Jet Formation Flying
By Harold Cannon, Editor, EAA Warbirds Briefing, firstname.lastname@example.org
The most vivid memory of my first trip to EAA Oshkosh over 15 years ago was that of the Warbirds of America air show. All of those formation takeoffs were fantastic. I thought that those pilots must all have been ex-military fighter jocks of the highest caliber. For certain, many of them were, but just as many were civilians with a love of flying and history. They had spent resources and time to become proficient, and this was their time in the “big show.”
A few years later I found myself working on formation skills in a T-34, and behind the curve a lot. With help from those with formation experience (and a fair amount of patience on their part), things finally came together. Last Sunday it was time for some practice in the L-39. If you’ve wondered what that’s like, click below to ride along. For my elders and betters…I’m still learning, and some days more than others.
All formation flights start with a brief. Good practice to follow, and illegal without. This flight began with a phone call from an L-39 friend who lives about 120 nautical miles away. When schedules allow, we often meet for a formation practice session over an airport about halfway between our homes. Weather and work, the two least wanted thieves of time, were going to be out of the way in the morning so that a plan was made.
Early morning drives to the airport have their own checklist: flight suit, boots, helmet, gloves, and oh yeah – keys to the hangar. On this morning I was out early. It seems that the work at hand always expands to fill the allotted time, and on that day it was really true. Getting the tug started, pullout, fuel, and a careful preflight all took time. My backseater arrived at 7:30, and I was already about an hour-and-a-half into prep time. He was briefed, and at 8 local my cell rang. Steve is punctual.
The real brief commenced. Company frequency, emergency fields, altitudes, and airspeed for a join-up. Planned procedures (breaks, joins, cross-under, loose and close trail), time hack, and we’re ready to go; 8:30 engine start, 8:40 wheels up, and over the target airport at 8:55.
I got my backseater strapped in.
L-39s are wonderful machines and have the great characteristic of being independent of a ground huffer or auxiliary power unit (APU). Starting is straightforward – power to switches one and four, check voltage, hack clock, sapphire start button pressed (the onboard APU). As the small sapphire turbine completes its internal checks, the turbo-start light comes on, and you’re ready to light the “Ivchenko-Progress” AI-25TL engine. (You have to love Soviet-era names.) The engine itself is as simple as pushing the start button. Three seconds later the throttle comes out of cutoff to idle, and you watch exhaust gas temperature and tachometer as it comes alive. All switches on, cabin pressurize lever forward, air condition to auto. Speed brakes, flaps, and hydraulic checks, and we’re good to taxi.
Unlike most American jets, the L-39 does have a first flight of the day engine run-up. This checks the mechanical fuel controller against certain parameters and makes sure that today’s spool-up times are within limits. All of this takes time and accounts for the 10 minutes we allotted between start and wheels-up. That day, all checks were good, and we lined up ready to go.
Power up, brakes released, rolling and steer with the brakes. One or two taps will do, and at 30 knots the rudder becomes effective. Rotate at 95 knots and hold the pitch, the mains unstick at about 102, and we’re flying. One hundred and twenty knots, positive rate, and gear up. This day, it seemed to take the nose gear just a second or two longer to lock up and indicate gear door closed, something to watch next time. One hundred and forty knots, flaps up, hold pitch, and at 180 knots we had the best angle of climb speed – it’s pitched and turned to the downwind, which pointed us to our destination.
If you want a long pause from your local air traffic controller, try letting them know that you know you have 400-knot closure on a target off your nose. I find this is best done right after establishing flight following. A quick explanation that this is a briefed flight, and that we will have 1,000 feet of altitude separation, is appreciated. It took little time to get there, and right on schedule I found myself in orbit 15k above a small rural airport and looking down for Steve, who was in orbit at 14k. At this point I possessed untold respect for those who had flown in our defense. It’s a big sky, and one other aircraft is hard to find...even when you know where to look. That morning, traffic information service pointed the way, and I had him on the Garmin and the Chelton glass as well. A quick call to slow to 220, head 360, and I found that small speck I was searching for.
Joins are flown in a turn. If you aim at where the lead will be, rather than where he is, you’ll get there with him, without having a higher airspeed. At least that’s the theory, and by George, it worked again this day. I’d been flying a lot this spring, and this one worked in under 180 degrees of turn, resulting in one big grin. It’s now time for the air work. In a two-element flight, most things are accomplished with hand signals rather than radio calls. No sooner than we’re settled in, Steve raised his fist and signaled the first cross-under. I complied and came in on the power a little late, resulting in trailing out of position. Another signal and back to the other side I went. Steve enjoyed playing yo-yo with me until I got a couple more or less right. Then it’s a few 180-degree turns, shallow at first and then up to about 45 degrees. Not a real steep turn, but steep enough for me this day. Just as with most things in life, what goes around comes around. In a few minutes, Steve gave over the lead and it’s my turn to torment. He got more of the same, as well as some breaks, trail, and rejoin.
In a break and rejoin, lead signals his intention, and then rolls, pulls, and completes an agreed heading change (180 degrees this day), rolling out on altitude and airspeed (210 knots in this case). Three seconds later, the wingman does the same, placing him in extended trail. After Steve called in, I dipped a wing to the left indicating that I’m about to start a turn to left. This would allow him to use cutoff to rejoin on my left wing. Things went well, so no bragging rights about the most efficient rejoin that day. We completed two more, and it’s now my turn to follow. Lead changed back to Steve, and as soon as I was keeping my station, he signaled, pulled, and was gone. We had been pulling about 3g in the breaks. Nothing for the pro, but plenty for me. These planes don’t bleed energy quickly (at least in comparison to piston aircraft), and the g stayed on for the full 180-degree turn. At least that’s my story, and during this pull, my backseater started to wonder if breakfast was a good idea. It’s always good to have someone in the back to blame when it’s time to head for home. The rejoin was completed, we waved goodbye, and broke. This time a gentle descent to home, talking to the guy in back. I hate cleaning cockpits, and that day I didn’t have to. It was a great start to a good day.