Questions tagged [high-altitude]

Regions on or above the earth's surface located higher than 8,000ft or 2,500m above sea level.

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Does Indicated Stall speed increase with altitude (Coffin Corner)?

It is my understanding that Indicated Stall speed is mostly constant with altitude, the one that increases is True Stall Speed. Given that PFD show speed as IAS, how come the yellow speed range ...
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What measures do airliners and fighter jets take to protect the pilots and passengers from cosmic radiation? [duplicate]

How are passengers and crew of airliners and private jets, and fighter pilots, protected from cosmic radiation at high altitude? What protective measures were taken on the Concorde which cruised a ...
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Does breathing 100% oxygen cause health issues?

When flying at high altitudes in an unpressurized plane, you use portable oxygen tanks to prevent hypoxia and other altitude-related symptoms. but does this 100% pure oxygen cause health issues when ...
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What does the "High Alt Landing" guarded push button on the A320 exactly do?

I am aware that not all variants of the A320 are equipped with the HIGH ALT LANDING guarded push button. I know that it is pushed before landing at high altitude airfields. Was wondering what it does ...
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How is airliner pressurization being coped with at high altitude airports? [duplicate]

Cabin altitude in a passenger airliner must not become more than 8,000 ft, but what if an airliner flies to or from an airport at a higher elevation, such as Quito and La Paz? How is onboard pressure ...
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How was the AeroVironment Helios able to fly to the edge of space at no more than 23.5 kn?

The NASA/AeroVironment Helios holds the FAI record for the highest sustained horizontal flight at 96,900 ft (29.5 km) MSL. It reportedly spent more than 40 min above 96,000 ft. It could fly no faster ...
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Is the L-39 Albatros able to go above 40,000 ft in steep flight?

The L-39's service ceiling is 36,100 ft / 11 km but would it be able to easily reach and surpass 40,000 ft MSL if flying a parabola?
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Why are planes required to cruise at round flight levels only above 18000 ft of altitude?

AFAIK, planes flying at up to FL180 (18,000 ft pressure altitude) are allowed to fly at both round and semi-round altitudes (e.g. 15,000 ft or 15,500 ft). Planes flying above FL180 must fly at a round ...
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Are there any gliders that can fly over the Himalayas?

Do gliders (sailplanes) use ridge and wave lift in the Himalayas to go to extreme altitudes, possibly above Everest's peak?
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What is the highest operational ceiling for a nuclear scramjet?

A similar question is: What is the highest operational ceiling for an air-breathing jet engine? The answers point to scramjets. Cited reports focus on combustion kinetics. The Wikipedia Scramjet page: ...
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What prevents a small plane like a Cessna or Piper from flying as high as a jet?

Obviously taking oxygen in consideration. What prevents a small plane from being able to fly at a much higher altitude? I know some business jets can fly up to 40,000 ft. Does it have to do with the ...
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Is it possible to file for a flight level ABOVE an Airway altitude limitation (for high en route airways)?

I'm just curious if it's ever possible to file for, and/or fly, an altitude that is above an airway restriction. Say if the airway has an altitude restriction of FL410 or less. Is it ever possible to ...
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Are there any high altitude flying options for a private pilot?

I would like to ask: if you are a private pilot that wants to fly really high, what are their options? I know that for gliders it's not uncommon to reach FL160. Beechcraft Baron can reach FL190. ...
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What is the straight-and-level altitude record for a heavier-than-air winged/lifting-body aircraft?

There are many variants of the flight altitude record. The highest on the list is SpaceShipOne but rocketry isn't really "flight" in the sense of aerodynamic lift. What is the highest ...
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What is the altitude record for the F/A-18 Hornet?

Does anyone know how high (above MSL) the F/A-18 ever went? Its service ceiling is 50,000 ft, but when going up steeply, is it able to surpass 100,000 ft altitude?
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Could the Perlan II glider be used for nearspace tourism?

I asked the same question about the SR-71 Blackbird, and I'm also curious about the Perlan II sailplane which travelled above 70,000 ft, and is planned to be flown to 90,000 ft, if it could be used ...
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How high can manned subsonic planes go?

What is the maximum altitude a manned plane that flies subsonically can reach? Subsonic airplanes can't go as high as super- and hypersonic ones of course, so record holders are the latter ones. But ...
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Could the SR-71 Blackbird be used for nearspace tourism?

The Blackbird had two seats onboard. Could it be reactivated for nearspace tourism, placing a paying tourist in the other seat? If no, why not or why isn't it being proposed? In leveled flight, the ...
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What limits high altitude powered paragliders other than the engine?

Due to their extremely low wing loading, powered paragliders stall at very low indicated airspeeds compared to other airplanes. A typical paraglider can continue flying all the way down to 10-15 ...
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What's the highest altitude ever achieved by a (rocket-?)plane for level flight?

As probably most of us know, the SR-71 Blackbird holds the altitude record for leveled flight for (manned) jet planes (and ground-launched planes) at 90,000 ft MSL. However, the very altitude record ...
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Did every X-15 pilot become weightless when flying into the upper strato- and mesosphere?

The North American X-15 was aimed at breaking airspeed and altitude records. The flights that sought to achieve new airspeed records (Mach 5+) were rather leveled but the flights into the upper ...
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Are there jet aircraft for whose flights astrodynamics must be taken into account? [duplicate]

Civilian jet airliners don't need to push their yokes down to follow the curvature of the Earth because within the atmosphere the curvature is accounted for by automatical systems, right? I wonder ...
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Could one see stars from the Concorde in daytime?

The Concorde flew to an altitude of 60,000 ft (18.3 km) where stars should be visible at noon, aren't they? This question asks on how high stars become visible, and it is said Blackbird pilots could ...
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How is altitude reached by aircraft flying above the stratosphere measured?

Aircraft flying above the stratosphere (above 30km) are rare, but there is still the X-15 and the spaceship two. For those aircraft, maximal altitude is measured to within 500 ft. As described in this ...
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What is the maximal altitude at which an emergency slide can be deployed?

If I understand correctly, the mechanism to inflate an emergency slide relies on a tank of inert gas and on an "aspirator" that sucks ambient air. This aspirator works thanks to depression ...
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How does 'standalone' propeller efficiency change with altitude?

I've seen questions regarding propeller aircraft and altitude and their interaction. But I'm wondering what the relationship between just the propeller and altitude (changing air density) is. How does ...
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What happens in an F-16 once the aircraft exeeds its service ceiling?

What exactly is the sequence of events that would unfold as an F-16 attempts to exceed its service ceiling? The scenario is simply full afterburner and attempting to simply climb higher and higher (at ...
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What happens if an aircraft goes above maximum altitude? [duplicate]

We all know what happens when a plane goes overspeed... but what happens when a plane goes above their max. altitude? And why are planes certified maximum altitudes anyway? Is it because there won't ...
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267 views

How to adjust time of useful consciousness for pilots acclimatised to high altitudes?

The time of useful consciousness (TUC) is the length of time an average pilot, breathing ambient-pressure air without supplemental oxygen, is capable of functioning usefully at a given altitude. For ...
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Does high density altitude affect your landing speed?

So I had this question asked in my recent commercial-pilot checkride: The DPE asked me about high-density-altitude airports; he specifically asked me if I should add airspeed when I'm on landing ...
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Which aircraft can fly at FL600 or above?

I would like to know some examples of aircraft (specific models) which can fly at FL600 or higher. I am interested in aircraft which can or could fly at that altitude on a regular basis (service ...
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How does latitude affect the air temperature at 8 km altitude where planes fly?

Is the air temperature (at 8km) above the North or South poles colder than the same altitude above the equator? Why? Ground level air temperature difference between coldest and warmest places on ...
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Do the Mt. Everest rescue helicopters have modified engines to operate at high altitudes?

There are so many climbers on Mt. Everest today that there is now a helicopter rescue service there. They operate rescue up to 21,000 + ft. Because this is essentially stationary service it seems that ...
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Where and when would a 737-700 be taking off at an altitude of 19 kft?

Another question triggered by reading the 737 technical site; according to this section of the page on the 737's pressurisation system, the 737-700 comes with an option that allows it to safely take ...
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What kind of drone might be able to fly so high that it "operate(s) outside national boundaries"?

In the question What is a propellant burner trailer? I mention that CNN and NPR have pointed out that the US president recently tweeted a surveillance photo of an explosion of a rocket on a launch ...
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Why do private jets such as Gulfstream fly higher than other civilian jets?

I heard in a TV show that private jets such as Gulfstream can fly at about 50,000 ft, higher than other civil jets. Is it an aerodynamic reason (lighter aircraft to be sustained in a less dense air) ...
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Could a hybrid electric steam plane be more efficient at altitude than at sea-level, and how to optimise it to frigid air?

In the thirties a steam powered plane was built. video Could a hybrid electric steam plane be more efficient at altitude than at sea-level, and how could such a steam engine be optimised to benefit ...
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How do carbureted and fuel injected engines compare in high altitude?

I couldn't find enough information on the internet for this topic. What I found can be paraphrased as: Carburetor means easy engine start while fuel injected means manual fuel start up and ...
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What lights to use for a high-altitude weather balloon?

I am designing a high-altitude weather balloon for a college project. The balloon may fly at night, which means that, per FAA regulations, I need a light that is visible for 5 miles. Does anyone ...
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Proportionally, what is more affected by a hot and high takeoff - a electrically driven propeller or a turbofan?

My assumption would be the electrically driven propeller would be less affected compared to turbofans at high altitudes and take off as although the air would be less dense at these ambient conditions,...
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How do planes know what altitude they're cruising at?

I know that when planes enter the aerodome containing the airfield of destination, the ATIS will tell them an altimeter setting so the system knows how to calculate their altitude above their field; ...
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What will happen to a modern high bypass engine at 80 000 feet with cruise speed of 0.8 Mach?

While keeping the typical cruise speed of 0.8 Mach, will the engine shut down due to "air starvation" at such high altitude? Is it possible to design a turbofan engine, which is able to provide thrust,...
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Has fuel boiling ever been an issue for high altitude aircraft?

Are special measures being taken to prevent fuel from boiling inside the fuel systems at high altitudes? If so, when (with what aircraft) did this practice start? (question is pertaining to air-...
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Difference between Mach buffet and shock stall

What is the difference between Mach buffet and shock stall?
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Why do suborbital planes feature H-tail and/or large wingtips?

Spaceplanes that are suborbital are mostly supersonic and feature H-tail or rather large wingtips. This looks to be similar to a H-tail configuration but I'm unsure abut how it works, which is why I ...
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Why does aircraft stability increase when it transitions from subsonic to supersonic flight?

I am puzzled why would the aircraft be more stable at high speed flight at high altitudes. Given that the Centre or Pressure moves gradually towards the 50% MAC region, once past Mcrit. Has this got ...
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What forces act on an airplane's door from the outside in cruise?

The inside cabin pressure from what I understand is pressurized to the values found at 6000-8000 feet high (11.34 psi at 7000 feet), at which point we can find the amount of force can be found acting ...
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Why do high altitude air-launch plane designers choose to use two fuselages?

We see double fuselages in both the huge Stratolaunch vehicle and in Virgin Galactics high altitude launch vehicle. What about this design makes it desirable?
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If maximum speed was a priority for modern military fighter jets and bombers, approximately how fast would they likely be?

Burt Rutan talks rather passionately about the lack of innovation in space flight, but also mentions how fighter jet (maximum) speed performance has stalled: In fact,...
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Is there a limit to the possible altitude for electric jets?

So I was thinking about Elon Musk's supersonic electric jet idea. Assuming we have sufficiently energy-dense batteries, where would the limits be in terms of speed and altitude. His logic seems to ...