Surfactant

A chemical added to a liquid to help it spread, soak in, and clean better. It's why soapy water cleans an oily part that plain water just rolls off of.

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Saturday, September 26, 2026TurbofanA jet engine with a big fan up front. Some of the air the fan moves goes through the middle of the engine where fuel is burned, and the rest is pushed around the outside. Both streams of air combine to push the airplane forward, which makes the engine more efficient and quieter than a plain jet.
Friday, September 25, 2026DVRSN — DiversionWhen a flight cannot or should not continue to its planned destination, the pilot changes course and lands somewhere else instead. That change is called a diversion.
Thursday, September 24, 2026rectangular cross-checkA way of moving your eyes around the cockpit instruments in a rectangle shape so you keep checking all of them in turn, instead of staring at just one.
Wednesday, September 23, 2026JET BA jet fuel that is a mix of kerosene and gasoline, used mainly in very cold places because it does not freeze as easily as standard jet fuel.
Tuesday, September 22, 2026inspectionA required check of the aircraft to confirm it is safe and legal to fly. The check is done by a qualified person and the results are written into the aircraft's logbooks.
Monday, September 21, 2026parachute jump aircraft operationsFlights where small aircraft climb up so skydivers can jump out. The places where this regularly happens are marked on charts so other pilots know to watch out for the aircraft and the people coming down under canopy.
Sunday, September 20, 2026engine compressor stallThe fan-like blades inside a jet engine stop pulling air through smoothly. Instead of a steady stream of air being squeezed and pushed back, the airflow breaks down, and the engine loses power until normal flow is restored.
Saturday, September 19, 2026OBS — omnibearing selectorIt is the knob on the VOR instrument you turn to pick which course line, measured outward from the station, you want to fly. Once you set the course, the needle on the instrument tells you whether you are on it or off to one side.
Friday, September 18, 2026landing flareJust before the wheels touch the runway, the pilot gently pulls back on the controls to lift the nose, slowing the descent so the airplane settles onto the runway softly instead of hitting it.
Thursday, September 17, 2026crosswind and headwind component chartA chart that breaks a reported wind into two parts: how much of it is blowing straight down the runway, and how much is blowing across it. Pilots use it to check whether the crosswind is within what the aircraft and the pilot can safely handle.
Wednesday, September 16, 2026EutecticA specific blend of metals (or other materials) that melts at a lower temperature than any of the metals would on their own, and changes from solid to liquid all at once instead of gradually softening.
Tuesday, September 15, 2026tubular ductsTiny tube-shaped channels inside the ear that hold fluid. When the head turns, the fluid shifts and tells the brain which way the body is moving.
Monday, September 14, 2026hand proppingStarting the engine by pulling the propeller through by hand instead of using the electric starter button. It's done when the starter doesn't work or the airplane was never built with one, and it must be done carefully because a spinning propeller can seriously injure or kill someone.
Sunday, September 13, 2026air defense identification zoneA buffer zone of airspace, usually near a country's borders or coastlines, where aircraft must identify themselves before entering. If you fly through one without filing a flight plan and talking to ATC, the military may treat you as a potential threat.
Saturday, September 12, 2026Runway Incursion ProgramAn FAA effort to reduce mistakes that put aircraft or vehicles on a runway when they shouldn't be there. As part of it, the FAA flags trouble spots at specific airports so pilots know to be extra careful in those places.
Friday, September 11, 2026Dc AmplifierA circuit that boosts a steady or slowly changing electrical signal so it is large enough to drive a meter, indicator, or control system.
Thursday, September 10, 2026idle detentA built-in catch in the throttle quadrant at the idle position. The pilot has to deliberately lift or move the levers past this catch before they can pull them back into reverse. It stops the levers being yanked into reverse by mistake.
Wednesday, September 9, 2026document completion of prerequisitesWriting it down — usually as a signed logbook entry — that the student has finished everything required before they can take the checkride.
Tuesday, September 8, 2026TMF — Traffic Management FacilityIt is an air traffic control office whose job is to keep too many aircraft from arriving at the same airport or airspace at the same time, by slowing, spacing, or rerouting flights before problems occur.
Monday, September 7, 20267 microphone clicksAt many smaller airports, the runway lights are off until a pilot turns them on by pressing the radio's talk button seven times in five seconds on the airport's published frequency. Seven clicks gives the brightest setting.
Sunday, September 6, 2026transponder returnsThe signals that come back from an aircraft's transponder and show up on the controller's radar screen, telling the controller who the aircraft is, where it is, and how high it is flying.
Saturday, September 5, 2026performance evaluationIt is the part of a lesson where the instructor watches the student perform what was taught and judges how well it was done compared to the standard set for that lesson.
Friday, September 4, 2026P-staticStatic and noise on the radios caused by the airplane picking up an electrical charge while flying through rain, snow, dust, or ice crystals, then shedding that charge into the air.
Thursday, September 3, 2026Current Into And Out Of The Rotor WindingThe electricity that flows in and out of the spinning coil inside a generator or motor. Since the coil is turning, the current is passed through metal rings on the shaft and small carbon blocks that press against them, so the wires don't have to twist.
Wednesday, September 2, 2026Albert BanduraA psychologist whose work showed that people learn a lot by watching others, not just by doing things themselves. He also showed that a learner's belief in their own ability to succeed strongly affects how well they actually learn.
Tuesday, September 1, 2026Delay Indefinite (Reason if Known) Expect Further Clearance (Time)ATC is telling you: 'You're going to be held up. We don't know for how long. Here's why, if we know. Check back with us at this time and we'll have more information for you.'
Monday, August 31, 2026filed routeThe path you wrote down on your flight plan and gave to ATC before takeoff. It is the route you asked to fly.
Sunday, August 30, 2026pitot-static pneumatic systemIt's the set of small air tubes that carry two kinds of outside air pressure into the cockpit: the pressure caused by the airplane moving forward, and the pressure of the still air around it. The flight instruments use those two pressures to figure out how fast and how high the airplane is flying.
Saturday, August 29, 2026aircraft performance figuresThe numbers that tell you what your aircraft can and cannot do — how far it needs to take off, how fast it climbs, how much fuel it burns, how high it can fly, and how heavy it can be loaded.
Friday, August 28, 2026metal fatigueWhen metal is bent, flexed, or loaded over and over again, tiny cracks slowly form inside it. Given enough cycles, the part can fail — even though no single load was ever strong enough to break it on its own.