources say the service investigators have not found any single explanation for the Raptor's woes. The problem can't be duplicated on the ground, nor do the hypoxia-like incidents occur during any consistent altitude or phase of flight-if in fact the cause happens in the air.

Raptor Weapons School Back In Action

The F-22 Raptor division of the U.S. Air Force's elite Weapons School is back up and running after last year's grounding, a service official said.

"Raptor has been back fully integrated at Weapons School since we returned to fly," said Col. Robert Garland, the school's commandant. "Four students in class 12A started this past Monday."

Classes at the school started Jan. 9 for all of the squadrons, whose students will graduate in June.

Known as the "Satan's Angel's," the 433rd Weapons Squadron runs classes for both the Raptor and F-15 Eagle, an arrangement that makes the unit somewhat of an oddity among the Weapons School's 17 squadrons. The 433rd also works closely and shares its Raptors with the 422nd Test and Evaluation Squadron, which tests new hardware and develops new tactics, because only 187 production F-22s were built.

The Weapons School selects the best of the Air Force's instructors and molds them into weapon and tactics officers who become the service's tactical gurus.

The course runs for six months and the school runs two courses a year. About 80 students graduate per class.

Asian Navies Shift to Bigger Vessels, Downplay Littoral Ops

TAIPEI - As Western navies build fewer aircraft carriers, destroyers and submarines, Asian navies are moving in the opposite direction, ignoring the littorals with construction and procurement of larger warships and submarines.

The U.S. and Europe have stepped back from larger platforms designed for the Cold War and invested in smaller platforms such as the U.S. Navy's Freedom-class Littoral Combat Ship (LCS). But this is not the case in East Asia and the Pacific, where there have been increases in spending on destroyers and submarines in Australia, China, India, Japan, South Korea and Taiwan, said Bob Nugent, vice president of naval advisory services at AMI International, based in Seattle.

One of the most notable cases involves Taiwan's procurement of four Kidd-class guided missile destroyers and plans to procure eight submarines. Japan and South Korea have also invested heavily in guided missile destroyers equipped with advanced phased array radars.

Even in budget-challenged Southeast Asian countries, the trend has been a shift from smaller to larger platforms, such as frigates and large corvettes. Examples include Singapore's Formidable-class frigates, Indonesia's SIGMA-class corvettes, Malaysia's recent decision on the SGPV/LCS frigates, and Vietnam's plan to buy SIGMAs and the pending delivery of Russian-built Kilo-class submarines.

The main reason regional navies are ignoring littoral capabilities has to do with geography. In the region, "the home team enjoys an enormous advantage of range and proximity and the attacker would have to be prepared to conduct pre-emptive strikes against the coast state's bases before conducting operations in the littoral," said Sam Bateman a regional naval specialist at the S. Rajaratnam School of International Studies, Nanyang Technological University, in Singapore.

The U.S. Navy should "think twice" about deploying classic sea control/power projection capabilities, such as carrier battle groups, within range of subs and land-based strike aircraft, Bateman said. The U.S. Navy's new LCS will be "hugely vulnerable without close-air support and that cannot be guaranteed."

The U.S. and Singapore have recently agreed to allow the U.S. Navy to station the LCS in Singapore.

Air support is the "elephant in the room" with littoral warfare, Bateman said. Littoral warfare is dependent on fire support directed against targets on land, either from aircraft close-air support or naval gunfire. Despite all the advances with missiles, "the big caliber naval gun remains an attractive and effective way of putting down fire in coastal areas."

Another problem in the Asia-Pacific has been increased tension over exclusive economic zone (EEZ) claims, particularly in the South China Sea. Many countries, including China, claim restrictions over naval operations in their EEZs.

Some within the region have invested in stealthy vessels to avoid detection in the littoral environment. Singapore's Formidable-class frigates are based on the stealthy French-built La Fayette-class frigates and Singapore's ST Engineering is conducting research to develop the 27-meter Stealth Interceptor and 57-meter Stealth Patrol Vessel.

Taiwan wants to build a stealthy 900-ton catamaran corvette and is manufacturing a stealthy 180-ton fast-attack missile patrol boat, armed with Hsiung Feng-2 anti-ship missiles. The stealthy SIGMA-class corvettes procured by Indonesia and now being considered by Vietnam are other examples.

For Asian countries dealing with the littoral issue, the challenge is finding the right investment balance among intelligence, surveillance and reconnaissance (ISR) and defensive and offensive technologies, Nugent said.

"Unmanned systems are critical to ISR and defense in the littoral now and will become more so for offensive littoral warfare as unmanned maritime systems are more widely armed for all domains in the future," he said. Investments in better sensors and C4ISR are the other areas where the "gaps that create vulnerabilities in ship's self-defense against missiles and torpedoes in the littoral are getting a lot of attention."

Another area of growing interest is the use of unmanned surface vehicles (USV) and unmanned underwater vehicles (UUV). ST Engineering is developing the 9-meter Venus USV ostensibly for harbor patrol, but the vessel has potential for littoral warfare.

USVs and UUVs will be "particularly useful for littoral warfare as they can be launched outside the EEZ or convenient surveillance range of the coastal state, which is unlikely to have the capabilities of detecting them," Bateman said. "They can be used for surveillance/intelligence collection and as an offensive weapon - to lay mines or fire torpedoes," he said.

There is also potential for anti-submarine warfare, but that capability is as yet "unrealized."

1st Two F-35Bs Delivered to USMC

The U.S. Marines' first two production F-35B Lightning II Joint Strike Fighters (JSF) arrived at Eglin Air Force Base (AFB), Fla., plane-maker Lockheed Martin announced Jan. 12.

BF-6, THE FIRST F-35B production jet delivered to the U.S. Marine Corps, arrives at its new assignment at Eglin AFB, Fla. (Angel DelCueto / Lockheed Martin)

The two short take-off vertical landing fighters were flown in separately by Marine aviators Maj. Joseph Bachmann and Lt. Col. Matt Taylor. The pilots flew aircraft BF-6 and BF-8 respectively.

Under an unorthodox arrangement, while the jets belong to the 2nd Marine Aircraft Wing's VMFAT-501 squadron, the unit resides with the U.S. Air Force's 33rd Fighter Wing alongside the Navy's VFA-101 and the Air Force's 58th Fighter Squadron.

The Marines could start training new students to fly the F-35B in August, a senior Defense Department official had said earlier. However, currently the Pentagon has not yet formally set a date for training to start at the Florida base.

The DoD has opted to use an approach based on reducing risks prior to starting training operations at Eglin, the official 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."

"[The U.S. Air Force and Department of the Navy] are waiting for aircraft flight clearance for test pilot maturation flights," the 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.

U.S. Won't Adopt E.U. Code of Conduct for Space

The United States will not adopt a European-written "code of conduct" for activities in space on the grounds that it is too restrictive, according to a senior State Department official.

"It's been clear from the very beginning that we're not going along with the code of conduct," Ellen Tauscher, undersecretary of state for arms control and international security, said during a Jan. 12 breakfast with reporters in Washington.

Asked why the U.S. government would not sign the document, Tauscher said, "It's too restrictive."

The European Union has been working the voluntary code of conduct for several years. The document lays out rules of the road for operating satellites and other space vehicles as space becomes increasingly congested, the idea being to minimize the chances of collisions or misunderstandings that could escalate.

The code also focuses on dealing with space debris, a problem that began getting greater public attention in 2007 after China destroyed one of its own orbiting satellites with a ground-launched missile.

"We made it very definitive that we were not going to go ahead with the European Code of Conduct; what we haven't announced is what we're going to do, but we will be doing that soon," Tauscher said.

Up to now, the U.S. government has been circumspect about its intentions with regard to the code. In April, for example, Ambassador Greg Schulte, U.S. deputy assistant secretary of defense for space policy, described the code as a "positive approach" but stressed that the U.S. government had not yet decided whether to sign the document.

Some U.S. lawmakers have raised concerns that the nonbinding agreement would tie the U.S. military's hands in space. "We've advanced further technologically in development and actual deployment of these systems than anyone else, and agreements [and] codes of conduct tend to … constrain our military," Sen. Jeff Sessions (R-Ala.) said during a hearing on the subject in May.

"We had never said we were going to do it; we just hadn't said 'no,'" Tauscher said.

Hinting at new U.S.-written rules of the road for space, Taushcer said, "You wouldn't be surprised to find out that we've found a nice sweet spot."

The Pentagon had concerns with the European strategy for space traffic management, but there are also "ways to deal with it," according to Michael Krepon, co-founder of the Stimson Center, a think tank here. The U.S. Defense Department did a lengthy assessment of the code of conduct and reviewed particular provisions that "would make sense for our national security."

"If the satellite is stealthy, or we want it to be stealthy, how does that fit into a traffic management system?" he said. "Now you argue … major space-faring nations can figure out the orbital characteristics of objects in space, but it you want to move an object in space do you provide advance notice of this or how do you handle that?"

If the Obama administration is going ahead with a new strategy, then the Pentagon's concerns have likely been addressed, Krepon said.

In 2004, the Stimson Center published a draft code of conduct for space, which is similar to the document pushed by the European Union.

"I think the problematic piece that the administration was struggling with was that it was made in Europe and that the really important space-faring nation felt no ownership of it," he said.

Russia, China, India and Brazil have all distanced themselves from the document, Krepon said. At the same time, Canada and Japan have endorsed the document.

"I think the conundrum that the administration is facing is how to bring in major space-faring nations that have kept their distance from the E.U.'s handiwork," he said.

The Pentagon supports a space international code of conduct, Lt. Col. April Cunningham, a DoD spokeswoman, said.

An AirSea Battle on the Potomac

It is clear from last month's commemoration of the 70th anniversary of the attack on Pearl Harbor that this disaster continues to impact the U.S. psyche and national strategy. "The next Pearl Harbor" has been a common theme in reports regarding 9/11.

One can assume the recently developed and classified AirSea Battle Concept has a similar vista. Addressing the "anti-access/area denial" environment, it purportedly discusses the growing influence of China and the importance of Asia to America's national interests. As the name states, air and sea power will be critical to the attainment of U.S. national interests.

While analogies to Pearl Harbor are understandable, they may be misleading on the challenges of tomorrow. A more appropriate lesson might be found in the Battle of Midway.

As the sun rose on June 4, 1942, the Imperial Navy of Japan was the most powerful navy ever to sail. By sunset, its eventual defeat was inevitable. Japan in 1942 possessed six world-class aircraft carriers and the finest naval aviators. Four carriers were lost on that day.

Lacking a robust industrial base, Japan would produce only seven additional fleet carriers by the end of the war (the U.S. more than 20). Rational or not, Japan started a war with a limited force structure and little ability to replenish loses.

Fast-forward to 2012. In a world of iPads, it is incredible, but the forces that will carry out the AirSea Battle construct reflect decisions made decades ago. Tomorrow's U.S. Air Force will possess a nominal force of bombers and a handful of sophisticated F-22s and F-35s. While highly capable, these fifth-generation fighters lack the range and payload necessary for conflicts in Asia. Friendly bases are few.

The airfields close enough for effective sortie generation rates with fifth-gen fighters will likewise be within range of Chinese ballistic and cruise missiles. This environment requires hardened facilities and a robust missile-defense system. The former do not exist and the latter only in limited numbers.

While U.S. naval forces will benefit from their mobility, they too will face a Chinese anti-access threat projected to acquire and target surface combatants. With a deck of F/A-18s and F-35s, our carriers will be as range-challenged as our land-based fighters. Getting the carrier to the fight will require expensive escorts to defend against missile attacks. Combat operations would quickly become problematic once the defensive armaments are depleted.

Complicating this bleak outlook is the acquisition death spiral of increased cost/reduced numbers. As weapon systems progress through the acquisition cycle, they invariably fall behind schedule from unforeseen production issues. This drives up the cost, reducing the number of systems that can be purchased. The spiral continues with the war fighter receiving fewer platforms, later than needed, and costing significantly more than planned.

These two flaws could leave the U.S. in the same position that Japan found itself in 1943, weakened and unable to reconstitute a viable force. A small fighter force will generate few effective sorties (this assumes sufficient aerial tankers. Fighters in Asia are static displays without tankers). The loss of a Nimitz-class carrier would rival Pearl Harbor in loss of life and drive our surface naval forces out of harm's way. Like Imperial Japan, a Midway debacle would cripple U.S. power projection. And like Japan of 1943, America of 2012 cannot quickly reconstitute our current weapon systems.

With senior leaders stating there are no alternatives to weapon systems currently in development, it's apparent their predecessors organized a Pickett's Charge decades ago and left the charge to them. Resolving this mismatch between force structure and strategy will require a proper focus on the challenges of combat operations in the Pacific.

Specifically, in the short term:

■ Expand procurement of standoff missiles, such as the Joint Air-to-Surface Standoff Missile-Extended Range.

■ Regain our superiority in electronic warfare that was lost in our infatuation with stealth.

■ Purchase low-end attack aircraft and remotely piloted vehicles for noncontested environments.

■ Limit the F-35 buy to 200 to 400 aircraft.

For the long term:

■ Develop manned/unmanned long-range penetrating precision strike platforms (both land- and carrier-based).

■ Research and develop 21st century battleships capable of firing ballistic and cruise missiles from long range.

On June 3, 1942, the Imperial Navy of Japan was the uncontested master of the Pacific. On the following day, American ingenuity, guts and a degree of luck made Japan's eventual defeat inevitable. The future naval and air forces of the U.S. could face a similar tragedy, one in which the finest air and naval forces are rendered incapable of effective combat operations due to a 20-year process where we purchased what we wanted instead of what we needed.

Perhaps the most important contribution from an honest assessment of the AirSea Battle construct will be to own up to this unfortunate fact.

Chris Choate is a retired U.S. Air Force colonel now performing operational test and evaluation work with the service as a civilian employee. These views reflect those of the author and not the Air Force, Defense Department or U.S. government.

Keep Investing in Stealthy ISR

A big danger with having sophisticated military systems is that you run the risk of losing them if you use them.

That appears to be the case with the U.S. Air Force RQ-170 Sentinel, the remotely operated reconnaissance aircraft that was recently lost over Iran. The stealthy aircraft, built by Lockheed Martin, entered service about a decade ago and has seen duty over hot spots worldwide since.

The United States has been using manned and unmanned aircraft for this mission for decades; the RQ-170 is only the latest that allows the United States to see into denied airspace.

The loss of any advanced aircraft poses special risks because it exposes its materials and technologies to enemy scientists and engineers. Now that the Iranians have the Sentinel - especially since it appears to have come into their possession largely intact - it's only a matter of time before China, North Korea and others learn about the UAV's stealth coatings, airframe structures and materials, sensors and electronic components, flight controls and more.

The Air Force is trying to learn as much as possible from the loss, such as why the plane lost signal and how it came to be recovered in one piece.

But more important, it must learn how to guard against such a dangerous loss of technology in the future. Such aircraft must be fitted with physical and electronic self-destruct mechanisms that will obliterate anything of interest as soon as it falls into enemy hands.

Last, the inherent value of having the kind of technology that makes an RQ-170 possible is a critical U.S. advantage in warfare. As defense budgets decline, continuing robust investment in advanced stealth, sensor and reconnaissance technologies is crucial to maintaining America's strategic and tactical advantages.

Iran Wargames Start Near Strait of Hormuz

TEHRAN - Iran on Dec. 24 began 10 days of wargames around the Strait of Hormuz, a vital route in the Gulf through which more than a third of the world's ship-borne oil passes.

IRAN'S NAVY COMMANDER Adm. Habibollah Sayari points at a map during a press conference in Tehran on Dec. 22, saying that Iran will launch 10 days of naval drills on Dec. 24. (Hamed Jafarnejad / AFP via Getty Images)

The Velayat-90 military exercises, announced Dec. 22 by navy chief Adm. Habibollah Sayari, kicked off as planned, Iran's Arabic-language broadcaster Al-Alam reported. Iranian navy forces were being deployed throughout the wargame area to the east of the Strait of Hormuz, comprising the Gulf of Oman around to the Gulf of Aden, in the first phase of the exercises, Al-Alam said, citing navy command.

The exercises were taking place at a time of heightened tensions between Iran and the West, with sanctions being ramped up over Tehran's nuclear program.

The United States, which maintains its own navy presence in the Gulf, has noted Iran's drill. Tehran in September rejected a Washington call for a military hotline between the capitals to defuse any "miscalculations" that could occur in the Gulf.

The wargames were ordered as the United States and its allies ratchet up economic sanctions on Iran, targeting its oil and financial sectors. More measures were expected to be imposed in coming weeks. The sanctions have helped fuel a depreciation of Iran's currency, the rial.

A rumor that spread last Dec. 13 from an Iranian lawmaker's comments that Tehran was to block the Strait of Hormuz in the drill sent the rial to a new low and oil prices soaring before it was denied by the government.

While the foreign ministry said last week such drastic action was "not on the agenda," it reiterated Iran's threat of "reactions" if the current tensions with the West spilled over into open confrontation.

Most Western countries believe Iran is seeking nuclear weapons, despite Tehran's denials. Iran-U.S. tensions have also worsened over U.S. accusations of a thwarted Iranian plot to kill the Saudi ambassador to Washington, Iran's capture this month of a CIA drone, and Tehran's arrest and detention of an American-Iranian it alleges is a CIA spy.

F-35 Wins Japan Fighter Competition

TOKYO - Japan on Dec. 20 chose the U.S.-built F-35 Joint Strike Fighter stealth jet for its next-generation mainstay fighter, as North Korea provided a timely reminder of the region's potential for instability.

U.S. AIR FORCE F-35A Joint Strike Fighters are shown in the skies over Eglin Air Force Base, Fla., in July. Japan announced Dec. 20 that it would buy the F-35A variant to replace its F-4 fleet. (Staff Sgt. Joely Santiago / U.S. Air Force)

In a deal estimated to be worth more than $4 billion, Japan went for the trouble-plagued jet to replace its aging fleet of F-4 fighters.

"The government shall acquire 42 units of F-35A after fiscal 2012 in order to replenish and to modernize the current fleet of fighters held by the Air Self-Defense Force," the cabinet said in a statement.

Lockheed Martin's F-35 beat off competition from two other jets: the Boeing F/A-18 Super Hornet and the Eurofighter Typhoon.

The government said Japanese companies would take part in building the new fighters.

The formal decision, which had long been expected, came the day after news of the death of Kim Jong Il sent jitters through the region amid fears a power transition could destabilize North Korea's hard=line regime.

Tokyo was originally expected to announce its pick last week. The selection comes as China's massive military machine continues to grow and Beijing becomes increasingly assertive.

The F-35 is the most expensive weapons program in Pentagon history and has been plagued by cost overruns and technical delays.

Co-developed with British defense giant BAE Systems, the F-35 was the costliest of the three models under consideration, with a price tag estimated at $113 million per aircraft.

Japan initially aimed to acquire the F-22 Raptor stealth fighter to renew its fleet, but U.S. law prohibits exports of the jet and the United States has halted production of the model.

Japan, which places its security alliance with the United States at the cornerstone of its foreign policy, has long depended on U.S. manufacturers for its military hardware.