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.
L Reid's user avatar
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48 votes
3 answers
197k views

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 ...
Gabriel Brito's user avatar
37 votes
2 answers
9k views

What do pilots landing on aircraft carriers do when the ship is not visible due to weather?

Say an aircraft takes off of a carrier to do a mission somewhere, and upon returning to the carrier the pilot comes to find that a thick layer of fog has formed just above the surface of the water in ...
I_am_WAAS_enabled's user avatar
37 votes
2 answers
65k views

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 ...
asheeshr's user avatar
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35 votes
4 answers
14k views

What is the meaning of the crosshatch marking on altimeters?

What does the crosshatched area on an altimeter tell you? It's only visible when below 10,000 ft indicated altitude. Can't be terrain awareness, a lot of terrain around here is over 10,000 feet. ...
Barrie Strachan's user avatar
34 votes
3 answers
40k views

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 ...
Hugh's user avatar
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33 votes
11 answers
11k views

How could "aggressor" pilots fly foreign aircraft without speaking the language?

Context I watched a couple documentaries recently and found one where they were mentioning the training of American forces against Mi-24 that were captured and brought back to the US to test fly them....
Pierre Chevallier's user avatar
33 votes
6 answers
31k views

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 ...
Hemang's user avatar
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33 votes
2 answers
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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 ...
Tony's user avatar
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32 votes
4 answers
7k views

Is it normal for gliders not to have attitude indicators?

This answer shows a picture of and describes a "modern" glider instrument panel, with two variometers, airspeed indicator, altimeter, compass, temperature gauge and radio controls. Notably (at least ...
cjs's user avatar
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31 votes
2 answers
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What is the purpose of the Dash 8’s “TOUCHED RUNWAY” warning light?

The DHC-8-400 (and possibly other DHC-8 variants) has (or, at least, had in late 2007, according to Appendix G of this AAR) a warning light labelled “TOUCHED RUNWAY”. The extract of the DHC-8-400’s ...
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31 votes
3 answers
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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 ...
Thunderstrike's user avatar
30 votes
3 answers
9k views

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 ...
AirCraft Lover's user avatar
30 votes
2 answers
8k views

Why are the colors of the MiG-15's attitude indicator inverted?

Why are the colors of the MiG-15's attitude indicator inverted (blue on the ground side, brown on the sky side)? Source: http://www.warbirdalley.com/mig17.htm
George Geo's user avatar
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29 votes
3 answers
18k 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 ...
shortstheory's user avatar
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29 votes
2 answers
6k 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 ...
Bassinator's user avatar
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29 votes
3 answers
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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 ...
Fattie's user avatar
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27 votes
6 answers
144k 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?
Danny Beckett's user avatar
26 votes
5 answers
94k 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?
Haris's user avatar
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25 votes
6 answers
8k views

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 ...
Zaz's user avatar
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25 votes
1 answer
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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 ...
tsrplatelayer's user avatar
24 votes
7 answers
26k views

How is a confusion possible between Western and Russian Attitude Indicators?

Yesterday I watched a documentary on Crossair Flight 498 accident. One of the factors that might have contributed to the accident was the confusion of the pilot on interpreting the attitude indicator; ...
Claudi's user avatar
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24 votes
3 answers
8k views

Why do digital flight instruments seem to fluctuate/flicker during landing or takeoff?

I happened to watched videos where landing was aborted due to some or other reasons. However, something interesting stuck me eyes: the digital flight instruments fluctuate/flicker (such as the ...
Viktor Wolf's user avatar
24 votes
1 answer
9k 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 ...
mike's user avatar
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24 votes
3 answers
8k 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 ...
shortstheory's user avatar
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23 votes
13 answers
12k views

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 ...
Pat's user avatar
  • 369
23 votes
2 answers
4k views

How was altitude calculated before the invention of the altimeter?

I just read David McCollough's "The Wright Brothers," and was surprised to find several references to the exact altitude attained by various Wright airplanes. For example, on page 235: The ...
nuggethead's user avatar
23 votes
3 answers
36k views

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 ...
fooot's user avatar
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22 votes
4 answers
10k views

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 ...
abligh's user avatar
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21 votes
5 answers
7k 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 ...
Pondlife's user avatar
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21 votes
2 answers
3k 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.
Andrius's user avatar
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20 votes
3 answers
6k views

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.
Arian's user avatar
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20 votes
4 answers
5k views

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 ...
user60684's user avatar
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20 votes
2 answers
5k views

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 ...
cat's user avatar
  • 383
20 votes
3 answers
13k views

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 ...
Haris's user avatar
  • 1,017
20 votes
2 answers
21k views

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 ...
Gabriel Brito's user avatar
20 votes
2 answers
4k 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 ...
kevin's user avatar
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19 votes
5 answers
3k views

Low visibility spins and spirals: difficult-to-understand explanation of false perception

I'm not a pilot. In the following excellent explanatory video I understand everything except for a single point. The presenter says that in cloud, if the instruments tell the pilot to level the wings ...
chasly - supports Monica's user avatar
19 votes
1 answer
3k 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 ...
gandalf3's user avatar
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19 votes
1 answer
7k views

Why do airplane indicators start at 12 (o'clock), unlike cars that start at 7?

A car's speed and RPM indicators usually start at 7, lower left, but airplanes' altitude and airspeed indicators start at noon. What's the origin of this convention?
Francesco's user avatar
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19 votes
2 answers
22k views

What do the green, white and yellow bands mean on an airspeed indicator?

what are these green and white and yellow bands in the Airspeed Indicator use for ?
Mohammad Gohardoust's user avatar
19 votes
1 answer
4k views

How do aircraft on the deck of a moving aircraft carrier align their INS/IRS?

I know that the F/A-18C is equiped with a rotary switch for inertial alignment. The switch has two positions, one for ground and the other for carrier operations. Leaving aside the GPS/GNSS, I wonder ...
O'Terror's user avatar
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19 votes
1 answer
96k views

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,...
Lnafziger's user avatar
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19 votes
1 answer
9k 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 (...
Alexander Johansen's user avatar
18 votes
5 answers
11k 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?
Super Hornet's user avatar
18 votes
2 answers
5k 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 ...
ryan1618's user avatar
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18 votes
2 answers
5k 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 ...
Amod's user avatar
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18 votes
2 answers
6k 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 ...
Steve's user avatar
  • 283
18 votes
1 answer
16k 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 ...
FreeMan's user avatar
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17 votes
5 answers
22k views

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 ...
h22's user avatar
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