The Pentagon, in Arlington County, across the Potomac River from Washington, D. C. is the headquarters of the United States Department of Defense. As a symbol of the U. S. military, the phrase The Pentagon is used as a metonym for the Department of Defense and its leadership. The building was designed by American architect George Bergstrom and built by contractor John McShain. Ground was broken on September 11, 1941, the building was dedicated on January 15, 1943. General Brehon Somervell provided the major motivating power behind the project. S. Army; the Pentagon is the world's largest office building, with about 6,500,000 sq ft of space, of which 3,700,000 sq ft are used as offices. Some 23,000 military and civilian employees, another 3,000 non-defense support personnel, work in the Pentagon, it has five sides, five floors above ground, two basement levels, five ring corridors per floor with a total of 17.5 mi of corridors. The central five-acre pentagonal plaza is nicknamed "ground zero" on the presumption that it would be a prime target in a nuclear war.
On September 11, 2001 60 years after the building's construction began, American Airlines Flight 77 was hijacked and flown into the western side of the building, killing 189 people, according to the 9/11 Commission Report. It was the first significant foreign attack on Washington's governmental facilities since the city was burned by the British during the War of 1812; the Pentagon is listed on the National Register of Historic Places and is a National Historic Landmark. The Pentagon building spans 28.7 acres, includes an additional 5.1 acres as a central courtyard. Starting with the north side and moving clockwise, its five façades are the Mall Terrace Entrance façade, the River Terrace Entrance façade, the Concourse Entrance façade, the South Parking Entrance façade, the Heliport façade. On the north side of the building, the Mall Entrance, which features a portico, leads out to a 600 ft long terrace, used for ceremonies; the River Entrance, which features a portico projecting out 20 ft, is on the northeast side, overlooking the lagoon and facing Washington.
A stepped terrace on the River Entrance leads down to the lagoon. The main entrance for visitors is on the southeast side, as are the Pentagon Metro station and the bus station. There is a concourse on the southeast side of the second floor of the building, which contains a mini-shopping mall; the south parking lot adjoins the southwest facade, the west side of the Pentagon faces Washington Boulevard. The concentric rings are designated from the center out as "A" through "E". "E" Ring offices are the only ones with outside views and are occupied by senior officials. Office numbers go clockwise around each of the rings, have two parts: a nearest-corridor number followed by a bay number, so office numbers range from 100 to 1099; these corridors radiate out from the central courtyard, with corridor 1 beginning with the Concourse's south end. Each numbered radial corridor intersects with the corresponding numbered group of offices. There are a number of historical displays in the building in the "A" and "E" rings.
Floors in the Pentagon are lettered "B" for Basement and "M" for Mezzanine, both of which are below ground level. The concourse is on the second floor at the Metro entrance. Above ground floors are numbered 1 to 5. Room numbers are given as the floor, concentric ring, office number. Thus, office 2B315 is on the second floor, B ring, nearest to corridor 3. One way to get to this office would be to go to the second floor, get to the A ring, go to and take corridor 3, turn left on ring B to get to bay 15, it is possible for a person to walk between any two points in the Pentagon in less than seven minutes. The complex includes eating and exercise facilities, meditation and prayer rooms. Tours for the public were suspended after the 2001 attack. Just south of the Pentagon are Pentagon City and Crystal City, extensive shopping and high-density residential districts in Arlington. Arlington National Cemetery is to the north; the Pentagon is surrounded by the complex Pentagon road network. The Pentagon has six Washington, DC ZIP Codes.
The Secretary of Defense, the Joint Chiefs of Staff, the four service branches each have their own ZIP Code. Before the Pentagon was built, the United States Department of War was headquartered in the Munitions Building, a temporary structure erected during World War I along Constitution Avenue on the National Mall; the War Department, a civilian agency created to administer the U. S. Army, was spread out in additional temporary buildings on the National Mall, as well as dozens of other buildings in Washington, D. C. Maryland and Virginia. In the late 1930s, a new War Department Building was constructed at 21st and C Streets in Foggy Bottom but, upon completion, the new building did not solve the department's space problem and ended up being used by the Department of State; when World War II broke out in Europe, the War Department expanded in anticipation that the United States would be drawn into the conflict. Secretary of War H
Tinker Air Force Base
Tinker Air Force Base is a major United States Air Force base, with tenant U. S. Navy and other Department of Defense missions, located in Oklahoma County, surrounded by Del City, Oklahoma City, Midwest City; the base known as the Midwest Air Depot, is named in honor of Oklahoma native Major General Clarence L. Tinker, the first Native American Major General. Tinker is the headquarters of the Air Force Materiel Command's Oklahoma City Air Logistics Center, the worldwide manager for a wide range of aircraft, missiles and avionics and accessories components; the commander of Air Force Sustainment Center is Lieutenant General Lee K. Levy II and the commander of the OC-ALC is Brigadier General Tom Miller; the host unit at Tinker is the 72d Air Base Wing which provides services and support for the Oklahoma City Air Logistics Center and its tenant organizations. The Wing and Installation Commander of Tinker Air Force Base is Col. Kenyon Bell. Tinker AFB is home to major Department of Defense, Air Force and Navy units with national defense missions.
The Oklahoma City Air Logistics Complex is the largest air logistics center in the Air Force Materiel Command. It provides depot maintenance, product support and supply chain management, information support for 31 weapon systems, 10 commands, 93 Air Force bases and 46 foreign nations, it is the contracting office for the Air Force's Contract Field Teams program. The 72d Air Base Wing is a multi-unit, multi-mission wing that includes base services and support for the Oklahoma City Air Logistics Center, associate organizations and retirees; the 76th Maintenance Wing includes the 76 Aircraft Maintenance Group, the 76 Propulsion Maintenance Group, the 76 Commodities Maintenance Group, the 76 Software Maintenance Group and the 76 Maintenance Support Group. The 38th Cyberspace Engineering Group, Air Force Space Command, has worldwide responsibility for engineering and interoperability of all communications and electronic facilities for the Air Force. Oklahoma Wing Civil Air Patrol Headquarters is located at the base ops building and provides state level support to the 17 units across the state.
The Flying Castle Composite Squadron is a Civil Air Patrol squadron, composed of cadet and senior members that meet Tuesday evenings. The 552d Air Control Wing flies Air Combat Command's E-3 Sentry AWACS aircraft; the E-3's radar and other sensors provide deep-look surveillance, interception control and airborne battle management. The 552 ACW encompasses 3 groups: 552d Operations Group, 552d Maintenance Group and 552d Air Control Group. Two Air Reserve Component wings operate twelve KC-135R "Stratotanker" air refueling aircraft at Tinker; the aircraft are operationally gained by Air Mobility Command, but the two units have different administrative chains. The 507th Air Refueling Wing of the Air Force Reserve Command is one of two Air Force Reserve flying units in the state of Oklahoma and administratively reports to Fourth Air Force; as an associate unit, the 507 ARW operates the Federal Aviation Administration's British Aerospace 125-800 aircraft in the aviation standards and navigational aid inspection mission.
The Oklahoma Air National Guard's 137th Air Refueling Wing assumed an aerial refueling mission in 2008 in accordance with the 2005 BRAC Recommendations. The 137th Airlift Wing relocated from Will Rogers Air National Guard Base to Tinker AFB, was redesignated as an air refueling wing, associated with the 507 ARW while its C-130H aircraft were redistributed to other ANG airlift wings; the United States Navy's Strategic Communications Wing One consists of three squadrons and a wing staff, employs over 1,300 active-duty sailors and 100 contractors to provide maintenance, operations, administration and logistic support for the E-6 Mercury aircraft fleet. The E-6B Mercury enables the President of the United States and the Secretary of Defense to directly contact submarines and missile silos enforcing the country's national security through nuclear deterrence; the wing operates alert facilities for E-6B aircraft at Travis AFB, California and Naval Air Station Patuxent River, Maryland. Defense Mega Center Oklahoma City is the local branch of the Defense Information Systems Agency.
The Mega center serves 110 other bases in 46 states. Tinker has on base several offices of the Defense Logistics Agency, the agency that provides supplies to the military services and supports their acquisition and transportation of repair parts and other materials. DLA Aviation has two offices at Tinker Air Force Base, DLA Aviation Customer Operations commanded by COL Rex Adee, USAF, DLA Strategic Acquisitions at Tinker AFB, under Frances Evans, Acting Director, DLR Procurement Operations. DLA Distribution Oklahoma City provides the receipt, issue and shipment of material, including material quality control and packaging, transportation functions and pick up and delivery services in support of the Oklahoma City Air Logistics Center, other tenants at Tinker Air Force Base, other global customers. Support to the Air Logistics Center is for programmed depot maintenance for aircraft and engines; the majority of the items shipped from Oklahoma City are destined for "customers" on base including the 552nd Air Control Wing, the U.
S. Navy Strategic Communications Wing One, the 507th Air Refueling Wing and the 3rd Combat Communications Group. DLA Document Services provides a full portfolio of document services including traditional offset printing, on-demand printing, online document services. DLA Document S
Boeing KC-135 Stratotanker
The Boeing KC-135 Stratotanker is a military aerial refueling aircraft. Both the KC-135 and the Boeing 707 airliner were developed from the Boeing 367-80 prototype, it is the predominant variant of the C-135 Stratolifter family of transport aircraft. The KC-135 was the US Air Force's first jet-powered refueling tanker and replaced the KC-97 Stratofreighter; the KC-135 was tasked with refueling strategic bombers, but was used extensively in the Vietnam War and conflicts such as Operation Desert Storm to extend the range and endurance of US tactical fighters and bombers. The KC-135 entered service with the United States Air Force in 1957; the KC-135 is supplemented by the larger KC-10. Studies have concluded that many of the aircraft could be flown until 2040, although maintenance costs have increased; the KC-135 is to be replaced by the Boeing KC-46 Pegasus. Like its sibling, the commercial Boeing 707 jet airliner, the KC-135 was derived from the Boeing 367-80 jet transport "proof of concept" demonstrator, called the "Dash-80".
The KC-135 is similar in appearance to the 707, but has a narrower fuselage and is shorter than the 707. The KC-135 predates the 707, is structurally quite different from the civilian airliner. Boeing gave the future KC-135 tanker the initial designation Model 717. In 1954 USAF's Strategic Air Command held a competition for a jet-powered aerial refueling tanker. Lockheed's tanker version of the proposed Lockheed L-193 airliner with rear fuselage-mounted engines was declared the winner in 1955. Since Boeing's proposal was flying, the KC-135 could be delivered two years earlier and Air Force Secretary Harold E. Talbott ordered 250 KC-135 tankers until the Lockheed's design could be manufactured. In the end, orders for the Lockheed tanker were dropped rather than supporting two tanker designs. Lockheed never produced its jet airliner, while Boeing would dominate the market with a family of airliners based on the 707. In 1954, the Air Force placed an initial order for 29 KC-135As, the first of an eventual 820 of all variants of the basic C-135 family.
The first aircraft flew in August 1956 and the initial production Stratotanker was delivered to Castle Air Force Base, California, in June 1957. The last KC-135 was delivered to the Air Force in 1965. Developed in the early 1950s, the basic airframe is characterized by 35-degree aft swept wings and tail, four underwing-mounted engine pods, a horizontal stabilizer mounted on the fuselage near the bottom of the vertical stabilizer with positive dihedral on the two horizontal planes and a hi-frequency radio antenna which protrudes forward from the top of the vertical fin or stabilizer; these basic features make it resemble the commercial Boeing 707 and 720 aircraft, although it is a different aircraft. Reconnaissance and command post variants of the aircraft, including the RC-135 Rivet Joint and EC-135 Looking Glass aircraft were operated by SAC from 1963 through 1992, when they were reassigned to the Air Combat Command; the USAF EC-135 Looking Glass was subsequently replaced in its role by the U.
S. Navy E-6 Mercury aircraft, a new build airframe based on the Boeing 707-320B. All KC-135s were equipped with Pratt & Whitney J-57-P-59W turbojet engines, which produced 10,000 lbf of thrust dry, 13,000 lbf of thrust wet. Wet thrust is achieved through the use of water injection on takeoff, as opposed to "wet thrust" when used to describe an afterburning engine. 670 US gallons of water are injected into the engines over the course of three minutes. The water is injected into the diffuser case in front of the combustion case; the water cools the air in the engine to increase its density. This allows the use of more fuel for proper combustion and creates more thrust for short periods of time, similar in concept to "War Emergency Power" in a piston-engined aircraft. In the 1980s the first modification program retrofitted 157 Air Force Reserve and Air National Guard tankers with the Pratt & Whitney TF-33-PW-102 turbofan engines from 707 airliners retired in the late 1970s and early 1980s; the modified tanker, designated the KC-135E, was 14% more fuel-efficient than the KC-135A and could offload 20% more fuel on long-duration flights.
Only the KC-135E aircraft were equipped with thrust-reversers for aborted takeoffs and shorter landing roll-outs. The KC-135E fleet has since either been retrofitted as the R-model configuration or placed into long-term storage, as Congress has prevented the Air Force from formally retiring them; the final KC-135E, tail number 56-3630, was delivered by the 101st Air Refueling Wing of the Maine Air National Guard to the 309th Aerospace Maintenance and Regeneration Group at Davis–Monthan Air Force Base in September 2009. The second modification program retrofitted 500 aircraft with new CFM International CFM56 high-bypass turbofan engines produced by General Electric and Snecma; the CFM56 engine produces 22,500 lbf of thrust, nearly a 100% increase compared to the original J-57 engine. The modified tanker, designated KC-135R or KC-135T (modified KC-
The mechanical structure of an aircraft is known as the airframe. This structure is considered to include the fuselage and wings, exclude the propulsion system. Airframe design is a field of aerospace engineering that combines aerodynamics, materials technology and manufacturing methods with a focus on performance, as well as reliability and cost. Modern airframe history began in the United States when a 1903 wood biplane made by Orville and Wilbur Wright showed the potential of fixed-wing designs. In 1912 the Deperdussin Monocoque pioneered the light and streamlined monocoque fuselage formed of thin plywood layers over a circular frame, achieving 210 km/h. Many early developments were spurred by military needs during World War I. Well known aircraft from that era include the Dutch designer Anthony Fokker's combat aircraft for the German Empire's Luftstreitkräfte, U. S. Curtiss flying boats and the German/Austrian Taube monoplanes; these used hybrid metal structures. By the 1915/16 timeframe, the German Luft-Fahrzeug-Gesellschaft firm had devised a monocoque all-wood structure with only a skeletal internal frame, using strips of plywood laboriously "wrapped" in a diagonal fashion in up to four layers, around concrete male molds in "left" and "right" halves, known as Wickelrumpf construction - this first appeared on the 1916 LFG Roland C.
II, would be licensed to Pfalz Flugzeugwerke for its D-series biplane fighters. In 1916 the German Albatros D. III biplane fighters featured semi-monocoque fuselages with load-bearing plywood skin panels glued to longitudinal longerons and bulkheads. Similar methods to the Albatros firm's concept were used by both Hannoversche Waggonfabrik for their light two-seat CL. II through CL. V designs, by Siemens-Schuckert for their Siemens-Schuckert D. III and higher-performance D. IV biplane fighter designs; the Albatros D. III construction was of much less complexity than the patented LFG Wickelrumpf concept for their outer skinning. German engineer Hugo Junkers first flew all-metal airframes in 1915 with the all-metal, cantilever-wing, stressed-skin monoplane Junkers J 1 made of steel, it developed further with lighter weight duralumin, invented by Alfred Wilm in Germany before the war. I of 1918, whose techniques were adopted unchanged after the war by both American engineer William Bushnell Stout and Soviet aerospace engineer Andrei Tupolev, proving to be useful for aircraft up to 60 meters in wingspan by the 1930s.
The J 1 of 1915, the D. I fighter of 1918, were followed in 1919 by the first all-metal transport aircraft, the Junkers F.13 made of Duralumin as the D. I had been. Commercial aircraft development during the 1920s and 1930s focused on monoplane designs using Radial engines; some were produced as single copies or in small quantity such as the Spirit of St. Louis flown across the Atlantic by Charles Lindbergh in 1927. William Stout designed the all-metal Ford Trimotors in 1926; the Hall XFH naval fighter prototype flown in 1929 was the first aircraft with a riveted metal fuselage: an aluminum skin over steel tubing, Hall pioneered flush rivets and butt joints between skin panels in the Hall PH flying boat flying in 1929. Based on the Italian Savoia-Marchetti S.56, the 1931 Budd BB-1 Pioneer experimental flying boat was constructed of corrosion-resistant stainless steel assembled with newly developed spot welding by U. S. railcar maker Budd Company. The original Junkers corrugated duralumin-covered airframe philosophy culminated in the 1932-origin Junkers Ju 52 trimotor airliner, used throughout World War II by the Nazi German Luftwaffe for transport and paratroop needs.
Andrei Tupolev's designs in Joseph Stalin's Soviet Union designed a series of all-metal aircraft of increasing size culminating in the largest aircraft of its era, the eight-engined Tupolev ANT-20 in 1934, Donald Douglas' firm's developed the iconic Douglas DC-3 twin-engined airliner in 1936. They were among the most successful designs to emerge from the era through the use of all-metal airframes. In 1937, the Lockheed XC-35 was the first aircraft constructed with cabin pressurization to underwent extensive high-altitude flight tests, paving the way for the first pressurised transport aircraft, the Boeing 307 Stratoliner. During World War II, military needs again dominated airframe designs. Among the best known were the US C-47 Skytrain, B-17 Flying Fortress, B-25 Mitchell and P-38 Lightning, British Vickers Wellington that used a geodesic construction method, Avro Lancaster, all revamps of original designs from the 1930s; the first jets were not made in large quantity. Due to wartime scarcity of aluminum, the de Havilland Mosquito fighter-bomber was built from wood—plywood facings bonded to a balsawood core and formed using molds to produce monocoque structures, leading to the development of metal-to-metal bonding used for the de Havilland Comet and Fokker F27 and F28.
Postwar commercial airframe design focused on airliners, on turboprop engines, on Jet engines: turbojets and turbofans. The higher speeds and tensile stresses of turboprops and jets were major challenges. Newly developed aluminum alloys with copper and zinc were critical to these designs. Flown in 1952 and designed to cruise at Mach 2 where skin friction required its heat resistance, the Douglas X-3 Stiletto was the first titanium aircraft but it was underpowered and supersonic.
The North Sea is a marginal sea of the Atlantic Ocean located between the United Kingdom, Norway, Germany, the Netherlands and France. An epeiric sea on the European continental shelf, it connects to the ocean through the English Channel in the south and the Norwegian Sea in the north, it is more than 970 kilometres long and 580 kilometres wide, with an area of 570,000 square kilometres. The North Sea has long been the site of important European shipping lanes as well as a major fishery; the sea is a popular destination for recreation and tourism in bordering countries and more has developed into a rich source of energy resources including fossil fuels and early efforts in wave power. The North Sea has featured prominently in geopolitical and military affairs in Northern Europe, it was important globally through the power northern Europeans projected worldwide during much of the Middle Ages and into the modern era. The North Sea was the centre of the Vikings' rise. Subsequently, the Hanseatic League, the Netherlands, the British each sought to dominate the North Sea and thus access to the world's markets and resources.
As Germany's only outlet to the ocean, the North Sea continued to be strategically important through both World Wars. The coast of the North Sea presents a diversity of geographical features. In the north, deep fjords and sheer cliffs mark the Norwegian and Scottish coastlines, whereas in the south, the coast consists of sandy beaches and wide mudflats. Due to the dense population, heavy industrialization, intense use of the sea and area surrounding it, there have been various environmental issues affecting the sea's ecosystems. Adverse environmental issues – including overfishing and agricultural runoff and dumping, among others – have led to a number of efforts to prevent degradation of the sea while still making use of its economic potential; the North Sea is bounded by the Orkney Islands and east coast of Great Britain to the west and the northern and central European mainland to the east and south, including Norway, Germany, the Netherlands and France. In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean.
In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively. In the north it is bordered by the Shetland Islands, connects with the Norwegian Sea, which lies in the north-eastern part of the Atlantic; the North Sea is more than 970 kilometres long and 580 kilometres wide, with an area of 570,000 square kilometres and a volume of 54,000 cubic kilometres. Around the edges of the North Sea are sizeable islands and archipelagos, including Shetland and the Frisian Islands; the North Sea receives freshwater from a number of European continental watersheds, as well as the British Isles. A large part of the European drainage basin empties into the North Sea, including water from the Baltic Sea; the largest and most important rivers flowing into the North Sea are the Elbe and the Rhine – Meuse watershed. Around 185 million people live in the catchment area of the rivers discharging into the North Sea encompassing some industrialized areas.
For the most part, the sea lies on the European continental shelf with a mean depth of 90 metres. The only exception is the Norwegian trench, which extends parallel to the Norwegian shoreline from Oslo to an area north of Bergen, it has a maximum depth of 725 metres. The Dogger Bank, a vast moraine, or accumulation of unconsolidated glacial debris, rises to a mere 15 to 30 m below the surface; this feature has produced the finest fishing location of the North Sea. The Long Forties and the Broad Fourteens are large areas with uniform depth in fathoms; these great banks and others make the North Sea hazardous to navigate, alleviated by the implementation of satellite navigation systems. The Devil's Hole lies 200 miles east of Scotland; the feature is a series of asymmetrical trenches between 20 and 30 kilometres long and two kilometres wide and up to 230 metres deep. Other areas which are less deep are Fisher Bank and Noordhinder Bank; the International Hydrographic Organization defines the limits of the North Sea as follows: On the Southwest.
A line joining the Walde Lighthouse and Leathercoat Point. On the Northwest. From Dunnet Head in Scotland to Tor Ness in the Island of Hoy, thence through this island to the Kame of Hoy on to Breck Ness on Mainland through this island to Costa Head and to Inga Ness in Westray through Westray, to Bow Head, across to Mull Head and on to Seal Skerry and thence to Horse Island. On the North. From the North point of the Mainland of the Shetland Islands, across to Graveland Ness in the Island of Yell, through Yell to Gloup Ness and across to Spoo Ness in Unst island, through Unst to Herma Ness, on to the SW point of the Rumblings and to Muckle Flugga all these being included in the North Sea area.
Lockheed CP-140 Aurora
The Lockheed CP-140 Aurora is a maritime patrol aircraft operated by the Royal Canadian Air Force. The aircraft is based on the Lockheed P-3 Orion airframe, but mounts the electronics suite of the Lockheed S-3 Viking. "Aurora" refers to the Roman goddess of dawn. Aurora refers to the Aurora Borealis, the "northern lights", that are prominent over northern Canada and the Arctic Ocean; the CP-140A Arcturus was a related variant used for pilot training and coastal surface patrol missions. The CP-140 Aurora is similar externally to the Lockheed P-3C Orion, but is different internally, using two sets of mission systems that were first installed in yet another Lockheed anti-submarine warfare aircraft, the carrier-based S-3A Viking; the aircraft's sensors are intended for anti-submarine warfare work but are capable of maritime surveillance, counter-drug and search-and-rescue missions. The CP-140 is Canada's only strategic Intelligence Surveillance and Reconnaissance aircraft, conducting long range missions over land and littoral areas.
These missions are flown in support of Canadian Joint Operations Command, the RCMP, several other federal government departments. In 1991, Lockheed shut down its production lines in Burbank, for the P-3 Orion, which shares the same airframe with the CP-140. Three surplus airframes on hand were purchased by the Air Command, but delivered without the anti-submarine fit; these three aircraft were designated the CP-140A Arcturus and were used for pilot training and coastal surface patrol missions. The Aurora Incremental Modernization Project, initiated in 1998 to upgrade electronics of the Aurora fleet was halted by the government on 20 September 2007 to evaluate whether the aging fleet should continue to be upgraded or replaced by more modern aircraft. On 18 December 2007 the Department of National Defence rescinded this work suspension so that the project could continue. Work includes upgrading computer, navigation and radar systems as well as making structural improvements to ten of eighteen aircraft.
The intent of the modernization project is to "keep the aircraft safe and operationally viable until 2020.". AIMP is divided into four'blocks". Block I is concentrated on the replacement of unsupportable systems. Block II brought a glass cockpit with the Navigation and Flight Instruments component provided by CMC Electronics, a complete replacement of the communications suite. Block III is in progress, is a wholesale replacement of the aircraft's sensors and mission computer. Block IV will consist of further upgrades to mission systems; the Aurora Structural Life Extension Project is proceeding with 14 of the 18 Auroras scheduled to receive new wings and the replacement of key structural components. The complete ASLEP solution replaces the aircraft's outer wings, centre wing lower section and horizontal stabilizers with new production components. All fatigue-life limiting structures on the aircraft are replaced with enhanced-design components and improved corrosion-resistant materials that will reduce maintenance costs over the aircraft's service life.
This program is expected to extend the CP140s' service life by 15,000 flight hours per airframe. The Aurora was acquired in the early 1980s to replace the CP-107 Argus and to further support Canada's anti-submarine warfare mission obligations under NATO for the northwest Atlantic sector. Short deployments to Alaska, Iceland, the UK, Norway were the norm. However, since the end of the Cold War, they have been used in coastal surveillance and sovereignty patrols by providing an all-weather mission surveillance platform; as the CP-140 moves into the 21st century, it is employed for domestic and international surveillance by CANCOM for security, counter-terrorism and smuggling, as well as to monitor foreign fishing fleets off Canada's coasts. CP-140s have been deployed on operations such as Operation Assistance and Operation Apollo. Deployments have included OP SHARPGUARD, OP SIRIUS, OP APOLLO, counter-narcotics patrols in the Gulf of Mexico and Pacific. Through all this, patrols of the Canadian Arctic continue to take advantage of the airframe's unique abilities.
In 2011-2012, CP-140 aircraft performed maritime patrol missions in the Libyan waters in order to help in the enforcement of the no-fly zone over Libya under Operation Odyssey Dawn and Operation Unified Protector. As of January 2017, two CP-140s are conducting overland surveillance missions against ISIL as part of Operation Impact; however one aircraft was withdrawn in May 2017. Lacking the expensive and sensitive anti-submarine warfare as well as the anti-surface warfare fittings of the CP-140 Aurora, the Arcturus was more fuel efficient and was used for crew training duties, general maritime surface reconnaissance, search-and-rescue assistance and Arctic sovereignty patrols; the Arcturus did possess a superior AN/APS-507 surface search radar, incorporating modern functions such as track-while-scan that the Aurora's AN/APS-506 radar lacks but the Arcturus did not have an integrated mission computer, or mission systems. It did, maintain the same military communications suite as the CP-140 Aurora.
All three aircraft were based at 14 Wing. Upon retirement from flying operations, one was used for techni
Contrails are line-shaped clouds produced by aircraft engine exhaust or changes in air pressure at aircraft cruise altitudes several miles above the Earth's surface. Contrails are composed of water, in the form of ice crystals; the combination of water vapor in aircraft engine exhaust and the low ambient temperatures that exist at high altitudes allows the formation of the trails. Impurities in the engine exhaust from the fuel, including sulfur compounds provide some of the particles that can serve as sites for water droplet growth in the exhaust and, if water droplets form, they might freeze to form ice particles that compose a contrail, their formation can be triggered by changes in air pressure in wingtip vortices or in the air over the entire wing surface. Contrails, other clouds directly resulting from human activity, are collectively named homogenitus. Depending on the temperature and humidity at the altitude the contrails form, they may be visible for only a few seconds or minutes, or may persist for hours and spread to be several miles wide resembling natural cirrus or altocumulus clouds.
Persistent contrails are of particular interest to scientists because they increase the cloudiness of the atmosphere. The resulting cloud forms are formally described as homomutatus, may resemble cirrus, cirrocumulus, or cirrostratus, are sometimes called cirrus aviaticus. Persistent spreading contrails are suspected to have an effect on global climate; the main products of hydrocarbon fuel combustion are water vapor. At high altitudes this water vapor emerges into a cold environment, the local increase in water vapor can raise the relative humidity of the air past saturation point; the vapor condenses into tiny water droplets which freeze if the temperature is low enough. These millions of tiny water droplets and/or ice crystals form the contrails; the time taken for the vapor to cool enough to condense accounts for the contrail forming some distance behind the aircraft. At high altitudes, supercooled water vapor requires a trigger to encourage deposition or condensation; the exhaust particles in the aircraft's exhaust act as this trigger, causing the trapped vapor to condense rapidly.
Exhaust contrails form at high altitudes. They can form closer to the ground when the air is cold and moist. A 2013–2014 study jointly supported by NASA, the German aerospace center DLR, Canada's National Research Council NRC, determined that biofuels could reduce contrail generation; this reduction was explained by demonstrating that biofuels produce fewer soot particles, which are the nuclei around which the ice crystals form. The tests were performed by flying a DC-8 at cruising altitude with a sample-gathering aircraft flying in trail. In these samples, the contrail-producing soot particle count was reduced by 50 to 70 percent, using a 50% blend of conventional Jet A1 fuel and HEFA biofuel produced from camelina; as a wing generates lift, it causes a vortex to form at the wingtip, at the tip of the flap when deployed These wingtip vortices persist in the atmosphere long after the aircraft has passed. The reduction in pressure and temperature across each vortex can cause water to condense and make the cores of the wingtip vortices visible.
This effect is more common on humid days. Wingtip vortices can sometimes be seen behind the wing flaps of airliners during takeoff and landing, during landing of the Space Shuttle; the visible cores of wingtip vortices contrast with the other major type of contrails which are caused by the combustion of fuel. Contrails produced from jet engine exhaust are seen at high altitude, directly behind each engine. By contrast, the visible cores of wingtip vortices are seen only at low altitude where the aircraft is travelling after takeoff or before landing, where the ambient humidity is higher, they trail behind the wingtips and wing flaps rather than behind the engines. At high-thrust settings the fan blades at the intake of a turbofan engine reach transonic speeds, causing a sudden drop in air pressure; this creates the condensation fog, observed by air travelers during takeoff. The tips of rotating surfaces sometimes produce visible contrails. Contrails, by affecting the Earth's radiation balance, act as a radiative forcing.
Studies have found that contrails trap outgoing longwave radiation emitted by the Earth and atmosphere at a greater rate than they reflect incoming solar radiation. NASA conducted a great deal of detailed research on atmospheric and climatological effects of contrails, including effects on ozone, ice crystal formation, particle composition, during the Atmospheric Effects of Aviation Project. Global radiative forcing has been calculated from the reanalysis data, climatological models and radiative transfer codes, it is estimated to amount to 0.012 W/m² for 2005, with an uncertainty range of 0.005 to 0.026 W/m², with a low level of scientific understanding. Therefore, the overall net effect of contrails is positive, i.e. a warming effect. However, the effect varies daily and annually, overall the magnitude of the forcing is not well known: Globally, values range from 3.5 mW/m² to 17 mW/m². Other studies have determined that night flights are responsible for the warming effect: while accounting for only 25% of daily air traffic, they contribute 60 to 80% of contrail radiative forcing