Unexpected route deviation

Maintain control

Keep the aircraft clear of terrain and on a known path. Use a suitable selected heading if necessary and permitted in the simulation.

Initial FMA and targets

Before correcting several things, note the lateral FMA, navigation source, active waypoint and selected heading.

Inspect the active plan

Open FPL and check the active leg, discontinuities and any pending MOD plan. A displayed modification may not yet be active.

Compare the map

Check the leg geometry and aircraft position against the chart and clearance. An active route can still be the wrong route.

Navigation source

Check whether the intended FMS source is selected and whether LNAV is armed or active. HDG and TRACK will not automatically follow the route. FSS says armed LNAV engages when climbing through 200 ft; above 200 ft, pressing NAV engages it. Confirm the FMA and aircraft response.

Correct the cause

If a route edit is needed, review and activate the MOD. If a mode change is needed, select it and verify the new FMA.

Confirm the response

Watch the actual turn and ground track. If the aircraft still behaves unexpectedly, preserve the recorded build, mode and route details for further analysis. ^[37]

A support exchange on 7 November described LNAV and VNAV failing to arm on a later leg while LOC1 was selected. The reply advised selecting FMS1 for route guidance. This matches the FSS guidance on LNAV source selection, but it is one diagnosis, not a confirmed product defect. If route guidance will not arm, check FMS1 and the FMA before changing the route. Community exchange, 7 November 2026 ^[186].

Do not diagnose a bank-limit problem from the BANK indication alone. FSS’s 0.10.48 note says BANK/half-bank apply during LNAV cruise, but it does not define the 1.1.0 limit. An 8 November support report says the BANK indication stayed on with LNAV active; its PFD image shows LNAV but not the selector position or aircraft build. The thread has no reply, so it does not establish a 1.1.0 fault. Separately, a 9 November user reported 25° turns where 30° was expected; FSS requested two WASM logs, but no diagnosis was posted. Service Update 1 lists a general fix for autopilot pitch and roll oscillation, but does not say that it addressed either report or the 25°/30° limit. Check the selected limit and actual bank angle. If the mismatch recurs, record the build, route, FMA and selector, and include the requested logs in a support report. FSS #news, version 0.10.48, 10 September 2026 ^[89] · Community-support report, 8 November 2026 ^[187] · FSS #general-talk, 9 November 2026 ^[122] · Service Update 1 changelog ^[2].

A 9 November community-support post reports an occasional abrupt bank when AP is engaged, including with HDG selected and the heading bug matched to the current heading. The post says “Version 1” but gives no exact build; no reply or diagnosis was visible. Treat it as an unconfirmed report, not a known defect. If it happens, take control of the flight path and note the FMA immediately before and after AP engagement, the active lateral mode, heading and bank, aircraft variant, build and control bindings. FSS says ROLL holds the existing bank when the bank is above 6° and below 35°. The post gives no FMA snapshots, so it does not establish whether HDG was active when the bank began; that distinction is worth recording, not a diagnosis. Community-support report, 9 November 2026 ^[188] · FSS lateral modes ^[37].