How do I plan and fly a jet descent for landing?

To plan and fly a jet descent for landing in Aviation & Real-World Flying, work backwards from the altitude and speed required at the approach fix. Use about 3 NM per 1,000 ft as a first estimate, then adjust for wind, restrictions, deceleration and track miles while monitoring energy and stabilised-approach criteria.

What information do you need before starting the descent?

Before descending, confirm where the aeroplane must be, how high it must be and how fast it may fly at each important point on the arrival.

• The expected or assigned runway, STAR, transition and approach
• The first firm altitude and speed constraint on that route
• Present flight level and the altitude cleared by ATC
• Track miles remaining, including likely vectors or shortcuts
• Terrain, minimum safe altitudes and runway elevation
• Descent winds, icing conditions and expected anti-ice use
• The distance needed to slow, extend flaps and lower the landing gear

Read each charted constraint carefully. An altitude may be mandatory, at or above, at or below, or inside a window; treating those as interchangeable can make an otherwise accurate descent plan unusable.

Check the flight-management system after any runway, arrival or approach change. Common simulator errors include an unresolved route discontinuity, a deleted constraint, the wrong approach transition and a direct-to instruction that removes more track miles than expected.

For real-world flying, approved aircraft procedures, charts and ATC clearances override every rule of thumb here. A calculated top of descent is not permission to leave the cleared altitude.

How do you calculate a jet's top of descent?

A normal three-degree descent needs approximately 3 NM for every 1,000 ft of altitude to lose.

Descent distance in NM = altitude to lose in thousands of feet × 3

Calculate altitude to lose against the required crossing altitude, not automatically against runway elevation. If an approach must be joined at 3,000 ft, that is normally the useful target for the en-route calculation.

The answer is a geometric starting point. Add track distance for level segments, speed restrictions and configuration, and use the actual route rather than straight-line distance to the airport. Our more detailed explanation of top-of-descent timing and the corrections that alter it covers these allowances.

Wind does not change the mileage of a fixed three-degree geometric path, but it changes the vertical speed required to remain on that path. It can also move an FMS-calculated idle-descent point because the aircraft's energy and deceleration predictions depend on forecast winds.

Example: descent from FL350 for a JFK landing

A hypothetical descent from FL350 to cross a JFK approach fix at 3,000 ft involves losing 32,000 ft, which gives a basic distance of 96 NM before that fix.

(35,000 − 3,000) ÷ 1,000 × 3 = 96 NM

If the fix were 10 NM from the runway threshold, the geometric top of descent would be about 106 NM from the threshold. This is an arithmetic example, not a JFK STAR or clearance: the selected runway, published restrictions, vectors and ATC shortcuts determine the usable profile.

FL350 means flight level 350, treated as 35,000 ft for this mental calculation. An Airbus A350 is the aircraft type; in an A350 simulation, the same three-to-one check remains useful, but its managed descent, drag prediction and mode logic should be flown according to that aircraft's documentation.

What vertical speed gives a three-degree descent?

A three-degree path requires roughly five times groundspeed in feet per minute; multiplying by 5.3 gives a closer result.

Vertical speed in ft/min ≈ groundspeed in knots × 5 to 5.3

• 300 kt groundspeed: about 1,500–1,600 ft/min
• 240 kt groundspeed: about 1,200–1,270 ft/min
• 180 kt groundspeed: about 900–950 ft/min
• 140 kt groundspeed: about 700–740 ft/min

Use groundspeed, not indicated airspeed. A fixed vertical-speed selection will drift away from the intended angle as groundspeed changes; our guide to maintaining a three-degree path in the simulator explains the live cross-checks.

Which autopilot descent mode should you use?

Choose the descent mode according to whether the immediate priority is the programmed vertical path, a selected speed, an ATC-assigned altitude or a small path correction.

Mode names and behaviour differ between Boeing, Airbus and other flight decks, and add-ons do not all model them to the same depth. After every selection, read the flight-mode annunciator. Pressing a button or turning an altitude selector does not prove the expected mode engaged.

How do you fly the descent correctly?

Fly the descent by controlling vertical path and speed together, checking each restriction instead of waiting until the final approach to discover an energy problem.

1. Brief the arrival. Confirm the route, runway, approach, minimums, missed approach, transition altitude or level and likely landing configuration.
2. Validate the FMS. Check waypoints, discontinuities, altitude and speed constraints, forecast winds and the destination pressure data available to the aircraft.
3. Calculate a mental top of descent. Compare the three-to-one estimate with the FMS prediction. Investigate a large difference rather than automatically trusting either one.
4. Set only the cleared altitude. In real-world operations, remain at the assigned level until authorised to descend. Terrain and published minimum altitudes still apply during shortcuts and vectors.
5. Select and verify the mode. Confirm the active pitch, thrust and autothrottle modes on the annunciator, then check that speed and vertical path respond as expected.
6. Recheck after every change. A new runway, direct-to clearance or vector changes the miles available. Recalculate altitude remaining against track miles remaining.
7. Manage energy early. Use thrust and approved drag devices before the aeroplane becomes both high and fast. Observe every flap, gear and speed-brake limitation.
8. Set the altimeter at the correct point. Change between standard pressure and the local pressure setting at the published transition altitude or transition level, which varies by location.
9. Arrive ready for the approach. Reach the intercept area at a legal altitude and a speed from which normal configuration is possible. For an instrument arrival, follow the correct process for setting up and capturing the ILS from the descent.

When should a jet slow down and configure for landing?

A jet should begin slowing early enough to reach approach speed and landing configuration without steep manoeuvring, excessive drag or rushed checklist work near the runway.

There is no universal flap schedule. Weight, wind, icing procedures, flap and gear limits, traffic spacing and aircraft type all affect the sequence. Use the simulated aircraft's operating guidance rather than copying speeds from a different jet with a similar cockpit.

Published or regulatory speed limits must be planned before reaching the altitude where they apply. Do not treat 250 kt below 10,000 ft as a worldwide rule without checking the applicable airspace and ATC instruction.

Jets generally do not lose a large amount of altitude and speed efficiently at the same time. A steep idle descent converts height into speed; speed brakes may increase the available descent rate without producing the deceleration expected. A shallower or level segment is often more effective when speed, rather than height, is the main problem.

How do you recover from a high descent or high approach?

A high descent or high approach should be corrected early with permitted drag, a modest path adjustment or extra track miles; if those cannot produce a normal intercept and stabilised approach, discontinue the attempt.

A quick way to judge the problem is to divide altitude remaining by track miles remaining. A three-degree path is about 318 ft per NM. Losing 6,000 ft in 10 NM would require about 600 ft per NM, close to a 5.7-degree path before any allowance for slowing.

• Slightly high with plenty of distance: increase the descent angle modestly or use approved speed-brake deployment while monitoring speed and configuration restrictions.
• Fast but on the correct path: reduce thrust and begin slowing earlier. If clearance permits, a shallower or level segment may shed speed more effectively.
• High and fast: request vectors, extended routing or a hold where ATC is in use. Landing gear can add substantial drag, but only within its extension limit and the aircraft's procedures.
• Above an ILS glideslope: do not dive to force capture from above unless the aircraft and operating procedure explicitly permit that technique. Standard interception is from below; reposition or go around when a normal intercept is no longer available.
• Below the planned path: reduce the descent rate or level temporarily and add thrust. Remaining at idle while becoming lower and slower compounds the error.

A mistake we see constantly in simulators is selecting a very high vertical speed to recover the profile, then trying to remove the resulting excess speed in the last few miles. Monitor the trend, not just the instantaneous altitude error.

Is a high descent rate acceptable near landing?

A high descent rate is acceptable only when it matches the required path and remains within the aircraft's stabilised-approach criteria.

At high groundspeed, 1,500 or 2,000 ft/min can be normal during the en-route descent. Near landing, the same rate may indicate a steep or unstable approach. Many procedures treat more than about 1,000 ft/min near the stabilisation gate as requiring specific justification or a go-around, but the aircraft or operator criterion controls.

If the rate is unexpectedly high, check the active autopilot mode, target speed, thrust state, speed-brake position and altitude selection. Do not correct by pulling abruptly or adding large thrust changes close to the ground.

What should be true by 1,000 ft before landing?

By the applicable stabilisation gate—commonly around 1,000 ft above the landing elevation, though procedures differ—the jet should be on path, configured, near target speed and descending at a controlled rate with only small corrections required.

• The correct runway and lateral path are confirmed.
• The aeroplane is on the intended vertical path.
• Landing flaps and gear are set as required.
• Airspeed is within the permitted tolerance around target speed.
• Thrust is appropriate rather than being held at idle during a rushed recovery.
• The descent rate is acceptable for the approach.
• Required checklists are complete.

The exact gate and tolerances come from the applicable operating procedure, not from a universal simulator rule. If the approach cannot meet them without large corrections, go around and set up again. Once the descent is stable, our landing guidance covers the final approach, flare, touchdown and braking.