How do I descend and set up a Boeing 737 approach?

In a Boeing 737 in a general flight simulator, plan descent at roughly 3 NM per 1,000 ft to lose, plus distance for slowing and wind. Verify the FMC arrival, manage speed and configuration in stages, intercept an ILS glideslope from below, and be stabilised by 1,000 ft in IMC or 500 ft in VMC.

This guidance applies across general flight simulators, from default 737s to study-level add-ons. Exact FMC prompts, autothrottle behaviour, speed bugs and autopilot capabilities vary, so use your aircraft’s checklist and flight-mode annunciations as the final authority.

When should you start descending in a 737?

Start down about 3 NM for every 1,000 ft of altitude you must lose, measured to the first important altitude restriction rather than automatically to the runway.

Subtract the target altitude from your present altitude, divide the result by 1,000 and multiply by three. From 35,000 ft to a 3,000 ft platform altitude, for example, the difference is 32,000 ft, giving a basic top of descent about 96 NM before that point.

• Add deceleration distance. Allow roughly 10–15 NM as a starting margin for slowing from 250 kt towards approach speed and configuring. Do not add it twice if the FMC path already includes deceleration.
• Allow for wind. A strong tailwind increases the track miles covered during descent, so begin earlier. A headwind usually reduces the distance required.
• Use track miles. FMC distance along the programmed route is more useful than straight-line distance to the airport, especially on a curved STAR.
• Plan to each restriction. A speed-and-altitude constraint may require an earlier descent than the final approach itself.

An FMC top-of-descent marker is a useful prompt, not a guarantee. Wrong winds, an unexecuted route change, a shortcut, a discontinuity or an incorrect arrival can make the calculated path unusable. We always cross-check it with the 3:1 rule.

What should be set before top of descent?

Before top of descent, verify the arrival, approach, route constraints, landing data, navigation aids and the altitude the MCP will permit you to descend to.

1. Brief the arrival and approach. Confirm the runway, STAR and transition, final approach course, platform altitude, minima, missed approach and likely landing flap. Loading the correct runway with the wrong transition is a common cause of unexpected turns.
2. Check every FMC leg. Review waypoint order, altitude and speed constraints, route discontinuities and the connection between the STAR and approach. Do not clear a discontinuity until you know which legs should be joined. Our 737 FMC programming sequence explains the wider setup.
3. Set descent data. Enter forecast winds and transition-level data if your add-on models them. Set local QNH when passing the applicable transition level rather than leaving the altimeter on standard pressure.
4. Prepare the navigation aids. For an ILS, verify the frequency, identifier and inbound front course. Auto-tuning does not remove the need to check them. If the course selectors are unclear, see our explanation of how COURSE selection affects 737 guidance.
5. Set an appropriate MCP altitude. VNAV normally cannot descend below the selected MCP altitude. Select the cleared altitude or, without simulated ATC, an altitude compatible with the next restriction. Brief the missed-approach altitude now, but on a normal ILS it is usually placed in the MCP window after glideslope capture; add-on checklists may specify different timing.
6. Calculate landing data. Set the correct VREF and wind additive, landing flap, minima and autobrake. Arm the speedbrake at the point required by the modelled checklist.

Should you descend using VNAV, LVL CHG or V/S?

Use VNAV for a verified FMC path, LVL CHG for a simple speed-controlled descent, and V/S only when you can monitor both speed and path closely.

On radar vectors, heading select with LVL CHG or a modest vertical speed is often more predictable than forcing VNAV to rebuild the path. Watch the flight-mode annunciator: the mode shown as active there matters more than the button you pressed.

If VNAV does not descend at top of descent, first check that the MCP altitude is lower, the route modification has been executed and no constraint is holding the aircraft level. Use altitude intervention only if your model supports it and you understand which restriction it will remove.

How should you manage speed, flaps and landing gear?

Reduce speed before final approach and configure progressively, because a 737 is difficult to slow while also descending steeply.

1. Cross 10,000 ft at 250 kt or less unless local restrictions or ATC instructions specify otherwise. Complete most of the approach preparation before this point.
2. Begin slowing before base or final intercept. Follow the FMC manoeuvring-speed bugs and flap placard limits. Flap 1 near the appropriate manoeuvring speed and flap 5 around 180–200 kt form a workable sequence in many 737 simulations, but they are not universal limits.
3. Prepare for glidepath capture. On an ILS, a common flow is gear down and flap 15 as the glideslope becomes active, followed by landing flap around capture. On an RNAV or visual approach, use an equivalent distance or descent-path cue.
4. Reach target speed early. On final, fly the calculated VREF plus the applicable additive. Avoid large thrust, pitch or configuration changes near the stabilised-approach gate.

Flap 30 is the routine landing choice in many 737 procedures. Flap 40 provides more drag and generally a lower reference speed, but it also changes the thrust and pitch picture; select it because landing performance or the procedure calls for it, not by habit.

If energy is building, use speedbrake while clean or lightly configured and use the landing gear for predictable drag when within its speed limit. Stow the speedbrake before final landing configuration unless the aircraft’s documented procedure says otherwise. Dumping flap late is not a safe substitute for energy planning.

How do you set up and capture a 737 ILS approach?

Set the correct ILS frequency and front course, intercept the localiser at a shallow angle, and approach the glideslope from below at the published platform altitude.

1. Verify the signal. Tune or confirm the ILS frequency, identify it if the simulator models the identifier, and set the published inbound course. Models supporting dual-channel approaches may require both course selectors to agree.
2. Select the correct navigation source. Older or simpler panels may continue following GPS guidance until switched to NAV. The panel-specific process is covered in our FSX ILS tuning and capture walkthrough.
3. Intercept the localiser sensibly. Use a heading that gives roughly a 20–30° intercept rather than flying across the beam at a large angle. Be level or only gently descending at the charted intercept altitude.
4. Stay below the glideslope. Arm APP when valid localiser and glideslope signals are present and capture is plausible. Do not descend through the platform altitude to chase a glideslope from above.
5. Read the annunciations. Confirm localiser capture followed by glideslope capture on the flight-mode annunciator. After glideslope capture, set the missed-approach altitude at the normal checklist point.

Pressing APP does not by itself provide autoland. Dual-autopilot engagement, radio-altimeter logic, flare and rollout modelling differ substantially between add-ons. Unless you are deliberately practising an autoland in a model that supports it, treat the approach as a normal ILS and be ready to disconnect for landing.

What if the glideslope will not capture?

A missed glideslope capture is usually caused by intercepting from above, using the wrong frequency or source, arming APP too late, or approaching too fast for a controlled capture.

Level off and re-establish below the beam if there is enough room; otherwise extend the approach or go around. Our guide to diagnosing ILS glideslope capture failures covers the checks in order.

What changes for an RNAV approach?

For an RNAV approach, verify the FMC waypoint sequence and vertical constraints, then use only the guidance modes supported by that aircraft and procedure.

Many advanced 737 add-ons use LNAV and VNAV, while some model Integrated Approach Navigation with FAC and G/P modes armed through APP. Simpler aircraft may provide lateral guidance but require manual vertical-speed control. Do not expect an ILS G/S indication where no ILS exists, and do not arm APP merely because the aircraft is turning onto final.

What descent rate should you use on final?

For a normal 3° final approach, multiply groundspeed by five to obtain a useful starting vertical speed in feet per minute.

• 140 kt groundspeed: about 700 fpm
• 150 kt groundspeed: about 750 fpm
• 160 kt groundspeed: about 800 fpm
• 180 kt groundspeed: about 900 fpm

Use groundspeed, not indicated airspeed. A tailwind requires a higher descent rate to remain on the same path, while a headwind requires less. Follow the actual glidepath indication rather than holding the calculated rate regardless of deviation.

How do you recover from a high-and-fast approach?

Correct a high-and-fast approach before final intercept by reducing speed, adding drag or creating more track miles; do not attempt to rescue it with a steep dive near the runway.

If you reach the final approach fix still high, fast or incompletely configured, the disciplined choice is usually a go-around. Gear and speedbrake are useful drag devices within their limits, but neither makes an unstable final acceptable.

What counts as a stable Boeing 737 approach?

A stable 737 approach is on the correct lateral and vertical path, at target speed, in landing configuration and requiring only small corrections by the chosen gate height.

• The aircraft is tracking the correct final course and descent path.
• Speed is at VREF plus the calculated additive, within the tolerance used by your procedure.
• Landing gear and selected landing flap are set.
• Thrust is appropriate and the sink rate is consistent with the approach; any unusually high rate has been briefed.
• The landing checklist and approach briefing are complete.

A widely used simulator benchmark is stable by 1,000 ft above aerodrome level in instrument conditions or 500 ft in visual conditions. Some operators use a stricter gate, so follow that standard when recreating their procedures. Stability also does not replace landing minima: go around at DA, DH or the missed-approach point if the required visual reference is absent.

When a go-around is required, select the modelled TO/GA command, follow the flight-director pitch guidance, confirm a positive climb, retract the gear and clean up on the published schedule while following the missed approach. An early go-around is far easier to manage than a landing attempted from a bad setup.