HAL Seeks Airborne Early Warning and Surveillance Radar Systems for New Dual Band Multirole Helicopters

Hindustan Aeronautics Limited (HAL) is pushing forward with the development of its Dual Band Multirole Helicopter (DBMRH) platform, issuing two Requests for Information (RFI) for advanced radar systems.

These RFIs seek to equip two DBMRH variants with specialized radar capabilities: an Airborne Early Warning (AEW) radar for the DBMRH-AEW and a Surveillance radar for the DBMRH-S Special Operations variant.

The first RFI targets an Airborne Early Warning (AEW) radar system for the DBMRH-AEW variant. This variant is intended to bolster India's air defence capabilities with comprehensive airborne surveillance and target tracking.

The radar is required to operate in the S or C bands, with 360° azimuth and ±60° elevation coverage, and a detection range exceeding 300 km for targets with a 2 m² Radar Cross Section (RCS). To ensure seamless integration with the helicopter's design, HAL has specified a conformal antenna and a weight limit of 700 kg.

The second RFI focuses on a Surveillance radar system for the DBMRH-S Special Operations variant. This variant will be tasked with conducting high-risk, low-altitude missions, demanding specialized capabilities for sea and ground surveillance, including terrain following and terrain avoidance. The radar will also incorporate ground mapping, weather detection, and beacon interrogation functionalities.

With a single fixed AESA antenna, the radar must be lightweight (under 40 kg) and power-efficient (1.5 kW), while providing detection ranges exceeding 15 nautical miles for small targets and up to 65 nautical miles for larger vessels in sea surveillance mode.

Both RFIs are open to Indian and foreign vendors under the “Make in India” initiative, promoting collaboration and technology transfer within the country's defence industry.

HAL has set ambitious deadlines, with the AEW radar system expected to be ready for integration by June 2027 and the surveillance radar by March 2027. To meet these timelines, vendors will be required to establish design and production facilities within 60 months.

These advanced radar systems will significantly enhance India's air defence and surveillance capabilities. The DBMRH, equipped with this cutting-edge technology, is expected to play a crucial role in expanding India's aerial and maritime surveillance capabilities, addressing a wide range of security challenges.

 

[Anant]

Right now, the question is if we will have the IMRH and DBMRH prototypes by 2027. Originally, the type was supposed to first fly in the first half of 2024, which is already gone.

The partnership with Safran for developing the IMRH engine was signed in August this year, with HAL themselves estimating 3-4 years for a prototype and 5 years for operationalisation. That would suggest that the engine will not be ready by 2028 or so at the earliest.

This means that if we have the IMRH and DBMRH prototypes ready by 2027, we either need to use some other engine for testing, or we simply push the whole thing to 2029-30.

P. S. Even if we are going for a helicopter-based AEW&C platform, one hopes the challenges that the Ka-31 faces are mitigated to an extent.

 

[PARTHAJIT JANA]

Good, no more romeos and russian heli.

 

[Anurag]

Right now, the question is if we will have the IMRH and DBMRH prototypes by 2027. Originally, the type was supposed to first fly in the first half of 2024, which is already gone.

The partnership with Safran for developing the IMRH engine was signed in August this year, with HAL themselves estimating 3-4 years for a prototype and 5 years for operationalisation. That would suggest that the engine will not be ready by 2028 or so at the earliest.

This means that if we have the IMRH and DBMRH prototypes ready by 2027, we either need to use some other engine for testing, or we simply push the whole thing to 2029-30.

P. S. Even if we are going for a helicopter-based AEW&C platform, one hopes the challenges that the Ka-31 faces are mitigated to an extent.

Do we have another option?? Helicopter based AEW may not sound good but it is the only option that we have now!!
In my opinion without anything atleast have something that's much more better!!

 

[Sandeep]

This is a very important and critical necessity that we need to 100% indigenously design, develop and manufacture with indigenous content only.

We need to first start to design the naval IMRH helicopter as the platform will be different from the land IMRH. Then we need to decide and develop either a fixed circle shaped AESA radar or a rotating radar system. Also we will need to develop the advanced critical technology, equipment, engine, software, computer systems, net centric system and much more.

We will also need to develop an armed variant which can fire anti ship missiles or general attack missiles with different ranges. Also we need to develop an anti submarine helicopter which can search and track for submarines and also launch a light to heavy weight torpedo with long ranges.

All of these different helicopter variants and its systems, technology, hardware, software etc will take a long time to develop and at least 10 years from fabrication to passing all of its tests and getting certified. It will also be ideal if the private sector can develop a lot of the critical technology and equipment so there isn’t any long delays at all.

 

[Anant]

Do we have another option?? Helicopter based AEW may not sound good but it is the only option that we have now!!
In my opinion without anything atleast have something that's much more better!!

Oh, I absolutely agree. We don't have any other options. That said, I am only saying that we should try to alleviate some of the constraints we have seen with the Ka-31.

 

[Anant]

We need to first start to design the naval IMRH helicopter as the platform will be different from the land IMRH. Then we need to decide and develop either a fixed circle shaped AESA radar or a rotating radar system. Also we will need to develop the advanced critical technology, equipment, engine, software, computer systems, net centric system and much more.

Boss, a helicopter-based AEW&C system will have a folding radar dish at the bottom of the helicopter, similar to what we see with the Ka-31. You can't exactly fit a radome.

 

[Anant]

Good, no more romeos and russian heli.

We'll still need a few more Romeos given that a dedicated ASW variant of the DBMRH hasn't even been cleared yet, and we are lacking somewhat in that department given the impending retirement of the Sea King and the Navy's upsizing.

 

[Sandeep]

Boss, a helicopter-based AEW&C system will have a folding radar dish at the bottom of the helicopter, similar to what we see with the Ka-31. You can't exactly fit a radome.

We can certainly use both actually. We can fit a fixed radome at the bottom and also on top of the central main rotor blade similar to the latest Apache helicopters that has a MMW radar on top.

 

[Anant]

We can certainly use both actually. We can fit a fixed radome at the bottom and also on top of the central main rotor blade similar to the latest Apache helicopters that has a MMW radar on top.

Perhaps, but given ground clearances and weight distribution, neither radome would be too big.

That said, I had not considered the top radome similar to the Apache. Let's see how this pans out.

 

[Radha Ramanan]

There is no helicopter in the Indian Navy that can host the AWACS antenna. The British made one on their Sea King. The Russian AEW Ka-31 is a planar radar but really old. China also has it. But China has managed to copy the American Hawkeye E-2, which itself is a great achievement by any means.

We need a large helicopter to host the system, and the IMRH seems to be the only Indian choice if it is going to be a desi one. There is also a large power and cooling requirement for the antenna as it is an AESA.

The Navy made a good decision to have an antenna that is conformal to the sides of the helicopter. This is more aerodynamic. A large antenna can be fixed on the sides with a smaller one on the nose to have 300-degree coverage like the Netra Mk2 A320 type. The other option is to have a circular housing dome on the belly of the helicopter, where the distance from the belly radome to the ground is a major factor.

The Russian Ka-31 AEW does not have control capability as a normal AWACS. It's just an early warning system. It has a foldable large underbelly antenna, which is a nightmare for aerodynamics as it rotates as well, creating disturbance in airflow, but it was a trade-off.

The Italian SeaSpray 7500E AESA radar is the state-of-the-art airborne radar. The Israelis have an AESA version of the EL-2022 that we use on the Dornier maritime aircraft.

The Uttam can easily be modified to fit the helicopter on the sides and can have a larger antenna, and there is sufficient space for power, cooling, etc. Some helicopters have the SeaSpray radar on the underbelly as well, but they have multi-role requirements.

 

[Sandeep]

Perhaps, but given ground clearances and weight distribution, neither radome would be too big.

That said, I had not considered the top radome similar to the Apache. Let's see how this pans out.

It depends on the weight, size and high power requirement and performance. Also there is lower maintenance, more safe and secure. With a rotating radar at the bottom of the helicopter it can get damaged more easily along with it being an easy target to destroy or damage from small arms fire on the ground up.

 

[Anant]

It depends on the weight, size and high power requirement and performance. Also there is lower maintenance, more safe and secure. With a rotating radar at the bottom of the helicopter it can get damaged more easily along with it being an easy target to destroy or damage from small arms fire on the ground up.

True. Regardless, a rotating radar at the bottom is highly unlikely. It is far more likely that such a radar would be a folding radar array similar to the Ka-31. As for the top radome, that is definitely a possibility.

 

[Spectre]

Oh, I absolutely agree. We don't have any other options. That said, I am only saying that we should try to alleviate some of the constraints we have seen with the Ka-31.

what constraints you have seen with KA-31 and what you are trying to alleviate, you should be a consultant to DRDO/ADA and Navy, coz you have seen the constrains that they haven’t seen or heard off.

 

[PKPRS]

Do we have another option?? Helicopter based AEW may not sound good but it is the only option that we have now!!
In my opinion without anything atleast have something that's much more better!!

It is the best solution for space constrained ship’s, we don’t have any other option, even Western navies with smaller Aircraft Carriers like UK, Spain and Italy had to use AEW&C helicopters and in Asia japan and South Korea are doing this, until we have a larger displacement Aircraft carrier with catapult launcher to launch AEW&C Aircrafts this is our only best possible option.

 

[Spectre]

Good, no more romeos and russian heli.

Don’t enjoy too fast, right now all the ideas are in paper as drawings and up in the Air, only when it happens we will know for sure.

 

[Abs29]

True. Regardless, a rotating radar at the bottom is highly unlikely. It is far more likely that such a radar would be a folding radar array similar to the Ka-31. As for the top radome, that is definitely a possibility.

May be they can explore something like the British Crows nest system which has a foldable gondola that carries an AESA radar. But yes will probably need a much larger helicopter than the Dhruv and even a modified IMRH.

 

[PKPRS]

It depends on the weight, size and high power requirement and performance. Also there is lower maintenance, more safe and secure. With a rotating radar at the bottom of the helicopter it can get damaged more easily along with it being an easy target to destroy or damage from small arms fire on the ground up.

Royal Navy uses something called Crownest Radar (CROWSNEST Airborne Surveillance and Control (ASaC) programme made by Lockheed Martin) that they fix on the side of their Merlin MK2 naval helicopter that folds and drops down, they have deployed these helicopters in both their flat decked Aircraft carriers, IMRH is a good size to carry power generators for these type of Radars.

 

[Anant]

what constraints you have seen with KA-31 and what you are trying to alleviate, you should be a consultant to DRDO/ADA and Navy, coz you have seen the constrains that they haven’t seen or heard off.

The biggest constraint, and this is something that has been publicly spoken of on occasion, is the fact that the Ka-31 has a relatively short endurance. The Ka-31 can manage between 2 and 2.5 hours on station, which means you need about 3-4 of them to maintain constant cover, and that assumes none of the choppers faces any mechanical problems during operations. Considering that our overall fleet is a total of 14 Ka-31s, that means almost half of the fleet has to be deployed at any point, which isn't sustainable in wartime, especially if you lose a few airframes.

Looking at some other helicopter-based AEW&C platforms, the AW101 AEW&C manages 4 hours on station, the Sea King variant manages 3.5 hours, and China's Z-8AEW and Z-18F can both manage between 3 and 4 hours on station.

That in itself is not a major issue till you look at one more thing: Armament. The Ka-31 cannot carry any munitions by itself, while the other choppers mentioned above can each carry ASW weapons. That means the Ka-31 is useless in a role that does not involve AEW&C duties.

Both our carriers normally carry 10-12 helicopters apiece. Of these, the normal composition is 4-5 utility choppers, 4-5 ASW choppers, and 2-4 AEW&C choppers. That is 20-25% of the chopper wing restricted to a single-use choppers, while the Chinese and the British can use those choppers for ASW, SAR, and other duties too.

 

[Anant]

It is the best solution for space constrained ship’s, we don’t have any other option, even Western navies with smaller Aircraft Carriers like UK, Spain and Italy had to use AEW&C helicopters and in Asia japan and South Korea are doing this, until we have a larger displacement Aircraft carrier with catapult launcher to launch AEW&C Aircrafts this is our only best possible option.

Agreed. We don't have any other options for now, and so should focus on getting the best possible helicopter-based AEW&C platform. That means we will have to work to avoid some of the Ka-31's constraints (such as endurance) in the AEW variant of the DBMRH.

 

[PKPRS]

Agreed. We don't have any other options for now, and so should focus on getting the best possible helicopter-based AEW&C platform. That means we will have to work to avoid some of the Ka-31's constraints (such as endurance) in the AEW variant of the DBMRH.

We really don’t need much endurance for ship based AEW$C helicopter, what ever endurance KA-31 has is more than adequate, we have other platforms like Sea Guardian and P8 for greater enfurance.

 

[Igo Pilot]

The biggest constraint, and this is something that has been publicly spoken of on occasion, is the fact that the Ka-31 has a relatively short endurance. The Ka-31 can manage between 2 and 2.5 hours on station, which means you need about 3-4 of them to maintain constant cover, and that assumes none of the choppers faces any mechanical problems during operations. Considering that our overall fleet is a total of 14 Ka-31s, that means almost half of the fleet has to be deployed at any point, which isn't sustainable in wartime, especially if you lose a few airframes.

Looking at some other helicopter-based AEW&C platforms, the AW101 AEW&C manages 4 hours on station, the Sea King variant manages 3.5 hours, and China's Z-8AEW and Z-18F can both manage between 3 and 4 hours on station.

That in itself is not a major issue till you look at one more thing: Armament. The Ka-31 cannot carry any munitions by itself, while the other choppers mentioned above can each carry ASW weapons. That means the Ka-31 is useless in a role that does not involve AEW&C duties.

Both our carriers normally carry 10-12 helicopters apiece. Of these, the normal composition is 4-5 utility choppers, 4-5 ASW choppers, and 2-4 AEW&C choppers. That is 20-25% of the chopper wing restricted to a single-use choppers, while the Chinese and the British can use those choppers for ASW, SAR, and other duties too.

KA-31 is meant for doing short distance perimeter search for surface and sub surface enemy assets, we Indians only have 2 carries, at any given point of time IN only uses 2 KA-31 in each carrier and mix it with 4-6 Romeos and Sikorsky UH-3H Sea King, that is plenty for 40K displacement carriers, they always keep plenty of helicopters from each brand on reserves, so there is absolutely no maintenance downtimes there, I don't know whether you have any basic knowledge of how these AEW&C helicopters operate and within what range, if you would have at-least known the basics you wouldn't have spent time typing these many lines tarnishing one of the Navy's favorite helicopter, if you don't know please ask the experts here, don't make a fool of yourself.

You will understand the expertise of people here by reading their comments, feel free to ask them.

KA-31's range is 370 NMi
Navy's requirement for the new DBMRH-S helicopter is 65NMi.
Even the brand new MH-60Romeo's range is only 450NMi.

These helicopters only operate 50-75Nmi around the perimeter of the ship at any given time.

For long endurance and long range we Indians have plenty of other capable platforms.

 

[PKPRS]

Boss, a helicopter-based AEW&C system will have a folding radar dish at the bottom of the helicopter, similar to what we see with the Ka-31. You can't exactly fit a radome.

Radome and that too 360 Degree is impossible on a helicopter it will stand in the way of rotor and will affect the radars's effectiveness also affect the aero dynamics of the helicopter and cause a lot of turbulence, the best spot for it is either on the side that folds down or the under the belly like the KA-31 and MH-60Romeo.

 

[PKPRS]

We can certainly use both actually. We can fit a fixed radome at the bottom and also on top of the central main rotor blade similar to the latest Apache helicopters that has a MMW radar on top.

It is too big to fix the radar on top of the main rotor, I think you talking about the radar AN/APG-78 Longbow milli meter wave fire control radar on top of Apache's Main rotor, it is too small compared to AEW&C radars in Naval Helicopter, the best place for water search radar is under the belly of the helicopter for good visibility under the water and on the surface. For an example the radar under MH-60Romeo helicopter APS-153 Multi-Mode Radar with Automatic Radar Periscope is too heavy to fit on the Main rotor, also the one in Ka-31 E-801 Oko L-band radar is also too heavy to fit on top of the main rotor.

 

[Anant]

KA-31 is meant for doing short distance perimeter search for surface and sub surface enemy assets, we Indians only have 2 carries, at any given point of time IN only uses 2 KA-31 in each carrier and mix it with 4-6 Romeos and Sikorsky UH-3H Sea King, that is plenty for 40K displacement carriers, they always keep plenty of helicopters from each brand on reserves, so there is absolutely no maintenance downtimes there, I don't know whether you have any basic knowledge of how these AEW&C helicopters operate and within what range, if you would have at-least known the basics you wouldn't have spent time typing these many lines tarnishing one of the Navy's favorite helicopter, if you don't know please ask the experts here, don't make a fool of yourself.

You will understand the expertise of people here by reading their comments, feel free to ask them.

KA-31's range is 370 NMi
Navy's requirement for the new DBMRH-S helicopter is 65NMi.
Even the brand new MH-60Romeo's range is only 450NMi.

These helicopters only operate 50-75Nmi around the perimeter of the ship at any given time.

For long endurance and long range we Indians have plenty of other capable platforms.

1. Two Ka-31s can provide a decent bit of air cover, but having heard first-hand from naval officers who serve on one of the carriers, you need a minimum of 3 for optimal coverage.

2. When I say maintenance, I am referring to post-sortie maintenance on the carrier. After an aircraft or a helicopter comes back, you usually can't just turn them around then and there. There is a bit of work that goes in even if there were no problems reported.

3. The Indian Navy is satisfied with the Ka-31 because it is sufficient and capable in its role, and because it is a capability the Navy has not had before. We never operated Sea Kings in the AEW variant. That said, they have also noticed points that can be improved upon, and I am saying that these should be incorporated into the AEW variant of the DBMRH.

4. Regarding ranges, the Ka-31 doesn't operate too far from the carrier, but as we have seen in a number of exercises, the operating range of such AEW aircraft will have to increase due to the increased range of sea-launched and air-launched munitions.

Oh, and I have no problem in asking someone when I don't know. I also try not to take unnecessary potshots at others, which is something you evidently don't seem to do. If you don't agree with me, that's fine. Put your points forward (as you did), and we can have a discussion. Let's keep this civilised.

 

[desigandu]

Boss, a helicopter-based AEW&C system will have a folding radar dish at the bottom of the helicopter, similar to what we see with the Ka-31. You can't exactly fit a radome.

Question - Doesn’t the Apache AH64Es, have a top (above the rotors) dome fire control radar! 1. Could such an arrangement work for 360 AEW/AWACS type coverage in DMMRH? 2. Could multiple drones like MQ9B Sea Guardians launched from IAC perform a similar function?