What do aircraft speed, ceiling and range figures mean?

An aircraft specification describes a type. It does not tell you exactly what one aircraft is doing, or how much fuel it has left.

Game controls + real-world concept · v0.8.16.0

Instructions use this version’s reference and controls. Your bindings or a later version may differ.

On this page

Unfamiliar word? Select a dotted-underlined term for its meaning.

Three different questions

Question	Where to look
What kind of aircraft is this?	Aircraft Data: the type and its reference figures.
What is this flight doing now?	Flight Info and its trackblock: the selected contact’s details.
Can my aircraft complete this job?	Its current task, fuel, position and the route back to land.

Read each specification

Label	Plain-English meaning
Maximum speed	A reference for how fast the type can fly under stated conditions. It is not a speed every flight should reach.
Cruise speed	A usual speed for the main travelling part of a flight. Taking off, climbing, turning or landing are different parts of the job.
Service ceiling	An upper altitude based on the aircraft’s remaining ability to climb under specified conditions. It is a performance reference, not a recommended cruising altitude or the selected flight’s current height.
Stall speed	A reference for specified flying conditions. A stall is a loss of lift as airflow over the wing breaks down; it does not mean the engines have stopped.
Typical range	A reference distance the type can fly. This is not the radar’s detection range, the distance to the contact or fuel remaining.
Climb rate	How quickly height changes, usually in feet per minute. A listed climb rate is not the selected aircraft’s current climb.
Typical crew	People operating the aircraft and its equipment. This is different from PAX, which means passengers.
Powerplant	The engine or engines fitted to the aircraft.

Knots, feet and nautical miles

Knots measure speed: one knot is one nautical mile per hour. NM means nautical miles, a unit of distance; one NM is 1.852 kilometres. ft means feet. For example, at a steady 300 knots an aircraft covers 5 NM per minute. That is a speed-to-distance example, not a fuel or intercept prediction.

Why stall speed needs context

In real flight, a wing stalls when its angle to the oncoming airflow becomes too large. The aircraft’s weight, its turn and the position of its flaps (movable parts of the wings) can change the speed at which that happens. A single catalogue speed is therefore not a universal stall boundary. Where no stall-speed value is supplied, the directory says so; do not treat a missing figure as a measured speed of zero.

Range is not a fuel gauge

Suppose a catalogue lists a range of 1,000 NM. That does not mean your selected aircraft can still fly 1,000 NM from where it is now. It may already have used much of its fuel. Read the fuel-planning guide and plan the flight back to land, including any refuelling you need.

Match the exact version of the aircraft

F3, GR1 and GR4 name different Tornado versions. Nimrod R1 and MR2 have different jobs. Even aircraft in the same family can have different engines or equipment. Match the full name before using a specification; a broad family figure may not apply to the version you are studying.

Use the numbers in the game

Open Aircraft Data for the type reference, then read the selected flight. Use the fighter speed controls when you need to change a supported fighter’s speed mode. Changing a speed mode does not command the aircraft to match every figure in its catalogue entry.

Try a reference check without issuing an order

Select one contact. Write down its callsign, TYPE, present ALT and present SPD from Flight Info. Read its track serial from the scope data block.
Open Aircraft Data. Write down the type heading and whichever reference fields are available: cruise speed, maximum speed, service ceiling and range. Keep the field labels with the numbers.
Check whether the type heading matches Flight Info. If it does not, keep both names and follow the reporting steps; do not compare them as if they were the same type.
Return to Flight Info and confirm that you still have the same contact. Explain which numbers describe this flight now and which describe the type. No task or speed change is needed for this exercise.

Who produced the source?

CAA means Civil Aviation Authority; check the country in the source name. NZ CAA and UK CAA are different authorities. FAA means the United States Federal Aviation Administration. An authority’s report can help you check a design; it is not a live report about your selected contact.

Approval, first flight and delivery

Term in the source	What it tells you
Type certificate	Approval of the design against the applicable rules. A type certificate data sheet describes important design details and limits.
Type acceptance	A country’s recognition of a design approved elsewhere. Read which models and serial numbers it covers. A serial number is the manufacturer’s number identifying one individual aircraft.
First flight	When an example first flew. This is a different event from design approval.
Delivery	When an aircraft was handed over to its customer. This is not necessarily when that model was first approved.

What does Category B mean for a helicopter?

Category B does not assure continued flight after an engine failure; an unplanned landing is assumed. Two engines alone do not establish Category A capability. The S-76 report lists separate Category B and later Category A approvals. A date alone does not tell you the approved procedure for a particular flight.

Check the right entry

Keep the complete model name, including letters such as S-76A, S-76B or S-76C.
Open the source listed on that aircraft’s page. Check its date, model and which individual aircraft it covers.
Keep the labels attached to figures and dates. A newer report can describe older approvals; its publication date is not the aircraft’s first flight.
For your current game contact, return to Aircraft Data and Flight Info. A design document does not replace that flight’s displayed information.

Understand the engine entry

Powerplant names the engine or engines. Read how piston engines, turbojets, turbofans, turboprops and turboshafts differ before comparing types.

Sources & further reading

Further reading on the real-world concepts discussed here. These sources do not document Air Defender’s controls or behaviour.