High/Low Key maneuvers?

I live in Las Vegas, and well I'm out at Nellis all the time spotting. I have a scanner to listen to radio comms and almost everyday I hear F-16 doing High and Low Key maneuvers. What is High/Low Key?

Also why do F-16 only do it I have never seen a F-15 or A-10 do this?? Its pretty neat to watch they orbit high and then do a sweeping diving turn onto a final approach then do a low approach go around and climb to 5-8000+ feet then do it all over again. Some do it 2-4 times while others do it 6-8 times depending on fuel I would assume.

Thanks,
Luke

Not sure of the exact definitions of High and Low Key, but the pattern you describe sounds like an overhead Simulated Flameout (SFO) approach.

High Key looks like the point in the pattern where they start the descending turn and Low Key is the point they turn base to final. But don't quote me on that. There are various rules-of-thumb to calculate High and Low Key based on the airfield and the given conditions.

Yes allmost!

In an FO,you dont know the exact altitude that you will pass the airbase(if you are not for going straight in FO)
Well, it depends on wind if you need to touch in an other runway.

Every key has different procedures to find the short final-degrees of descend-lag to the runway etc..

High key 7000-10000AGL
Low key 3000-5000AGL depends on weight
Base key 2000AGL minimum

In a real FO, yes. But in an SFO, they tend to use the same altitudes as it makes traffic control much easier.

The reason Eagles and Hogs don't do this is that an SFO is typically only an issue for single engine birds. The F-106 also required SFOs...when done near the end of the mission and low on fuel, these were a hoot because the Six had tremendous T/W and could climb like a homesick Angel...straight up!

Base key is more or less the 'short final' engine-out position, you want to be lined up with the runway and on speed.

High Key is correctly defined as the locus of points from which base-key can be made within parameters. It can extend from overtop the airfield to many miles away depending on altitude and energy. If you were at 500' and 500 knots a few miles away from the airfield and your engine quit, you'd technically be at a key position. That being said, for training purposes it is more closely aligned with what the previous posters have said.

If you are by Nellis and hear them calling 'high key' and 'low key' they are fying SFO's. SIMULATED flameouts. The altitudes are specific. It is like an overhead pattern, except much higher, steeper and faster.

Since the navigation computer knows where the intended point of landing is, by checking airspeed, altitude, accleration etc from the air data computers, it could give the pilot an alert if the field can or cannot be made. Sure could be a help to a pilot with their hands full.

Yeah, it's called the "Flight Path Marker" in the HUD, and it works whether you have the steerpoint selected or not. Since the flight path marker tells you instantaneously where the jet is going, it's pretty easy: If the flight path marker sits on or beyond the airfield and you aren't losing airspeed, you can make it. If it sits short of the field, you're not going to make it without an engine. If you can't see the airport, it's really simple, since the F-16 has a 1-to-1 glide ratio. If you're at 20,000 feet (above the ground - that's an important thing to remember), you can make it 20 miles, so you'd better find a good piece of concrete within that range, or it's time to get out and push.

Rexxxx wrote:If you can't see the airport, it's really simple, since the F-16 has a 1-to-1 glide ratio. If you're at 20,000 feet (above the ground - that's an important thing to remember), you can make it 20 miles, so you'd better find a good piece of concrete within that range, or it's time to get out and push.

Please correct me if I'm wrong here, but wouldn't a 1:1 glide ratio mean that for every foot you go forward, you lose one foot in altitude? If that's the case, 20K feet of altitude would only get you about 3.79 miles. To get 20 miles of glide distance out of 20,000 feet altitude, you'd need a glide ratio of 5.28:1.

You are correct. Mathematically (and aerodynamically) speaking, a true "1:1" glide ratio does mean exactly that if you speak in statute miles. In the aviation world, we deal in Nautical miles, and 1 NM is 6000 feet. It makes the math a lot easier. So, the F-16's glide ratio is actually closer to 6000:1000 or 6:1, mathematically speaking (in all honesty, it's a little better than that, but when your engine quits, it's much better to be conservative than exact).

At any rate, the mental math is a whole lot easier to just say the glide ratio is 1NM per 1000 feet, or "1:1" for simplicity sake (and since all our instruments measure in nautical miles). One less thing to think about when the engine quits.

6:1 is surprising. I thought that the glide ratio would be a lot less until I remembered the leading edge extensions and low wing loading. Still, is this part of the reason that fighters come back to base at cruise speed and only slow down after the break to downwind?

Not really, there are a few reasons for that, not the least of which being that we like to be able to maintain the capability to maneuver the jet as long as possible. Coming back to base at "cruise speed" allows us to still be able to effectively maneuver the jet away from traffic, birds, etc. as long as possible, among other things.

Thanks Snake...

TWO!

Rexxx,
Thanks for the clarification - I see what you mean now .

JR and Bloke,
THREE !!! Any idea what the glide ratio for the Zipper is?