How To Land On A Carrier
By Matthew Hummer
Before I talk about how we land on a carrier I should explain angle of attack, or AOA. Angle of attack is the angle between the mean chord of your aircraft's wing and the relative velocity of the oncoming air. Coupled with the optical landing system it's the heart and soul of a carrier-based landing.
Angle of attack is important because it's one of the factors affecting lift that you can change in flight. When you pitch up, you momentarily rotate the aircraft about its lateral axis. This causes the angle of attack to increase, and as AOA increases your wing develops more lift. Your plane climbs. Increasing AOA increases lift. At a constant AOA and power setting AND when the plane is straight and level, all forces are in balance. Knowing this we can also deduce that in straight and level flight and at a constant angle of attack, an increase in power will also cause the plane to climb. The increase in thrust produces a corresponding increase in airspeed, and since our AOA is constant, with the increase in airspeed we develop more lift. The airplane climbs.
In order to maintain straight and level flight while increasing airspeed, you must reduce AOA. To fly slower you have to increase AOA. HOWEVER...you can only increase angle of attack so far until the oncoming wind can't wrap around the wing anymore. The angle is too sharp. It separates off the backside of the wing and this is called an aerodynamic stall. The point on the angle of attack graph where this happens is called critical AOA. Note that theoretically you could be going extremely fast, pull back really hard on the stick, and if the plane rotates about its axis fast enough you could exceed the aircraft's critical angle of attack and stall the wing even with sufficient airspeed for flight.
Here's the important stuff. At a constant angle of attack in straight and level flight, a DECREASE in power will cause the plane to DESCEND. This is the underlying principle of flying an AOA approach, which is exactly how we do it going to the boat.
Since angle of attack is measurable by the angle of the wind to the chord of the wing, we can tell our AOA by sticking a probe out on the wing and showing the readout in the cockpit. AOA is measured in arbitrary "units". Typically, the high 20's is where you'll find critical AOA. In the T-45C Goshawk, critical AOA with gear and flaps down is 26 units. Increasing AOA past 26 units will result in a stall. Besides the AOA gauge, we also have what's called an AOA INDEXER. This is the little green, amber, and red thing next to the HUD that turns on when the gear is down and locked.
We know that as we slow down we must increase angle of attack, but we also know that we can't slow down and increase AOA TOO much or we'll stall. One way to tell just what speed and AOA we need is from tables and graphs...but the simple way is by the AOA indexer. When the amber donut in the center of the indexer is the only indicator illuminated, you're flying just the right speed for approach. This is called being on-speed. If you get too slow for the approach the green chevron will illuminate. The color and direction are important...it tells you exactly what you need to do to fix the situation. Green means go...add power. Adding power will flatten out your approach and reduce the angle of attack. Your angle of attack is high because you're slow or your descent angle isn't steep enough. The chevron points down...lower the nose. Lowering the nose will increase your rate of descent. Either action will cause the chevron to disappear in favor of the amber donut, but always remember that with a correction of pitch you're going to need to adjust the power. The opposite is the red chevron. The red chevron points up. Pitch up. Red means stop...back off the power. In either case you'll increase angle of attack, which is exactly what the indexer is telling you you need to do. Keeping the amber donut illuminated will keep you on a nice slightly nose-high glide to the deck.
If you slow to on-speed and stabilize in straight-and-level flight you'll find an associated airspeed given your weight. For the T-45C this is roughly 141 with gear down and half flaps. Once stabilized with the airplane trimmed out it should fly itself. The beauty of an AOA approach is that once you have that condition you're basically done making serious inputs. Decreasing power will cause the airplane to descend without changing angle of attack and the opposite is true for adding power. Trim the plane for on-speed. When it comes time to descend from pattern altitude, smoothly reduce power slightly and bump the nose over just a touch to start the aircraft descending. From here on, all corrections to descent rate should be made with power only. The only thing you're using the stick for is lateral control.
But how do we get to that point? Like this...
So this picture is from one of my pubs about field carrier landings but it applies just the same. Instead of a runway, substitute the boat. The setup begins 3 miles directly behind the carrier...not behind the approach course, but behind the boat itself and aligned on the same course that the boat is driving. We want to be 800' above water's surface at 250-300 knots and heading straight for the ship with the hook down. What we're aiming to do is fly past the ship just slightly to its right and as we pass the bow we're going to flop, chop, and pop: flop the plane over into a 70 degree angle of bank left turn across the bow of the ship for 180 degrees while simultaneously deploying speedbrakes to full and chopping the power to idle. This is called an overhead break (sometimes also called the overhead, or carrier break). The turn in combination with the loss of thrust and speedbrakes should bleed off a ton of energy. The goal is to roll out after 180 degrees of turn at 200 knots or less (safe gear speed). The speedbrakes stay OUT from then until landing. We land with the speedbrakes out to provide a margin of error and to allow the engine to operate at a higher rpm for a given airspeed where it'll be more responsive.
We're on downwind now, 180 degrees to our original course and on a reciprocal of the ship's course with the speedbrakes out and our airspeed below 200 kts. Descend to 600'. Drop the gear and bring flaps to full. Perform landing checks...gear down, flaps/slats full, hook down, harness locked, speed brakes extended, anti-skid switch OFF, checklist complete. Abeam your intended point of landing (the ship) make your radio call to the LSO. "Blazer 302, gear & flaps, 122 knots, 2.5 (fuel in thousands of pounds), number 1 (qual number), downwind". 15 seconds after making your abeam call (at what's called the 180) start a 2-300 fpm, 30 degree angle of bank descending turn to the left. You should be focused on the instruments and not outside for the first half of the turn to final. Halfway through the turn (called the 90) establish a 500 fpm descent, 30 degrees AOB turn, on-speed, and start peeking outside. As you finish your 180 degree turn you get to a point called the start. The start is just what it sounds like...the start of the groove. The groove is carrier talk for the final approach. Roll out wings level, 425 feet, 15 seconds behind the boat at approximately 3/4 mile and spot the Fresnel lense on the aft left side of the ship. If you see it, call the "Ball". If not, call "Clara". From here you should be concentrating on two things: Keeping the orange "meatball" centered top to bottom and side to side in the big green cross, and maintaining that on-speed airspeed (amber donut). The ball is your position on the glideslope and the amber donut is your angle of attack. Keep the descent coming down all the way to the deck. From the time you hit the start until touchdown NOTHING SHOULD CHANGE. Don't flare. Hold the amber donut until you impact the deck. Hopefully you would've picked up a wire but either way when the wheels touch, throttle comes to MRT, speedbrakes retract, and expect to go around. If you "bolter", leave gear and flaps down, establish a climb to 300' and turn downwind while climbing at 130 or on-speed, whichever is greater. Re-enter the pattern and do it all over again until you trap!
That's it on the landings.
Matthew Hummer is an instrument-rated, multi-engine, commerically licensed pilot with C172/PA28/DA42/T6B/T45C time, currently on active duty in the US Marine Corps