What is the lowest altitude a plane can fly

If you’re a frequent flier, you may barely pay attention to the routine stages of flight. The airplane takes off, then climbs for the first 15 to 20 minutes of the flight. Once the plane reaches cruising altitude, flight attendants start making their rounds, and the pilot may announce that you’re free to move around the cabin (though you still have to leave your phone on airplane mode). Once the descent begins, it’s time to fasten those seat belts in anticipation of landing. In that time between ascent and descent, the airplane is cruising at a steady altitude. But how high do planes fly? And why do they have to stay at a set altitude? If you’ve ever asked these questions during those long hours spent staring out that little round window, we’ve got the answers to this burning bit of airplane trivia!

The cruising altitude of a commercial aircraft depends on the size of the plane. But generally, most commercial passenger jets cruise at between 32,000 and 40,000 feet—or six to seven-and-a-half miles off the ground. Turboprop planes, which are smaller aircraft that typically carry a handful of passengers, rather than hundreds, fly at a lower altitude of about 25,000 to 30,000 feet. But since these propeller planes are often used for short-haul flights, they may stick to lower altitudes simply because by the time they reach a higher altitude, it’s time to begin their descent.

What happens if an airplane flies too high?

Remember the story of Icarus, the character from Greek mythology who flew too close to the sun and perished when his wings melted? Passenger planes aren’t at risk of melting if they fly too high, but there are cabin-pressure and oxygen concerns that dictate that they remain below set altitudes. Theodore Kyrazis, an Airbus A-320/321 captain and a retired USAF F-15 pilot, explains it in non-aeronautic speak:

• Emergency oxygen supply: Airlines impose altitude limits, Kyrazis says, “to ensure there is enough oxygen supplied to all the masks for the amount of time it takes to accomplish an emergency descent to an altitude where the oxygen masks are no longer required (around 10,000 feet).”
• Sudden cabin depressurization: A loss of cabin pressure can occur if a plane flies too high, and if that happens, passengers and crew—including pilots—can lose consciousness. When it happens with a fighter jet, Kyrazis explains, “it’s a simple matter of rolling over and going straight down back to a comfortable altitude in less than a minute. It’s not so trivial for a commercial aircraft.”
• Equipment failure: “Almost all modern aircraft have sophisticated computers monitoring aircraft weight, speed, outside air temperature, wind speed and direction, and the angle of the wing relative to the incoming wind,” Kyrazis says. “If a pilot were to try climbing above the recommended altitude and keep going, either the engines would not produce enough thrust to keep climbing or the wings would stall.”

The bottom line? You want your pilot to stick to the recommended altitude!

Commercial airlines need to operate as efficiently as possible in order to make money—and not just by charging for in-flight Wi-Fi. This makes fuel economy one of the most important factors in how high planes fly. The short answer, according to Kyrazis, is that turbojet engines burn less fuel as the air density gets lower. There are some fancy calculations involved, but essentially, the speed and angle of degrees at which the plane climbs are determined both by weather conditions and the size of the plane; bigger aircraft weigh more, in part, because they’re carrying so much heavy fuel, which burns off as they climb.

According to Kyrazis, one hour of climbing may burn off a whopping 10,000 pounds of fuel. And get this: “If a major airline saved just one gallon of gas on every one of its flights for a full year, the cost savings on that one item would be over $15 million!”

Speed

The higher a plane flies, the faster it can fly—to a point. “Less-dense air at higher altitudes means the actual speed the aircraft is traveling over the ground is much faster than the aircraft speed indicator shows the pilots in the cockpit,” says Kyrazis. That means the plane is making better time than even the instruments show. But the flip side is that extremely cold temperatures will slow the plane down. To balance that out, pilots find that happy medium between fuel-saving high altitude and the slowing effects of subzero temperatures. In case you’re wondering, this is not why it’s so cold on airplanes.

No one likes to encounter turbulence on a flight, but it’s most likely to occur during ascent and descent. “Much turbulence associated with weather systems can be avoided above 35,000 feet,” says Kyrazis, which is part of the reason commercial airliners like to climb above storms and stay there. The exception, he says, are thunderstorms, which can reach 50,000 feet into the atmosphere. When that happens, the airplane has to either go through the storm or around it.

What happens if a plane flies too low?

Despite all the frightening things that can happen if a plane flies too high, flying too low can be just as dangerous. Apart from flying through lower-lying bad-weather systems, there’s a lot more general aviation traffic at lower altitudes, including that of smaller commercial and private aircraft.

Another big risk of flying at low altitudes? Running afoul of birds. “Most bird strikes occur during takeoff and landing,” says Kyrazis. That includes the 2009 “Miracle on the Hudson” and the heroic landing by Captain “Sully” Sullenberger. Flying above 10,000 feet greatly reduces the risk of an encounter between bird and plane.

Next, find out what happens when you flush an airplane toilet.

Originally Published: May 03, 2022

Low flying aircraft can be an awesome sight or a terrifying sight depending on which side of the fence you sit. To the majority of people, a low flying aircraft can be a nuisance and if it happens regularly it can become very stressful.

An aircraft can legally fly as low as 500ft above the ground & if in sparsely populated areas or over water there is no minimum height limit but must remain at least 500 feet from any vessel, structure, or person. Aircraft can also fly lower than 500ft when landing and taking off.

Depending on where you are when you see a low flying aircraft will dictate which of the rules the pilot ‘should’ be following. Let’s take a look at those rules and give you an idea of what is legal and what is a nuisance!

Legal Limits To Low Flying

To keep this simple there are several parts to one of the FAA regulations that govern low flying rules in the US.

The main regulation is 14 CFR Sec. 91.119 – Minimum safe altitudes: General of the FAR (Federal Aviation Regulations).

In a nutshell, what this rule stipulates is that Except for Landing and Taking Off a pilot:

• Must not fly anywhere upon which they cannot safely land in an emergency without causing damage to people or property.
• If overflying congested areas, the pilot must maintain 1000ft above the highest obstacle within a 2000ft radius.
• If overflying a non-congested area, the pilot must maintain 500ft above the ground.
• If overflying sparsely populated areas, the pilot must maintain at least 500ft to any person, vessel, vehicle, or structure. Note no altitude restriction!

But, a caveat to these rules is that if it is a helicopter it may be operated at less than those minimums, provided the pilot operating the helicopter complies with any routes or altitudes specifically prescribed for helicopters by the FAA.

This could mean a low flight corridor for helicopters through a busy airspace. A great example of this is the Thames River Low-Level Routes through London, UK to help keep helicopters out of the way of the heavy iron flying into Heathrow, Gatwick, Luton & Stanstead airports.

Another example is the heli routes around Boston, MA. Most large cities will have low flight routes for helicopters to help with separation from the bigger aircraft.

But why do helicopters seem to be able to not follow the 500ft and 1000ft minimum height rules that planes do? It all comes down to the space required for a helicopter to land in the event of an emergency.

A good, well-trained helicopter pilot should be able to land a helicopter with no engine power in an open space the size of a tennis court. Because of this, helicopters are allowed to fly lower, providing they are able to reach a suitable area if that emergency ever occurs.

Helicopters with 2 engines generally do not have to worry so much about this because if one engine fails they still have another donkey still kicking to allow them to carry on flying or take them to a suitable landing location.

Another caveat to this regulation is what is classed as ‘A Congested Area’? The FAA has purposely kept this a gray area to analyze each infraction on a case-by-case basis to balance the pilot’s actions vs the public’s safety.

So would a gathering of half a dozen or a dozen people in a farmer’s field be considered congested? Your guess is as good as mine! If a pilot is conducting a landing they are fine, but a low pass at less than 1000ft high and within 2000ft of the spectators will technically put the pilot into infraction territory!

Learn More…
Try These Articles:
* Helicopter or Airplane: Which is Easier To Fly?
* Can You Land a Helicopter Anywhere? What Will Get You Busted!

Police & Air Ambulance Helicopters

This may be the most common low flying aircraft you will see depending on where you live. Generally, most pilots flying these machines will try to maintain the limits set out in the regulations above just for noise abatement.

Being courteous to the neighbors in your city is just good airmanship. I know when I would leave the hospital helipad in the middle of the night and overfly my house and woke my small kids, my wife would kill me! It is no different for any household!

If you are unlucky enough to live by a hospital or police helipad, then that’s just a noise you will have to live with I’m afraid.

Police helicopters and News helicopters could be over a scene for a prolonged period of time covering the incident and should depart once the action is all over. Air ambulances will tend to circle to assess the landing zone then be in and out causing minimal disruption.

Military Aircaft

Military aircraft can and will do whatever they want! They are generally not governed by the FAA rules and regulations that civilian aircraft are bound to but they will follow the same rules when flying within the national airspace system.

Military aircraft can be on urban training exercises, remote low-level tactical training, or even operations concerning national security. If they need to buzz through your neighborhood at 200 ft then that is what they will do.

However, they will, if they can try to abide by noise abatement procedures, especially if they are operating in the same areas regularly. This can include the route/s to and from the areas of operation. If you live in one of the many military training areas then there is not a lot you can do for low flying aircraft!

If low flying military aircraft is something you love to see then one of the best places in the world is the ‘Mach-Loop’ in North Wales, UK.
Check out the video below:

For those of you in the US, then a trip to Rainbow Canyon in Death Valley National Park, California – also referred to as ‘Star Wars Canyon’, will give you up-close encounters with fast military jets!
Check out the video below:

Utility Helicopters

Many small aircraft or helicopters may be seen working low-level at times doing things like powerline and pipeline patrols. A lot of these machines when operating in urban environments will probably use two engines, especially since the 2008 single-engine helicopter crash in Cranbrook, BC, Canada that while on a low-level powerline patrol through the town crashed killing the 3 occupants of the helicopter and a member of the public walking on the sidewalk.

Low flight needed to survey infrastructure, waterways, traffic and other services is a common occurrence but may only be in your area for a short period of time.

In Canada, we have to apply for Aerial Work Permits from Transport Canada if we are going to be working around people and property at low altitudes. This is basically a plan and risk assessment that helps to identify hazards, minimize risks, and can also help to inform the public of intentions so dozens of homeowners do not flood the 911 dispatch with calls!

The US FAA can issue waivers to companies to be able to legally break the low-flight regulations for things like aviation events or specific work tasks to enable the flights with some pre-planning & risk analysis.

Most of the time working aircraft are not the ones that cause a lot of the stress, this group falls into my next category.

Learn More…
Try These Articles:
* Police Helicopters: All Your Questions Answered!
* How Do Pilots See At Night? Everything You Want To Know!

Nuisance Pilots

We have all seen them, we have all heard about them and for sure we have all seen the videos surfacing on the internet of their antics.

Unnecessary low flying and showboating is one of the biggest downsides to this great activity, as usual, it is only a select few that create all the problems.

Low flying over property, livestock, people are just a small incident away from being a major catastrophe. Flying at low altitudes leaves very little time for emergency assessments, drastically reduces your emergency landing locations, and can be the difference of a rescued aircraft vs a demolished one let alone the carnage that can be caused to innocent bystanders!

For those pilots that intentionally break the laws and make peoples lives a living hell then they deserve everything they get and to help report these pilots you can use this excellent guide on what evidence to collect and then who to contact in your area:

FAA Low Flying Complaints Guidelines

To Finish

Low flying has its place whether it be for airshows, training, aerial survey, or as part of an air traffic control system. Low flying just for the sake of showing off and annoying people is unacceptable.

As time goes on I hope more pilots learn that respect of those on the ground is just as important as the respect that you show to others in the air and the trouble makers will gradually be weeded out. Unfortunately, I don’t think we will ever achieve it as there will always be that one jerk!