Formation flying is something that not very many civilian pilots do, with the exception of pockets of homebuilt RV pilots here and there, who frequently have some ex-military pilots at their core.
Military pilots receive training in formation flying, and their skills vary, depending upon what kind of flying they did in the military. However military pilots often fly formation in a very particular manner (eg similar types, stepped formation, positive G only, etc).
In the civilian world you will find a wild variety of skill and proficiency in formation flying, from zero to highly expert. As such, you have to be very careful with whom you fly formation with. The good news is that you can size up the formation skills of any pilot extremely quickly (within seconds), but I’m getting head of myself.
Let’s consider the basic element of two aircraft, which is how you should learn to fly formation. It is suicide to learn to fly formation in a large group, because the potential for something horribly wrong goes up exponentially with the number of aircraft in the formation.
In a two aircraft formation, one aircraft flies the “lead” position, and one aircraft flies the “wing” position. They are very different activities.
The lead pilot is responsible for the safety of the formation and must worry about fuel burn, navigation, airspace, traffic and NOT hitting the ground. He must fly smoothly and must think well ahead, because he cannot manoeuvre as sharply as a single aircraft can, because he will throw the wing off.
The lead pilot is actually flying a very large aircraft – the entire formation - and as such can use high angles of bank and pitch, as long as he keeps his rate of change of pitch and bank low, to give the wing pilots time to keep their position.
Ideally the lead pilot should be the most experienced pilot in the formation – he should be an expert wing formation pilot. That’s the way it is in the military. Unfortunately in the civilian world this is usually reversed – generally the most experienced formation pilot flies wing, and the least experienced pilot flies lead. This can lead to horrible consequences. Free advice: never fly wing on a someone unless he is a better pilot than you, because you are trusting your life to him.
While the lead pilot’s job can be roughly described as not hitting the ground, the wing pilot’s job can be similarly described as not hitting the lead.
Flying wing is a hand-eye co-ordination stunt, a lot like standing on a basketball. It doesn’t require a lot of brains to do it, but it requires pretty good hands and feet. There is simply no substitute for practice when it comes to flying wing. The more you do it, the better you will be at it. Please have realistic expectations about your performance. There has never been a single human being in the history of aviation that didn’t get good at formation flight without an awful lot of practice. Don’t expect to be the first, ok?
The wing pilot should maintain a constant position, by maintaining a sight picture, which is defined as keeping parts of his airplane lined up with parts of the lead airplane, regardless of how the lead pilot manoeuvres. Most people start out with the classical 45 degree echelon, with the wing aircraft aft of the lead on the right side. Please try to spend an equal amount of time on the left side. Some formation pilots will only fly one side, which is about as ridiculous as a NASCAR driver that can only turn left.
Military pilots will often “step” the wing aircraft down, which is a something I would expect from someone with a rainbow sticker on their car. We fly formation level, for several reasons. Put your wingtip next to the lead’s tail, and your spinning prop next to his wingtip, and get used to it.
Another formation position – which is a favourite of mine but rarely used – is line abreast. It not only looks symmetrical with two aircraft, it also has the huge advantage that both aircraft are doing exactly the same thing during vertical aerobatics. Most pilots don’t like line abreast formation because there are fewer visual cues to help the wing maintain position. It’s easy for the wing to get bank on and not even know it. Not only does this look ugly, it creates drag for the wing which is a performance penalty for him. The lead pilot must continually coach the wing pilot to keep his wings parallel to the lead. It is a skill that comes with practice.
Most people think that formation flight is easier with identical aircraft, and this isn’t really true. Ideally the wing aircraft should have a huge power advantage over the lead aircraft, so the lead pilot can shove his throttle all the way forward and dive and turn away from the wing, so the wing can use his extra power to stay in position. With identical aircraft, if the lead pulls that dumb a stunt – going WOT with the wing flying a larger radius and thus a greater distance – he will shake the wing off, which is stupid.
The lead pilot must have a lower power setting than the wing when he is turning away from him, to give the wing some extra power to fly the higher speed on the outside. The military way is for the lead to run a continuous less-than-maximum power setting, but that’s severely suboptimal and simply won’t work in the piston/prop world, where there isn’t incredible excess thrust available. A good lead will reduce his power when he turns away from the wing, and increase his power when he turns into the wing, in order for the formation to maintain maximum energy. In effect the lead pilot is formating on the wing with respect to power, which is military heresy. Get over it.
The lead pilot must never fly in such a manner so as to leave his wing pilot helplessly behind at full throttle, nor must the lead ever cause the wing aircraft to stall, which is quite possible if the lead turns into the wing at slow speed. The wing is now flying a smaller radius than the lead and thus at a slower speed and thus at a higher angle of attack. I once had a very poor lead turn into me at slow speed and low altitude. If I had stuck on his wing, he would have killed me, when I stalled/spun during the turn he had attempted. See above note about never flying wing on a pilot unless he is a better pilot than you.
As mentioned above, the job of the wing pilot is to maintain position while not hitting the lead aircraft. He does this by never taking his eyes off the lead aircraft until he gains considerable experience, and then only for a very brief moment.
The wing pilot ideally anticipates the movement of the lead aircraft. This is often not possible, and if the lead maneuvers gently enough at a low enough power setting, doesn’t matter.
When the lead pilot turns away from the wing – watch the lead’s head and ailerons – the wing must immediately add power for the increased radius he must fly, and simultaneously pop up with back stick in order to maintain the same relative position to the lead.
When the lead pilot turns into the wing, the wing must immediately reduce power and push forward on the stick in order to maintain the same relative position to the lead. This sounds complicated but like screwing, once you do it a few times it will become automatic.
As you might imagine, the above is an ideal receipe for a PIO – pilot induced oscillation, caused by over-controlling. It is easiest to fly formation in smooth air – you can hope for a cloudy day with an inversion, or fly early in the day, or climb above the base of the first layer of clouds if you have plenty of power.
If you fly formation in smooth air, every movement of the wing’s aircraft will be a result of your inputs, which is educational. Flying formation in bumpy air is work, and takes practice to get any good at, because you are continually being pushed out of position by the bumps and must continually correct for it. Most people find this very tiring. If you fly formation in the bumps, dial in some more nose down trim. I usually fly wing with a constant 5 lbs of nose-down pull on the stick to dampen out the natural PIO tendency in pitch. With bumpy air, increase it as required to 10 or even 20 lbs of pull. At the end of the flight you will be exhausted, sweaty and you will swear that your right arm is 2 inches longer than your left. That means you are doing it correctly.
Most people find flying close wing tiring under any circumstances at first. Although it is military heresy, it is efficient to trade the lead position back and forth during a training flight so both pilots get practice at both positions, and a rest.
Wing Position & Visual
Above I mentioned two common formation positions for the wing: classical 45 degree echelon and line abreast. Note that I specifically did not mention the lateral distance between the two aircraft.
Beginner wing pilots like to give themselves lots of lateral room from the lead, to give them a false sense of security. I call this the ``comfort zone``. This is a very poor choice, because the farther out the wing is from the lead, the harder it is to keep position because of the “crack the whip” effect – the wing will have to manoeuvre with ever-larger displacements in the vertical during turns, the farther out he is.
Also, there is a fatal trap with being farther out. Because of the reduced visual cues and the common tendency of the wing to relax and bury his head in the cockpit when he is positioned farther out, horrible close rates can develop. This simply doesn’t happen when the wing is tucked in tightly; the lead aircraft is huge, and the wing pays complete attention to flying formation.
Now, on occasion the wing pilot will have to stick his head in the cockpit briefly, and not look at the lead. A good example of this is a radio frequency change. The wing does this by temporarily sliding out – NOT back – performing the frequency change, and then sliding laterally back into position. It’s neat to watch a vic formation (lead with both right and left echelon aircraft) quietly do this. Note that a wing aircraft never slides back, for two reasons: he might not have enough excess power to move forward again, and the wing must always be in sight of the lead pilot. If the lead can’t see the wing, he must assume that the wing has quietly fallen out of formation and must now go look for him.
I should mention that there is something called battle formation, which is used by the military to manoeuvre a formation with all aircraft at high power settings, but that is outside the scope of this article which merely concerns itself with close aka parade formation.
One last thing I should mention in this article – God, I skipped over so much stuff – is that you probably won’t be taking off and landing in formation when you start your formation training. That comes later.
So, if you’re going to take off separately from the lead, you’re going to need to learn how to join up on him, into position. This is non-trivial and has really nothing to do with close formation flying. It has more to do with air-to-air combat. You know, that Knights Of The Sky silk scarf crap, except in a formation joinup the lead pilot isn’t trying to stop you from maneuvering into position on him. He should try to make it as easy as possible for the wing to get into position on him.
The worst thing a lead pilot can do during a joinup, is fly straight and level at a high power setting away from the wing. It’s going to take all day for the wing to chase the lead down in that situation.
What a lead pilot does during a joinup, is fly a gentle turn at a nice safe altitude – NOT down low. This allows the wing pilot to turn inside of the lead pilot, and aim ahead of him. The wing pilot should dive down until his aircraft is on the extended plane of the lead’s wings, and slide up into position on the lead. As you get more and more practice at joinups, you can do this faster and more aggressively. When you get really good at it, you can take a great bloody run at the lead and do a barrel roll around him, into position, which is probably one of the top ten fun things you can do with your pants on. This is not an advisable manoeuvre to perform without considerable formation and aerobatic experience.
To understand what’s going on in a joinup, you need to understand just a little bit of physics, because that’s what you’re doing: applied physics. If you understand it just a little, it will go well. If you don’t have a clue what you’re doing, it’s going to go badly.
The total energy of an aircraft can be expressed as the sum of the potential energy (due to height) and kinetic energy (due to airspeed). One can easily be converted into the other and back again, and that’s exactly what an airshow pilot does: fast and low at airshow center, and high and slow during the reversals at the ends of the box, as he drives up and down the runway.
For a successful joinup, both the lead aircraft and the wing aircraft must have the same total amount of energy. If the wing attempts to join the lead from above, at the same (or God help you, faster) airspeed, when he descends to the lead’s altitude he will have gained airspeed from the lost altitude, and he will blow past the lead like the lead is tied to the guardrail. Not cool.
Even trying to join without turning at the same altitude can be tricky, because although both aircraft have the same potential energy, the faster wing aircraft still has more kinetic energy than the lead, and again he will likely blow past the lead when he attempts to join up, even if he hauls the throttle all the way back to idle.
So for both aircraft to have the same amount of total energy – which means they will go the same speed when they are at the same altitude – the wing aircraft should be lower and faster than the lead aircraft. As he slides up into position on the lead, he converts his excess airspeed into altitude and if he does it right, slides nicely into position.
But what happens if he doesn’t? No big deal, because the lead is the only other aircraft in the sky – see above about big formations – and if the wing overshoots, he merely pushes forward on the stick (even though negative G is unpleasant, let gravity help you), slides under the lead, and joins up on the outside. The wing can then claim that he meant to do that. The lead won’t buy it, but it can’t hurt for the wing to try it on him.
Anyways. I have barely touched on the very basics of non-aerobatic formation flying, which is a fascinating and rewarding sub-discipline of aviation all it’s own. Try hard not to kill yourself or anyone else while you’re doing it.
firstname.lastname@example.org Oct 2011