Why the PLA’s new naval AEW&C aircraft matters – and why it will be delayed

By Dougal Robertson

Military analysts were surprised when photos appeared on 29 August 2020 of the Xi’an Aircraft Corporation (XAC) KJ-600 naval AEW&C on its maiden flight. Following the retirement of the Fairey Gannet AEW.3 from the Royal Navy Fleet Air Arm in 1978 – which was essentially a modified anti-submarine warfare airframe – the United States is the only other nation that has been able to build and successfully operate a dedicated carrier-based AEW&C aircraft.

Assuming the PLA plans to operate the KJ-600 from a Chinese aircraft carrier, it will become one of only three countries with a carrier-based AEW&C capability. The Northrop-Grumman E-2A Hawkeye entered service with the US Navy in 1964 and is now in substantially upgraded E-2D configuration. Of the six Hawkeye export customers, only France operates E-2Cs from a carrier, the FN Charles de Gaulle. 

Naval AEW&C aircraft are significant because they provide an expeditionary capability for air power. Without AEW&C coverage a carrier battle group is limited to detecting incoming hostile aircraft or ships at the radar horizon – usually around 200-250nm.

Helicopter-borne early warning radars can add up to another 50-80nm, but helicopters have limited time on station, are slow to transit, and operate at lower altitudes. A fixed-wing AEW&C integrates and enables the air battle – without it, an aircraft carrier must stay within the protective envelope of land-based air power in the presence of any credible air threat.

FIRST DETECT

Like most PRC military aviation programs, the KJ-600 is subject to rumour, misinformation, and disinformation, with intelligence ‘leaked’ to the internet from sources ranging between credible and unverifiable. This is what we currently know about the aircraft.

Internet sites began discussing the existence of a PLA maritime AEW program around 2011. This lines up with the commissioning of the first PLA Navy (PLAN) aircraft carrier, the former Kuznetsov class aircraft cruiser Varyag that was rebuilt and commissioned as Liaoning (PLA Type 001 class) in 2012.

The PLA clearly has a program for multiple aircraft carriers – the first Type 003 class carrier with catapult launch system is currently under construction. It’s likely the KJ-600 will operate from the Type 003 – not the ski-jump Type 001 and Type 002 carriers – and the development timeline supports this plan. Photos dating back to 2005 show an XAC Y-7 testbed with an AEW-type rotodome. This suggests KJ-600 development may have begun as early as 2003, and highlights the complexity and ambition of the PLA’s carrier program.

There may have been two technology demonstrators for the KJ-600 – the first initial Y-7 testbed for the radar, and a second airframe prototype. This second prototype is usually referred to as JZY-01, although it is unclear if it was a flying prototype, a static model, or the product of someone’s active imagination; the only internet photos of the aircraft show a Y-7 airframe with ‘JZY-01’ photoshopped onto the fuselage.

From 2011 onwards there was a mix of vague satellite photos, speculative artist impressions and aircraft models displayed at air shows purporting to represent the KJ-600. One thing common in all images was a strong resemblance to the US Navy’s Northrop Grumman E-2 Hawkeye. Key design features such as the multi-fin tail empennage, twin turboprop high wing configuration, and rotodome radar enclosure were always present.

Further photos in 2017 showed a full-scale mockup on the ‘carrier building’, a full-scale aircraft carrier deck at the Wuhan Institute of Ship Design, suggesting the KJ-600 was always intended for the Type 003 carrier. A satellite image from August 2020 showed the airframe at Xian in green primer in preparation for the maiden flight on 29 August.

AIRFRAME

While initial models suggested the KJ-600 may have been based on the XAC Y-7 twin turboprop airframe, it now appears likely the KJ-600 is a clean-sheet design. The closest contender for this design is the XAC MA700 ‘Modern Ark’ passenger airliner, similar in layout to the ATR-72 or Bombardier Dash 8 Q400.

While the MA700 has a longer fuselage (probably around 11-12 metres longer) than the stated size of the KJ-600, the nose section, wing, centre wing box and engine configuration appear identical. It’s unclear if the MA700 is a completely new design, as the XAC MA60 is based on the Ukrainian Antonov An-24. In 2007 Antonov signed an MoU with XAC to help with design and development work of the MA700.

The design sharing within XAC is unlikely to be coincidence. The MA700 design study began in 2006 and a model of the aircraft was shown at Airshow China in 2008. The aircraft was expected to make its maiden flight ‘sometime this year’ according to AVIC but appears to have been delayed. And the delay may be linked to problems with the MA700 / KJ-600 engines.

ENGINES

Display models from XAC and publicly available descriptions claim the KJ-600 is powered by Chinese-built WJ6C turboprop engines. The WJ6 is based on the Ukrainian Ivchenko-Progress (Motor Sich) AI-20M turboprop developed in 1955. The WJ6C engine already powers the PLAAF’s KJ-200 and KJ-500 AEW&C aircraft. But questions remain on the efficiency of the WJ6C

Compared to the Rolls-Royce Allison T56 on the E-2, the WJ6 probably underperforms in power by around 1,900 ehp (T56 A-425 compared to AI-20M) and weight by around 180kg. Fuel consumption is also around 10 per cent higher. Ongoing speculation surrounding the KJ-600 program has centred on whether the WJ6C engines have sufficient thrust to safely launch the aircraft from a carrier.

XAC states the proposed engine for the MA700 is the Pratt & Whitney Canada PW150C turboprop, a newly-developed variant of P&W’s successful PW100 family of engines. The PWC150C is almost identical in performance to the T56, but weighs around 200kg less.

But, as reported in ADBR.com.au in October, despite P&WC submitting an export request in 2018, the Canadian government has not issued export approval for the PW150C, citing concern the engine may be diverted to military programs or at risk of intellectual property theft. It is possible the Canadian government believes the PW150C engines for the MA700 may be diverted to the KJ-600 program as a stop-gap until an improved version of the WJ6C can be built.

China has struggled for decades to build aircraft engines to desired specifications, and the reduced performance of the WJ6C may be holding up the KJ-600. It is possible the aircraft in the current configuration is not able to safely launch from the deck of a carrier.

Further, the relationship between China and the Ukraine is complex, with an attempt by AVIC in 2017 to purchase military aircraft manufacturer Motor Sich blocked by a court in the Ukraine. Ukrainian media stated the sale was blocked due to concerns Motor Sich would be liquidated and key assets removed from the country. It appears that alternatives to the WJ6 will not be available to XAC in the short-term.

RADAR

The KJ-600 radar is reported to be a variant of the KLC-7 developed by the CETC 14^th Institute. The upgraded KLC-7 – also referred to as the ‘Silk Road Eye’ and ‘Belt and Road Eye’ – is likely a single-face AESA installed in the rotodome in the KJ-600.

The KLC-7 is also fitted to the Pakistan Air Force (PAF) ZDK-03 AEW&C aircraft. According to Pakistani sources the ZDK-03 is undergoing mid-life upgrades or has been upgraded in China. Part of the upgrade is reportedly a swap-out of the KLC-7 PESA array with an AESA array, improving detection range by a claimed 40 per cent to around 260nm.

Other sources claim the AESA array uses “second generation” transmit and receive modules, likely the smaller and more efficient Gallium Nitride (GaN) monolithic microwave integrated circuits (MMIC) now being fielded in multiple civilian and military applications.

The requirements for onboard power are unknown, however the use of an AESA in the KJ-600 may provide initial weight savings over a mechanically-scanned array, and the use of advanced AESA technology may reduce the onboard auxiliary power generation requirements.

COMMENT

Naval AEW&C aircraft are an extremely complex and difficult capability to develop. There is more to a naval AEW&C than simply fitting a long-range radar to a persistent airframe. Considerations such as drop testing, management of onboard power generation, crew resource management, and integration with the fighter force are brand new concepts for the PLAN.

China’s desire to build a carrier fleet is ambitious. It is aiming to deliver in 20 years of research and development what the US has taken more than 75 years to perfect. Central to the carrier battle group is the AEW&C – without airborne early warning, the primary mission of the carrier will be self-defence.

The KJ-600 appears to be a copy of the E-2C Hawkeye concept, perhaps using some technology from cancelled Russian programs such as the Yak 44 carrier AEW&C. XAC may even be using the MA700 program to defray costs in building the KJ-600 by using commercial sales to fund ongoing military development, but the lack of differentiation between XAC’s civilian and military aircraft programs has likely put the brake on P&WC’s planned sale of turboprop engines.

The KJ-600 will succeed – eventually – but it may be delayed by anywhere up to 10 years as China develops adequate engines for a carrier deck launch. A Chinese scientist stated in 2012 that, “China is the only permanent member of the UN Security Council that cannot independently develop advanced aeroengines. This is extremely disproportionate to China’s national security and status as a major power.”

An operational naval AEW&C would be a fitting counter-point to this perceived failing.