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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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How reliable are stick shakers?

I've read many accident reports, and seen reconstructions, where instrument failures, disagreeing sensor sources and auto pilot faults have led pilots into believing that they are over speeding when ...
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183 views

Why do aircraft stall warning systems use angle-of-attack vanes rather than detecting airflow separation directly?

Stall warning and protection systems on essentially all aircraft work by using several hinged vanes on the side of the fuselage (usually at least three, and preferably more), which align themselves ...
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609 views

What is the difference between a “compass swing” and “check swing” procedure?

What is the difference between a "compass swing" and a "check swing" procedure?
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136 views

Are magnetic turning errors due to the southern side of the compass being weighted?

When I was in college, I had an instructor who taught me that the turning errors in a magnetic compass were due to a counter-weight installed on the south side of the compass that was intended to ...
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0answers
54 views

Is it possible to selectively deactivate alarms? [duplicate]

My question is restricted to Airbus an Boeing's best sellers, namely the A320 and the B737. If relevant, answer can be extended to other types. In those aircraft, there are multiple possible alarms (...
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187 views

Why would a C150 tachometer be sluggish?

After having an issue with a tachometer bouncing so much that it fell off, I now have the opposite problem with the replacement (Mitchell D1-112-5025): The tachometer is sluggish. When I open the ...
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2answers
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How would the Airbus A320 PFD respond to failure of all pitot and AOA sensors?

In theory, if all 3 pitot tubes and all 3 AOA-sensors would fail simultaneously for a period of time, could the PFD still deliver correct roll angle and horizontal displays? How would the plane ...
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How does an Airbus pilot decide whether to use HDG-V/S or TRK/FPA guidance?

The Flight Control Unit of modern Airbus aircraft has a pushbutton for selection of either heading / vertical speed (HDG-V/S), or track / flight path angle (TRK-FPA) guidance for the Autopilot and ...
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2answers
808 views

How do I determine which radial intercept angle to use?

I'm studying for the (EASA) Instrument Rating exam and I found several questions about radial intercept angles in sample exams but nothing in the books I've studied and my flight instructor doesn't ...
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3answers
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What is Engine Pressure Ratio?

I kind of know what it is but I don't fully understand it. Wikipedia says, the engine pressure ratio (EPR) is the total pressure ratio across a jet engine, measured as the ratio of the total ...
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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
128 views

What is the relation between altitude and vertical speed?

I recently saw 2 graphs on a flight path on BBC, shown below. For those interested, it's the path of the recently crashed Boeing 737 max flight ET302, but that's irrelevant to my question. My ...
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969 views

What is the blue range indicating on this manifold pressure gauge?

This is baffling me. Does anybody with experience with this type of indicator have any idea what the blue range of this gauge means? It's mounted in a mock-up panel. I know nothing about where it ...
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1answer
168 views

Why don't all pilots receive at least basic instrument training?

Given the frequency with which non-instrument-rated pilots get themselves killed attempting to continue VFR flights into instrument conditions, why don't all pilots receive at least basic instrument ...
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2answers
203 views

Can a private pilot placard an inoperative instrument?

For certificated small aircraft that are not required to have a minimum equipment list. If you have an instrument break while on a cross country flight and it is not a legally required instrument for ...
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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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2answers
186 views

How do aircraft stall warning systems handle (or not) asymmetric-stall situations?

Most, if not all, new airplanes are required to have stall warning systems to (as the name should make clear) provide the pilots with a warning when the airplane is about to stall. Most stall warning ...
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1answer
110 views

Does the glide slope flag detect percent of modulation (80%)?

Please advise if the glideslope flag validates that the received frequency is being modulated at nominal 80% or 40% for a localizer.
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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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2answers
340 views

What dictates the shape of the attitude indicator display on the PFD?

I notice the atitude indicator displayed in the PFD is either squared-shape or truncated-circle-shaped. A good example of the square shape is the B747-400, It looks like a square whose corner are a ...
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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 ...
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1answer
2k views

How does a pitot plate work?

I understand the basic concept of the pitot tube in that it measures the air pressure coming into the tube in order to compare it to a static pressure measured elsewhere on the aircraft. The B-2 ...
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5answers
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Can VOR indication be reliable if one of its antennas breaks?

What will be the reliability of the VOR indication inside the cockpit if one of the two outside antenna is broken ? Can we trust it to make a VOR approach? What will be the consequences assuming ...
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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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1answer
205 views

Is the 737-800 circular PFD for AOA or RA?

So, I have seen some people on the Internet showing the 738's PFD circular gauge for RA, but others show that the gauge is used for AOA(angle of attack). Which one is true? Is there a switch to change ...
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4answers
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What is the difference between Turn Coordinator and Artificial Horizon?

I was reading this question about Turn Coordinator and Artificial Horizon, and now I want to understand the differences between those two components. What is the main difference between Turn ...
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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 ...
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1answer
95 views

What are these engine gauges in the Comet 4 for?

What are these gauges on the Comet 4's engine-gauge panel (between the captain's and first officer's instruments, above the throttle levers), marked "POWER LOSS INDICATOR", for? (Sorry for the blurry ...
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3answers
6k views

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 ...
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3answers
285 views

What’s the setting range altimeters can handle?

What’s the setting range altimeters can handle? Is there a standard requiring a certain range for aircraft to be certified? Are there many occasions where a QNH is so high or low that airplanes have ...
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1answer
987 views

Is there a type of instrument/display that guides pilots along a certain path?

What do you call an instrument that can help a pilot fly along a predetermined flight path (e.g. path thru GPS coordinates), showing them when they stray a little so they can correct? Not a control ...
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2answers
236 views

Why do Western aircraft manufacturers use FPS system while Russian aircraft manufacturers use MKS system for flight instruments?

Why is there a variation in aircraft flight instruments of aircraft from Western & Russian origin? Foot–pound–second system (FPS) Meter-kilogram-second (MKS)
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1answer
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How does turning Errors in the Air Driven Artificial Horizon work?

Turning through 90°, 180°, 270° & 360°, the error is different. I can understand what is turning error and pitch error individually. But why turning through different degree, the resulting error ...
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2answers
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What is the most effective way for a VFR pilot to scan the instruments during manoeuvres?

May I ask your opinion on what is the best and most effective pattern for a VFR pilot to scan their instruments during manoeuvres?
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2answers
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Why does the turn coordinator ball move to the right during a climb?

In a light aircraft like a C172 or PA-28, during a climb the ball in the turn coordinator moves to the right. Why?
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1answer
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Can a vacuum cleaner create sufficient vacuum to operate the artificial horizon?

Inspired by this question about breaking the glass of instruments, I was wondering if a sufficient level of vacuum can be achieved by using a vacuum cleaner on the inlet, or simply sucking through a ...
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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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1answer
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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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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 ...
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3answers
254 views

Do any aircraft have a “self-contained ILS”?

The ILS is an invaluable aid to pilots, especially those operating to/from the many airports where poor weather is common (low-visibility operations would be completely impossible without an ILS); ...
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5answers
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Can the pitch be very different from the angle of attack?

How much the pitch (horizontal orientation) can differ from the angle of attack? I am trying to understand the claim that "angle of attack indicator was unfortunately not available", contributing to ...
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1answer
322 views

What happens to manifold pressure reading following a reduction in both throttle and RPM?

This was one of the questions in my online ground school quiz (PPL), detail as follows: To set climb power, you reduce the throttle (manifold pressure) and then the props (RPM lever). After setting ...
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1answer
208 views

Why are airspeed gauges labeled above Vne?

Examples: Cessna 150L Vne = 141 knots (162 MPH), gauge labeled to 170 knots. It looks like there's room to extend the scale to 180. Cessna 152 Vne = 149 KIAS, gauge labeled to 170. Cessna 172R Vne = ...
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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
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How to navigate an aircraft without GPS? [duplicate]

In case of loss of GPS: how can an aircraft not only be navigated but navigated so precisely that it can pinpoint its destination airport ? (case in point: Finland and Norway are telling airline ...
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3answers
3k views

What does a helicopter “gas prod” gauge measure?

The beginning scenes of the movie "San Andreas" partly take place in a rescue helicopter. One of the panel gauges read "GAS PROD" above it. I googled it but didn't find much. Can someone explain what ...
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1answer
273 views

Lindbergh's panel— Ryan NYP— what is this instrument and how was it useful?

Lindbergh's panel-- Ryan NYP-- what is this instrument and how was it used? See this link-- it should allow you to zoom in by mousing around https://www.amazon.com/Instrument-Successfully-Atlantic-...
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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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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 ...
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2answers
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What are the fonts used in MCDU screens?

All MCDUs (and other screens) I've seen share a very similar, if not identical, set of fonts - a monospaced, sans-serif, very clean and easily readable font, often in two vertical sizes at the same ...