Learn how to use TCAS in PMDG aircraft: select TA/RA, show traffic on the ND, understand alerts and fix missing targets.
To use TCAS in a PMDG airliner, enter the assigned transponder code, select TA/RA on the ATC/TCAS panel before take-off, then press TFC on the EFIS control panel to place traffic on the navigation display. Keep altitude reporting enabled, monitor traffic advisories and follow resolution advisories.
The principle is broadly the same across PMDG Boeing aircraft in Microsoft Flight Simulator, FSX and Prepar3D, although panel labels and equipment options vary between the 737, 747 and 777 families.
How do I turn on TCAS in a PMDG aircraft?
In most PMDG Boeing airliners, TCAS requires an operating transponder, altitude reporting and the navigation display's traffic overlay.
- Power and initialise the aircraft. The navigation displays and ATC/TCAS panel must be powered. Complete the normal cockpit preparation far enough for the ND to show the aircraft's position and route.
- Enter the transponder code. Use the code assigned by ATC, or an appropriate code for an offline flight. If the aircraft provides ATC 1 and ATC 2 source selection, use the source specified by its checklist.
- Enable altitude reporting. Do not leave the selector in STBY or ALT RPTG OFF. Other aircraft need your pressure-altitude data for coordinated resolution advisories.
- Select TA/RA. This arms both traffic advisories and resolution advisories. TA ONLY displays traffic warnings but will not command an avoidance manoeuvre.
- Press TFC. The TFC button is normally on the EFIS control panel. It places TCAS targets on the navigation display; switching the transponder to TA/RA alone does not necessarily make them visible.
- Choose a useful ND range. Start with a shorter range so nearby targets are easy to see. Use NORM, ABOVE or BELOW filtering as required, remembering that a restrictive altitude filter can hide legitimate traffic.
- Return the system to the required ground mode. After landing, follow the model's checklist for selecting STBY or another operator-specific setting.
For the PMDG 737, our step-by-step Boeing 737 TCAS control walkthrough covers the pedestal selector and EFIS TFC control in more detail.
Which TCAS mode should I use?
TA/RA is the normal airborne selection, while the other modes are intended for ground operation, abnormal procedures or situations where resolution advisories are not wanted.
| Mode | What it does | Typical use |
|---|---|---|
| STBY | Transponder and TCAS surveillance are inactive. | Parking or shutdown, according to the checklist. |
| XPNDR | The transponder operates, but TCAS advisories are not armed. | Ground or operator-specific procedures. |
| TA ONLY | Shows traffic and issues traffic advisories, but no resolution advisories. | When required by an abnormal procedure or operating restriction. |
| TA/RA | Provides traffic advisories and vertical resolution advisories. | Normal flight when airborne. |
A common mistake is pressing TFC and assuming TCAS is fully armed. TFC controls the display overlay; the pedestal selector controls whether the system can issue TA or RA alerts.
What do PMDG TCAS symbols and alerts mean?
A traffic advisory identifies a potential threat, while a resolution advisory commands a vertical response to avoid it.
- White diamond: other or proximate traffic that is not an immediate threat.
- Amber circle: a traffic advisory, usually accompanied by the callout “Traffic, traffic”. Visually acquire the aircraft and prepare for a possible RA, but do not make an abrupt evasive manoeuvre based only on the TA.
- Red square: a resolution advisory. Follow the aural command and move the vertical-speed indication out of the prohibited red region and into the commanded safe region.
- Relative-altitude number: the target's altitude in hundreds of feet above or below your aircraft. A trend arrow indicates that it is climbing or descending rapidly.
Our explanation of TA and RA alert logic covers the correct response sequence. For the surrounding display indications, see our guide to Boeing PFD and navigation-display symbology.
Do not assume the autopilot will fly an RA. PMDG implementations and aircraft procedures differ, so use the manual supplied with that model and be ready to disconnect the autopilot and hand-fly the commanded vertical response. TCAS also suppresses some advisories close to the ground; a lack of an RA during take-off or landing can therefore be normal.
Why is PMDG TCAS not showing traffic?
A blank TCAS display usually means traffic is not being injected into the simulator, TFC is off, or the transponder is in the wrong mode.
- No active simulator traffic: TCAS does not generate aircraft. Enable AI traffic or use a traffic source that injects aircraft with position, altitude and transponder data. Static scenery aircraft cannot appear because they are not live simulator objects.
- TFC overlay switched off: press TFC and try a shorter ND range. The weather-radar display is separate and cannot substitute for TCAS traffic.
- Wrong selector mode: verify TA/RA or TA ONLY rather than STBY, XPNDR or ALT RPTG OFF.
- Altitude filter hiding targets: return the traffic filter to its normal setting while troubleshooting.
- Ground and low-altitude inhibition: some targets and advisories are deliberately suppressed near the ground. Test again after departure with airborne traffic nearby.
- Unsupported control binding: PMDG systems often use custom cockpit events. Operate the virtual selector and TFC button with the mouse first; if that works, the problem is the hardware or keyboard assignment rather than TCAS.
- Configuration or installation issue: confirm that the selected aircraft option actually includes TCAS and that the PMDG product is fully updated through the supported update method for that edition.
If the model provides a TCAS test position, run the self-test. A successful test confirms the aircraft's display and alert logic, but it does not prove that the simulator is supplying detectable traffic.
Does every PMDG aircraft have TCAS?
No; TCAS availability depends on the real aircraft type, the PMDG product and its selected equipment configuration.
Modern PMDG Boeing airliners generally model TCAS, but vintage aircraft and certain customer configurations may not. Check the aircraft's supplied manual or equipment options rather than expecting a generic simulator TCAS command to add a system that the cockpit does not contain.