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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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1answer
937 views

Where are the locations of the elevators or horizontal stabilizers in a Concorde?

I don't find the horizontal stabilizers or the elevators of a Concorde at the tail section like other aircrafts. Are they fitted beside the ailerons in the wings?
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2answers
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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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2answers
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What details do EICAS systems provide?

I was reading this article about EICAS: Engine-indicating and crew-alerting system (EICAS) includes instrumentation of various engine parameters, including for example revolutions per minute, ...
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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 ...
7
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1answer
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What is the correct crew procedure for an unreliable airspeed alert?

When the crew receives "airspeed disagree" message on the primary flight displays, they may face some hazardous situation. Is there any procedure, using a table containing pitch, power, altitude and ...
2
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1answer
237 views

Altimeter disagreement. What's the crew procedure to deal with that?

The crew is facing a situation, in which, the altimeters indicate different altitude (the port and starboard ones - cpt´s and FO´s). Is there any procedure to perform an IFR landing? If we consider a ...
28
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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 ...
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2answers
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How does a horizontal situation indicator (HSI) work?

I am trying to understand the Horizontal Situation Indicator. To my understanding there is a slaving transmitter, usually in a wing (the left wing in the Piper Archer and Seminole), which sends ...
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3answers
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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
8k views

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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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
317 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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2answers
626 views

Why was brown chosen to represent the ground side of an attitude indicator?

Is there any particular reason for having the ground represented by brown on an artificial horizon or PFD? Blue represents sky, brown represents earth, which will be used for easily identifying the ...
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3answers
954 views

Why don't transponders have active and stand-by value like radios?

This answer explains how pilots when switching code on transponder should either carefully avoid temporarily squawking one of the emergency codes, or should temporarily put the transponder in stand-by....
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2answers
738 views

What steps have been taken to rule out instrument failure due to blocked static ports or pitot tubes?

In the case of Aeroperu Flight 603, a fatal crash was caused by duct tape that was accidentally left over some or all of the static ports on the underside of the fuselage after the aircraft was ...
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2answers
2k views

Has the design-flaw with the Boeing 737's cabin-pressure switch been fixed yet?

At 42.21 minutes of this video about the crash of Helios' Flight 522 (a Boeing 737) caused by cabin depressurization, it was established that a major cause of the crash was a design flaw -- the main ...
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1answer
782 views

How is the the turning error of an aircraft magnetic compass calculated?

I have a major exam in school tomorrow and I still don't get how to get the turning error of an aircraft magnetic compass. For example, if given an initial heading of 120 degrees and final heading of ...
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2answers
3k views

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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4answers
2k views

Can helicopters land in a poor visibility scenario?

The Instrument Landing System and some others systems can provide to incoming aircraft guidance to the runway in poor visibility scenarios. With that in mind, I have these questions: Can helicopters ...
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2answers
1k views

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 ...
10
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1answer
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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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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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2answers
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OBI, RMI, HSI… What combination do GA aircraft w/o glass typically have?

I'm learning about radionavigation, and all the various analog displays that can be used: Automatic Direction Finder (ADF) - Provides basic bearing information to practically any radio source the ...
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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 ...
5
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1answer
6k views

What is the relation between roll angle and pitch angle?

I was wondering about roll angle and pitch angle values. Will I get same pitch angle at different roll angles and vice-versa? For example. At its initial position, the aircraft is standing on the ...
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3answers
8k views

How are attitude indicators kept accurate?

The attitude indicator is very important for any sort of instrument flying, so it must be accurate at all times regardless of the plane's movements. I presume that the indicator would be connnected ...
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2answers
12k 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 ...
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1answer
176 views

Can static electricity affect navigational instruments?

Is it possible for navigational instruments to get affected by static electricity or electrical discharges like lightning? If so, how does this happen?
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1answer
453 views

Can you identify those parts (sensors), on test aircraft and the purpose?

I have seen many photos with those sensors attached to the test aircraft, Can you provide why they are used and what do they measure? Here is another example on SuperJet:
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2answers
517 views

What if a aerobatic fighter pilot sneezes in middle of a maneuver?

No offense to any pilots, I am a student, curious. I just watched Spy (2015) and I was just wondering what happens if one of the pilot accidentally sneezes during a difficult maneuver. Jude Law ...
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2answers
2k views

Why Heading Indicator is not magnetic itself and need magnetic compass?

I read this while I was preparing for my knowledge test: The heading indicator is not direction-seeking. It is important to check its indication frequently and reset it with reference to the ...
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3answers
390 views

What is the standard procedure in case of inconsistent sensor readings?

After reading the answers I now know there are three independent sensors. I will leave the question as-is, to not take the answers out of context: I do remember reading that airliners have two ...
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3answers
495 views

Who checks the instruments and avionics before the crew boards an aircraft?

Before the crew boards the aircraft for a commercial airline flight, is there anyone who checks the instruments and avionics system? I'm sure the engines are checked but what about the avionics ...
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4answers
14k views

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
936 views

I'm thinking of building a balloon-launched glider, is this idea plausible?

So, I know nothing about aviation. I'm a student studying maths and computing and I feel like building a high altitude glider controlled by a Raspberry Pi and Arduino as a personal project. First ...
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1answer
981 views

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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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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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 ...
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2answers
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How does one reset an attitude indicator that doesn't have a cage?

I was up flying today – VFR – and the attitude indicator tumbled. It's a 6-year-old RC Allen 22-7, without the ability to cage, so I just wound up letting it be all off-kilter until things stabilized.....
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1answer
348 views

Do steam-gauge VSIs compensate for altitude?

A Vertical Speed Indicator indicates rate of altitude change. Traditional VSIs use a calibrated leak to measure the rate of pressure change, and therefore the rate of altitude change. However, ...
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2answers
559 views

What is the difference between targeted airspeed and selected airspeed?

Are Targeted Airspeed and selected Airspeed the same thing? And can someone explain in what cases managed airspeed or pilot selected airspeed would be used, i.e. for different flight phases/...
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2answers
506 views

How does an altimeter deal with the non-linear pressure gradient?

Altimeters work via an aneroid barometer to sense the atmospheric pressure. If I climb from 2000ft to 4000ft, the altimeter senses that the pressure has reduced by, let's say, 70hpa, and is calibrated ...
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1answer
4k views

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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5answers
2k views

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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1answer
15k views

What does the suction gauge actually show?

If I recall correctly correctly the vacuum suction gauge in the TB10 has a scale from 3 to 6, with the green range being 4 to 5 (I might slightly off on those numbers though). It's clearly marked as ...
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2answers
689 views

When is Minimum Safe Altitude Warning triggered?

I know that Minimum safe altitude warning (MSAW) alerts ATC and pilots if an airplane is under the risk of controlled flight into terrain. But when is this alarm triggered? What is the minimum ...
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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
4k views

How much lag does an Attitude Indicator experience?

How much lag does an Attitude Indicator exhibit when it is working as designed? Other than well-known problems like tumbling beyond certain limits in pitch and roll, and precession errors from the ...
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4answers
3k 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 ...
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2answers
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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 ...