Unrestricted Climb

Hey this is a question for some pilots,

It seems that when the local jets get cleared for takeoff they usually get an "unrestricted climb to FL 100 1-0-thousand feet" I was wondering why (if nothing else than for fun and because they can) they suck up the gear, go into a 70 degree pitch up and climb up to 8 or 9 grand then roll over for the remainder of the climb to 100? I mean, it looks like a ton of fun, but is that an actual procedure?

thanks,
mix

I think that they climb at a rate that is equivalent to their abilities, just as the 152 I fly climbs out and takes six hours to get to FL100, if you put it in proportion, they are all climbing out at the same speed.

Actual procedure? Yep. Defined steps to do it? Probably but it may vary with the driver or unit. The inverted level off is just to keep positive G on the jet. Doin' a pushover from 70 degress nose-up can't be too comfy I'm thinkin'.

During the Cold War whenever the ADF alert jets got an actual scramble order, they were usually cleared for an unrestricted climb to some altitude and then proceded with the rest of the intercept. For congested areas the altitude may be capped by local agencies to deconflict with other traffic. However, post-9/11 I think if an actual scramble is ordered ATC will manage the traffic to let the jets "play through", to steal a golf term. In outlying areas the normal altitude cap may be higher.

There's also a similar departure called a "Gate Climb" but I'm unclear if it's the same thing as an unrestricted climb.

if the runway is close to sivilian population they may do it to avoid flying over these areas at lower altitudes, if for no other reason than to limit noise polution.

Also makes sense that in a combat zone, the goal is to get the airplane as far away from the guy on the ground with a rifle as quickly as possible. Obviously some loadouts won't allow as quick of a climb, but as far as doing it stateside it is best to 'practice like you'll play', right? As far as rolling inverted and 'pulling' to level, it seems it would be a combination of pilot comfort and airframe limits- the publicly published negative-G limit for a -16 is only something like -4G, I think.
They'll also do a 'max climb' as the first part of an FCF profile, or better yet, when they're giving someone an incentive ride.

schweet, thanks for the info!

In a similar note, during an incentive ride for instance they will lift off and fly parrallel with the runway not too far off the ground then go verticle, how high will/ can they go? And you're saying that when they get to the point where they wanna level off they go inverted then roll right side up?

Well, how high then will/can go is based on a few things, like the loadout on the jet (tanks, etc), and mainly altitude restrictions in place from air traffic control. How long and how low they stay on the deck before the pitch-up also depends on the pilot and any local regs- I've seen some (FCF and/or incentive rides) where they rotated, made about a 10-15 deg climb to the end of the runway, and then pulled up to 60-ish degrees (not quite vertical, but still pointed up a good bit). I've also seen them stay right on the deck, pull to a solid 90 degrees (straight up) and go out of sight. To date my facorite was watching an FCF takeoff on my first airplane (90-0836 at Eglin, Block 50 D model, GE 129). He was clean (no tanks, missles, or pylons except 1 and 9), rotated before he hit the 1000 foot marker, tucked back down to about 20 feet over the runway, and did a hard pull to perfect vertical. He was an itty bitty spec when he rolled out to level. After the flight, he mentioned he rolled out at 15,000 feet, in excess of 350 KIAS. Kick a$$!!
Anyway they do roll 'inverted' sorta. They go vertical, or close to it, then at a designated altitude, roll, and 'pull' (loading the jet with posative "G") until they're flying level (or nearly) but inverted. Then they execute a roll to upright. As mentioned, that keeps them from having to hold negative G to 'push over' to level.

Yes, the maneuver you guys are referring to is called an "Immelman", and they are f#ckin' great to do on an incentive ride!

Max climbs may be restricted due to area traffic. For example, if you want to do a max climb out of Homestead, you must obtain permission from Miami Center. Generally, it isn't a problem, as civilian a/c are typically vectored away from MOAs whenever possible.

A max climb is a great way to start your incentive ride! On my rides in the Viper, we went to 15K, with an immelman recovery.

Great stuff. Highly recommended!

Beers and MiGs were made to be pounded!

Is there an speed / angle in which the F-16 climbs best with the least fuel consumption?

Yes, the maneuver you guys are referring to is called an "Immelman"...

Welllll.....you're partly right. Call it a Half Immelman (an "Imme"? ) An full Immelman results in a 180-degree heading change, whereas the inverted level off keeps (roughly) the same heading.

BTW - the roll inverted at the top of max climb is to prevent negative G's that would happen if you just pushed the stick forward to level out. It's also a good way to clear your tail (manpads) when departing in a combat zone.

The only times I've ever done unrestricted climbs were simply to wow an audience. First time was as we were departing an airshow in which we were just static displays, not performers. We still wanted to make a little noise and look cool though. The second time was departing another airshow, a few days after the show had ended (again I was static display, not a performer in the airshow). The only 'crowd' was my wife who had never seen me fly, so I wanted to look cool. There's not really any guidance as to how to perform one, just get really fast on the deck and put the nose up, try not to overshoot your altitude.

The problem with most clearances is that the radar facility that services the departing airfield generally only owns the airspace up to a certain level. I think in both instances I was cleared unrestricted to around 10-13K feet. To coordinate higher than that you have to start doing some more in-depth coordination, and aside from that, nobody can see a tail-end viper passing about 10,000 feet anyway so it doesn't matter. If I fly an unrestricted climb profile, my technique is to suck up the gear, accelerate level over the runway to about 450KCAS and start about a 5G pull to 60 degrees nose high. You'll find that you'll have accelerated to faster than 450 by the time the nose gets up there. It takes a slight unload to less than 1G to maintain a 60 degree climb initially. Approaching about 3,000' prior to level off altitude, I'll roll the jet over and start an easy 2-3G pull down to the horizon, timing the rate of climb to taper off to zero when I reach my assigned altitude.

Also, the inverted roll and pull is strictly for my comfort. I don't know what the actual climb rate is during one of these, but it would take a pretty aggressive nose-over to arrest it.

For FCF (Functional Check Flights), the unrestricted "Quick Climb" is done for safety. You can make a low key by departure end if the engine coughs. After departure end, your pretty much at a high key position.

Cylon

thanks for the great info, sounds like fun!