Use the iFly 737 MAX 8 autopilot in MSFS 2024: set up the FMC and MCP, fly LNAV/VNAV and ILS, and fix modes that will not engage.
To use the iFly 737 MAX 8 autopilot in Microsoft Flight Simulator 2024, programme and execute the FMC route, set the MCP speed, heading and cleared altitude, switch on both flight directors, arm autothrottle, select LNAV/VNAV as required, then engage CMD A once the aircraft is stable above 400 ft AGL.
What must be set before engaging the iFly autopilot?
The iFly autopilot needs a valid aircraft state, an executed route, performance data and sensible MCP targets before it can manage the flight. If starting with the aircraft unpowered, complete our iFly cold-and-dark start sequence first.
- Align the navigation systems. Confirm the IRS alignment is complete and that the primary flight displays show valid attitude, heading and position data.
- Programme the CDU. Enter and execute the route, runway and departure, then inspect the LEGS pages for discontinuities or an incorrect first leg. A route displayed on the MSFS 2024 EFB is not proof that it has been loaded and executed in the iFly CDU.
- Complete the performance pages. Enter the required PERF INIT, thrust-limit and take-off data, including cruise altitude, weights and V-speeds. VNAV may be unavailable or behave incorrectly when these entries are missing.
- Set the MCP. Put V2 in the speed window, the runway or assigned heading in the heading window, and the first cleared altitude in the altitude window. Do not set the final cruise altitude unless the clearance permits it.
- Prepare the automation. Switch on both flight directors and set
A/T ARMto ARM. ArmLNAVandVNAVon the ground only when the programmed departure and operating procedure support them. - Trim the aircraft. Set the calculated take-off stabiliser trim and confirm that no control axis or autopilot-disconnect binding is producing a continuous input.
The mistake we see most often is treating the autopilot as a flight planner. It can follow only the route, performance data and limits already supplied to it.
How do I engage the autopilot after take-off?
Engage CMD only after the aircraft is airborne, correctly trimmed and following sensible flight-director commands.
- Use TO/GA for take-off. Verify take-off thrust and TO/GA guidance on the flight-mode annunciator, or FMA, at the top of the primary flight display.
- Fly the initial climb manually. Raise the landing gear and follow the flight director. If LNAV was not armed, select
HDG SELor LNAV at the appropriate height. - Confirm the vertical mode. VNAV can manage the climb when the FMC is complete; otherwise select
LVL CHGafter reaching the appropriate acceleration height and set the required speed. - Engage CMD A. At or above 400 ft AGL, unless the departure requires a later engagement, release any pressure on the controls and press
CMD A. Keep flying until the command status is confirmed. - Read the FMA. Check that the intended autothrottle, roll and pitch modes are active. Retract the flaps on schedule while monitoring speed and thrust.
An illuminated MCP button may mean that a mode is merely armed. The FMA tells you which mode is actually controlling the aircraft: active modes are normally shown in green and armed modes in white. Our Boeing 737 MCP and flight-mode guide explains these annunciations in more detail.
Which iFly 737 MCP mode should I use?
Choose the MCP mode according to the immediate task rather than leaving VNAV and LNAV selected for every situation.
| Mode | What it controls | Use it when |
|---|---|---|
LNAV | Tracks the active FMC leg | The route is executed and the aircraft can intercept the programmed path |
HDG SEL | Turns to the MCP heading | Flying vectors or positioning to intercept an LNAV or localiser course |
VNAV | Uses FMC speeds, altitude constraints and the vertical profile | Following a fully programmed climb, cruise or descent |
LVL CHG | Uses pitch to hold the selected speed during a climb or descent | Making a direct altitude change without following the complete VNAV profile |
V/S | Commands a selected vertical speed | Making a controlled adjustment while closely monitoring airspeed |
ALT HOLD | Maintains the captured altitude | Stopping a climb or descent and remaining level |
APP | Arms localiser and glideslope capture | Established to intercept a correctly tuned ILS |
V/S needs particular care because an excessive rate can drive the aircraft towards an underspeed or overspeed. LVL CHG is usually the better choice when airspeed control matters more than a precise rate.
How do I make VNAV climb and descend?
VNAV follows the FMC profile only within the altitude permitted by the MCP window.
- For a climb: set the cleared higher altitude on the MCP and engage VNAV. It should observe programmed restrictions and use the FMC climb speed. Select
LVL CHGif a more direct climb is required. - At cruise: check that the FMC cruise altitude and MCP altitude agree. Turning the altitude knob alone does not command a climb or descent; an active vertical mode must do that.
- For descent: once cleared, set a lower MCP altitude before the top of descent and leave VNAV active. At the calculated point, the FMA should change into the appropriate VNAV descent mode.
- For temporary speed control: use
SPD INTVwhen appropriate. A blank MCP speed window in VNAV is normal because the FMC is then commanding speed.
If VNAV reaches a restriction and levels off, inspect the active LEGS and DES pages before overriding it. Altitude Intervention can remove or step through constraints, so it should not be pressed without confirming the clearance and the next restriction.
How do I use the autopilot for an ILS approach?
An ILS approach requires correct tuning, a suitable intercept and positive FMA confirmation; loading an arrival by itself is not enough.
- Prepare the arrival. Load and execute the arrival and ILS approach, enter the landing reference data, set minimums and brief the missed approach.
- Verify the ILS. Check the frequency and identifier, and set the inbound course. Set both course selectors if a dual-channel autoland is planned.
- Intercept correctly. Use LNAV or
HDG SELto approach the localiser at a modest angle while below the glideslope. - Select APP. Confirm that localiser and glideslope modes arm, then verify each capture on the FMA. If the aircraft is above the glideslope, APP will not make it dive down to recover it.
- Choose manual landing or autoland. One CMD channel can fly a coupled ILS for a manual landing. For autoland, engage the second autopilot at the correct stage and verify valid dual-channel, FLARE and ROLLOUT indications.
Dual-channel landing has additional requirements, so use the full 737 autoland sequence rather than assuming that pressing both CMD buttons guarantees an automatic landing.
Why will the iFly 737 MAX autopilot not engage?
Most engagement failures come from an incomplete aircraft setup, an invalid FMC route or conflicting MSFS control assignments.
| Symptom | Likely cause and fix |
|---|---|
| CMD will not engage | Confirm the aircraft is above the minimum engagement height, the MCP autopilot disengage bar is up, IRS data is valid and no disconnect command is being held. Release control pressure and stabilise the trim before trying again. |
| CMD disconnects immediately | Look for duplicate yoke axes, a noisy controller, a latched autopilot-disconnect binding, active AI assistance or a simulated system failure. Add a small dead zone where necessary. |
| LNAV will not arm or capture | Execute the route, remove discontinuities and confirm an active leg. If the aircraft is not on a suitable intercept, use HDG SEL to intercept the course or activate the correct direct-to leg. |
| VNAV is unavailable | Complete the FMC performance and take-off pages, check the cruise altitude and execute all pending changes. Verify that the MCP altitude permits the requested climb or descent. |
| Aircraft will not descend at top of descent | Set a lower cleared altitude on the MCP and confirm VNAV remains active. Also check for an unexpected route discontinuity or altitude constraint. |
| Autothrottle does not hold speed | Check the A/T ARM switch and read the autothrottle FMA. THR HLD during take-off is expected and does not provide normal speed control. Hardware throttle movement can also override or disturb commanded thrust. |
| APP does not capture | Recheck the ILS frequency, identifier and course. Intercept the localiser first from a sensible angle and remain below the glideslope. |
During fault-finding, operate the virtual MCP rather than a generic MSFS autopilot panel or keyboard shortcut. Complex aircraft use custom systems, and stock commands or duplicate bindings can toggle the wrong function.
How should I disconnect the autopilot?
Use the control-wheel autopilot-disengage switch or its correctly assigned hardware command rather than pressing random MCP modes. The first press disconnects CMD; a second press silences the warning. Autothrottle is separate, so disconnect it independently when the landing procedure requires it and match the physical throttle position to prevent a sudden thrust jump.
Whenever the aircraft does something unexpected, check the FMA before changing another control. It will usually show that the aeroplane is following a different active mode from the one the pilot assumed was engaged.