When an aircraft takes off, what happens after it gets in the air? Climbing to a cruising altitude with a typical airliner can take about 20 minutes. I know that some people do not realize that the aircraft reaches its cruising altitude unless a pilot makes an announcement. Others are tuned in the “movie” that will be watched for the whole flight.
I know my aviation “peeps” take notes as to what occurs on their flight. But why do planes spend so much time climbing? Why aeroplanes do not fly at a lower altitude? How high can planes fly? There are reasons for all of this.
Why Planes Climb
Everyone wants to get to their travel destination fast and safe. Airliners want to do this while saving money. Flying at a higher altitude is the solution to this.
The less drag a plane experiences, the faster it can fly (while thrust is constant). Air at lower altitudes is more dense than the air at higher altitudes. Think of it as finding more “particles” per cubic inch with the more dense air. These particles hit the aircraft as it flies, thus contributing to the drag. Lower density altitudes allow for an aircraft to fly farther, faster and save more fuel.
In aviation, when you have an engine failure, for example, altitude is on your best friends. A plane can stay in the air for a while and glide. The more altitude a pilot has, the more time he or she has to identify the emergency, come up with a plan and land safety. Did you know your commercial airliner can fly on one engine with no problem?!
What would you expect to find at 30,000 feet? You will not find a lot of man-made objects at these heights. To provide the space needed for aircraft travelling 500 mph, they can fly high and avoid the unnecessary object. Buildings, mountains, and other planes can be a problem if a fast-moving jet is nearby.
At cruise, pilots do their best to avoid bad weather. Flying in a thick thunderstorm would not be enjoyable by many passengers. Most adverse weather conditions are found closer to the surface. Since airline pilots are not “hurricane hunters”, they will climb over it.
A lot of bad weather can be avoided by climbing to a higher altitude. Pilots commonly ask air traffic control (ATC) to change their heading or course temporary. All of this done, to ensure you are happy watching your movie!
Here are the maximum heights for some aircraft.
- Cessna 310 (twin piston) – 20,000 feet
- Dash 8 Q400 (twin-turboprop) – 27,000 feet
- Embraer 175 (Regional Airliner) – 41,000 feet
- Boeing 737 (Commercial Airliner) – 41,000 feet
- Boeing 747 (jumbo-jet) – 45,000 feet
- Gulfstream (private jet) – 51,000 feet
So you might be thinking that these are the cruising altitudes that these aircraft go for each flight, but no. Temperature, winds, flight time, weight, weather, and more can factor into choosing a cruise altitude. For example, you would mostly find a 737 cruising between 31,000 feet-38,000 feet.
We Stay Cruising
Next time your captain announces your cruising altitude, you should have an idea as to why your flight is there. Can you remember what altitude you last flight cruised at? Let me know in the comments below.