X-Plane HUD Simulator Turns Pilots into HUD Heroes

 - December 2, 2012, 2:45 AM
Using the FlyRealHUDs X-Plane plug-in, the author shot the ILS 25R into LAX at night in the Boeing 777. The acceleration tape and cue (caret) show the jet accelerating and too fast, so the power needs to be reduced. The flight director cue is slightly to the left of the flight-path vector, indicating the need for a slight correction to the left.

There is a new way to learn how to fly with a head-up display (HUD) without booking time in an expensive simulator or trying to learn in the airplane. FlyRealHUDs.com has developed an inexpensive HUD simulator plug-in that runs on the X-Plane personal-computer flight simulator program. The FlyRealHUDs (FRH) plug-in replicates the symbology and flight dynamics of real HUDs and comes in two configurations, for business jets and airliners. (Full disclosure: I was a beta tester of the FRH HUD before its release in late October.)

The FRH HUD can be flown with any X-Plane airplane. I have tested it with a variety of airplanes but found that the X-Plane Boeing 777 works well. This is mostly because the flight deck is fairly simple and most of the avionics and controls that need to be set are readily available without having to move the panel sideways (which requires switching to 3-D mode in X-Plane). I have also tested the FRH HUD with a Gulfstream G650 ($18 from X-Hangar.com), and that works well, too.

The FRH HUD simulator runs in the PC and Macintosh versions of X-Plane Version 9 or 10. X-Plane costs $69.99, and the FRH HUD costs $59.95, either in bizjet or airliner configurations. A simple way to run the FRH HUD is to use the Location menu to place the airplane on a 10-nm final to a runway with an ILS approach, then hit the pause button (“P” on the keyboard). On the 777, I set the IAS to 150 knots, the number-one nav to the ILS frequency, heading and OBS to the correct inbound course, click LOC and G/S on the flight director panel, put the gear down, select full flaps and turn the strobe lights off (for night operations). A quirk in X-Plane requires an additional step, clicking on the Local Map in the Location menu then changing the altitude to what is correct for that approach (usually around 3,500 feet at 10 nm). Otherwise you’ll have to fly level for a bit until you intercept the glideslope because X-Plane starts the flight at a lower altitude.

The last step is to set the flight director control to flight director for a hand-flown approach or autopilot if you want to observe how the HUD works. You can even click the autothrottle button on the panel so there is no need to control the power during an autopilot approach, and the sim will maintain the selected IAS (150 knots). Then unpause and watch the fun. To fly, keep the donut (flight director guidance cue) inside the hole (the flight-path vector).

As Close as It Gets to a Real HUD

The FRH HUD is no simple toy but is a real HUD trainer. I’ve flown a test rig at Rockwell Collins’s Head-up Guidance System HUD division and a Rockwell Collins HUD in a Challenger 604 and Global 6000, plus a G550 full-motion simulator HUD, and the FRH HUD is as close as it gets to a real HUD. The FRH HUD accurately replicates the flight path vector, flight director cue, acceleration tape and cue, angle-of-attack, EVS mode, glideslope and localizer indicators, rollout guidance, runway remaining and so on.

The airspeed control and display of the acceleration tape and cue is incredibly precise as you fly an ILS with the FRH HUD. Even with a relatively unsophisticated simulator joystick, tiny movements of the throttle control are replicated accurately on the FRH HUD, with the acceleration cue and tape moving exactly as they would on a real HUD.

X-Plane works best on computers with lots of processing power and high-end graphics, and you might notice some instability in the FRH HUD when flying X-Plane with too high a level of terrain detail selected. The solution is to select medium or lower resolution terrain detail. There is a way to check the frame rate in X-Plane, and I’ve found that the FRH HUD is stable above rates of 30. You can select any type of weather in X-Plane, and it’s fun to try to hand-fly the FRH HUD to Cat II or III minimums. The weather doesn’t seem to slow down the frame rate as much as high-resolution terrain.

I tested the FRH bizjet HUD with a 40-knot direct crosswind to see how it works. When the crosswind is so strong that the HUD field of view doesn’t allow the flight path vector to point accurately at the runway, the vector changes to “ghost” mode (shown in dashes). Running on autopilot, I could see how the HUD works and experiment with the caged mode, which is useful in crosswinds because it moves the flight-path vector to the center while retaining display of vertical motion. In a high crosswind, of course, you would have to monitor the localizer to stay on course, and this is shown on the FRH HUD.

The FlyRealHUDs.com HUD is a useful tool and should be helpful for pilots who are learning about HUD for the first time and want to get the most out of their full-motion simulator training time. Flight departments with HUD-equipped airplanes might also find the FRH HUD helpful to practice approaches into unfamiliar airports, or to game plan unusual conditions such as high crosswinds, weather at minimums or just to maintain HUD proficiency.