Questions tagged [terminology]

For questions about words, phrases and definitions that are specific to aviation or used in a different way in aviation.

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9
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2answers
1k views

Is induced drag essentially nothing more than a specific type of form drag?

If I were standing outside on a windy day holding a flat rectangular object such as a food tray up in the wind, orthogonal to the direction of flow, the drag created would be classified, mostly, as ...
36
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3answers
138k views

What are the differences between Bearing vs Course vs Direction vs Heading vs Track?

This answer from English.SE does not focus on aviation, and does not explain 'Track'. In basic, simple English, would you please compare and contrast all 5 terms in my question's title? The ...
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2answers
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What is the difference between centre of pressure, aerodynamic centre and neutral point?

I have just started learning some aerospace concepts, and I am not able to understand the difference between the three terms centre of pressure, aerodynamic centre and neutral point. What are their ...
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5answers
65k views

What does the term “trimming” most commonly mean in aviation?

Why does an airplane need trim, and what does it do during the flight? Does an autopilot adjust the trim automatically?
16
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4answers
7k views

What is a canard?

While browsing this Stack Exchange, I regularly come across mentions of canards. I am not familiar with this term, and Google only gives information about ducks when I search for "canard". So, what is ...
32
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3answers
55k views

What is the difference between “flight level” and “altitude”?

I have seen references to "FL180" and "FL300", and I know that they stand for Flight Level 180 and Flight Level 300. I've also seen references to "an altitude of 18000ft" or "an altitude of 30000ft". ...
4
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1answer
9k views

What's the difference between FMS and FMC?

What's the difference between FMS (Flight management System), and FMC (Flight management computer)? Can the flight management computer be thought of as what's manipulating the input information from ...
9
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2answers
4k views

Where does the term 'steam cockpit' come from?

Why are traditional style cockpits with gauges called 'steam cockpits'? Do the instruments actually run on steam?
20
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1answer
18k views

What is the difference between aviation “accident” and “incident”?

When I hear speaking about aviation crashes, sometimes I hear about "accidents" and other times about "incidents". What distinguishes them? Is there an international standard that determines how ...
14
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3answers
7k views

What is the name of the maximum altitude at which a helicopter can fly?

What is the name of the maximum altitude at which a helicopter can fly? I recall it as "vertical limit", but I can't find a Wikipedia page for it other than a movie of the same title, which seems to ...
17
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1answer
8k views

What is the difference between “sensitive” and “non-sensitive” altimeters?

In this answer reference was made to "sensitive" and "non-sensitive" altimeters. What is the definition of each, what are the differences, and why would one be used in preference to the other? And ...
6
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4answers
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Does the expression “stall speed” have a definition?

I read, not only on this site, that the stall speed of an airfoil doesn't exist, and I usually make the effort to stay away from this expression. While an airfoil can stall at any airspeed, it's ...
10
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2answers
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Is there a name for the area for aircraft to back track near the runway threshold?

Some airports have an area, on the threshold, used to back track the aircraft, mainly because of the their wingspan, they look like a half wheel. Is there any designation for this area?
4
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3answers
9k views

What is a flat rated engine?

I've heard that a "Flat Rated Engine" is an engine where the power is reduced to keep the internal temperature within certain limits when the ambient temperature is above a certain point. Is that ...
3
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1answer
421 views

What does leading edge radius mean?

What does leading edge radius mean amongst these parameters of a st cyr 24 airfoil?
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6answers
4k views

What would be a technical or slang term for 'in the air'?

I'm writing a sci-fi story involving aircraft and space craft. I'm struggling to get the terminology right for referring to a pilot being 'in the air' either on a mission or a training exercise. I ...
6
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3answers
924 views

Jettison and Dump fuel - Do they have separate meanings?

According to the definitions, is there any difference between Jettison and Dump fuel? Does one of them use a different procedure, or they are simply synonyms?
4
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3answers
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Why does the Trent XWB have intermediate compressor stages?

I realized that the Rolls-Royce Trent XWB on the Airbus A350 has intermediate compressor stages. Why is that? Other engines like the CFM56 or IAE V2500 that power most of the A320-family have low ...
37
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2answers
13k views

What do jet pilots say during the takeoff as they are speeding down the runway?

I was watching a documentary on youtube and the pilots always say something that sounds like "B1E" when they have enough speed to take off. What exactly are they saying, and why do they say it?
18
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2answers
13k views

What is the difference between a fix, a waypoint and an intersection?

It seems these terms are used interchangeably. Are they the same thing? Do they all refer to the points in space that are given 5-letter names?
16
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3answers
28k views

What is the difference between GPS, GNSS and RNAV?

I would like to know the fundamental difference between GPS, GNSS and RNAV. How are they related each other? Are all/some of them synonyms?
41
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4answers
16k views

Why is the autopilot called “George?”

The autopilot of an airplane is frequently referred to as "George" (for example, in this answer). When did this nickname enter common usage, and what is its origin? Please cite sources if possible!
17
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2answers
20k views

What exactly is a QRH?

In this question about aircraft dumping fuel I was told that there may possible be guidance in the QRH. I know that there are a lot of guidelines given to pilots, but I've never heard of this one. ...
13
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1answer
1k views

Is GOCE a satellite or aircraft?

This vessel (GOCE) is in orbit and maneuvers by using air similar to a plane to create lift and turn. The solar powered ion thrusters powers it continuously inside the atmosphere for years. Is this ...
6
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5answers
13k views

Why is port-starboard terminology used in aviation?

I am not a pilot - just a student & play Ace Combat sometimes Intrigued by the words Starboard & Port-side I researched why these words are used instead of the simple ones, I found that: ...
48
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4answers
8k views

What is a running rabbit?

My father used to work as an air traffic controller, and often I heard mention of a 'running rabbit'. Obviously, vermin on the runways of airports can be a bad thing, but I don't think he was ...
19
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2answers
5k views

Why do we call it a ramp?

Airport ramps are close to level, not inclined. What is the history and etymology of this aviation term?
16
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1answer
5k views

What is the difference between fail-safe and fail-soft?

I have heard the following terms related to safe system design but I cannot really see a difference between fail-safe and fail-soft (graceful degradation). To get a common understanding I will just ...
15
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4answers
40k views

What is the difference between a nacelle and a cowling?

I see these terms used almost interchangeably. To my understanding they both refer to the covering of an engine. Is there a technical difference between the two?
15
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1answer
2k views

When buying airliners what is the difference between “orders”, “options” and “purchase rights”?

I've often seen announcements by aircraft manufacturers or operators along these lines "Qantas announced today that they will buy 10 A380's and have taken options on another 10". What does it mean to ...
12
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3answers
19k views

What is the origin of the term “pax”?

Pax in commercial transport is used as something like persons or passengers, in the context of counting people, e.g. 150 pax onboard. (Amadeus capture, source) I observed that in German writers tend ...
5
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2answers
2k views

What, exactly is “on the MEL”?

The MEL, minimum equipment list, defines whether fault of some equipment on the aircraft prevents it from being dispatched for flight or not. However, sometimes (e.g. in comments to this question) ...
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1answer
136 views

What is an “unsafe airline”? [closed]

Question: Is there any internationally accepted definition for what an "unsafe airline" is based on objective criteria (e.g. fatalities per million passengers) ? Or is there an international standard ...
20
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3answers
11k views

What are the differences between various simulator levels?

I've heard of level A, B, C, and D simulators, (as well as FTD and AATDs) but know nothing about them. What criteria is used to certify a sim as a particular level?
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3answers
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Why is the “Dutch” roll called so?

Why is the "Dutch" roll called so? When did this name enter common usage, and what is its origin? Please cite sources if possible!
16
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3answers
7k views

Why is it called “Dry Thrust”?

When reading the specifications of a jet aircraft anywhere on the Internet, it usually states that its engine produces X pounds of "dry thrust". Why is it called "Dry" Thrust? As opposed to what?
15
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3answers
5k views

What's an “altitude engine”?

FAR 91.205(b)(8) says that you need a manifold pressure gauge for each "altitude engine", whatever that means. What's an "altitude" engine?
13
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3answers
2k views

What does “out of trim” mean?

Our flight was delayed from takeoff because the captain reported it to be "out of trim". What does this mean?
12
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5answers
8k views

Are “Tally-ho” and “no joy” acceptable ATC terms for civil operations?

I keep meaning to ask this question. I heard "Tally-ho" used for the first time by a pilot on Liveatc.net. I know these are pretty standard phrases in military aviation but I wondered if civil pilots ...
10
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1answer
258 views

In the United States, are ultralights legally considered aircraft?

I sometimes hear it stated that in the United States, ultralight vehicles are not legally considered to be aircraft. For example, Wikipedia used to state: In the United States ultralights are ...
10
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2answers
6k views

What is the true meaning of the word “roger” when used on the radio? What is its origin?

When pilots learn to talk on the radio they can generally learn that the word "roger," when used on the radio, is a way to acknowledge that a message was received. What is the textbook definition of ...
10
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1answer
884 views

What is Flexible Gunnery in the US Air Force?

I read many times in English Wikipedia that some servicemen were trained in Flexible Gunnery schools, but I don't get what that exactly means. Example: In January 1942, the 2d Air Force was ...
9
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2answers
1k views

Is an engine surge classed as an engine fire?

Sometimes flames come out from the exhaust due to bearing distress or turbine blade fracture. Can such flames/fire be considered an engine fire?
8
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4answers
11k views

What are the differences between air brakes, spoilers and lift dumpers?

So many people use these words interchangeably, but after a little searching on Google, I found they are not quite the same thing. All the links I read explain things in a misleading way which pushed ...
8
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1answer
617 views

What is TAPS in this report?

In researching for this question, I came across some reports from EASA referring to TAPS. What is the meaning of TAPS in this context?
8
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2answers
36k views

How do terms apron, ramp, tarmac, taxiway, parking area, gate, hardstand relate to each other?

The terms apron, ramp, tarmac, taxiway, parking area, gate, hardstand are used in a way that I cannot understand. Boeing Everett Factory. Photo by Andrew Hunt at Airliners.net (url unknown). Cropped ...
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3answers
2k views

Is “General Aviation” a well-defined term in the US, in the EU and/or elsewhere?

In this earlier question I tentatively assume that GA means civil aircraft operations other than scheduled passenger transport - what I think of as "airliner" operation though it could include quite ...
8
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1answer
188 views

What is weight-climb speed?

I have a question about a document published by the Association of European Airliners. The name of the document is “Long Range Aircraft - AEA Requirements.” In the Appendix titled "Definitions and ...
5
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2answers
999 views

What is an Airline?

What is a good definition for the term "Airline"? The term is used extensively, and it's meaning is well understood at the one end of the spectrum: air carriers flying passengers on large aircraft on ...
5
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2answers
14k views

What is the difference between Cruise and Service ceilings?

I am looking at aircraft performance data. There are charts for "Cruise Ceiling" and "Service Ceiling." What is the difference? (The cruise altitude is lower.)