9 minute readNavy’s P-8I design finalized for assembly

An artist's impression of the P-8. Source: Boeing

Boeing has announced the completion on July 16 of the Final Design Review (FDR) for the P-8I, the Indian Navy’s long-range maritime reconnaissance and anti-submarine warfare aircraft. The P-8I, based on the Boeing 737 commercial airplane, is a variant of the P-8A Poseidon that Boeing is developing for the US Navy.

According to a company statement, ‘completion of the FDR locks in the design for the aircraft, radar, communications, navigation, mission computing, acoustics and sensors, as well as the ground and test support equipment’. The statement says it ‘paves the way for the program to begin assembling the first P-8I aircraft’.

“The P-8I’s unique capabilities are tailored to India’s maritime-patrol requirements. It has the reach and capability to defend India’s vast coastline and maritime waters,” said Vivek Lall, vice president and India country lead, Boeing Defense, Space & Security. Leland Wight, P-8I program manager for Boeing, said in the statement, “For P-8I, we are incorporating not only India-unique design features, but also India-built subsystems, so this agreement that the design addresses all customer requirements is a huge milestone,” adding, “It also leads us to the program’s next stage: We are on track to start fabricating the P-8I’s empennage section before the end of this year.”

Four Indian Naval officers huddled with Boeing officials during the five-day FDR in Renton, near Seattle in Washington, to ‘review relevant design information and performance against specifications’. The FDR addressed each functional subsystem in the aircraft, such as radar, flight deck, EO/IR and MAD and described their respective architecture, contractual requirements and compliance, besides displays for and usage by crew and ways for verification and demonstration of performance prior to delivery.

Boeing says in the statement, it will deliver the first P-8I to India within 48 months of the original contract signing, which took place in January 2009. India is the first customer for the P-8 outside the United States. Australia has also signed a Memorandum of Understanding with the US Navy for the aircraft.

The Indian Navy’s first P-8I is to be delivered by January 01, 2013 and has certain capabilities and equipment different from the US Navy’s P-8A, while enjoying the benefits derived from the design, specific to US Navy requirements, including a shorter development timeframe, focusing on specific elements that the Indian Navy asked to be added to the aircraft. It has also leveraged the tests, verification, integration and development that took place under the guidance and funding of the US Navy.

Boeing conducted a Preliminary Design Review (PDR) in Fall 2009 focusing on the distinct requirements of the Indian Navy, such as the aft radar and the indigenous communications equipment, and then a nine-day Provisioning Conference in Seattle in last February to better understand the planned Indian Naval operation of the aircraft in terms of force-integration structures, mission types and training time in flight and on ground to be able to formulate recommendations for spares and ground-support equipment technical maintenance manuals for the Indian Navy.

The Indian Navy asked for an aft radar on the aircraft to enable it to conduct surveillance over areas to monitor the picture and make sure no covert activity took place behind it, especially in littoral, coastal areas. The aft radar is more effective at lower speeds, but working with the forward radar, allows the creation of a more complete surveillance picture.

Boeing has recently been laboratory testing two pieces of indigenous equipment, the Electronics Corporation of India (ECIL) speech secrecy equipment and the Bharat Electronics Limited (BEL) Datalink 2. BEL is also building the IFFI interrogator, Avantel the mobile satellite system (satellite communication relay), Dynamatics is providing the mission and power equipment cabinets (interior cabinets with racks that house various live/replaceable units that power the sensors). Hindustan Aeronautics Limited (HAL) will supply the IFF transponder and weapons bay doors for the aircraft, which will work towards compliance with the 30 per cent offset, under the Indian Defense Procurement Procedure (DPP) of 2006.

Source: Boeing

The P-8 airframe is a 737-800 fuselage with the wings from a 737-900 and the aircraft will run CFM56 engines, beside four wing pylons on station where Harpoons as well as depth bombs can be carried. The weapon’s bay is under the mid-part with place for another five weapons, such as torpedoes (or depth bombs), which are launched into the water as standard torpedoes from a maximum launch altitude below 1000 feet.

The contract for all the stores on the aircraft, including weapons and sonobuoys is being negotiated separately between the Indian Navy and the US Navy. The sonobuoys, incidentally, are located in the back of the aircraft with the launchers.

Source: Boeing

The antennas for the indigenous IFFI interrogator and transponder are distributed around the aircraft. The universal receptacle is behind the crown of the aircraft, around which is also the antenna for the mobile satellite system made by Avantel. Unique to India are the aft radar for surface surveillance, manufactured by Telephonix, underneath the wing root as well as a magnetic anomaly detector for identifying large magnetic elements underwater. The forward radar has been manufactured by Raytheon.

A crew onboard the P-8A.

There are five side-facing operator stations and two observer stations with a picture window, through which visual checks can be made, especially in low-flying, search and rescue operations. The operators have five mission operator work stations, with upper and lower screens, to enable them to selectively monitor the sensors onboard. Operators can customize their console screens depending on their mission. There are a total of 21 crew seats throughout the aircraft, in case additional crew are required.

In terms of range of operations, the aircraft has a self-deployment of 4800 nautical miles and an operational radius of 1200 nautical miles, allowing for at least around four hours time on station, which can be increased by refueling enabled by the universal aerial refueling receptacle in case increased loiter, range or persistence is required.

The 737 assembly line at Puget Sound.

The P-8I manufacturing process is such as to duplicate, as much as possible and practical, the 737 commercial production system into the P-8 line, which Boeing calls Line 3. This line is fully capable of producing commercial 737 aircraft, with employee training and certification common to the P-8 and a similar assembly process. The production flow for the P-8A and the P-8I is considerably longer than for the 737 – about three to four months – so it makes sense for the two aircraft to be in the production system together.

Source: Boeing

Boeing asks for employees to volunteer for work on the aircraft as it requires extra and more challenging work than the commercial 737 aircraft demands. Since a commercial 737 passes the assembly line at the rate of one a day, the same crew stays in that flow day. But with the P-8 the same crew builds the aircraft throughout the process. The indigenous equipment unique to the P-8I, mission systems, as well as weapons will be installed by the Boeing Defense unit, once it goes to the installation and check-out line, and not during assembly by the Boeing Commercial Aircraft unit. Boeing plans to do something similar for the tanker it has proposed for the KC-X competition.

The T2 P-8A aircraft at Puget Sound.

The first P-8 aircraft Boeing manufactured was to test airworthiness and was delivered to the Naval Air Station at Patuxent River in Maryland last April for flight tests by the US Navy. The aircraft, T1, is not missionized, but has substantial test gear on it to collect data for to expand the airworthiness envelope. The second aircraft, T-2, which is a platform for testing mission systems, successfully completed the program’s first mission systems test flight on June 8 in Seattle. The third aircraft, T3, will be tested for stores and weapons payload besides its mission systems after it is delivered in the next couple of weeks. All three flight-test aircraft are expected to be variously tested by the US Navy at Patuxent River by the end of summer.

The T2 P-8A aircraft at Puget Sound.

The aircraft’s static test article has already undergone static tests, with the application of the maximum ultimate and design load to verify the response of the structure to the anticipated limit as analyzed, to determine the ultimate strength of the design through a projection. The fatigue test article, S2, will be tested to two lifetimes worth of fatigue, in other dedicated ground test aircraft later this summer. This test is expected to indicate the life of the structure, keeping in mind the dynamic movement of the aircraft, like buffet, and flight loads, by measuring the ability of a structure to withstand cracking or delaminations and gauge the strength of the materials used in the aircraft. Normally, these tests are not conducted to failure, but to a percentage of the design load, since the former is more dangerous and conducted less often, especially with the basis of the airframe, which has already been put under many these stresses, remaining the same.

Upon delivery to the Indian Navy, each P-8I aircraft will be required to undergo acceptance tests scheduled by the navy as part of a process called Joint Receiving Inspection, which will focus on the functionality of the aircraft. The contract provides for more extensive testing of the first one or two aircraft and with possibly less exhaustive tests for successive aircraft, depending on the confidence inspired in the delivered product. At any rate, the P-8I aircraft will not separately and individually undergo the more fundamental testing as described above to be carried out by Boeing and the US Navy. In fact, if such testing were mandated by India, the price of the aircraft would more than double in value. Also, since the P-8 is a platform conceptualized by the US Navy, which is expected to procure them in numbers speculated to be around a 100, it is the US Navy which will certify the aircraft and not the Federal Aviation Authority (FAA).

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