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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3answers
2k views

What prevents a Machmeter from being the standard airspeed indicator?

Airspeed is more accurate when displayed by a Machmeter than when displayed by an airspeed indicator. It isn't affected by ambient temperature / density changes. It is still affected by position error,...
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1answer
139 views

Why is the turn coordinator gyro tilted?

I’ve read many places (such as the FAA’s Instrument Flying Handbook) that a turn coordinator can sense both roll rate and turn rate due to the gyro being tilted 30 degrees. However, why does tilting ...
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1answer
149 views

Why do planes not employ a non-technological banking indicator? [duplicate]

I apologise if this is a very daft question with an obvious answer. I've been enjoying Air Crash Investigation episodes and there have been a few where the pilots, through differing training or faulty ...
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1answer
142 views

Is the turn coordinator showing yaw or roll a mix of the two?

I'm not talking about the ball, but instead the plane symbol shown on the instrument: Is it showing a roll or is it yaw that it shows? Or is it a mix of the two? IE, if I do my darndest to fly ...
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0answers
160 views

What are those green LED arrays on top of the instrument panel called?

Below is the link showing a fire fighting aircraft From 0:23 to 0:45 an LED array can be seen. The peculiar thing about that is as aircraft approaches the site, all ...
4
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1answer
114 views

If an airplane has a Vertical Speed Indicator is there a requirement that it be periodically checked for accuracy?

I believe I understand that there is no specific US FAA requirement for aircraft to carry a Vertical Speed Indicator (VSI). I believe I understand the basic operation of a VSI. It measures the rate ...
6
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3answers
444 views

What aircraft equipment produced the three recordings of unidentified aerial phenomenon released by the US Pentagon in 2020? What does black signify?

I don't follow these things closely and my question is carefully scoped to ask ONLY about the type of aircraft equipment used and what the various gray levels in the images indicates. In CNN "The ...
6
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1answer
1k views

Is it illegal to fly a Cessna 172S under day VFR with an inoperative vacuum gauge?

Let's say my vacuum gauge is not working on my C172S and I want to go day VFR flying. There is no MEL. 14 CFR 91.213 details procedures for inoperative instruments, and I think the following ...
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5answers
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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
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What is that instrument with two knobs and what looks like range rings?

I just flew a Piper Warrior today and I got confused with the instrument shown below, it's the one above the CDI and to the right of the altimeter.
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2answers
314 views

Do the rules used in modern soaring competitions forbid gyroscopic flight instruments, or forbid the use of AHRS-driven attitude displays, etc?

In the past, the rules for soaring competitions in the US and many other countries have not permitted gliders (sailplanes) to have working gyroscopic instruments installed, to prevent pilots from ...
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5answers
325 views

What causes the ball to not be centered in a slip/skid?

I've reviewed quite a few questions on this forum including Forces in a slipping turn is-this-vector-diagram-of-the-forces-at-play-in-turning-flight-correct what-does-the-balance-ball-actually-...
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What is the difference between a pitot tube and a pitot-static tube?

What is the difference between a Pitot tube and a Pitot-static tube? If an aircraft fitted with Pitot tube and static holes on the fuselage, is it necessary to consider the static pressure ...
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5answers
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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 ...
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1answer
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How does the A320 FMGC (autothrust, autopilot) decide which radio altimeter readings to use?

How does the A320 (or other Airbus FBW aircraft, for that matter) decide which radio altimeter reading to use (say, for FMGC functions like autothrust), or whether to reject the radio altimeter data ...
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2answers
308 views

Have attitude indicators ever had triple failure in a commercial aircraft?

I'm wondering about couple of well known crashes (mainly AF447 and AirAsia 8501) and thinking: is there any case where triple redundant attitude sensor failure has ever occurred? In those accidents it ...
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0answers
165 views

Is this vintage altimeter from the Cuatro Vientos?

My father who was a pilot, passed away some years ago and I have a vintage altimeter that he told me someone gave him. They assured him that it belonged to the Cuatro Vientos airplane, but I'm not ...
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1answer
97 views

Is rate of turn information (both Turn Coordinator and Turn Indicator) accurate only in balanced turns?

I was studying the difference between the TC and TI, and I thought I heard or read somewhere before that the turn rate information on the TC or TI are only accurate when the ball is in the middle. Let'...
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2answers
180 views

Where do flight sims get their data on aircraft flight characteristics?

Flight sims offer very realistic simulations of how a particular aircraft feels, claimed by pilot interviews on youtube. But how do sims get their data? First, does all this data even exist, i mean ...
19
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1answer
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?
3
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1answer
3k views

How is the terrain displayed on the ND in a A320?

When you turn on "TERR ON ND" in a A320, you see terrain info on you navigation display (ND), but where does its source come from ? if data comes from FMGS stored inside its memory, then how come it ...
8
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1answer
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How is the wind direction and wind speed measured in flight?

Most large aircraft have a wind direction and wind speed indicator. How is this measured? The vector difference between TAS and ground speed? How accurate is this? In the below picture (taken from ...
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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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4answers
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How do instructors simulate instrument failure in basic training aircraft with glass cockpits?

While working towards my private pilot's license in the United States in 2004-2005 (in a steam gauge only airplane), I very much remember my instructor covering one or more instruments to simulate ...
3
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1answer
211 views

What is this instrument?

I am looking to sell this instrument, but it has no part numbers or any other identifying marks other than it says "Kollsman" on the back. Anyone know what it is and what it might be worth?
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1answer
122 views

What is the required accuracy of an airspeed indicator?

What FAA document specifies the accuracy to which an airspeed indicator must be calibrated to?
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3answers
162 views

What kind of airspeed does a (3D) GPS measure?

Assuming a GPS receiver is advanced enough to compute 3D position/velocity with reasonable accuracy, it can indicate not only the aircraft's ground speed (which ignores altitude changes), but ...
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3answers
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How can I check pitot static leak without a test box?

More than once on the ramp, I've wished I could check an aeroplane's pitot-static system for leaks, but I didn't have the test box. I've since seen, in the FAA's handbook for checking homebuilts, a ...
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1answer
151 views

Is it possible for an indirect (Russian) attitude indicator to work in 3D without tumbling?

For a reference of direct and indirect attitude indicator, see How is a confusion possible between Western and Russian Attitude Indicators?, and https://www.skybrary.aero/index.php/...
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2answers
514 views

What are the ANT and ADF modes on an NDB receiver?

I am seeing this in a simulator, so I don't have a manual for it… On the Bendix King KR87 NDB receiver, the leftmost button labelled “ADF” switches an indicator above it from “ANT” to “ADF” When ...
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1answer
159 views

How does the heading selector on the ADF work?

How does the ADF indicator work in terms of pointing the needle in the direction of the NDB signal? I understand that the ADF needle points towards the direction of the NDB signal for a given ...
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1answer
169 views

Why don't airliners use light strips on physical controls (yoke/stick, throttle and trim) to indicate who has control - pilot or flight computer?

I've watched a lot of Air Disasters episodes about crashes where pilots thought auto-pilot, auto-throttle, auto-trim were "in control" but they weren't (or vice-versa) due to some innocuous ...
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6answers
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What instrument can be used to check that constant attitude is maintained?

In Sporty’s training, the following question came: One way to determine that you are maintaining a constant attitude is to occasionally check: A. The vertical speed indicator B. The tachometer C. The ...
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2answers
2k views

Are turn rate indicators calibrated to a certain speed? If so, what speed?

Are turn rate indicators calibrated to a certain speed? If they are, what speed are they calibrated to, and why aren't all the turn rate indicators calibrated for the same speed?
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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 ...
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1answer
372 views

Altimeter setting and pressure altitude

Student pilot here. I thought I was smarter than this, I’m struggling with this concept. I got the ASA test prep book and there’s a question asking what happens to the indicated altitude when the ...
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1answer
149 views

In some "turn coordinators", does the gyro spin opposite to the direction it spins in a "turn rate indicator"?

In some "turn coordinators", does the gyro spin opposite to the direction it spins in a "turn rate indicator"? A "turn coordinator" has a symbolic airplane on the display ...
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3answers
444 views

May turn rate indicators (and turn coordinators) be calibrated to be accurate at all airspeeds, or only for one? [duplicate]

2 related questions: may a turn rate indicator be calibrated to be accurate at all airspeeds, or only for one? Likewise for a turn "coordinator". The meaning of "accurate" intended in this question ...
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6answers
27k 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 ...
4
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2answers
168 views

Why does GBAS broadcast Final Approach Segment data when SBAS does not?

Ground Based Augmentation Systems broadcast message four, the Final Approach Segment, along with corrections for GNS signals in messages one and two. Since the FAS is essentially a semi-static ...
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3answers
1k views

Why are pitot-static measurements preferred over other velocimetry techniques?

I believe hot wire anemometers (HWA, frequently used in wind tunnels to measure flow velocity) or other sensitive techniques could be used to determine the airspeed. Are there specific reasons for why ...
3
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2answers
107 views

What's a normal response delay for a paragliding vario?

I'm a paragliding pilot with P4 licence and I've purchased a 2nd-hand FLYMASTER B1NAV flight instrument for XC flights – mainly for logging the flights (route, distance, max. speed etc). It is an ...
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1answer
439 views

For purposes of the FAA instrument written, which system becomes primary for pitch following an AHRS failure?

Sheppard Air claims to have questions exactly from the FAA test. I'm wondering what folks think of the Q&A for this one. It asks In the event of an AHRS failure, what becomes your primary pitch ...
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1answer
195 views

Is Cessna 150 with incorrectly marked ASI airworthy?

I've looked a bit at the CFRs trying to determine this for sure, but haven't found a clear answer.. One of the Cessna 150s that I rent from the local FBO had it's airspeed indicator swapped out four ...
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2answers
301 views

Does an instrument exist to measure the different types of drag?

Does a 'drag meter' exist that separately shows total, induced and parasite drag? If it doesn't, and in theory, would it be possible to build one?
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1answer
113 views

How do AHRS systems meet the "gyroscopic" requirement of 14 cfr 91.205.d?

EDITED Among the instruments listed as required for IFR operations in the US FAR is are various "gyroscopic" instruments, including those for the turn coordinator, attitude and heading. In ...
37
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2answers
7k 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 ...
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4answers
2k views

What is 'level' to a G1000?

I used to fly a Cessna 550 with 'steam gage' mechanical gyros. The Attitude Indicator always had its flight director solidly on the horizon in level flight -- to the extent a mechanical instrument ...
4
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1answer
299 views

Artificial horizon - "horizon bar" or "symbolic airplane adjust"

(Student pilot, ~ 22hrs training) On a box-standard AI in a C172 there is a knob that allows you to move the symbolic airplane up and down. I've never managed to ask what it is for, but have now been ...
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3answers
253 views

When flying on a glide slope, does the G meter show 1G or less?

If your angle of attack in landing pattern is 14 degrees but your vertical velocity is 600 feet/minute, does the HUD show you 1G or not? Why?

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