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Jack Screw	A jack screw is a mechanical device used to adjust the position of aircraft components such as trim tabs, stabilizers, or landing gear. It converts rotary motion into linear movement, allowing for precise adjustments. Proper maintenance is critical as failure can lead to loss of control or instability.
Janet Airlines	Janet Airlines (N36°05'29.92" W115°09'53.97") is a covert U.S. government-operated airline transporting personnel to classified facilities like Area 51 and the Tonopah Test Range. Operating from a private terminal at Harry Reid International Airport, it uses unmarked aircraft with red cheatlines. Officially unacknowledged, Janet serves Special Access Programs, shuttling cleared military and contractor staff under tight secrecy protocols.
JATO (Jet-Assisted Takeoff)	Jet-Assisted Takeoff is a system where additional rocket or jet boosters provide extra thrust for aircraft operating on short runways or under heavy load conditions. JATO was commonly used in military and cargo operations requiring rapid takeoff performance.
Jet-A Fuel	Jet-A is a type of aviation fuel commonly used in commercial aircraft. It is kerosene-based, with high flash points and additives for stability, anti-icing, and safety. Jet-A is the standard fuel for turbine-engine aircraft in most parts of the world.
Jet-A1 Fuel	Jet-A1 is an aviation fuel similar to Jet-A but with a lower freezing point, making it suitable for long-haul international flights. It is the standard jet fuel used outside North America and in extreme cold-weather operations.
Jet-B Fuel	Jet-B is a specialized aviation fuel with a higher gasoline content, providing improved cold-weather performance. It is used in Arctic and military operations but is less common in commercial aviation due to handling risks and volatility.
Jet Blast	Jet blast is the high-speed exhaust stream produced by a jet engine during operation. It can generate strong winds and turbulence behind the aircraft, posing hazards to nearby personnel, equipment, and other aircraft. Airports implement jet blast deflectors and safety protocols to mitigate risks.
Jet Bridge	A jet bridge, also called an aerobridge or passenger boarding bridge, is an enclosed, movable structure connecting the airport terminal to an aircraft. It allows passengers to board and disembark comfortably without exposure to the elements. Jet bridges improve accessibility and enhance security in modern airports.
Jet Cargo Aircraft	A jet cargo aircraft is designed for freight transport using high-powered jet engines for rapid delivery of goods. These aircraft feature large cargo doors, reinforced floors, and specialized loading equipment.
Jet Exhaust Nozzle	A jet exhaust nozzle is the final section of a jet engine that directs high-speed exhaust gases to generate thrust. Some nozzles incorporate afterburners for additional power, while others are designed with noise suppression features to reduce engine sound levels.
Jet Fuel	Jet fuel is a specialized aviation fuel used in jet engines, with types including Jet A, Jet A-1, and Jet B. It is highly refined and contains additives for stability, anti-icing, and combustion efficiency. Proper fuel management is essential for aircraft performance and engine longevity.
Jet Fuel Contamination	Jet fuel contamination occurs when water, microbial growth, or particulate matter compromises fuel quality. Contaminated fuel can lead to engine damage, filter blockages, and reduced combustion efficiency, necessitating strict fuel monitoring and filtration systems.
Jet Lag	Jet lag is a temporary sleep disorder caused by rapid travel across multiple time zones. It disrupts the body's circadian rhythm, leading to fatigue, disorientation, and impaired cognitive function. Pilots and frequent travelers use strategies such as hydration, proper sleep, and gradual time adjustments to mitigate jet lag.
Jetliner	A jetliner is a large, jet-powered commercial aircraft designed for passenger transport over medium to long distances. Jetliners feature efficient aerodynamics, high-bypass turbofan engines, and advanced avionics to optimize performance, fuel efficiency, and safety in modern air travel.
Jetliner Autopilot System	The autopilot system in a jetliner automates key flight tasks such as altitude maintenance, navigation, and approach procedures. Modern autopilots use computer-controlled avionics to enhance flight safety and reduce pilot workload.
Jetliner Cabin Pressure	Jetliner cabin pressure refers to the controlled pressurization system inside passenger aircraft, ensuring a comfortable and safe breathing environment at high altitudes. It prevents hypoxia and allows aircraft to operate efficiently above 30,000 feet.
Jet Noise	Jet noise is the loud sound produced by jet engines due to high-velocity exhaust gases and fan blade movement. Noise-reducing technologies, such as chevron nozzles and high-bypass turbofan engines, help minimize environmental noise pollution.
Jet Pipe	A jet pipe is the duct that channels exhaust gases from a jet engine to the atmosphere. It plays a crucial role in managing engine thrust, noise reduction, and heat dissipation. Some military aircraft use adjustable jet pipes for thrust vectoring to improve maneuverability.
Jet Propulsion	Jet propulsion is the principle by which jet engines generate thrust through the expulsion of high-speed gases. This method powers commercial airliners, military jets, and spacecraft, making it one of the most efficient forms of propulsion for high-speed travel.
Jet Pump	A jet pump is a device used in aircraft fuel systems to transfer fuel using the Venturi effect rather than mechanical moving parts. It improves fuel distribution, minimizes weight, and enhances reliability by reducing failure-prone components.
Jet Stream	A jet stream is a high-altitude, fast-moving air current that influences weather patterns and aircraft performance. Pilots use jet streams to reduce fuel consumption and flight time when flying in the same direction, while avoiding them when flying against strong headwinds.
Jet Trainer Aircraft	Jet trainer aircraft are used for pilot training, providing high-speed flight experience before transitioning to operational fighter or commercial jet aircraft. These trainers feature dual controls, safety systems, and performance characteristics similar to frontline aircraft.
Jet Wake	Jet wake is the turbulent airflow left behind by a moving jet aircraft. It can create significant wake turbulence, posing challenges for following aircraft, particularly during landing and takeoff. Pilots follow specific spacing guidelines to avoid jet wake hazards.
Jet Winglets	Jet winglets are vertical or angled extensions at the wingtips of jet aircraft, designed to reduce drag and improve fuel efficiency. By minimizing vortex formation, winglets enhance range and stability while lowering operational costs.
Jettison	Jettison refers to the emergency procedure of discarding cargo, fuel, or equipment from an aircraft to reduce weight, improve performance, or manage an emergency. Fuel jettisoning is common for long-haul flights when an aircraft needs to return to an airport shortly after takeoff.
Joint Aviation Authorities (JAA)	The JAA was a regulatory body that coordinated aviation safety standards among European countries before being replaced by the European Union Aviation Safety Agency (EASA). It played a key role in harmonizing flight regulations, aircraft certification, and pilot training requirements.
Joystick	A joystick is a control column used in aircraft to manipulate pitch and roll movements. Common in fighter jets, helicopters, and some modern airliners, joysticks provide pilots with precise control over the aircraft’s attitude and flight path.
Junction Box	A junction box is an electrical enclosure in an aircraft that houses and protects wiring connections. It ensures proper electrical distribution, reduces the risk of short circuits, and allows for organized maintenance access to critical electrical components.
Jump Seat	A jump seat is an auxiliary seat in the cockpit or cabin, used by off-duty pilots, flight attendants, or authorized personnel. It provides a secure place for crew observation and training while ensuring compliance with safety regulations.
Jump Start (Aircraft Battery Boosting)	Jump-starting an aircraft involves using an external power source to provide an initial electrical charge to the onboard battery or auxiliary power unit (APU). This process is necessary when an aircraft’s battery is drained and cannot start the engines independently.
Jury Strut	A jury strut is a supporting brace used in aircraft wing structures to provide additional stability and strength. Found in light aircraft, it prevents excessive wing flexing and enhances overall aerodynamic integrity.