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
108 views

What is the difference between autopilot and autoflight?

Can you please give me some explanations about autopilot and autoflight system?
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3answers
13k 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 ...
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1answer
8k 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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1answer
65 views

What Makes G1000 NXi Different From G1000?

The new displays are installed on the brand new Cessna aircraft and upgrade plans are ready. But what is the difference from the G1000 that was there from the early 2000s? Is the tablet/phone ...
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4answers
212 views

Does temperature affect dynamic pressure?

Taking off on a cold day (5°C), it can take 10 seconds to reach rotation speed but on a hot day (40°C) degrees it will take longer to reach the same speed. Is this due to the dynamic pressure? How ...
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1answer
96 views

How do altimeters cope with varying lapse rate?

How do barometric altimeters measure altitude above atmosphere datum if the laps rate of the pressure is not uniform, not constant? Imagine these lines representing pressure lapse rate: ...
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1answer
261 views

How do fighter jets measure how high they are?

I know most of the commercial planes use altimeter to find how high they are. I was just curious in finding out what fighter jets use to to find their height and what are the other technologies that ...
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2answers
2k views

Why was the WWII RAF fighter joy stick loop design not used widely?

WWII RAF fighters had a loop on top of the joy stick in case of hand loss or injury - Anyone know why the Allies didn't copy this very helpful idea?
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1answer
201 views

How does an airspeed indicator look from the inside?

How does a typical GA airspeed indicator look from the inside and how does it work?
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1answer
180 views

What is the difference between an Instrument and Equipment?

In an aircraft, what things is an instrument and what things is an equipment? For example the ILS, is the Antennas located in the runway considered to be an instrument or an equipment? Or is there ...
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2answers
103 views

How does the aneroid wafer expands? (ASI) [duplicate]

So, how does it expand? (aneroid wafer - intend to the airspeed indicator) I have two “theories” (from what I’ve learned) which are : The ram air entering through the pitot tube physically hitting, ...
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1answer
62 views

Question about CDI/OBS and HI [duplicate]

Could somebody please explain me the differences between using the OBS and the Heading Indicator? As much as I could understand, once you tune into the VOR, the OBS starts to show how much deflection/ ...
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1answer
163 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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2answers
114 views

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

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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2answers
251 views

What is the correlation between RNP level and the CDI indication?

I got a question regarding the connection between RNP (required navigational performance) accuracy and cdi sensitivity of the HSI. According to the instrument flying handbook the standard for RNP on ...
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3answers
312 views

Why are Vertical tails generally tapered?

I'm just intrigued to know why the vertical tail of a majority of aircraft is tapered? Is it due to aerodynamics, structural design or due to some instrumentation or multiple other reasons?
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2answers
288 views

In the ARINC specification, why is baro altitude (label 204) measured in Knots?

I am currently designing a system that reads the baro altitude (on label 204) from an LRU. Ultimately in my software I would like to display the baro altitude reading in real-time using a graphical ...
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2answers
147 views

Can a Skylane fly without electricity?

Some Hobbs Meters uses master electricity switch to keep the track of time. So what If an cheapskate Skylane pilot wants to fly without electricity to lessen rent? Which main six instruments would ...
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4answers
5k 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 ...
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2answers
3k 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 ...
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4answers
423 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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2answers
264 views

How useful are the AOA Indexers and indicators for jet pilots and civillians?

I dont see them neccessary unless you are landing on a aircraft carrier. I just don't know a lot about them. I understand what they do but they just dont seem neccessary unless you are landing a jet ...
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0answers
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Are there any softwares that can integrate with desktop sims that accurately simulate third party EFIS retrofits?

So, are there any softwares out there that can integrate into desktop simulators, that can accurately emulate third party EFIS instruments for example, Dynon EFIS or Aspen Avionics Evolution?
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3answers
1k views

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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2answers
777 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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3answers
264 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
57 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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2answers
222 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
4k 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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2answers
2k views

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
2k 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
1k views

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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5answers
8k 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?
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1answer
167 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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2answers
1k 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
186 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
547 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
49k 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 ...
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2answers
285 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
145 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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6answers
6k 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 ...
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2answers
374 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 ...
29
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3answers
8k 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 ...
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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
3k 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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3answers
122k 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 ...
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1answer
321 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
24k views

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
10k 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 ...
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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 ...