Pakistan’s JF-17 Fighters Faces Serious Maintenance Issues with Its Structure and Engines

Martin-Baker Illustration highlighting Sino-Pak JF-17 ejection seat. source Martin-Baker.

Pakistan will not replace the JF-17’s Russian-made Klimov/Sarkisov RD-93 power plant with a new Chinese engine in the foreseeable future despite Chinese reports to the contrary, IHS Jane’s Defense Weekly reveals.

The Pakistan Air Force now faces serious difficulties. Its frontline fighter, the JF-17, developed with the help of the Chinese, has maintenance problems that are getting worse every day.

Situation is so dire that PAC even plans to establish a full-scale servicing and overhaul facility for the Klimov/Sarkisov RD-93 engine in Kamra, also known as Aviation City, and the center of aircraft manufacturing in Pakistan.

The reason is the JF-17’s Russian made engine, the RD-93 and the sanctions by the United States of America on Rosoboronexport, the Russian defense trade agency, since 2018. Engines need to be overhauled; they need to be replaced after a certain number of hours of flying. And only Rosoboronexport can ensure overhauling and provide new engines.

The RD-93MA is a derivative of RD-33MK and RD-93 used by Indian Navy’s MiG-29K and Indian Air Force’s MiG-29UPG respectively.

The sanctions prevent Rosoboronexport from doing US dollar transactions. So, there are payment issues which the two governments and the concerned banks have not sorted out, sources said. As a result, ensuring the JF-17 is ready to fly is becoming more difficult and will be more so in the future. 

Engine Problems

The powerplant used in the system is Klimov RD-93MA which is a variant of the RD-33 engine from Russia. Russians found it useless but when Chinese Engineers were developing a cheap fighter for Pakistan, they selected Cheap RD-93. It has an increased thrust level but decreased service interval from 700hours to 400Hours and life cycle from 4000 Hours to 2200 hours. This engine is known to generate thick black smoke (due to partial burning of fuel) resulting in easy spotting of aircraft from tens of miles away. Only JF-17 uses this engine in the entire world. This resulted in a low thrust to weight ratio. Today Pakistani JF-17 cannot pull a 9G manoeuvre even with zero weapon system and 65% of Fuel.

Interestingly, such notorious was the performance of this Engine that when Myanmar decided to buy 16 x JF-17 from Pakistan, it refused to take this RD-93 engine and separately procured original RD33 Engines from Russia.

Weak Structure

Because of poor thrust to weight ratio, its structure is exposed to serious threats when going beyond permissible “Gravity” limits. It is reliably learnt that more than 40% of the existing JF-17 are grounded because of cracks in their Strake area. This is the area most affected by Gravity related postures. There are reports that the damage to stake areas of wingtips has even resulted in damage to wingtip hardpoints in few of the machines. There was news of breaking of arresting gear in few aircraft while landing too.

High Fuel Consumption

Since JF-17 has a higher rate of fuel consumption, it would need to be refuelled in the air for any long-distance operation. Pakistan claims this aircraft to be capable of carrying out air-to-air refuelling but surprisingly no air-to-air refuelling has ever been carried out till date. Indeed, they carried out this exercise on the ground which makes another mockery of Aircraft Engineering.

WS-10 or WS-13

As a way out, the PAF and the China National Aero-Technology Import and Export Corporation or CATIC are trying to replace the Russian RD-93 engine with a Chinese version. However, China is yet to produce a reliable engine for any of its domestic aircraft and does not have the mass production capability of the WS-10 engine.

For Pakistan, changing to another engine would not make any sense and would be disruptive and cause a huge expense for the JF-17 program. China’s aircraft industry has had difficulties in designing and building a powerful enough and reliable indigenous jet engine for some time.

Even the People’s Liberation Army Air Force’s fighter prototypes, the Chengdu J-20 and Shenyang J-31, both are flying with older Russian-made jet engines, the J-20 with the Saturn AL-31 and the J-31 with the Klimov RD-93.

One reason for Beijing’s recent purchase of 24 Russian-made Sukhoi Su-35 multirole fighter jets is the Russian aircraft’s powerful AL-117S turbofan engines, which China can now reverse engineer. The most advanced Chinese-made military turbofan currently in use is the WS-10, which, however, continues to underperform.

Consequently, there is little reason to believe that Pakistan will procure Chinese-made engines for the JF-17 in the foreseeable future.

The RD-93 Smoky Engine

“When we designed the JF-17 we evaluated a number of design alternatives and we determined that the RD-93 in this single-engine installation is absolutely right for this application,” another PAC representative said. “We worked extensively with the people from Klimov bureau in St Petersburg [Russia] and this engine turned out to be an ideal solution.”

MiG-29’s RD-33MK hot engine fume is an invitation to shot it down with IR-guided missiles. RD-93 is a derivative of RD-33MK.

In December 2014, Russia and Pakistan also announced a defense cooperation agreement, which stipulated that Islamabad would buy the the Klimov RD-93 engine directly from Moscow, instead of acquiring the hardware vicariously via China.

The state-owned United Engine Corporation controls development and manufacturing of all engines for military, civilian and space use in Russia and for Russian exports. The UEC’s Klimov plant in St Petersburg had been developing the RD-93MA engine, which is a modification of the RD-93 engine, used on the JF-17 fighter, being built by Pakistan and China.

In a press release on its website, UEC said the RD-93MA engine had been shipped from St. Petersburg to Moscow for thermal pressure chamber trials at the Central Institute of Aviation Motors (CIAM). The pressure chamber trials at CIAM are expected to subject the RD-93MA engine to simulated heat and altitude conditions the power-plant would experience in actual flight.

The UEC press release states, “The RD-93MA engine has improved performance. In particular, increased thermodynamic parameters, an improved design of the fan and the hot part, an upgraded automatic power-plant control system… An additional emergency engine start mode was provided… and the possibility of emergency fuel drain was realised. All this is due to the specifics associated with the possible use of the power-plant on a single-engine aircraft.”

The reference to use in single-engine aircraft has given rise to speculation that the new engine is destined for the JF-17 fighter. This is because Russia does not have any active single-engine fighter project at the moment.

Pakistan has already built over 100 JF-17 fighters for its air force and officials have indicated 62 JF-17 Block 3 fighters will be ordered by 2024.

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