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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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Why use turbofan engines for high altitude flight?

I noticed that a lot of high altitude aircraft have turbofans for engines. So I researched and figured out that turboprop engines are more efficient. But most high altitude aircraft like the Global ...
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1answer
45 views

How do changes in flight affect L/D max and the speed at which I must travel to maintain it?

I have an plane flying at L/D max and I want to maintain L/D max. Firstly, if this plane burns through a portion of fuel and becomes lighter, how would I have to change the speed to maintain it? My ...
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198 views

What is the highest a helicopter can fly?

What is the highest theoretical and current flight a helicopter can achieve?
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54 views

Why does V165 have two different MEAs over the same route section?

Why does V165 have two distinct MEAs which vary by a large factor (apart from the 180$^{\circ}$ rule of altitudes) considering they would be clearing the same obstacles and receiving signals from the ...
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59 views

Identify a change in Altitude based on direction and WCA applied?

Question below is from study material for the EASA PPL license MET course. It's an unlikely question but it's interesting to review. You are flying from west to east with WCA +6°. How is your true ...
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Why does the Hinch Mountain VOR (as an example) have void areas under certain altitudes published in the AF/D?

I was digging around the SE region AF/D, and I was reading KSRB (Sparta, TN), and this "VOR unusable" listing is contained in it: The sectional chart shows that it is nearly on top of a hill. I've ...
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How is The Published Runway Touchdown Zone Elevation Decided?

The touchdown zone of a runway can be up to 3,000 feet long if the information I have is accurate. How is the published Touchdown Zone Elevation determined? Is it the center, an average of the ...
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2answers
246 views

How can I estimate pressure altitude?

How do I find pressure altitude? Find pressure altitude using rule of thumb for 1498 feet when the altimeter setting is 27.83" Hg. I did (29.92-27.83)*1000+1498=3588 Did I do this correctly?
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172 views

Calculation QNE and QNH, with flight level and QNH set lower (higher) than QNE

Hi Student pilot here. Lets say Mr pilot is flying at FL75 and QNH is set at 995 hpa, however there is a mountain in the way at 7000', will he below or above the mountain? If you could visually ...
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Is there a way to code Minimum Enroute Altitude using ARINC 424 file format?

I am studying ARINC 424 file format, and I have noticed that there is not any reserved space for coding Minimum Enroute Altitude (MEA), as far as Instrument Flight Procedures are concerned. I find ...
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97 views

How can I figure out critical altitude?

In Vmc situation (minimum speed where pilot can maintain altitude), How can pilot figure out the Vmc? And also, why critical altitude is important to know?
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What is the critical altitude?

What is the definition of critical altitude and why is important to know in Vmc graph? Also, is there any critical altitude in the Piper PA-44 Seminole?
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How are altitudes handled with airports near or above transition altitude?

Transition altitude refers to the altitude above which all altimeters are set to a standard pressure setting (typically 29.92 inHg) instead of to the local surface pressure, and altitudes are given in ...
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86 views

Wind vs high altitude cruise [duplicate]

Yesterday I flew back from Tokyo down south against great head wind around 150kt at 34000’, the original flight plan was to cruise at FL240 for a while then climb up, but the captain decided to get up ...
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How much the true altitude will be lower than indicated altitude by 10°C colder?

Aproximately how many perecent the true altitude will be lower than your indicated altitude , if the temperture is 10°C colder than standard ?
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How do pattern and overflight altitudes work for airports underneath Class C airspace?

Lowell City Airport (24C) has an elevation of 700 feet MSL. So normally, the pattern altitude is going to be 1,700 feet, and the altitude for overflying the pattern is going to be 2,200 feet. However,...
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Is there research suggesting that VFR cruise altitude rules improve safety?

In the United States, 14 CFR 91.159 prescribes cruising altitudes for level flight under VFR: (a) When operating below 18,000 feet MSL and (1) On a magnetic course of zero degrees ...
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Was the transatlantic crossing for Concorde too short to reach optimal cruising altitude?

When listening to Gander/Shannon ATC on shortwave, you could hear Concorde communicate its planned flight levels at longitudes from 20 West till 50 West. What I remember is that it would continue ...
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Is vertical separation based on geometric difference or altimeter difference?

In the comments below one of the answers to this question about the influence of temperature on vertical separation, the question was raised whether ATC ensure 1000ft vertical separation based on ...
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Why is 0 ft a valid target altitude for an autopilot?

Inspired by this story; The pilot of a Flybe plane that dropped 500 ft (152m) in 18 seconds had selected the wrong autopilot setting shortly after take-off, an inquiry has found... ...The ...
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3answers
802 views

What's the difference between flight level and pressure altitude?

When should we say flight level and when should we say pressure altitude? I know they both set QNE 1013.25, but there is a difference between them. Anyone know?
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Maintaining straight and level altitude [duplicate]

just a completely random question that I suddenly thought - doesn't straight and level flight prove that the earth's surface is not a globe? Once cruising altitude is reached, the plane remains at the ...
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221 views

Why can't I ever get my right ear to pop on descent in a plane?

Whenever I'm flying, there's a period of descent where my right ear just refuses to pop. This has been bothering me for at least ten years. There seems to be a long stage of descent where my ear is ...
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Is there a rule of thumb for reading AGL vs MSL? [closed]

Recently, I read that as it pertains to directions: if you read it, it's true, if you hear it, it's magnetic. This is mostly correct, one edge case though is runways are written/drawn with magnetic ...
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320 views

Why would a plane drop 14.000 ft mid flight?

Just noticed American Airlines flight 221 dropped 14.000 ft mid flight today. Curious, what could have caused this? Here are the flight details.
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491 views

Why do planes fly so high? [duplicate]

It so occurs to me that commercial airliners cruise at altitudes of over 30,000 feet. But why do they fly so high if there are many dangers such as cabin de-pressurization when they can simply fly ...
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274 views

Calculating the maximum altitude of a drone [duplicate]

Is there an equation to find the maximum altitude that a drone or quadcopter can fly to ?
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443 views

Can a commercial aircraft theoretically reach 60,000ft? [duplicate]

As per this question: Altitudes above 60,000 feet are class E airspace. That means that, if you are lucky enough to have an aircraft that flies that high, once you get there you could ...
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494 views

Why would a Mode-C transponder report a different altitude than an altimeter/GPS?

This is related to a small single-engined plane. On a recent flight, the controller kept telling me that I was 300 ft higher than it appeared on my altimeter and GPS (which were in sync). This was ...
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1answer
738 views

How much air does a GE90 ingest at sea level and at cruise level per meter?

I just wanted to know how much air PER METER a GE90 turbofan engine sucks in considering the same thrust output at different altitudes to better understand how the engine can travel further while ...
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What does it mean when ATC says “altitude indicates”?

I've noticed that ATC sometimes calls out traffic (a traffic advisory?) to aircraft using the "altitude indicates" phraseology, and sometimes a specific altitude is given without the phrase "altitude ...
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949 views

What are Altitude, Attitude and Heading Hold?

Can someone give a good and simple explanation about these three dynamics? Altitude Hold Attitude Hold Heading Hold
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2answers
163 views

How to interpret the published altitudes for each of US STAR procedures?

I have been studying the STAR procedures, as published by FAA, and I am trying to understand the way that the altitudes are defined for each fix/route. Take, for example, CAMRN4 of JFK. I see the MEA ...
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How do I calculate true altitude? [duplicate]

Currently doing my CPL and in class we were shown a formula on how to calculate the true altitude, which as I understand it is the distance between the ground and the plane while taking into account ...
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Why do we say “climb” and not “ascend”?

The term for moving to a lower altitude is "descending." Why, then, is the term for moving to a higher altitude "climbing" and not "ascending"? The latter goes better with the term "descending." Does ...
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Why do NY ARTCC Standard Operation Procedures have different altitude limits than the NY Class B airspace?

The NY Class B airspace is defined, officially, as seen in this document, which can be found in the VFR Class B Graphics in the FAA website. In this graphic (and in the corresponding shapefile, Class ...
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254 views

What is the standard temperature used in this true altitude equation?

The control tower of a certain airport with true altitude of 2000ft informs the pilot that QNH is 900hPa and the temperature at the airport is -10 degrees Celsius. The airplane is at FL300 (vertically ...
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Does the reference for AGL include obstacles?

Let's say a plane flies 10m above some trees, that themselves are 10m above the underlying ground. Would that be 10m or 20m AGL? Or, in more abstract terms: What exactly is the reference point for ...
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What is the maximum altitude ATC would deal with?

What's the maximum altitude ATC would deal with? Any example of jets service ceiling certified for above 45.000? Commercial & Business jets?
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What is the relation between drag and weight?

Given an aircraft type and fixing its wing configuration (flaps, slats) and fixing its speed and altitude and assuming it flies horizontally, what is the relationship between the aerodynamic drag and ...
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1k views

How can you find AGL if the altimeter is set to MSL?

Without doing the math, how do you know your true altitude AGL when your altimeter is set to MSL
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Why do high altitude sky-divers say 'Exit' multiple times?

This is something that has always puzzled me. https://sndup.net/6vn8/a Unfortunately, I can't find a video in which I heard them say it, but right before they left the plane, I heard Exit exit ...
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How exactly can an airship lose lift?

On this wiki page (under 'Comparison with heavier-than-air aircraft'), the altitude record of the L-55 Airship states: The ultimate altitude record for a rigid airship was set in 1917 by the L-55 ...
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Are altimeters calibrated to ISA geopotential altitude or ISA geometric altitude?

Altimeters convert a pressure measurement to an indication of altitude. When set to standard pressure setting (1013.25 hPa / 29.92"Hg), they assume the atmosphere is according to the ICAO Standard ...
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What is the reference point for AGL? [duplicate]

I am about to start my PPL soon (still flying in FSX) and I do not understand one thing. As per FAR 91.159 if my altitude is above 3000' AGL I must maintain certain altitude depending on my course, ...
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6answers
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Would a slower speed and lower altitude reduce fatal incidents?

If it became plausible to fly commercial aircraft much lower in the future (due to developments in technology and airway regulations permitting it), say at a standard height of 5,000ft, but with a ...
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Why do some airplanes fly at a very low speed (like this one) at a speed of 433 km/h (234 knots) at a whopping high altitude of 26,500 ft?

Okay. So I'am just having a doubt on this flight (BA359) flying from Lyon, France en-route to London Heathrow. It is flying at a way low speed of 433 km/h (234 knots) in which i think is a bit weird. ...
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On Air France 447, what would have been the lowest altitude to initiate recovery after the stall developed?

What could the lowest altitude of Air France 447 have been to recover the (stalled) flight, where the co-pilot informed the captain that he was pulling up the whole time? The co-pilot didn't inform ...
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What VFR cruising altitude should be flown to the west below 4500 feet?

This is similar question to this question, but different scenario. Let me describe the situation: I am at KDYL in class G airspace. Accroding to ATIS the clouds are at 4700 scattered. I am going to ...
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900 views

How do I know my AGL altitude while in flight?

I am about to start my PPL, still flying in my FSX. I have a question, let's say I am flying from airport A to airport B. Both airports are in G airspace and I would like to stay in G airspace and ...