How do pilots choose climb speed and cruising altitude?

Pilots choose climb speed from the exact aircraft manual or operator schedule: Vx for best obstacle clearance, Vy for maximum climb rate, or a faster cruise-climb schedule. They choose cruising altitude by balancing terrain, weather, winds, airspace, aircraft performance, fuel, oxygen or pressurisation limits, and the distance available to climb.

For Aviation & Real-World Flying, and for realistic simulator operation, neither choice has one universal number. The correct target depends on the aircraft variant, weight, configuration, temperature and immediate objective.

Which climb speed should pilots use?

The correct climb speed is the published airspeed or IAS/Mach schedule that matches the required climb objective.

Vx should not normally be held for the whole climb. Its relatively low speed and high nose attitude can reduce cooling, visibility and energy margin. After clearing the obstacle or meeting the required gradient, the pilot normally accelerates to Vy or the published cruise-climb schedule.

Vy is also not automatically the best normal departure speed. It maximises climb rate under the conditions for which it is published, but a slightly faster cruise climb may be kinder to the engine and easier to fly.

How is Vy read, and is it a vertical speed?

Vy is pronounced “Vee why” and means the best-rate-of-climb airspeed; it is not a target in feet per minute.

The pilot reads the published Vy in the POH, AFM or operator data and holds it on the airspeed indicator, normally as indicated airspeed unless the source states otherwise. Power and pitch are adjusted to maintain that airspeed, and the vertical speed indicator shows the resulting climb rate.

A mistake we see constantly in simulators is selecting an aggressive vertical speed and allowing IAS to decay. If the aircraft cannot sustain the commanded feet per minute, reduce the vertical-speed target or use an airspeed-based climb mode. Do not keep raising the nose to recover the lost rate.

On many multi-engine aeroplanes, the blue radial line marks Vyse, the best single-engine rate-of-climb speed. It should not be mistaken for ordinary all-engines Vy.

Why do Vx and Vy change with altitude?

Vx and Vy can change because altitude, weight, temperature, configuration and available power or thrust alter the aircraft’s excess performance.

In many normally aspirated piston aeroplanes, published Vx in indicated airspeed rises with altitude while Vy falls, causing the two to approach each other near the ceiling. That is a general tendency, not permission to invent corrections: use the values or corrections for the exact aircraft.

Lighter weight usually changes both the required speed and achievable climb rate. Flaps, landing gear, ice, anti-ice use and an incorrectly leaned piston engine can produce a result far below the clean book figure. Our explanation of using aircraft-specific performance charts with weight, temperature and altitude shows how those variables are applied during planning.

Wind does not change the aeroplane’s basic aerodynamic Vx or Vy through the air, but it changes the climb path over the ground. A tailwind makes the ground-relative gradient shallower, which matters when terrain or a departure gradient is involved.

What is cruising speed, and is it the same as cruise-climb speed?

Cruising speed is the speed selected for level cruise, while cruise-climb speed is an airspeed used during the climb.

In a piston aeroplane, cruising speed normally results from the selected power setting, mixture, altitude and aircraft weight. In a jet, it is commonly flown as a Mach number or an economy schedule calculated by the flight-management system. Published cruise figures may be stated as indicated airspeed, calibrated airspeed, true airspeed or Mach, so the unit matters.

A cruise-climb speed is normally faster than Vy and accepts fewer feet per minute in exchange for cooling, visibility, comfort or economy. It is not a universal speed category such as Vx or Vy; the manufacturer or operator specifies it. See our practical guidance on matching cruising speed to altitude, weight, range and fuel priorities when planning the level segment.

What is crossover altitude?

Crossover altitude is the altitude at which the scheduled indicated airspeed and scheduled Mach number represent the same operating point.

During a typical jet climb at constant IAS, Mach number gradually increases. At the crossover altitude, the climb changes from the IAS target to the Mach target; above it, maintaining constant Mach generally causes indicated airspeed to decrease.

Crossover altitude is not one fixed number for every airliner. It depends principally on the selected IAS/Mach pair. A schedule of 280 knots/Mach 0.76, for example, has a different crossover from another IAS/Mach combination, so pilots use the aircraft’s flight-management calculation or published schedule rather than guessing.

It must not be confused with transition altitude. Transition altitude concerns the change from a local altimeter setting to standard pressure; crossover altitude concerns the change between IAS and Mach speed targets.

What is the best rate-of-climb speed for an A320 or A330-900?

An Airbus A320 or A330-900 does not normally use one pilot-selected Vy figure for the whole climb.

Initial Airbus climb guidance is provided by the take-off guidance mode and is tied to V2, engine condition and the certified take-off logic. Once acceleration is permitted, the crew follows the flap-retraction schedule and then the managed climb target calculated by the flight-management system. That target can change with weight, altitude, cost index, speed restrictions and the IAS-to-Mach crossover.

For an A320 simulator flight, the practical answer is to configure the flight-management system correctly and follow the managed speed or the operator’s published schedule. The same principle applies to the A330-900. Do not copy a speed from an older A330 variant, another engine option or a generic “best A320 climb speed” list.

Holding an arbitrary vertical speed is particularly troublesome in a heavy Airbus. Use the appropriate managed climb, open-climb or other aircraft-supported airspeed mode, and let the resulting climb rate vary. Mode names and behaviour depend on the simulated aircraft.

How do pilots choose a cruise altitude or cruise level?

Pilots first eliminate unsafe, illegal or unreachable altitudes, then select the most useful level remaining for the complete flight.

Cruising altitude is the altitude maintained during the cruise segment. Above the applicable transition altitude, aircraft normally operate using a flight level referenced to standard pressure. A flight-planning field labelled cruiselevel or “Cruise Level” usually asks for that planned cruise altitude or flight level, but its expected units must be checked.

1. Establish the minimum safe altitude. Consider terrain, obstacles, route minima, departure and arrival procedures, and the applicable visual or instrument-flight rules.
2. Find the practical upper limit. Check climb capability at the planned weight and temperature, along with oxygen, pressurisation, equipment, icing and aircraft limitations. Service ceiling is not a sensible routine target.
3. Screen the weather. Avoid levels affected by thunderstorms, severe turbulence, icing or unsuitable cloud conditions. A smoother lower level can be better than a theoretically efficient high one.
4. Compare winds and total fuel. Include the time, distance and fuel required to reach the level. A strong tailwind may favour one altitude, while a headwind can make another faster or cheaper.
5. Apply route and cruising-level rules. Direction-of-flight requirements differ by jurisdiction and between VFR and IFR. Under IFR, the usable level must also agree with the ATC clearance.
6. Check the length of the flight. On a short sector, climbing to the theoretical optimum may leave almost no level cruise before descent has to begin.

Is the highest possible cruising altitude always best?

No. Maximum altitude, optimum altitude and permitted cruise level are three different things.

Jets often gain efficiency at higher levels, but a heavy aircraft may have too little climb margin to start there. Airliners commonly begin lower and make step climbs as fuel burn reduces their weight. Our account of how weight, winds, weather and step climbs shape an airliner’s cruise level explains why the highest available level is not automatically selected.

A normally aspirated piston aeroplane loses available power as it climbs. A higher cruise can still help with terrain, cooler air, weather or a favourable wind, but the slow climb may consume more time and fuel than the cruise segment saves.

How do you set cruise altitude in Microsoft Flight Simulator 2024?

In Microsoft Flight Simulator 2024, set the planned altitude in the flight planner or EFB, then confirm the aircraft’s flight-management system and autopilot altitude selector are configured separately. Changing the planner value alone does not command the aeroplane to climb.

Aircraft integration differs between default and add-on models, so a route transfer may populate all, some or none of the FMS performance entries.

1. Build the route. Enter the departure, destination and route in the MSFS 2024 flight planner or the aircraft’s supported planning system.
2. Enter the planned cruise altitude. Use the cruise-altitude or cruise-level field and follow the format shown. A field expecting a flight level may use FL350 or 350, whereas a field expecting feet may require 35000.
3. Transfer or load the plan. If the aircraft supports planner-to-avionics transfer, send the route and inspect it rather than assuming every field copied correctly.
4. Verify the FMS. Confirm the route, cruise level, aircraft weight, performance data and relevant speed constraints. Enter the cruise level manually if it was not imported.
5. Set the cleared altitude. Use the autopilot altitude selector for the first cleared or procedure-limited altitude, not blindly for the final cruise level.
6. Select the correct climb mode. Depending on the aircraft, use VNAV, managed climb, flight-level change, open climb or another airspeed-based mode. Monitor thrust, IAS or Mach and active constraints throughout the climb.
7. Update the selected altitude as authorised. Continue towards cruise as restrictions end or further clearances are received, then verify that the correct pressure setting is used above the transition altitude.

If the aeroplane levels off early, inspect the selected altitude, active flight-plan constraint and autopilot mode annunciation. The planned cruise altitude may be correct while the autopilot is obeying a lower selector setting or altitude restriction.

Why can’t the aircraft reach its planned cruise altitude?

An aircraft usually fails to reach cruise because the level is unrealistic for its weight and conditions, or because speed, thrust, configuration, automation or an altitude constraint is preventing the expected climb.

• Airspeed is decaying: reduce the commanded vertical speed or select an airspeed-based climb mode.
• Climb thrust is not set: check the relevant thrust mode, throttle position or detent for that aircraft.
• Drag is still present: verify landing gear, flaps, spoilers and any simulated icing.
• The aircraft is too heavy or the air is too warm: choose a lower initial cruise level and plan a step climb later.
• An altitude constraint is active: inspect the flight plan and mode annunciations before overriding it; it may represent a genuine procedure restriction.
• The planner and FMS disagree: enter the intended cruise level in the aircraft systems and confirm the autopilot selector separately.
• The wrong variant’s data was used: recheck engine type, aircraft model, payload and performance source.

When the limitation is aerodynamic rather than an avionics setup problem, our diagnosis of weight, temperature, drag and limited excess power provides the next checks to make. The safe response is to accept a lower cruise level, not force the climb while airspeed and performance margins disappear.