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J52 Engine

The J52P-408A Engine provides propulsion and power service for the EA-6B Prowler Aircraft which has the primary mission of Command & Control Warfare in support of joint service operations. The aircraft and engine programs are in the out of production sustaining support phase with retirement planned for about 2015. As of 1999 there were 123 EA6B aircraft with a desired PAA of 104 supported by 366 active J52P-408A engines.

Providing the power of the only radar jamming aircraft in the Department of Defense, which makes it the only aircraft included in every aircraft carrier's deployment, is the Pratt and Whitney J-52-P408 turbo-fan engine. Each engine provides 11,200 pounds of thrust for takeoff. Although Pratt and Whitey no longer manufactures the engine, it continues to be the main engine for the Navy's Prowler and in 2003 enjoyed the highest supportability levels in two years. The Defense Logistics Agency manages a total of 6,981 items exclusive to the J-52 engine. The Defense Supply Center Columbus manages 2,147 of those items, while Defense Supply Center Philadelphia provides 2,746 and Defense Supply Center Richmond manages 2,088.

One type of icing is called "pogonip," a meteorological term originally used by Native Americans to describe the frozen fogs of fine ice crystals that settle on trees, fences and plants. NATOPS prohibits operating the J52 motor in ice-fog conditions, unless operational necessity dictates. Most commanding officers will agree that training missions do not qualify as operational necessity, so NAS Fallon airwing events don't launch in ice fog. NATOPS warns specifically of rapid ice build-up on engine-inlet vanes and blades in extreme low temperatures, high humidity, or visible moisture conditions. The engine's anti-ice capability cannot overcome the tremendous ice-producing capability of ice fog being sucked through the high-velocity inlet of a Prowler intake.

The Prowler community has had a close call in these weather conditions. In 1992, a Prowler at NAS Fallon started engines in ice-fog conditions. Ice fog had been moving in and out of the area for several hours. The crew started engines and immediately turned on the anti-ice system. The aircraft taxied for takeoff. While waiting for departure clearance, the port motor flamed out with no abnormal engine indications. While the crew was taxiing back to their line to investigate the problem, the starboard engine also flamed out. After towing the aircraft back to the line, mechs dove the ducts. They found a half-inch of ice buildup on the back of the first stage compressor blades. The anti-ice capability of the motor at idle could not handle the ice build-up.

Interim Rapid Action Change (IRAC) 34 to the EA-6B General Information and Servicing Manual changed the temperature/ humidity restrictions for turning a J52-P408A/B motor. It says, "at temperatures between 28 and 42 degrees Fahrenheit, with a relative humidity above 50 percent, engines being turned with FOD screens should be monitored constantly for ice build-up on the screens. If ice starts to form, the engine should be shut down immediately." Common sense would dictate that, in any extremely low temperature, high-humidity, visible-moisture conditions, constant monitoring of the engine inlet/FOD screens should be the norm.

NAS Fallon normally only sees one pogonip episode per year, and it usually lasts only one or two days. However, two significant episodes occurred during the winter of 2004-2005. This particular incident started around Jan. 15 and continued into February. A temperature inversion settled over the valley, trapping the cold, moist air between the Sierra Nevadas. Meanwhile, warmer El Nino air from the south moved over the dense, cold air, packing it down and holding it.

An example of Navy and industry partnering to provide enhanced logistics support is the EA-6B pilot Program. Contractor field teams have partnered with organic maintenance activities to achieve a "zero bare firewall" status by almost doubling the quarterly throughput of J52 engines at one Intermediate level maintenance facility. This has significantly enhanced the operational availability of the EA-6B, allowing it to better perform its mission.

A long term, 5 year, DVD NAVICP contract with Pratt & Whitney provides main engine rotor repair at NAS Whidbey Island with contractor furnished material. A portion of the J-52 engine rotor repair will be performed at a contractor supported site located within NAS Whidbey Island. Repair will be in accordance with the depot repair manual for the engine rotors.

Pratt & Whitney will obtain and install required equipment for assembling and balancing rotors at the repair site, about $500K. Contractor will furnish material for repair support in order to meet rotor repair turn around time. The introduction of more durable material including improved designs will be accelerated by the partnering process with contractor furnished material. AVDLR costs for main engine rotors may decrease over all due to DVD process and reduced transportation and handling.

Oversite would be retained by the Engine FST vice DCMC. All direction and decisions are made by the FST regardless; DCMC simply adds a layer of administrative delay. Oversite of the remote repair process will require in-service engineering and logistics resources from the FST. These resources are being reviewed along with other J-52 priorities.

Delays in Commerce Business Daily announcement occurred while resolving public law and FAR applicability. Congressional concerns related to organic depot workload. Team had several discussions concerning contract strategy such as: 1) warranty type/length/cash benefit; 2) contract type: Commercial vs. Negotiated Procurement; 3) ILA format; and 4) contract length.

Partnering can reduce the O & S cost for an out of production, fielded program during sustainment even when durability modifications are in process. The role of the inservice engineering team, FST, will become more critical with the addition of a commercial repair site as all individual component repair criteria, as well as the over all repair process, will be included in their responsibilities even if DCMC is included in the contract management.

In early 2002 the in-flight loss of two EA-6B Prowler aircraft was blamed on the failure of the vital 4.5-inch engine bearings. Further fleetwide investigation found the engine bearings were highly vulnerable to early failure and the situation affected not only the entire J52 engine fleet, but the Navy's vital EA-6B Prowler.

Technical experts rapidly improved the bearings design but the daunting task of installing it in the midst of a wartime requirement fell to four engine rework sites around the United States and overseas. AIMD Whidbey, Naval Air Depot Jacksonville and Marine Aviation Logistics Squadrons 12 and 14 were called to the task. The Navy estimated it would take until November 2003 for the entire J52 fleet to be brought back to a fully operational status. This mark of completion is signified by the term "zero empty firewalls," which means that all aircraft would be fully supplied and supported with an operational engine and an on call, ready for issue backup engine in the supply system.

On the afternoon of 22 November 2002 in the 400 Division working bay, Capt. Brian Bennett, commander, Electronic Attack Wing, U.S. Pacific Fleet; AIMD's Officer in Charge; AIMD command staff and a large representative group of Sailors and civilian workers presided over the last J-52 engine completing its bearing replacement cycle. This "motor," number 678217, brought the Navywide J-52 fleet to its "zero firewall" status a full year ahead of schedule.

A total of 152 of the J52 engines were accepted, broken down, rebuilt and returned to duty by the Power Plants Division of Aircraft Intermediate Maintenance Department (AIMD). Work centers 51 Charlie, 51 Bravo, 530 and 600 Division of the AIMD here processed nearly 12,000 engine parts in less than six months. More than 8,600 total man-hours were expended in this evolution. Thirty-one engines a month passed through the facility, and at the peak of the effort, more than 100 engines sat stacked in rows behind AIMD, waiting their turn on the processing floor.

By streamlining the production process and hiring additional civilian workers, many with past Navy experience with the J52, the process became fast, efficient and effective. With additional manpower, the power plants division operated six full maintenance crews in two operational shifts. Looking at the larger situation with the war on terrorism and enforcement of United Nations' mandates on Iraq's Saddam Hussein, this record performance could not have been more critical. The EA-6B is a crucial component of the U.S. military's electronic warfare inventory. The loss or lapse of the ready availability of these aircraft could hamper or endanger the military's war against terrorism and the means to contain dangerous regional threats.

By 2004 the Joint Oil Analysis Program Technical Support Center (JOAP-TSC) had developed a technique to analyze the debris from in-line jet engine oil filters by energy dispersive x-ray fluorescence (FDA-EDXRF). Six beta prototype instruments were manufactured under a Productivity Reliability Availability and Maintainability (PRAM) project that are capable of performing FDA-EDXRF in an automated mode. J52 engines were suffering from what appeared to be sudden, catastrophic failures - where the root cause of the failure began with the lack of lubrication in the 4 bearing area followed by fracturing of the 4 bearing cage. Initially, analysis of oil samples by rotrode emission spectroscopy (RDE) did not indicate the failure mode. FDAEDXRF was employed to establish wear limits for the debris extracted from engine oil filters; particle count wear profiles were developed from the debris extracted from the engine oil filters and abnormal bearing wear could be diagnosed.

Initially, filter debris obtained from J52 filters that indicated abnormal amounts of bearing wear were also analyzed by Pratt & Whitney Aerospace laboratory using a scanning electron microscope (SEM). The SEM results confirmed the presence of bearing wear. Subsequent teardowns of a portion of the engines having abnormal bearing wear had fractuered 4 bearing cages. The JOAP-TSC beta prototype instruments and FDA technology have kept the J52 fleet flying.

A variety of factors limit the wear particle detection efficiency of rotating disc electrode (RDE) spectroscopy used throughout the Joint Oil Analysis Program (JOAP). Rotrode Filter Spectroscopy (RFS), a proven technology for large wear particle analysis. RFS enhances the sensitivity of the existing RDE spectrometer by extending its analytical capability to vaporize wear particulates greater than 10 :m and can identify their elemental composition to determine if alloys, such as M50, are generating these particles. LaserNet Fines (LNF), a relatively new technology developed for the Office of Naval Research (ONR) by Lockheed Martin, will be discussed. LNF is an instrument that optically counts particles from 4 :m to greater than 100 :m and creates images of those particles which exceed 20 :m and classifies them into wear particle categories such as fatigue or severe sliding.

The application of these two particle identification technologies to condition monitoring of J52 aviation gas turbine engines at NAS Whidbey Island was innovative and has provided valuable insight into enhanced wear particle analysis capability. Field and laboratory data were gathered from an eight month evaluation of the effectiveness of these technologies.

The J52 engine is a legacy gas turbine engine, which powers the EA-6B and has been in service since the 1960's. The J52 Engine Improvements initiative will capitalize on R&D efforts funded through the Engine Component Improvement Program (CIP) and OMN funded analysis of engine failure odes. Specific reliability discrepancy trends have been identified and appropriate Engineering Change Proposals (ECP) and Power Plant Changes (PPC) have been developed to address the risk of uncontained turbine blade failures and improve engine reliability and time on wing. The results include an improved Turbine Exhaust Case (TEC) that provides low pressure turbine (LPT) containment and other durability and reliability improvements designed to increase engine time on wing. 20 TEC kits purchased with FY02 funding will be on contract in June 2004. These kits were to be delivered not later than 1Q FY06.

Funding will also be used for the Power Trim Indicator system and engineering and logistics labor required to complete development of maintenance planning products across all 10 ILS elements. Efforts include the analysis of J52 data, maintenance plan, Level of repair analysis, reliability centered maintenance to establish preventive maintenance schedules, development of technical manuals, provisioning technical documentation, and logistics support tail for associated support equipment. Also includes the development of source data, and imits to revise engine build standards in order to meet J52 reliability goal of 760 hours time on wing.

Development of the Improved Turbine Exhaust Case (TEC) began in FY95 using engine CIP and contractor funds. Testing and ECP approval was completed in the first quarter of FY98 (OCT 97), followed by a production contract award. All ECPs are approved and Technical Directives (TD) are completed or in process. Incorporation of initial PPC 306 TEC kits is in process. Initial PPC 304 kits are on order and NAVICP is currently procuring attrition parts. FY 2002 received $6.524M Defense Emergency Response Funding (DERF) for J52 and bought 32 TEC/Turbine blade containment kits.




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