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Questions tagged [altitude]

A measurement of vertical distance. Usually measured at either Mean-Sea-Level (MSL) or Above-Ground-Level (AGL).

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Temperature change & Altimeter indication

Ref: FAA Pilot's Handbook of Aeronautical Knowledge 2023 (faa-h-8083-25c) Page 8-4, column 2, paragraph 3 (including figure 8-3) through page 8-5, column 1, paragraph 1. As a background to my ...
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Why is MH370's location data from the Malaysian military considered reliable if the altitude data isn't?

This is another question originating from the video "The Vanishing of Flight 370", by Lemmino. At 13:52 he says The data recorded by the Malaysian military ...
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ADS-B - Measure distance from position on ground to an aircraft

I have a docking station for autonomous drones in the field. It is equipped with a Raspberry Pi, an 1090 MHz ADS-B stick, and it knows it's geometric position from a previously done precise ...
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Does one need to make temperature corrections for airspace avoidance?

This answer claims that airspace boundaries are based on true altitudes, not any particular altimeter setting. But temperature errors can cause indicated altitudes to vary wildly from true altitudes. ...
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Max Range Relationship to Altitude for Propeller-Driven Aircraft

Chapter 11 of the PHAK states, "If a change in altitude causes identical changes in speed and power required, the proportion of speed to power required would be unchanged. The fact implies that ...
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Calculating True Altitude from ADS-B Data [duplicate]

I am working on a project and need to determine the altitudes of airplanes (trying to determine when they are landing/doing a touch and go). I have an ADS-B receiver receiving data from the airplanes. ...
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AS8003 Altitude Encoders: How are readings from silicon pressure sensors converted to pressure altitudes?

Encoders such as the ACK A-30 use uncompensated silicon pressure sensors (e.g. MPX100 series according to this video) which are kept at a constant temperature. I presume they are heated so as to stay ...
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Do ATC say "Climb to XXXX on standard" or "Climb to standard XXXX" or something else?

Do ATC say "Climb to XXXX on standard" or "Climb to standard XXXX" or something else? By "standard" I'm referring to altimeter pressure settings (set to standard pressure)...
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What are the survival rates from different altitudes?

In this video of someone making a homemade electric aircraft, at around 19:44 into the video, the creator shows his estimates of survival chances if he stalled and crashed from various altitudes, a ...
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Why does Vx increase with altitude and Vy decrease?

As an airplane climbs, the best angle of climb airspeed (Vx) increases and the best rate of climb airspeed (Vy) decreases. I can't figure it out, why does it happen? I Hope someone explains it to me I ...
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Why was the Me 262's top speed at 6km?

The P-80 had its top speed at sea level, but the Me 262 achieved its top speed at 6km altitude. What were the reasons for this? Was it that the engine was designed for such an altitude to deal with ...
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Is it safer to fly over 3,000ft for General Aviation?

I have been reading over the UK Airprox annual report of 2021 and it states: In 2021 – 76% of all events and 83% of all aircraft-to-aircraft events took place at or below 3000ft altitude. In 2021 – ...
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What is meant by altitude correction above Transition level?

I am a system engineer dealing with Thales ATC product. In my system there is a server called sensor data processor, one of its function is to receive QNH data to do altitude correction. I can't ...
mahmoud youssef's user avatar
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1 answer
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How does elevator control effectiveness change with altitude/ air density?

Suppose an unpowered, rigid, mechanical, lightweight aircraft (e.g. sport glider) is descending at a steady glide in a constant trim (hands off) configuration in a standard atmosphere. The pilot ...
Oleg Pryadko's user avatar
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4 answers
7k views

How can skydivers start at 15,000 feet without the jumper suffering from hypoxia?

Many commercial skydiving facilities offer jumps at 15,000 ft. However, when I took my ground theory exams, it was reiterated many times that hypoxia starts at 10,000 feet. How does this work? Is it ...
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What is a good sight picture for telling urban vs rural areas (wrt minimum AGL)?

I'm studying for PPL and am struggling to imagine a clear "sight picture" for urban vs rural areas with regards to minimum AGL. I found that urban areas are outlined over at the Federal ...
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how to determine the optimum FL for A320 to make a flight plan?

I want to make an ifr flight plan for A320 based on fcom, but I don't understand how to make one
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2 answers
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How is true altitude derived? [duplicate]

I read everywhere that the true altitude is computed as: True Altitude = Indicated Altitude + (ISA Deviation × 4/1000 × Indicated Altitude) But why is that the case? How is that derived? Where does ...
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Is there anything important to know about flying at ~9000ft for the first time?

When I did my NPPL training, there was a module on flying at minimum altitude, but nothing around high altitude flying, in fact, I've never flown over 3,500ft. This weekend, I intend to fly up to ...
Cloud's user avatar
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Am I correct about how airships control their altitude?

I have read about how airships work, especially about how they control their altitude. Because what I understand from readings about the Zeppelin airships is that they were able to perform long range ...
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Is it possible to calculate Calibrated Airspeed from True Airspeed, Temp, and Pressure Altitude? [duplicate]

Looking at a digital E6B, there is a function for calculating CAS that I am trying to recreate and program myself. Inputs: Pressure Altitude Temp in Celcius True Airspeed Outputs: CAS Mach # ...
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What are the component terms that make up this pressure altitude calculation?

I am a bit confused by pressure altitude, in my ground school we were taught and equation ((29.92 - altimeter setting)*1000)+ altitude) is equal to something. I believe that something to be pressure ...
Cats 15's user avatar
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1 answer
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What altitude does the "Apt Elev" on the Jeppesen charts represent?

What altitude does the "Apt Elev" on the Jeppesen charts represent? According to my research, the height we call "airport elevation" indicates the highest altitude on the landing ...
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Why do all trend vectors in the G1000 on airplanes indicate the status 6 seconds later? Why 6? Why not 5 or 10?

Why do all trend vectors in the G1000 on airplanes indicate the status 6 seconds later? Why 6? Why not 5 or 10? The fact that the trend vector shows after 6 seconds allows us to turn 3 degrees per ...
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Who was the first person to fly above 20,000 feet, and what aircraft was used?

Oh! I have slipped the surly bonds of Earth And danced the skies on laughter-silvered wings; Sunward I’ve climbed, and joined the tumbling mirth of sun-split clouds, — and done a hundred things You ...
Someone's user avatar
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23 votes
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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 ...
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Although the missed approach point in the profile view is 1.1 DME-400 feet, the GS out reference altitude is given as 410 feet in 1.0 DME. HOW?

Although the missed approach point in the profile view is 1.1 DME-400 feet, the GS out reference altitude is given as 410 feet in 1.0 DME. HOW?! Based on GS out reference altitudes, we are expected ...
pilot162's user avatar
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Why don't the Altitude-DME values in the approach profile match the Groundspeed-FPM values in the conversion table?

Why don't the Altitude-DME values in the approach profile match the Groundspeed-FPM values in the conversion table? When the calculation is made with the values given in the conversion table, the ...
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Why are the altitudes on an RNP IAC shown on the point while for a conventional approach are parallel to the route? Is there an actual difference?

The RNP approach for LGIR runway 27 has the altitudes on some of the points underscored. I had the impression (and I'm afraid I'm wrong) that these are "crossing restrictions" and the ...
Stelios Adamantidis's user avatar
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1 answer
176 views

Does this symbol in the pictures below represent height above ground level or altitude above sea level?

Does this symbol in the pictures below represent height above ground level or altitude above sea level? There are huge differences between them and the Grid MORA values, so I think there may be ...
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175 views

ADSB DF17 Altitude decoding

I develop ADSB DF17 messages decoding device. I see that barometric height decoding differs between documents, describing the encoding standard: https://mode-s.org/decode/content/ads-b/3-airborne-...
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1 answer
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Payload capacity of a quadcopter/helicopter with increasing altitude

I am trying to create a simplified model of a heavy-lift drone payload at different altitude during hover mode. I tried to derive it simply by considering that the thrust, $T$ is equal to the weight ...
Khalid Owl Walid's user avatar
1 vote
1 answer
307 views

Why does true airspeed decrease with altitude?

I was having a discussion with a friend who's going for a record speed over distance attempt. We were discussing which altitude will have the fastest TAS, and I suggested it would be the highest ...
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4 votes
4 answers
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What difference does altitude make on fuel efficiency? [duplicate]

Most commercial flights are between 29,000 and 42,000 feet in altitude apparently. But I realise I don't know why. My guesses are: If you fly too high the air pressure gets very low and you have to ...
Simd's user avatar
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Does baro altitude from ADSB represent height above ground level or height above mean sea level?

I am retrieving ADSB data from Opensky-network.org. I would like to know what the baro altitude represents, is it the height above ground level or above mean sea level ?
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3 answers
4k views

Confused about this Pressure Altitude vs True Altitude Question

The standard question on a knowledge test: "Under which condition will pressure altitude be equal to true altitude?" The answer is: "when atmospheric conditions exist, i.e., 29.92" ...
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2 answers
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How to convert barometric altitude to gps altitude? [duplicate]

In my work I have some challenge with an aircraft altitude values: I was provided with some data from aircraft flight in my country. The data contains variety sensors data (like lat, long, altitude, ...
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How to compute the airspeed change based on the Altitude change

The plot shows that: when I fly with fixed MACH, the true air speed decreases when the altitude increase; when I fly with fixed CAS, the true airspeed increases when altitude increase. So how could I ...
VvV's user avatar
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Why did this flight, that usually flies around 40,000ft only fly at around 29,000ft for the route?

Looking at the flight BY6272 BRS-PMI, it was considerably delayed and flew (according to the flight radar app) at 29,000 feet rather than its usual 40,000 for this same route. It is a Boeing 787 ...
Chris's user avatar
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2 votes
1 answer
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Is it safe for a huge all black helicopter to be flying BELOW 500 feet over my house, for an hour now, spraying pesticides all over the area

How dangerous is it for a huge all black helicopter to be flying below 500 feet over my house, for a half hour now, spraying pesticides all over the area and my farm animals. It is shaking the whole ...
Eileen Field's user avatar
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1 answer
272 views

Is the ISA still up to date?

The Standard Atmosphere dates back to 1962 when Earth was colder. The 1976 update didn't make changes within 50 km altitude (the tropo- and stratosphere). It assumes 15°C at sea level, decreases until ...
Hidden User's user avatar
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3 answers
670 views

Does a plane's service ceiling vary with season/temperature?

Aircraft use barometric altitude, e.g. FL300 is the barometric altitude of 30,000 ft MSL. In winter however, FL300 is actually lower than the absolute altitude of 30,000 ft because of a cold and ...
Hidden User's user avatar
2 votes
1 answer
2k views

What was the reason for my flight’s low cruise altitude?

I’m a fairly new aviation enthusiast and am just curious to know the answer to this question. I flew Boston to Newark yesterday 14/6/22 (UA2396) and we cruised at or under 16000 feet for the whole ...
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10 votes
2 answers
1k views

Why does ADS-B altitude from multiple landed planes vary so much from one plane to another?

When viewing ADS-B data from sites like FlightAware and Flightradar24 (and also from a personal antenna), the landed altitudes vary greatly from one aircraft to another. What accounts for this ...
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1 vote
1 answer
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Is it appropriate to determine approximate flight altitudes based on ADS-B landed altitude compared to runway elevation?

For small aircraft flying below 2,500 ft. AGL, is it appropriate to compare the landed ADS-B altitude (pressure calibrated AMSL) to the elevation of the runway in order to compute a reference offset ...
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3 votes
1 answer
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Minimum Safe Altitude vs Emergency Safe Altitude

Is there a difference between Minimum Safe Altitude and Emergency Safe Altitude? Or are they same things used by different authorities (MSA by EASA and ESA by FAA)?
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33 votes
1 answer
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What is the operating altitude of jetliners?

I am performing a science project, and this involves knowing the average operating altitude at which commercial passenger airplanes (jetliners) fly. I am trying to find minimum operating altitudes and ...
inquiries's user avatar
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6 votes
3 answers
1k views

Do pitot tubes account for reduced pressure at altitude?

Do pitot tubes account for reduced pressure at altitude? Does indicated airspeed reduce with altitude? If so, how much? Is it different for small planes vs big commercial airliners?
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3 answers
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What is the AeroVironment Helios' Kármán line?

If it's true that the NASA/AeroVironment Helios maintained level flight 96,000 ft above sea level at a maximum airspeed of 23.5 kts (43.5 km/h) I assume it must have a very high Kármán altitude, the ...
Better not tell's user avatar
7 votes
2 answers
672 views

Is the U2's 74,000 ft the highest a turbofan plane ever has gone?

What is the altitude record for a turbofan? The (usually) turbofan-powered U2 has gone to 74,000 ft (22.6 km) MSL, but did any turbofan plane surpass that, in a zoom climb for instance and with ...
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