P-8I “Neptune”: Indian Navy’s Eye in the Sky


A week ago, we woke up to a news. An Indian Navy officer and a solo sailor, Abhilash Tomy was seriously injured while attempting to complete the famous Golden Globe Race. As a fellow officer needed help, Indian Navy quickly deployed nearest assets to locate and rescue Abhilash Tomy, stranded somewhere about 3,200km from the Australian coast.

Cmdr. Abhilash Tomy’s sailboat spotted by a P-8I of Indian Navy, an Indian Navy pic

Among the assets pushed to the rescue effort was Indian Navy’s most potent aircraft in her inventory. The Boeing P-8I “Neptune”. Indian Navy’s eye in the sky. The P-8I was the first aircraft to make visual contact of Abhilash. Let us dive deep into the secrets of this bird, which is also dubbed as the “Submarine-Killer” for the Chinese subs prowling the Indian Ocean.

The Boeing P-8I “Neptune”

The Boeing P-8I is a long-range, multirole maritime patrol aircraft which is a derivative of the P-8A of US Navy, built for Indian Navy. The P-8I is specifically built for maritime surveillance and is the perfect replacement for the ageing Tu-142M maritime patrol aircraft of Soviet origin. The aircraft can perform basic surveillance missions to combat operations too. The aircraft comes with the punch to perform Anti-Submarine Warfare (ASW), Anti-Surface Warfare (ASuW), and also intelligence gathering and early warning missions.

In 2008, there were clues dropped by the Indian government to seek an alternative to the ageing Tu-142M maritime surveillance aircraft. Boeing has been eyeing the deal and proposed a variant of the US Navy’s P-8A “Poseidon” to the Indian authorities.

In 2009, Boeing won the contract for supplying the Indian Navy with 8x P-8I “Neptune”. The deal was soon modified for an additional 4x aircraft for the Indian Navy. The deliveries are sought to be over by 2020.


  • Airframe: Boeing 737-800ERX
  • Length: 39.47 m (129ft 5in)
  • Wingspan: 37.64m (123ft 6in)
  • Height: 12.83 m (42ft 1in)
  • Empty Weight: 62,370kg (138,300lb)
  • Max. Takeoff Weight: 85,820kg (189,200 lb)
  • Engine: 2x CFM56-7B producing 120kN each
  • Operating Base: INS Rajali, Arakkonam


One of the key aspects of the P-8I is that it includes two additional systems that aren’t present in the US version. Those are the Telephonics APS-143C OceanEye aft radar and a Magnetic Anomaly Detector.

APS-143C OceanEye radar

APS-143 OceanEye – an advanced ocean surveillance radar capable of deployment from both fixed and rotary winged aircraft. The radar combines multiple modes, offering a broad set of long-range maritime visual identification, Inverse Synthetic Aperture Radar (ISAR) and overland Synthetic Aperture Radar (SAR) imaging, weather avoidance and Search and Rescue Transponder (SART) beacon modes.

MAD housing on the aft of a P-8A Poseidon

CAE AN/ASQ-508A Magnetic Anomaly Detector(MAD) – MAD is a system which gives the P-8I the ability to detect submarines lurking under the ocean. Even if the submarines can keep itself safe from sonars, it is highly unlikely for subs to be hidden from a MAD. A very sensitive MAD system can find even find the smallest pieces of metal buried or submerged, which renders the aircraft with rescue capabilities. P-8I aircraft was an active participant for the MH-370 crash.

Raytheon APY-10 surveillance radar – a very advanced all-weather radar capable of providing real-time precise data to mission control room. It is also the only system of its type to provide a dedicated short exposure submarine periscope detection mode as well as ultra-high resolution imaging modes for maritime and overland operations, delivering uncompromised performance in every operational environment.

Indian made systems onboard the P-8I. Credits: Boeing

Other key systems: IFF transponder(HAL), Data Link II comm system(BEL), Avantel mobile satellite system, Speech secrecy system from Electronics Corporation of India (ECIL), IFF interrogating system(BEL)


The P-8I has a total of 5x internal stations for torpedoes, depth charges, mines and bombs, and 6x external stations for ASW or ASuW missiles. In 2010, Indian Navy requested the sale of AGM-84L Harpoon Block II missiles for its P-8I fleet. This add-on will definitely amp-up the whole punch of the aircraft. The move can be seen as a possible move to defende India’s sovereign waters against Chinese sub incursions.

Indian Navy P-8I spotted with Harpoon missiles on the wing pylons. Credits to owners

COMCASA Agreement and P-8I

At the time of sale of P-8Is to India, the US government withheld some key communication equipment to protect its national interest. It wasn’t just the P-8I but also C-130J and C-17 featured these exemptions of comm systems. This had a very negative effect on the operation of these aircraft, forcing them to not be operated at their fullest potential.

However, India and USA have signed the COMCASA agreement recently in a 2+2 dialogue. Even though we are unclear on whether the key systems left out could be inducted in currently flying aircraft, the agreement would surely have an effect on the overall operations of American aircraft operated by the Indian forces.


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