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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9
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2answers
8k 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?
12
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3answers
2k views

Is the altimeter setting corrected for temperature?

In an ATIS or AWOS/ASOS recording, is the reported altimeter setting corrected for temperature? I think it must be, because on a hot day, the altimeter should still show correct field elevation. If ...
16
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5answers
2k views

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 ...
21
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3answers
31k 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 ...
32
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2answers
58k 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 ...
17
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5answers
18k 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 ...
25
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3answers
7k 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 ...
13
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1answer
766 views

Can St. Elmo's Fire cause instruments to fail?

Can St. Elmo's Fire on an aircraft cause instruments to fail or give erratic readings, primarily with glass cockpits? Are there backup instruments that would not be affected? Does it affect radio ...
29
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3answers
16k 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 ...
14
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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 ...
12
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1answer
723 views

Are there any studies on the safety of glass versus steam instruments?

Has anyone come across any academic study on the effects of information provided by "glass" instrumentation that affects, favorably or unfavorably, situational awareness, skill and performance, and ...
6
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1answer
508 views

What kind of malfunction is an "artificial horizon"?

I was once (like ten years ago) on a transpacific flight with Northwest from KIX/RJBB to KDTW on a Boeing 747 and our flight as delayed at the gate for about an hour because of some issue with a "...
13
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4answers
6k views

When/How may I replace the Turn Coordinator with an Artificial Horizon?

I've seen a few panel shots where the traditional turn coordinator has been replaced with a second artificial horizon, as shown below. The benefits seem obvious - if my artificial horizon failed I'd ...
18
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1answer
88k 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,...
21
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3answers
12k 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 ...
9
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1answer
1k views

What instruments or avionics do balloons usually have?

For normal sightseeing flights in a typical hot air balloon, what instruments or avionics does the pilot usually carry? Do balloons have a minimum equipment list?
4
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2answers
2k views

Is IAS without instrument error the same as CAS?

I was reading a POH which stated something along the lines of NOTE Except as noted, all airspeeds quoted in this handbook are Indicated Airspeeds (IAS) in Knots and assume zero instrument ...
35
votes
3answers
35k 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 ...
21
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5answers
5k 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 ...
16
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1answer
3k 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, ...
19
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2answers
4k 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 ...
25
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5answers
85k 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?
27
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6answers
131k 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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