Okay, okay. One more time. The head-up display, the HUD, does not cause spatial disorientation. The HUD is a better way to fly instruments.
Of course, this presupposes that you know how to fly basic instruments in the first place. In previous articles for Code One, I have tippy-toed all around this subject. I have said, with quiet understatement, that you have not been trained to fly in the weather. I did not elaborate. The time has come, however, to stand up and speak the unspeakable: emperator est nekidus jaybirdus. For you ag majors, that would read the emperor has no clothes. (I hope there are no classic Latin instructors on the magazine distribution list.) Even if your Latin is as shaky as mine, you can probably deduce that we're on to something that nowadays is seldom, if ever, hauled out in the open for serious discussion. So take a deep breath. Here it is.
Until you put real people in real airplanes and fly them in real weather with the luxury of an IP growling, "Not so fast, dummy," you are not going to train people who have a real capability to fly in weather.
Until new pilots have been shown how to budget and/or ration their time, depending on the task at hand, spatial disorinetation incidents probably will continue to plague us. This assertion is entirely consistent with Capt. Milt Miller's reasoning in his great dissertation on low-level flying. The logic of an awareness of time to ground impact for a particular altitude and task should be processed in the same manner in regard to SDO (and perhaps ground impact as well) when you are flying without benefit of a visible horizon. From the insights of a conscientious and caring instructor (plus a lot of self-inspection on your own) you should be able to develop a feel for just how much time you can devote to any other task except watching your attitude (preferably on the HUD). And it is imperative that you guys recognize this fact. Countless man-hours and millions of dollars have been expended in an attempt to correct supposed HUD deficiencies that are, in reality, directly attributable to two things. They are simply that the pilot's internal time clock has never been correctly regulated and that the pilot has not been completely conversant with what the HUD is saying.
Regardless of the type of display that you use (HUD, head-down, multifunction display or MFD, steam gages, and so on), you are going to look up suddenly and see an attitude you don't instantly recognize if you allow yourself to be distracted by some other task. However, you can handle it if, from pilot training and your own reservoir of experience, you know that the task at hand when combined with the present weather conditions, requires ten, twenty, fifty, or even ninety percent of your attention to stay oriented. The voice of experience might tell you, for example, that you had to devote 100 percent (that's nearly all of it for you BA majors) just to stay right side up. Ergo, you would ignore any other request on your time until the situation eased, verdad? Just like the book says in nearly every case: maintain aircraft control. You cannot develop this feeling for available time by getting the majority (read waaay too much) of your training in a simulator. The myriad destabilizing stimuli are not available in simulators for one thing. For another, you cannot remove the feeling that the floor of the sim building is comfortably and solidly beneath you or, put another way, that you're not fixing to die.
For these reasons, then, you may not have a clue about what your personal reaction would be while on final at Hahn AFB with the low level fuel lights starting to Ricker, a partially obscured ceiling, vis one-eighth mile in blowing snow, and a reported runway condition reading of less than six. (The same thing applies in the middle of the 10 - that's Indian Ocean for you landlubbers. The only difference is that RCR isn't as important on the ship.) That's why it is vital to take the time to evaluate how you fly instruments. If you cannot mentally visualize what your personal response would be to various types of weather, if you don't have a feel for how much attention you must pay to the attitude of the aircraft, if you don't have a feeling for just how much time you can spend looking for the proper approach plate prior to the IAF, and if you're not clear and certain about the proper response when the controller changes the runway while you're on the downwind at 2,000 feet above ground level, then now is a very good time to think about what your personal responses will be in these situations. And while you're thinking about that, remember to factor in how your responses would change as the weather changes, better or worse.
When was the last time you reviewed AFM 51-37? There's some good poop in there. And I recommend that you talk instruments in general and disorientation events in particular in flying safety meetings. Plus, get away from covering only the canned items during annual instrument refresher training. And just a word to you stan eval flight examiners. Are you tailoring your instrument flight evals to include true learning situations? Really? If you are not, you are cheating yourselves and your fellow Air Force and Navy aviators. Flying aircraft of any kind in weather is an unnatural act. It requires a conscious, deliberate operation that does not take kindly to inattention on your part. If you do not know the basics, you had better take the time to learn them. And if you think you already have a handle on them, better not forget that they never change or go away. If you don't think of them every time, you can get just as disoriented with 10,000 hours of experience as you can with 200. As easy as the handsome ski instructor makes it look, if he doesn't think constantly about keeping his knees together, he looks like hell.
Now that we're all d'accord, all psyched up with the mental self-discipline necessary to fly instruments, gather around. Joe Sweeney and I are going to show you how you can make it all a little easier, how you can find a little extra time to do other tasks, and how you can still keep yourself right side up.
We showed you before that, with the HUD, you now have the ability to view directly the flight path of the airplane. You really do. But lest you dismiss this as a commonplace statement unworthy of our usual revelatory pronouncements, think again. It's profound, n'est-ce pas? Why? Since you now have the ability to view directly the flight path of the airplane, mental gymnastics to interpret the control and performance instruments are superfluous. You can reallocate that time to perform other tasks. Moreover, what we have been calling the cross check could probably be better described as the point check. The philosophy of flying aircraft on instruments, using the HUD, has changed. We know more, so we can do more. Knowledge is power.
You can get all the information you need for determining the performance and for controlling that performance by looking at one and only one point on the face of the HUD. When your internal clock whispers to your brain time's up on the task at hand and you redirect your attention to airplane control, all you have to do is look at the flight path marker on the HUD. You then immediately have all the info you need to control the aircraft. You can tell the bank angle immediately and know instantly if you are maintaining level flight, or climbing, or diving. You can do this directly with no interpretation required without moving even your eyes, much less your head.
All right, now, before I begin to hear screams of anguish: I do look at the complete HUD display, and I would advise you to do the same to fill in all the gaps in the great situational awareness picture in the sky. It is important to keep track of the altitude, airspeed, heading, DME, and so forth. The main point is simply that, to control all these parameters, you can use the flight path marker to control the performance and determine the magnitude of the performance all in one – and only one – place. It's important to grasp this for more than one reason. The most important reason, however, is the ability to control the aircraft directly and much more precisely using HUD techniques. The next thing to realize is that to further improve HUD displays, it is not necessary to try to make HUDs look like the head-down displays you have used in the past. If you insist on using this approach, all you are going to do is screw up an excellent control device. Come to think of it, though, wouldn't it be a good idea to borrow from the F-18's bag of tricks and be able to put the HUD presentation head-down on one of the MFDs?
Well, back to this tendency to try to improve HUDs by making them clones of the head-down displays we all know and love. An example of this counterproductive tendency is a bank-angle display. You simply do not need a bank-angle display in order to fly the airplane precisely. Granted, there are a few weapon system operations that may need a precise bank angle, but it is altogether unnecessary on basic instruments. Joe and I disagree a little as to the actual magnitude, but we are in complete accord that you can control the bank angle very closely using the flight path marker. I can look back on every basic instrument maneuver, or complete approach, I have flown in the past and look forward to every one I'm going to fly in the future and know I never have needed and never will need to use exactly thirty degrees of bank. If you look at the angle formed between the stubby little wings on the flight path marker and the pitch ladder, that is the bank angle of the airplane. Even the most junior nugget among us can tell if he or she has a small amount of bank, a moderate amount of bank, a steep bank, or – Sweet Hey-Zeus – I'm upside down. In short, your performance is not going to suffer the least bit by not using exactly thirty degrees of bank. Ipso facto, your overall performance will improve because, as you establish about thirty degrees of bank, you know the turn is perfectly level (without having to look elsewhere). You cannot do this with an attitude direction indicator, or ADI. And the fact that I have twenty-eight or thirty-two degrees of bank established only serves to make a very slight change in the rate I approach the new heading I want. I am still going to roll out on the desired heading, regardless of how fast or how slow I approach it.
As an example, the question of tailoring the HUD display scale to be able to detect small rates in changing airspeed is no longer that important because the actual magnitude of the airspeed does not have the direct effect it has had in the past with the attitude, head-down type of flying associated with ADIs. In the past, a change in the airspeed meant (through the resultant changed angle of attack, or AOA, loop) that the picture I was holding on the ADI was no longer correct (that is, the flight path angle, or vector, if you prefer, had changed but I had no indication of that). As a result, I had to change the picture to make sure I was still doing what I wanted. Further, in the interim as I was correcting the airspeed, I had to check the other instruments to determine what effect this subtle change in the flight path angle had wrought on the other flight parameters. (I was also compelled to check to see if the new attitude picture was having the desired effect, and so forth ad nauseam. Whew.) This is simply not the case with the flight path marker on the HUD. If I am holding the flight path marker on the horizon, I know I am in level flight whether the airspeed has changed or not. Whoa, now, I am certainly not saying that I ignore the airspeed; it is simply not as important a parameter as it used to be. Why, then, spend a lot of time and money improving that part of the display?
A case in point. I have flown precision approaches where, as the controller said, start your descent, I went to full afterburner. At decision height, I had in excess of 650 knots (just below the Mach). But, by holding a picture of two and one-half degrees down, all the controller said was, on the glide path, although he didn't say it very many times. Incidentally, this was at a USAF installation. It would be different at other locations. It might even be other than two and one-half degrees at a USAF base, so you'd want to check the approach plate ahead of time.
This is not the way to fly ground-controlled approaches. (It also drives the controllers out of their trees.) Just remember that airspeed is no longer as important as it once was. Why? Because direct knowledge of just what the flight path angle truly is offers a whole new approach to instrument flying. Please do not construe this as a license to steal. You must not ignore totally any of the parameters you checked in the past. However, since the velocity vector combines in one location much of the information you once secured only after a series of mental interpolations and extrapolations, the manner, frequency, and order that you secure information from the HUD is different from the pitch attitude approach you have been using head-down in the past.
To see what I mean, look over my shoulder as I fly an instrument landing system, or ILS, precision approach. After assuring myself that I have the localizer nailed with a little back-and-forth check between the tadpole, the raw localizer line on the HUD, and the heading, I check the airspeed enough to establish that the required airspeed I had mentally calculated in relation to thirteen alpha was correct. At that point, I stop paying a great deal of attention to the airspeed and fly using the AOA bracket. I am looking at the tadpole and the velocity vector to establish the proper vector to stay aligned on the localizer and the glide slope. The tadpole should be very close to the glide-slope angle published for this particular approach (if I have smoothly started the descent at the proper time). If not, situational awareness, or SA, should be on top of the fact that the required correction will briefly call for a different descent angle.
If I am holding thirteen alpha, or even eleven if you choose, I can now easily and precisely control the airplane in all six degrees of freedom by looking in a very narrow window toward the bottom of the HUD combining glass. (Being in the bottom is another very good reason not to have any kind of bank angle display to clutter up the picture.) With an occasional glance toward the altitude to check the progress toward minimums, I am in complete control of the situation with a high degree of SA using a point check, not a cross check. Understand that, drawing on my own experience, there is still a small amount of time checking the entire display to keep SA as high as possible and to be alert for any possible malfunctions. Malfunctions of any kind are indeed rare, but I want to be alert to handle anything. Are you still with me?
And you run another risk of degrading the HUD if you try to install flight director bars. Remember them from the T-38? The actual tadpole might be changed slightly to improve its readability in every situation, but trying to make the HUD look like the head-down approach from another airplane would reduce your ability to utilize the HUD to its fullest potential. Instead, take the time to realize that the tadpole position represents the intersection of the pitch and bank steering bars in a much more efficient and space-saving display. Otherwise, you will have to expand your point check to find the now-displaced raw ILS data.
Your good manners, gentle reader, have overcome my enthusiasm for this subject. I can see you suppressing a yawn. I will therefore end this modern fable with a few scraps of clothing for the heretofore nekid emperor, to wit:
- Spatial disorientation is not a new phenomenon, nor is it going to go away with some magic change in display technology or format. Deprived of a visible horizon, you can't even function in two dimensions. I can put any one of you in an automobile in the middle of a large parking lot, blindfolded, and you can't drive in a straight line for any length of time. Why should you be able to in a three-dimensional world? If you didn't leave UPT with a warm fuzzy feeling as to your own reaction to various weather situations, you had better begin a selfstudy program to bring yourself up to speed. You instructor pilots in the fighter lead-in or replacement training unit bases should be alert for the lack of this capability in your students (and yourselves, for that matter). Know cold your personal reaction to various combinations of day, night, weather, rain, snow, formation, or single-ship. That way you can anticipate what's coming next. Think in terms of how much time you can afford to allow for other than maintaining aircraft control. Do nothing but that, if the situation demands.
- Flying the HUD in the F-16 or flying in any other HUD-equipped airplane requires a game plan different from any you have ever used before. It is more precise and allows a slightly reduced level of effort to maintain aircraft control if you now play ball in the new diamond. Learn the new rules. I will give you my personal guarantee that you will be a better, more precise instrument pilot if you do.
- Make sure you know what it is that you are being asked to evaluate before you start making suggestions to improve HUD presentations. If you insist on trying to make the HUD look like the instrument panels on the F-4, the F- 14, or the T-38, all you are going to accomplish is to plunge the weather-flying business back into the dark ages. HUDs can be improved, but there are only a few areas that really need improving. Therefore, make sure that you are a complete HUD flyer before you go off open-loop with all your requirements to qualify the HUD as an instrument-flying device.
- Please call our hand. Joe and I are prepared any time to demonstrate what we are saying. We are not talking concepts. Concepts are always free. We actually practice what we have been putting forward.
- Finally, let us know about your techniques when it comes to flying the HUD. Joe and I are more than open to suggestions as to how to maybe make it better. I am not at all reluctant to plagiarize somebody's better technique if it improves my own. We'll make every effort to get the word out to the field. Our main purpose is to make you better instrument pilots, not only in the F-16 but also in other airplanes. Give us a holler.
Check six, when your internal clock tells you that you can spare the time.
