What’s interesting about this short video clip is that it shows a bare-naked F-15 taking off, a rare event. You see, a naked fighter is useless … it carries no weapons and can’t perform any of its combat missions. They don’t let you fly ’em naked because they aren’t supposed to fly naked. This Oregon Air National Guard Eagle is stripped to the skin: no missiles, no external fuel tanks, no pods, not even the underbelly and underwing pylons used to carry missiles, tanks, and pods.
The only time they fly a stripped Eagle (or any other fighter) is after major maintenance, flight control work, or engine replacements, when a jet requires a full checkout before it’s returned to the line. The checkout is called a functional check flight, or FCF, and every F-15 unit has a specially-trained FCF pilot.
I was the squadron FCF pilot during my first two operational tours: Soesterberg Air Base in the Netherlands and Elmendorf Air Force Base in Alaska. FCF pilots are regular squadron pilots, and flying FCFs was an additional duty. At Soesterberg, because of noise restrictions and international relations, we only flew FCFs during normal daylight working hours, Monday through Friday. No such restrictions existed in Alaska, and I sometimes had to come in on a weekend to fly one. There’s a special checklist you have to follow, and a strict and busy flight profile … it can be a push to get everything done with internal fuel only, so you have to stick to the profile.
But lordy, FCFs are fun to fly, even if you do have to keep a close eye on fuel remaining. Not many Eagle drivers get to put the jet through all its paces, which include not just max performance takeoffs like the one in the video, but procedures you’d never perform on a normal flight: things like shutting engines down and restarting them (one at a time, of course), working the emergency gear lowering system, stomping on the brakes during landing rollout to make sure the anti-skid works, and my favorite, checking the rudder limiter.
That one deserves a bit of explanation: The Eagle has two rudders, one on each tail. They deflect up to 30 degrees and can really move the nose from side to side, pretty useful in a dogfight. But full deflection above the Mach could rip the tails right off, so a limiter kicks in above Mach 1.5 and full deflection is reduced to five degrees. To check it, you first have to accelerate to Mach 1.5. In the Eagle, that meant climbing up above 40,000 feet, going full afterburner on both engines, and lowering the nose a few degrees to help you accelerate through the Mach. Once supersonic you can level off and let the jet accelerate, then gingerly feed in rudder in both directions once you’e above Mach 1.5. After the rudder check, you let the jet keep accelerating to see how fast it’ll go, and on one memorable occasion over the North Sea I got a D model up to Mach 2.21 before hitting bingo and having to pull the throttles back. The D is the two-seater with the bulgier canopy, which I guess proves canopy shape is not a huge factor in top speed.
FCFs aren’t training missions, and you aren’t working for operations when you fly one: you’re working for maintenance. They’re counting on you to execute every procedure in the checklist, thoroughly write up every discrepancy, and spend one to two hours going over those writeups with them afterward. Normally there’ll be a few things that need to be adjusted or fixed, but I don’t remember ever failing a jet.
In the Navy and Marine Corps, each squadron will designate a junior pilot as maintenance officer: his or her job is to work with maintenance on a daily basis and it’s a great education. In the Air Force, we’re more stovepiped: squadron pilots don’t get that opportunity. FCF pilots do, and I put a lot of value on the experience. And boy did I get to know the ins and outs of the F-15 Eagle.
It’s been a while since I’ve done any Air-Minded posting. I hear there’s a possibility the USAF will buy some new F-16s, in a move similar to the one that gave us the F-15EX Eagle II, and even some talk about reopening the C-17 production line. I should have something to say on these topics, and likely will, so please check back.