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Questions tagged [flight-instruments]

Flight instruments provide the pilot with information about the flight situation of that aircraft, such as altitude, speed and direction; and are of particular use in conditions of poor visibility, such as in clouds, when such information is not available from visual reference outside the aircraft.

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Why are cockpit instruments white on black dials?

Which is easier to read: white on a black dial or black on a white dial? It would seem most aviation instruments are white on black.
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3answers
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What are N1 and N2?

When I'm reading something about jet engines, it's common to see references to N1 and N2. I've never fully understood what N1 and N2 are on engine instruments and how they relate to thrust and the ...
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3answers
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Why don't pilots always use autoland?

In aeroplanes that are equipped for autoland and landing at an airport with a working and adequate instrument landing system for the conditions, why would a pilot choose not to use autoland? If I had ...
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5answers
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How can pilots fly inside a cloud?

I heard that sometime an aircraft fly inside a cloud, and I'm wondering how that works - how clearly can the pilot see while inside the cloud? What if a cloud is "too large"? (Is there a maximum size ...
29
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3answers
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What is this object in the cockpit of an ultralight?

This is a tool (probably) in on an ultralight airplane. Initially I guessed that it is a tilting meter (to level between right and left), but seems it is not as it just a vertical tube filled up with ...
29
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1answer
4k views

Can we replace an attitude indicator with a ball half full of liquid?

Attitude indicators (artificial horizons) use a gyro to display pitch and bank. I was wondering if it would work to use a ball half full of liquid to replace the artificial horizon (using the water ...
29
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2answers
5k views

Can instruments be fixed via a swift punch?

I remember reading a book about private piloting techniques, (I can't remember the title; it has been so long; perhaps I can check my library history or something to see later), and I saw something ...
28
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3answers
12k views

How does a Mach Meter determine the speed of sound at a given altitude?

By my understanding, the Mach Number at a given altitude is calculated by dividing IAS by the speed of sound at that altitude. So how is this speed of sound calculated to display the Mach Number on ...
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2answers
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How does an alpha (AoA) vane work?

The alpha vane (also called AoA vane) is an external probe used to measure the angle of attack. I have been trying to understand how exactly it works, but I can't find any clear explanation or ...
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3answers
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What's the UX in modern airliner avionics for diversion choices, and does it integrate to autopilot?

This question mentions a flight that had to divert, in that case to Iqaluit (YFB). I was wondering: in modern large airliners, what is the user interface like when diverting? How is the case of "what ...
26
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2answers
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Why does the speed tape on the Lockheed U-2 go the opposite way?

I found this clip online that shows the speed tape on the Lockheed U-2 going what I perceive is the opposite direction to the 'normal' convention. On most aircraft, the higher values are above and so ...
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6answers
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Why would a C150 tachometer bounce so much that the needle fell off?

On a long flight in a C150E, the tachometer started bouncing a little bit and the severity of the bouncing gradually increased until it was extreme: The tachometer was spinning in loops and making a ...
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3answers
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How does an A330 detect stall without airspeed?

On Air France 447 the crew had experienced complete failure of the pitot static system, which meant they lost their readings on their airspeed indicators, but according to the Mayday / Air Crash ...
25
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1answer
3k views

Identification of this control panel for a four-engine plane

While cataloguing a printer's copper plates I came across a control panel image, and I have attached it here in the hope someone can identify what plane it's from. The Lorenz blind-landing instrument ...
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13answers
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How did planes measure their speed relative to the ground before GPS?

How did planes measure their ground speed before GPS? If they used some sort of anemometer to measure speed, that would only measure the speed of the plane relative to the air through which it is ...
24
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1answer
6k views

How does the head-up display on a spitfire work?

It turns out that the Spitfire from World War 2 had a head up display. Does anybody know how it worked exactly? All I could find was this picture, but no explanation: Source The source does not ...
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5answers
90k views

What's the difference between True vs Magnetic headings?

What is the difference between a true and a magnetic heading? Why are/were magnetic headings used in aviation?
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4answers
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What is this INOP instrument and when is it safe to fly with INOP instruments?

I flew ZRH->LHR on BA0711 today on G-EUOG. I noticed through the cabin door one of the instruments had a yellow INOP sticker across it (see photo). Which instrument was it? I am presuming the ...
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3answers
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Who decides what measurement units are used for altitude, and why is there no standard?

I know that some countries (Russia and China for instance) use meters to measure altitude while the rest of the world uses feet. Why isn't this standardized around the world? I guess all modern ...
21
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5answers
4k views

Why the pitot tube is heated but the static port isn't?

In some light aircraft, like a Cessna 172, the pitot tube is heated but the exterior static port isn't. The usual reason I've heard is that static ports are much less susceptible to icing, but why is ...
21
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5answers
61k 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?
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2answers
2k views

What does it mean when pitch numbers move all over the HUD screen?

In this video from an F-16: You can see pitch angle move out of screen or be on the side at the end.
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3answers
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What was the first flight instrument ever used in an airplane?

It's not magnetic compass, turn coordinator, stopwatch, wind meter, VVI, and airspeed indicator. I want to know what is the first flight instrument.
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2answers
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How can pilots lacking instruments interpret vectors given by ATC?

This video is about European Air Transport flight 2939, a Boeing 737, which "lost all the instruments of the aircraft" shortly after takeoff. BCS2939: We are flying heading now, and we don't have ...
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4answers
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Why is a clock necessary for IFR?

According to FAR 91.205 (d)(6), one instrument required for IFR is: A clock displaying hours, minutes, and seconds with a sweep-second pointer or digital presentation. Why is it necessary to ...
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2answers
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How does the weather radar work?

I was reading this question about turbulence and how pilots foresee it, and in one of the answers, @Rhino Driver states: Weather Radar Just like using your eyes, except the radar can see further ...
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5answers
8k views

Why is there a difference between GPS Speed and Indicator speed?

I just played with flight simulator and noticed that the GPS shows different speed from the speed indicator in the cockpit. Also, GPS speed is higher than the Indicator. Any Idea why?
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1answer
2k views

What do these instruments do?

This is sort of the reverse of an aircraft-identifcation question. I am attempting to build a virtual model of a Gee Bee R1 (for fun). Unfortunately I haven't had much luck finding plans or images of ...
19
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3answers
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Where did the standard pressure 29.92" come from?

Below the transition altitude (18,000 feet in the US), pilots use local pressure readings to calibrate their altimeters. Above the transition altitude, pilots set a standard pressure to calibrate the ...
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2answers
2k views

What is the purpose of the string taped to the front of the canopy on gliders?

What is the purpose of the piece of string taped to a glider canopy? Is it effectively a turn coordinator, but then what advantages would it have over a gauge such as the ones fitted in powered ...
19
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2answers
3k views

If I fly a balanced turn long enough, will the AI show I'm level?

Attitude Indicators are essentially gyroscopes. Mechanical gyroscopes have a "rigidity in space" property, which allows them to preserve their orientation when the support rotates. However, like ...
18
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1answer
3k views

What do the yellow lashes/wings on the B737 PFD indicate?

When I was looking at a YouTube clip of a B737 doing a landing, I couldn't help but notice something on the PFD: What do these yellow lashes/wings indicate on the artificial horizon? Image Source (...
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2answers
4k views

Are modern aircraft provided with analog consoles in case of a software failure?

I am curious about the redundancy they provide in modern era commercial aircraft. Here are the questions: If an aircraft suffers partial or complete software malfunction, do the pilots have the ...
17
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1answer
7k 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 ...
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3answers
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Are NDBs and VORs dying as a navigational method?

I am new to aviation, so bear with me on this question: I have read in multiple places that the VOR/NDB navigational aids are dying out to GPS. Is this true? Are more modern aircraft being built with ...
16
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2answers
1k views

Why did the manifold pressure gauge on the Ki-61 have negative values?

The manifold pressure gauge of the Japanese Ki-61 has values which go from +40 to -40. I know this has to be relative to something since negative pressure can't exist (you can't get more vacuum than a ...
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4answers
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How do aircraft altimeters calculate altitudes accurately while airborne?

While an aircraft is airborne, the local barometric pressure can change, causing an altimeter to no longer display the correct altitude. How are altimeters re-calibrated to display the correct ...
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2answers
839 views

What is this nose cowl mounted display?

(YouTube) A crop duster's nose mounted display. It looks like a poor man's HUD to keep the display and the outside view at roughly the same focus distance, but what is its function?
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4answers
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Why don't both black boxes hold the same data?

As I understand, there are two black boxes on-board an aircraft. One black box, the Cockpit Voice Recorder holds the cockpit conversations and the other, the Flight Data Recorder holds essential ...
15
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1answer
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What is the difference between OAT, RAT, TAT, and SAT?

When I first started flying jet aircraft, I found different instruments that measure temperature in different ways and it was quite confusing. What is the difference between Outside Air Temperature,...
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1answer
2k views

Why does the EGT gauge in 172s have no numbers on it?

So the EGT gauge on the 172 (and other cessna singles?) doesn't have a numerical scale on it, just markings every 25 degrees. I know that one is supposed to use the EGT for leaning operations (ROP, ...
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2answers
1k views

What are these lights above the panel in a Blue Angels cockpit?

I found the following picture on the Blue Angels Facebook page: What is the purpose of the lights over the pilot's panel? (The two on the top are green)
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2answers
10k views

How precise are altimeters?

How precise and how accurate are typical altimeters these days? That is, if two planes are flying (side-by-side, very near each other), and both altimeters show the same Flight Level, what is the ...
13
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4answers
11k views

What is the advantage of combining the rudder and brake pedals in aircraft?

I've read about several aircraft having their rudder and brake pedals very close together. To me this seems confusing and prone to error. It looks easy to mistake the rudder / brake pedals and ...
13
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2answers
3k views

What types of attitude indicators are there?

Learning to fly in general aviation in the west since the mid 2000s I'm used to the common attitude indicators like this one. I've also seen older ones that are black and white as well as many ...
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5answers
4k views

What will the pilot do if all the airspeed indicators fail?

Are there any alternate instruments to indicate the airspeed in case of pitot tube failures?
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2answers
2k views

Are solid-state attitude indicators subject to gimbal lock?

With all the shiny new glass cockpits it would seem that the days of the spinning mechanical gyro (and associated tumbling due to gimbal lock) should be over: Sparing everyone the boring math it ...
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2answers
5k views

How does an energy variometer work?

In a comment to an answer regarding instrumentation complexity, an "energy variometer" was mentioned, labeled in knots. What does this dial actually show, and how does it work? The image accompanying ...
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2answers
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How is the pitot/static system of a helicopter affected by rotor downwash?

Since the fuselage of a helicopter is affected by downwash from the rotors, how is the pitot static system affected?
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3answers
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What's the difference between orientation and position?

In INS (Inertial navigation system) sensors, is there a distinction between the following? Orientation (heading, pitch and roll) Position (latitude, longitude and altitude) Is the orientation ...