As I have wandered through the hallowed halls of the world of aviation, I have run across many of my fellow pilots who have had a real aversion to flying at night. I must admit that I, given a choice, would fly in the light of day. But I can now say truthfully, with the work we have been doing with the F-16 over the past few years, that flying at night is not so bad. It can even be a lot of fun.
With the exception of the usual night proficiency requirements and the occasional high flight, I didn’t do an inordinate amount of night flying until I wound up in Southeast Asia in 1967-1968. As a member of D flight in the 555tth TFS Triple Nickel, I was having a hell of a good time going north until LBJ, for reasons that he did not share with us, decided to keep us out of Route Packages 5 and 6.
As a result, 7th AF, now with an extra squadron on its hands, decided that we should join our fellow squadron, the 497th, in its efforts at night work. Although I personally never did mind flying at night, trying to use an F-4D as an instrument of war in the dark was not my idea of the most efficient use of the available equipment. In the daytime, I had the distinct impression that the cockpit had been laid out by a drunk hobo on a blind burro in a snowstorm. At night, the cockpit was even worse. With systems no more sophisticated than the human eyeball and the intelligent use of the occasional flare, we were supposed to deny the bad guys access to South Vietnam.
I was amused at all the advice the old heads were putting forth about the techniques to use at night.
- Don’t use the afterburner at night because that gives away your position. (How is that any different from the daytime, when they can see you all the time?)
- You must not strafe at night because the muzzle flash will give away your position. (Same reasoning as number one.)
- Don’t use more than sixty degrees of bank at night. (Are the laws of aerodynamics different in the dark?)
This advice, as well as the cockpit layout and the night lighting in the F-4, was, shall we say, less than optimal. I did take a cue from the guys in the 497th as to the use of tape. I know I must have shifted the center of gravity forward at least one percent after I had finished taping up the nuisance light sources in the cockpit. I finally arrived at the following solution. Heavy use of tape, then turning the cockpit light rheostats almost off (in some cases, completely). I would then take the red filtered map light, stretch out the cord to full length, route it under the manual canopy release handle on the right side of the cockpit, clip it on the glare shield, and point it to shine on the ADI.
With a three-axis gyro on the F-4 ADI and the use of the aural tone for angle of attack, I created a poor man’s head-up display, or HUD (although I didn’t realize it at the time; more on that later). I would then depend on my long-suffering GIB, or the guy in back, to provide me the rest of the information unless it was only available in the front cockpit. If that was the case, I would either fly straight and level or give him the airplane and turn up the lights to get what I wanted, turn them back down, and proceed with the mission. Despite all this aggravation, we did some very good work from time to time; although I hardly think we really affected more than ten percent of the night traffic inbound to South Vietnam (or Veeetnam, as Robert Strange used to say).
Why so dark? (Another of my rhetorical questions.) If you want to see out of your cockpit at night, then you must make sure the inside is dark as well. The same is true with the panel lights in your car. If you are serious about seeing anything while you are driving in the dark, you should ensure that they are turned way down. I am always tickled passing people on the freeway (they were only going fifty-four miles per hour) and seeing the level at which they have their panel lights. (Especially those with the latest fad digital panels. They are usually so bright the headliner, and the driver’s eyebrows, are starting to smolder. I doubt they can see past the hood ornament, but they want the rest of the bourgeoisie to know that their new car is on the leading edge of technology.)
The same holds true with today’s F-16. If you want to see outside at night, then it must be dark inside. But with today’s technology, there are a lot of other systems you can use besides the aforementioned mark-one, mod-zero eyeball, and the SUU25 flare dispenser.
The one you are probably most familiar with is Martin Marietta’s LANTIRN. A very good system to help you fly in the dark. However, we have been looking at some ways to be even more effective at night than with LANTIRN alone. Now I am not going to insult your intelligence by saying I am going to turn night into day. Only God can do that, and he has proprietary rights. But I will say that, with very few exceptions, you can fly the F-16 at night in exactly the same manner you can in the daytime. The same maneuvers, the same delivery systems - everything.
LANTIRN gives you a forward-looking infrared, or FLIR, picture that is then presented on the HUD and on a terrain-following radar, a TFR, system to allow you to fly at low altitude, which also makes the FLIR picture look better. All this is accomplished through the use of the navigation (NAV, but I’ll bet you knew that) pod that is installed on the left inlet chin station (5A). On the right inlet chin station (5B), you can carry the targeting pod that allows you to see further forward and off-axis by use of magnified and/or gimbaled FLIR images and to control and hand off weapons to other systems that are already on the airplane, to include performing laser designation for guided weapons. I certainly could have used this system many times in many parts of Southeast Asia. As such, LANTIRN provides a major step (but not necessarily the final increment) toward giving me and the rest of the F-16 pilots (and the rest of the TAF as well) a real capability to fly and fight at night.
A few systems can be added to the existing LANTIRN or used independently to improve still further the ability to detect, identify, and destroy the bad guys. Having firsthand knowledge of how well some of them work, I would love to re-fly some of my more memorable missions from the yesteryears in Southeast Asia. How sweet it would be.
Let me take the time to talk to you about what we have been doing (while staying in the unclassified category). What about navigation? In Southeast Asia, we had to depend on dead reckoning, or DR and the slim possibility of map reading in the dark, aided by the inertial system, or INS. What if I told you that you could use a system that would navigate you nearly 100 percent of the time to within fifty meters of where you wanted to go? It’s even better than that a large part of the time. For instance, tell me which end of the bridge or what corner of the building you are interested in, because it will usually take you precisely there. (We enter coordinates down to six feet of accuracy.)
If you have to fly over long stretches of water or extremely flat land, the system will degrade gracefully, meanwhile making automatic allowances for this degradation with no action required of the pilot. If the NAV symbol were in the center of the HUD, the worst you would see would be the target in the HUD field of view. This system falls in the category of digital terrain systems, or DTS, and, more specifically, TERPROM. TERPROM stands for terrain profile matching and is a product of British Aerospace. There are several other DTS systems in development, but this is the one we have been working with and it works in spades. It has to be seen to be believed. The accuracy, without the requirement to make any updates regardless of the length of the mission, is astounding. If you would allow me to put my retired US Air Force fighter pilot hat back on, I would say that it should be an urgent-action TCTO on every TAF aircraft that is presently equipped with INS.
By always knowing exactly where you are, and how long (to the second) it is going to take you to get exactly where you want to go, the reduction in cockpit workload is staggering. The Global Positioning System, or GPS, can also be very accurate. But because of the way it works, it can only do accurate navigation. The GPS is referenced to the center of the earth, or at best sea level, and does not have the first clue as to the big rock rapidly approaching the end of your pitot boom. However, because of the way that TERPROM works, you also get two other very important capabilities for the same price, size, and weight.
Since TERPROM uses the terrain profile for its navigation, it can also use the same data concurrently to provide a predictive, all-attitude ground-proximity warning system. The operative word here is predictive. Every other system in being, or under development, is an historic ground-prox warning. In other words, the system says, "By the way, Maverick, you just screwed up," as the nose of the aircraft starts deforming at ground impact. The TERPROM will tell you well in advance, regardless of the pitch or roll attitude of the airplane, that, if you insist in continuing with what you are doing, for the next ten to twenty seconds you are going to pass closer to some terrain feature than you told me to warn you about. This feature can work the same, whether the upcoming clearance problem is due to the ground or is a man-made object.
Finally, while TERPROM is doing the two tasks above, it can also provide indications on the HUD to allow you to fly a very covert, yet very accurate, terrain-following profile. These are the three main items that all go a long way to improve operability, increase safety exponentially, and make a drastic reduction in the cockpit workload. Not at the top of the list with the other three, but still very useful, is that TERPROM can provide a passive ranging to use with the present F-16 delivery modes. This passive ranging can actually improve continuously computed impact point, or CCIP, operation at shallow dive angles.
If you have seen the LANTIRN HUD, you will have noticed that it is not quite like the HUD used in the other C Models. The symbology is nice and clear and the field of view is about two and one-half degrees bigger on either side. This is nice to have if you are flying at night, depending only on the LANTIRN system. But we have seen a companion system that, as I said before, would improve the operation of LANTIRN or could be used independently. This falls under the heading of night-vision goggles, or NVG. While the LANTIRN HUD is nice at night, it is less than optimum in the daytime. And rather than try to improve the fixed field of view by making the HUD larger, why not work on the field of regard? This field of regard can be increased tremendously with the intelligent use of the right kind of NVG. The ones we have been using are called "Cats Eyes" (a product of GEC Avionics) and work very well.
It is important to make this distinction as other types of night-vision devices that, while they provide some measure of night vision, are not very compatible with the F-16 cockpit (or with any other fighter cockpit). I have heard all the arguments about how the NVG are heavy, awkward, have a narrow field of view, and so on. All these criticisms are true in varying degree. But I have to ask, What capability do you have without them? A big zero. There are better systems being developed and we will be flying them soon. For example, we are looking at helmets that integrate into the body of the helmet all the fixture that is hung out in front at present. But in the meantime, the NVGs provide several capabilities that are missing at present:
- Although there is a technique to using the NVGs that must be learned, the NVGs provide almost the same size field of regard that you have naturally in the daytime.
- Almost as important is that the goggles are simply light-amplification devices that use whatever available light is present to provide a usable picture to the wearer. Even on nights when there is only very faint starlight, the NVG can provide useful details to the pilot. Of equal importance is that the goggles operate in a different part of the spectrum than the FLIR systems utilize. As a result, the Air Force has much more likelihood of having some capability on any given night.
Although FLIR systems look good in the desert, they may not play so well in Southeast Asia (or in any other high-humidity area) during the wrong time of the year. The FLIR performance depends on the total amount of water vapor in the air. In other words, the absolute humidity and not the relative humidity. This characteristic is measured in terms of so many grams of water vapor per cubic meter, for example seven grams of water per cubic meter. It is important that you understand this characteristic as it makes a big difference in your mission planning. If you go on the more widespread relative humidity measurements, you can often come up with the wrong answer.
For example, I have flown in the area around Fort Worth when the weatherman was reporting a sixty-five percent relative humidity. Under these conditions, I had a FLIR image that showed me usable details less than two miles in front of the airplane. Conversely, I remember flights in northern Europe when the weather-guesser was calling the humidity at ninety-four percent and I could see nearly six miles. In the first example, the dew point was seventy-six degrees Fahrenheit. In the second, twenty-eight degrees Fahrenheit. As a result, the first flight was looking at an air mass containing more than twenty grams per cubic meter; the second contained less than three. I can remember flying in rain that was falling through a dry-enough air mass that I could still see about three miles. So when someone (your author excepted, of course) shows you a tape of some system’s FLIR performance, be very skeptical unless they specify under exactly what absolute-humidity conditions the flight was conducted.
The point is that you need both a FLIR system and some sort of low-light-level NVG to be sure of having a usable weapon system on any given night in any given area. In the same location, I have flown one night with a very wet air mass but with a quarter moon that resulted in great NVG performance and only marginal FLIR operation. At a slightly different time the following night (after a front passed), I was flying in a nice dry air mass before moonrise, with an overcast that extended to above 35,000 feet where I could see next to nothing with the NVG. Nevertheless, the FLIR was beautiful.
I have already touched on how I feel that the cockpit should be dark in order to see outside. This is vitally important if you are depending on seeing outside using just your eyeballs. It is even more important if you are trying to use NVGs. The underlying reason comes from opposite ends of the problem, however. Without the NVG, it is important that you dark-adapt. Any light will reduce your capability to adapt and use what innate night-vision capability that humans possess. With NVG systems, you never dark-adapt. But if the cockpit is not dark, the NVGs pick up reflections in the cockpit that you would not be aware of otherwise and reduce the capability of the goggles. A very insidious, and potentially very dangerous side effect exists for those of you who still want to fly around with your cockpit lights turned up.
On more than one occasion, I have visually tracked F-16s and F-15s outside of ten miles, at night, using nothing more than NVGs and the light cast by the glow in the canopy from their cockpit lights. Not a very good deal if you want to survive for the next sortie.
By now I can hear all the gears turning. How do you fly with a dark cockpit? Simple. With all the lights off, you will be using the HUD. Before you say anything, I know what the official policy is in that regard and I encourage you to reread the several previous articles on that subject in Code One (Vol. 2, Nos. 1 and 4; Vol. 3, No. 1). But what better way could there be? You have the FLIR image being displayed on the HUD, and, with the HUD symbology superimposed, you have nearly all the information you need to fly the airplane at very low altitudes and high airspeed. (Before this is all over, I will list what I think is the ideal equipment suite in order to safely and effectively fly at 100 to 200 feet, in excess of 540 knots, in the dark. So please stay tuned.) As I mentioned above, with the F-4, it is difficult to fly with the lights off all the time because I can’t see the fuel gage, the engine gages, and so on. So, from time to time, I was forced to find the light the rheostats (which meant changing hands and flying left-handed for a while - ughh) and turn the lights back up, check everything, and then turn them back down. This would be the case in the F-16 as well, except we made a very useful change in the interior lighting panel. We added what is, in essence, a master switch in much the same manner as the external lighting panel.
The only difference is that the interior master switch is in series with a hands-on switch that will go on the stick or throttle. Now, I use the rheostats to set the lights in the same manner I did in the past, except I set them up even brighter than before so I can see everything clearly, with no fear of misinterpretation. Arm the system with the master switch, labeled NVG (smart, n’est pas?) and turn the lights off with the hands-on switch until I need to check something. Then it’s - click - check what I want - click - off. The lights that I am talking about now are all the incandescent lights in the cockpit; you still set the HUD, SMS, REO, or MFDs independently as you did before.
As you recall, you do not have to worry about dark-adaptation. Remember, you never dark-adapt with the NVG anyway. Sounds kind of scary, but it works superbly. Everyone to whom I have demonstrated this technique, although maybe skeptical at first, has come away saying this is a very useful capability. The Israelis are putting it into their next block of aircraft. It really does work and allows you to keep the cockpit dark to keep the reflections down, see outside, and yet check the systems quickly when you wish. We also have finally come up with some effective filters for the REO in the A/Bs and the MFDs in the C/Ds that completely eliminate the reflections that would be left from them.
How about the goggles? I mentioned before that you would use the goggles to look outside of the HUD field of view using low-light-level techniques and the HUD for control of the airplane and to view the world as the FLIR system thinks it looks. How can I see the FLIR image while I’m looking through the goggles? Easy. We put a little sending unit at the base of the HUD field of view and a receiver on the goggles so that, as I look at the HUD, they shut off automatically and then turn on instantaneously when I look off the HUD field of view. I can also select the goggles to stay on while I’m looking at the HUD for those nights when the humidity has the FLIR working at a disadvantage. This allows me to look everywhere I could in the daytime as well as at night. With any background light at all, it is almost as good as the daytime, with the exception of the field of view (small, but the field of regard is still large) and the fact that everything is green. It works great.
The use of this HUD/NVG (with the cutoff) combination allows for another interesting technique. As I roll into a turn, I simply turn my head in a natural manner (avoiding the possibility of disorientation by using any kind of snap look techniques) and check what I can expect to encounter during the course of the turn. I then return my head toward the center and stop just short of the point that I would turn off the NVG. Now, with only eye movement (a technique with which you were born), I can look across both the NVG and HUD field of view.
This provides about a forty- to fifty-degree field of view, which does wonders for your situational awareness. Depending on the number of degrees to be turned, I glance well into the turn, as necessary, until I roll out, each time returning to the point just short of turning the NVG off. Smooth.
So, lots of background, but how does this all play together? Follow me.
- It goes without saying that TERPROM should come first on everybody’s list. With such a system, you can do everything better, day or night, rain or shine, regardless of what your mission is.
- Make the cockpit lighting mod. This capability is useful for all your night sorties, even if you can’t afford the rest of the equipment or your mission does not require you to fly at low altitude in the dark. With it, you are now ready to go to . . .
- NVGs. With the cockpit good and dark, you can now use the goggles like gang-busters on the nights where the ambient lighting conditions allow. By the way, the Cats Eyes are completely compatible with the HUD symbology, so there is no problem looking forward and seeing the HUD symbology at the same time. Don’t worry about not having the LANTIRN HUD. The goggles negate the requirement for the larger field of view anyway. Next . . .
- FLIR pod to be carried on Station 5A. If the equipment is not available or you can’t afford the LANTIRN system, there are several contractors who have supplied us usable pods that are very effective, for example Pathfinder (which is a derivative of the all-up LANTIRN NAV pod, also made by Martin Marietta), Atlantic (another product of GEC Avionics), and so on.
- Some sort of targeting pod at 5B. If you are lucky enough to have access to the LANTIRN system, use it. If not, there are other systems standing in the wings that may suffice.
You are now ready to go to work in the dark and gloom of night. As I said before, we have not turned night into day. But I will say in the strongest possible terms that, with the only exception of flying out a little longer and turning back in a little easier, if multiple attacks are required, I fly the F-16 with this equipment in exactly the same manner I do in the daytime. Exactly.
I have the navigation equipment to navigate and find the target. I have a system that I can use to fly covert terrain-following precisely. If I already have the full-up LANTIRN system available, I have the choice of which sensor I want to use as the tactical situation dictates. Or, with very little extra integration, I can run both through a Kalman filter arrangement to use both in the most effective manner. I can also use any bank angle that I can personally handle without fear of overloading the sensor. I have a FLIR system to use to actually see the countryside and goggles to fill in the field of regard, as well as back up the FLIR system on the nights when the weather does not cooperate. My precise navigation system is accurate enough that I can find the target in my precision strike pod (LANTIRN or otherwise) to ensure a first pass attack on the target, all the while reducing the cockpit work load and allowing me to scan for threats that I did not have the time to do before.
The goggles allow me to use the total field of regard to employ offset pop tactics in exactly the same manner as I would in the daytime. I can now be somebody at night. Although there will be doubting Thomases reading this, I can assure them that they can use this equipment to fly as low as 100 feet as fast as their configuration allows, pop for low-angle low drag or pop to the moon for really steep deliveries, release the weapon, and immediately dive steeply into a black hole to get back down to very low altitude - all on the first pass. I have had too many people doing it on their first sortie in the airplane to feel otherwise.
We are also working on a concept that shows a lot of potential as well. We have labeled it Falcon Eye. It involves a head-steered FLIR so you can use an IR system over the whole field of regard just as you would look around in the daytime. This offers the additional flexibility to display symbology in front of my eyes all the time instead of being restricted to the HUD (another boost to your situational awareness.) In order to provide the flexibility in the frequency spectrum that the FLIR pod-NVG combination does, we are meching up a low-light-level TV camera that will display on the HUD where the IR image used to be displayed. Slick. I’ll keep you advised.
It would sure be great if I could go back in time to the 1967-1968 era in Southeast Asia and take this equipment with me. I know a couple of nine-level gunners and truck drivers just north of Mu Gia pass and just off Thud Ridge I sure would like to cross paths with again.
I saw a good cartoon from the A-10 guys saying, "It doesn’t matter who won the air war if the Russian tank commander is eating his lunch in your snack bar." Well, it doesn’t matter how you are doing in the daytime if, as you walk out to your jet for the Dawn Patrol, you find your steed crushed into aluminum splinters by the tread of a T72 tank while you were in bed.
Check Six. Even in the dark.
