Are you having issues maintaining speed and altitude in cruise?
(If so, consider reading the information below. Some of your questions/concerns may be answered)
With the new release of global to Infinite Flight, there are many new things to learn in regards to your aircraft’s performance. The days of taking off from your favorite airport to cruising at FL390 within 20mins of departure are long over. Included in this tutorial are a few images that were screenshotted from FlightAware.com that will better help explain how Step Climbing is achieved. The flight in particular is Qantas 8 (QF8). This route departs Dallas-Ft. Worth, Texas (KDFW), and arrives in Sydney, Australia (YSSY) and utilizes the A380.
As you could imagine, the distance is quite large. About 8500nm. With that being said, it requires a hefty amount of fuel to get across the Pacific Ocean.
When aircraft are departing on long haul trips/routes such as this one, they are quite heavy at their originating airport. Full of passengers, cargo and fuel. The photos below will show you how the pilots respond to an aircraft with a high weight as they trek towards their destination.
What is Step Climbing?
A technique/procedure called “Step-Climbing” is utilized to assist an aircraft and the pilots in climbing to a higher cruise altitude. This process involves pilots flying at lower cruise altitudes until the burn off enough fuel to climb to the next highest cruise altitude for their route. The altitude that provides the most fuel-efficient cruise at the start of a long flight, when the aircraft is fully loaded with fuel, will not be the same altitude that would provide the most fuel efficient cruise near the end of the flight. This is due to the fact that most of the fuel onboard has been burned. Generally, the final cruise altitude is higher than the initial cruise altitude. By climbing gradually through the cruise phases of a flight, pilots can obtain the greatest fuel economy out of their flight.
In image 1.1, QF8 has just departed KDFW and is on its way to YSSY. They’ve been in the air for a little while and have leveled out at FL300. From the line green line graph you will see how there is a rise in the line and then it levels off. This was the initial step climb and cruising altitude for the flight.
As the aircraft burned some fuel off at FL300, the pilots then proceeded to climb up to the next highest altitude for the direction that they were traveling. See Cruising Altitudes for more information. Image 1.2 shows us that after the pilots flew at FL300 they climbed to FL320 and remained there for a few hours until they were able to burn even more fuel off so they could continue climbing to their final cruising altitude of FL400. Note the location of the aircraft in relation to the departure airport and arrival airport during this cruise portion.
In image 1.3, more time has passed by and the pilots have already climbed to FL340. Still making headway to their final destination, Sydney. Not too much more can be explained here as you should be getting the pattern thats occurring.
At about 60% completed with their flight and QF8 still hasn’t reached their final cruising altitude. However, they are cruising at FL360 compared to image 1.3 which was showing at FL340
With just a few hours left in their flight QF8 made the last climb up to their final cruising altitude, FL400. However this final cruise was achieved over a period of time. If you note the location where FL360 was shown in image 1.4, you will see that it the climb to FL400 began at the red line that is drawn on image 1.5. The climb to FL400 in this final step climb was very gradual. The 4000ft climb took place over a few hours.
If you are departing heavy at/or near Maximum Takeoff Weight (MTW) do not climb up to your final cruise altitude right away. You will need to plan the altitudes you will step climb to before your final cruise altitude.
Refer to Cruising Altitudes if you are unsure what altitude you should be flying at based on your direction of travel.
If you find yourself stalling in cruise, you have an unusual attitude (pitch of the aircraft), or you’re unable to maintain an altitude, you’re probably too heavy to be at that altitude. You need to descend to a lower altitude to burn off fuel and try climbing up gradually later on in your flight.
Only take the fuel required for the flight plus any for reserves, diversions, etc. Don’t load 100% fuel if you don’t need it. Loading 100% fuel will only restrict how high you can cruise.
Questions? Feel free to drop them below. Others might have the same question(s), so don’t hesitate to ask. Hopefully this will help some folks out.