Friday, February 12, 2010

F-18 Carrier Landing Nuances

The biggest mistake people make with landing on a carrier is using the pitch to control glideslope and power to control speed. This will only result in you landing in an incorrect aoa and speed. The proper technique is to use POWER to control glideslope and PITCH to control speed (or more accurately: AOA). What this means is that in a perfect world once you are set-up and start your approach, the stick should be relatively still with only small movements left and right to correct line-up (since you you should be trimmed "on-speed"). This is an ideal situation. In reality you will need to make SMALL adjustments to pitch as well. Power, on the other hand, should be moving CONSTANTLY. The throttle should not be in the same position for more that 2 seconds. This does not mean to go back and forth between idle and burner, it simply means that you should be constanly making adjustments. If you have ever heard a real Navy jet landing, you know how often power is being adjusted. According to this technique the proper situation remedies are:

Situation: High on glideslope
Remedy: Reduce power

Stiuation: Low on Glideslope
Remedy: Increase power

Situation: Fast (low aoa)
Remedy: Increase pitch

Situation: Slow (high aoa)
Remedy: Decrease pitch

It's imprtant to note here that this is a VERY simplistic view. In reality, every control input has a primary and seconday effect. If, for example, on approach you decrease pitch, the primay effect will be an increase in speed and a reduction in aoa. However, a secondary effect will be a slight increse in rate of decent. By the same token, if you get high and make the proper correction of reducing power, the primary effect will be a noticable increase in rate of decent, while the less noticable secondary effect will be a slight decrease in speed and increase of aoa. The point is to remember that all of your inputs are intertwined, but, primarily we use power for glideslope and pitch for aoa. That said, let's talk about the appraoch.

Get set up about 5 miles behind the boat at 1000 ft. Slow to 150kts while dropping the gear, flaps and hook. If you need to use your speedbrake make sure it is retracted by 3 miles so you can fly a stablized approach. While setting up for the approach you should be in the virtual cockpit so that you can see the aoa indexer. Continue to fly toward the boat level at 1000 ft. 

At about 3 miles reduce power slightly and slowly pitch up to maintain altitude while watching the indexer. As you get an "orange donut", hold your pitch and increase power to maintain altitude. This is where the throttle hand will start to get it's work-out and is also the point where power will control altitude/glideslope and pitch will control speed/aoa. As you do this, note the speed that gets you that "orange donut" (for this discussion we'll say that its 126kts) and trim the airplane. Remember, once an airplane is trimmed for a certain speed, it will maintain that speed as long configuration is not changed. So, if you are trimmed for 126kts and add power you will simply climb at 126kts, and if you reduce power you will decend at 126kts. Keep making power adjustments to hold altitude (for this discussion we'll say that the throttle is moving between 50-55% of its range to hold altitude).

At this point you will start to be able to see the ball which will be low and probably flashing the wave-off lights. Your scan at this point is: ball, line-up, aoa. As you approach 1 mile the ball will begin to come up to its center position. Now, this is important if you want to get aboard and holds even more true in real life: once on glideslope NEVER ALLOW THE BALL TO GO LOW. If it does go low add power to get it above center immediately. Then you can ease it back down to center. A bolter, while embarresing, is a lot better than a ramp strike.

Just as the ball centers, reduce power slightly to start down (now we'll say the throttle is moving between 45-50% of its range to hold glideslope). Keep the scan of ball, line-up, aoa. Once on glideslope, make any final pitch adustments to keep an orange donut and again note the speed. It should be the same speed as when you were level, so you should already be trimmed for it and it should still be 126kts.

At 3/4 mile switch to the 2D cockpit (HUD only). In real life, you simply use the indexer for speed and nothing else. However, in Flight Simulator, the only way to see the indexer is in the virtual cockpit which limits and obstructs your outside view. This is why you note the speed which gets you a donut. Speed now replaces aoa in the scan and your scan becomes: ball, line-up, speed. If the speed goes to 125 reduce pitch slightly to get it back to 126. If the speed goes to 127, increase pitch slightly. If the ball goes high, reduce power slightly, and then once you are back on glideslope increase power again. As stated before, if you get low add power now and get back above glideslope. Then ease it back down onto glideslope.

As you get in close, about 1/4 mile, you are trimmed on-speed so no further pitch adjustments should be needed. Your scan now becomes: ball, line-up.

As you cross the ramp, your line-up should be good (if you you have held it), and no further line-up corrections should be needed. The only thing you are looking at now is the ball. Fly it all the way to touchdown and you should trap a 3-wire. Another huge mistake people make is the desire to see the wires at touchdown. Remember that the hook is 50ft behind you and it should touchdown right in the middle of the wires to catch the 3rd. To do this the wires should disappear beneath you before you touchdown. Any pilot will want as much runway in front of them as possible when they land, but you have to get rid of that desire if you're trapping on a ship.

Another habit people have is the tendancy to flare at touchdown. DON'T. What will happen is the hook will snag a wire while you are pitching up and the force of the trap will slam the nose wheel down. Similarly, people tend to cut power as they cross the ramp. Once again, don't. Your rate of decent will increase rapidly and you'll slam onto the ship. Keep making power adjustments all the way to touchdown, then when you do hit, go to military power. The primary goal in a carrier approach is to keep the airplane at the exact same speed and attitude all the way to touchdown.

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