조기경보기 E-7의 E-3 대비 가장 큰 장점은 표적정보 갱신속도 (E-3의 경우 10초)

[위종민]

기계식 레이더를 쓰는 E-3의 갱신속도는 10초당 1회인데, 마하 1을 넘는 속도로 비행하는 제트기는 그 시간 동안 2마일 넘게 이동할 수 있다고 합니다. 반면 E-7의 MESA는 1개, 혹은 여러 개의 표적에 시선을 고정해 감시할 수 있으며 갱신속도 역시 E-3보다 매우 빠르다고 합니다. 자세한 성능은 기사상에선 공개하지 않았는데, 공개된 자료에서 노출된 적이 있었을지.. 

E-3는 2024년 회계년도 말까지 16대로 감축할 예정인데, 켄달 공군장관은 E-7이 도입되기 전에 E-3의 대수를 절반으로 줄여서 감시능력에 공백이 발생하는 게 아니냐는 우려에 대해 "E-3는 우리가 가장 우려하는 환경에 있어서는 본질적으로 효과적이지 않다. 센서는 구형화됐고 유지보수비용은 매우 비싸다."고 일축했다고 하네요. 

또한 비행승무원 4명 + 오퍼레이터 13~19명이 필요한 E-3와는 달리 E-7에는 기장과 부기장 + 10개의 스테이션 뱅크 운용자만 필요하며, 최소 오퍼레이터 1명만 태워 3명으로도 비행이 가능하다고 합니다. 작전시간이 24시간을 초과하는 등의 장시간 작전의 경우 기장과 부기장, 스테이션 오퍼레이터 10명과 예비인력 9명을 포함해 21명까지 탑승이 가능합니다. 

제작기간은 4년이 걸리지만 lead-in-time이 긴 부품들을 미리 조달하면 6개월 정도 단축이 가능하다고 합니다. 

E-7은 2027년에 1번기가 도입된 후 2032년까지 26기가 도입될 예정이라고 합니다. 프로그램이 개시되 생산라인이 풀가동되는 2020년대 말엔 연 4대 생산이 가능하다고 합니다. 

https://www.defensenews.com/air/2023/03/23/the-ability-to-stare-why-the-us-air-force-is-eager-to-get-the-e-7/

‘The ability to stare’: Why the US Air Force is eager to get the E-7

www.defensenews.com‘The ability to stare’: Why the US Air Force is eager to get the E-7

By Stephen Losey Mar 24, 01:22 AM

12-15 minutes

---

The U.S. Air Force has decided to buy a fleet of up to 26 E-7As from Boeing, similar to this E-7 Wedgetail from the Royal Australian Air Force, to replace its fleet of aging E-3 Sentry airborne warning and control planes. (Boeing)

AURORA, Colo. — For nearly 50 years, the E-3 Sentry aircraft served as the cornerstone of the U.S. Air Force’s ability to keep eyes in the sky. In the waning years of the Cold War, and throughout America’s wars in Iraq and Afghanistan, the airborne warning and control system aircraft, or AWACS, and its trademark 30-foot rotating radar dome swept battlefields and potential conflict zones around the world.

But that Northrop Grumman-made APY sensor takes 10 seconds to fully rotate and refresh its view of aircraft the AWACS crew is trying to track.

A lot can change in a 10-second blink of an eye: An aircraft flying at hundreds of miles an hour can move more than a mile in that timespan, and for a jet topping Mach 1, that could be more than 2 miles.

Boeing’s E-7A, the aircraft set to replace the E-3 AWACS, will give the Air Force a different way of looking at battlefields. Instead of periodic rotational sweeps, the E-7′s multirole electronically scanned array long-range sensor will allow operators to fix its gaze on a target — or several of them.

“It essentially comes down to the ability to stare at something,” Carson Elmore, who runs business development for Boeing’s international E-7 program, said in a March 8 briefing on the E-7′s capabilities at the Air and Space Forces Association’s AFA Warfare Symposium in Colorado.

And top Air Force generals aren’t hiding how eager they are to have the E-7 and its new capabilities at their disposal.

“I want them very quickly,” Pacific Air Forces commander Gen. Kenneth Wilsbach said in a roundtable with reporters at the conference that day.

The Air Force in February awarded Boeing a $1.2 billion contract to begin work on the E-7 fleet; the service plans to reach 26 aircraft by 2032. The air forces of Australia, Turkey and South Korea are already flying E-7s, and production is underway for a British fleet. The Royal Australian Air Force calls its E-7 the Wedgetail, but the U.S. has not decided on its own E-7′s name.

The U.S. Air Force plans to first buy two rapid prototype E-7s, with the first to be fielded in 2027, and then make a production decision on the remainder of the fleet in 2025. The service has repeatedly said its AWACS capabilities — which were state of the art when first fielded in the late 1970s — are out of date and not advanced enough for future conflicts.

Furthermore, the AWACS’ aging 707-based airframe and TF33 engines are increasingly hard to maintain, the service argued, and its radar capabilities are outdated. The Air Force is retiring its fleet of AWACS, which once numbered 31, and plans to be down to 16 by the end of fiscal 2024.

In a March 10 budget briefing with reporters at the Pentagon, Air Force Secretary Frank Kendall downplayed the risk of a capability gap emerging by slashing the AWACS fleet nearly in half before the first E-7 arrives.

“The E-3 is essentially not effective in the environments we’re most worried about,” Kendall said. “The sensor is pretty ancient at this point, and the aircraft are very expensive to maintain.”

At the symposium briefing, which took place in a trailer mocked up to resemble the interior of an E-7, Boeing officials walked reporters through how it plans to build the Air Force’s new E-7 fleet, and what makes them different from the AWACS.

New plane and fresh radar

The biggest differences between the AWACS and the upcoming E-7 will be how the sensors work and the views they provide, said Rod Meranda, Boeing’s head of business development for its domestic and international E-7 program.

The E-7′s multirole electronically scanned array, or MESA, will be able to lock its view on a target instead of having to sweep around, and the operators on the E-7 will be able to tell it to refresh that view at certain intervals. Boeing would not say how quickly the MESA will be able to refresh its view, citing security concerns, but Elmore said it would be able to do “rapid relooks.”

The MESA will also be able to look in several directions at once, allowing the operators at the E-7′s array of 10 stations to simultaneously monitor multiple angles. Elmore said this will allow the aircraft to considerably narrow down the possible location of an aircraft, resulting in greatly improved situational awareness.

E-7 controllers will also be able to set its array to conduct periodic sweeps in several directions, Elmore said. For instance, the controllers could set the MESA to watch targets on one side most of the time, and every so often look in the other direction “to make sure somebody’s not sneaking up on me,” he explained.

Northrop Grumman makes the multirole electronically scanned array, or MESA, surveillance radar that is mounted on Boeing's E-7. Northrop said its advanced long-range radar can allow the aircraft to detect threats from far away, without having to fly closer to dangerous areas. (Northrop Grumman)

Like the AWACS, the E-7 will also be able to listen for radar and other electronic signals a potential enemy aircraft is emitting, then locate the plane and check the signal against a database to help identify the type of plane.

Boeing officials declined to discuss the range of the E-7′s sensor and how it compares to the AWACS, as well as its self-defense capabilities, citing classification concerns. Boeing’s website lists chaff and flares among the E-7′s defensive measures.

Mounting the MESA array on the E-7, along with all the power and capabilities that its 737 body can carry, provides a more capable means of conducting surveillance compared to smaller drones, fighters and satellites, Meranda said.

“You can’t put this kind of power in an unmanned” aircraft, Meranda noted. “Space — same thing. [It’s a] massive array to give you a lot of capability.”

Cutting the crew

The E-7 will also require a smaller crew than the AWACS thanks to newer technologies, Elmore said. The Air Force’s AWACS fact sheet said it requires a flight crew of four, plus a mission crew of 13-19 specialists.

Boeing said the E-7 can get the job done with just a pilot and co-pilot, and a variable number of mission operators running the bank of 10 stations lining the aircraft, depending on mission requirements. That crew could be as small as three if a flight only needs one mission operator to use a scope.

And, for example, if an E-7 carries out a lengthy and complex mission — AWACS operations sometimes exceeded 24 hours — it can seat up to 21 people: the pilot and co-pilot, 10 mission operators at the stations, and nine more in reserve to rotate in and out. The cockpit also has a jump seat for a third pilot.

Each station — six on the port side, four on starboard — has two displays operators can use to spread out radar signals, and chat windows used to coordinate with other aircraft, the air operations center on the ground or other teammates elsewhere. The operators also have intercoms, and the plane’s radios will be able to use more capable Mobile User Objective System satellite communications.

Although the E-7 has several features that differ from the AWACS, Elmore said Boeing kept the stations and how they are controlled similar to what E-3 operators are used to. “We wanted to have a very short training and transition time frame for the operators when they get out of the E-3 and they come to the E-7,” he noted.

The E-7 also has a new situational awareness feature, which the AWACS lacks, called the flight deck tactical display, which alerts the pilot to what’s going on in the battlespace and what may be flying nearby. Elmore said the display is tied into the E-7′s electronic warfare self-protection capabilities, but would not go into more detail.

This display, which is mounted near the pilot’s knee, means the E-7 does not need a crew member found on the E-3 — the AWACS monitor — Elmore said. AWACS monitors fly in the back of the aircraft and keep in touch with their pilots to update them on what is in the area.

“All of the tracking on AWACS, you had a whole set of people who worked on tracking and identifying” other aircraft in the area, Elmore said. “We’ve eliminated them because the machine does it.”

Elmore said the E-7 will be able to link up with assets used by joint forces so it can share data — both drawing information that the E-7 can use and sending data to partner forces.

Building the E-7

It typically takes Boeing four years to make an E-7, though the company says it could shave about six months off that timeline by procuring long-lead items in advance. It takes two years to make the commercial 737-700, and then two more years “chopping this airplane up” to modify it into the E-7.

Meranda said that when the Air Force’s E-7 program kicks into gear, which could happen later this decade, Boeing wants to build four per year.

To make an E-7 for the Air Force, Boeing will first buy a 737 tube from Spirit AeroSystems in Wichita, Kansas, and bring it to its factory in Renton, Washington. Once the tube is on the factory’s “line 3,” which is dedicated to military work and is where Boeing builds P-8 Poseidon maritime patrol planes, Boeing will start beefing it up so it can handle the extra wear and tear military flying dishes out.

A Royal Australian Air Force E-7A Wedgetail received fuel from a U.S. Air Force KC-135 Stratotanker above Iraq in 2020. (Staff Sgt. Daniel Snider/U.S. Air Force)

The central feature of the E-7 is its blade-like MESA sensor, nicknamed the “top hat.” Installing it requires a significant amount of work, and Meranda said Boeing will cut the 737 plane in half to reinforce the structure to bear the weight of the MESA sensor.

The company will also install wings typically used on 737-800s, which Elmore said will give the E-7 greater lift capability, as well as stronger landing gear, among other modifications.

The U.S. version of the E-7 will be similar to the three Boeing is now building for the U.K., particularly in terms of the air frame, sensor and mission equipment, though the U.S. Air Force made unique requests Boeing declined to specify.

Boeing wants the E-7 fleet to be largely interoperable so it’s easier and cheaper to upgrade different nations’ fleets. Meranda said the E-7 will use a suite of open-mission systems software to simplify upgrades; the U.S. Air Force will test the technology in 2025.

The entire acquisition process for an E-7, including testing and Federal Aviation Administration certifications that occur after construction and modification, could take five years, but Boeing wants to get it done sooner.

The company said that advance procurement funding will lower the risk for businesses involved in building the E-7. For Boeing, that funding will allow it to start building the commercial plane earlier, Meranda said. And advance funding allows Northrop Grumman engineers and production facilities to start working on the planes’ sensors, he added.

But Boeing officials reiterated the Air Force’s statements that not much can be done to rapidly accelerate the process of acquiring new E-7s. While the U.K. purchased used planes to convert into its E-7s, Meranda said there’s not many more used airframes available to adapt into additional E-7s.

Elsewhere at the AFA Warfare Symposium, top Air Force generals made no secret of their desire to get their hands on the E-7 as soon as possible.

The E-3s “are a significant challenge to keep them in the air, just because they’re very old and they have a lot of maintenance requirements, and the E-7 obviously doesn’t have that,” Wilsbach said.

And in the air, “the E-7 has significantly greater capabilities [over the E-3] from the standpoint of what it can see and how it can contribute to the overall objectives,” the officer added.

Wilsbach told reporters he planned to visit Boeing within days to discuss how fast the company can produce E-7s.

In another discussion with reporters, Air Combat Command head Gen. Mark Kelly echoed Wilsbach’s urgency, saying he felt “like a proud father” to see the service make progress on acquiring the E-7.

“I just wanted more than twins,” he said, referring to the two rapid prototype E-7s. “I want as many of those kids as I can.”

The Air Force’s effort to update its electromagnetic spectrum aircraft, including the E-7, EC-37B Compass Call, and electronic warfare capabilities in the F-35 and F-15EX fighters, could make the difference between winning and losing a war, Kelly said.

“Coming in second in [the electromagnetic spectrum] is a horrible place to be.”

Stephen Losey is the air warfare reporter for Defense News. He previously covered leadership and personnel issues at Air Force Times, and the Pentagon, special operations and air warfare at Military.com. He has traveled to the Middle East to cover U.S. Air Force operations.

[백선호]

E-3의 시스템을 보잉 767에 올린 일본의 E-767도 구닥다리가 되었겠네요.

[위종민]

그러고 보니 그런 비행기도 있었죠. E-2D를 도입한다 하니 2020년대 후반 쯤엔 E-767도 2선급 기체로 밀려나겠습니다.

[마로]

항자대 E-2D랑 E-767은 운용 특성도, 소요도 다릅니다.

[마로]

APY-1/2는 장확히는 완전 기계식이 아니라 선배열 PESA라서 전자식 스티어링은 수직으로 밖에 안 되는거죠.

[ssn688]

전자주사라 표적갱신은 빠르겠지만 원거리탐지능력은 별개의 문제겠죠? 하긴 아무리 성능이 나온다 해도 고장이 잦고 수리가 어려우면 무쓸모이겠습니다만...