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I am interested in any information about angle of attack indicator
failures, including failure rate, accidents caused by failures,
emergency procedures for failures, and how pilots recognize AOA failures.
For example, has an AOA indicator ever failed during a carrier landing?
With what result? What is the procedure for this?
I can tell you that I was taught in US Navy flight school in the 80s to cross-check airspeed against the AOA gauge every time I dropped the wheels and got ready to land. In the jet world, every time you land you are practicing the carrier approach. Carrier approaches are flown "on-speed", which simply means you work toward, then sustain, optimum AOA. Flying on-speed, power then controls rate of descent. That's important, because flying on-speed sets the correct hook-to-eye distance.
The first thing you do when you slow to approach speed is check your fuel weight (fuel gauges are calibrated in pounds), add it to any other stores (e.g. bombs) you may be carrying, then compute what on-speed airspeed will be for that weight condition. Each aircraft type and model has a characteristic airspeed for on-speed at a base weight (for example, the TA-4F base weight was about 12,000 pounds), this varies from individual aircraft to aircraft, so it is painted on the nose gear door, or at least it was back then.
You add x number of knots (dependent on aircraft type) to base airspeed for each 1000 pounds of fuel and ordnance, then make sure that your AOA shows on-speed at that airspeed. And if it does not agree, you have to figure out which instrument is wrong.
As mentioned above, flying on-speed sets a certain hook-to-eye distance. That is a vertical distance between the pilot's eye and the hook point (the part of the hook that engages the arresting gear pendant). If you think about it, when you are flying the ball properly, you are maintaining your eye in the wedge of light that represents a centered ball. But it's the hook that catches the wire. A centered ball subtends something like 18 inches at the ramp (the ass end of the ship). In other words, there is a window 18 inches high at that point in space if the ball is centered. A centered ball at touchdown puts the hook on the deck just short of the 3 wire, ***but only if you are on-speed***.
If you are slow (cocked up, too-high AOA), your hook point is lower in space and may engage the wire while you are airborne. Since you are cocked up, that slaps the airplane onto the deck and may well collapse the nose gear, always the weak point in the system (the mains are stressed to take that big impact).
If you are fast (flat, low AOA), the hook point is higher in space and may miss the wires, or at least won't be pressed down against the deck as well by the snubber system. A hook-skip bolter is likely as a result.
On-speed is usually something like 1.2 times stall speed, so it's not like you are going to fall out of the sky if AOA is a couple knots off. If all else fails, you ask the LSO how you're looking. Those guys can tell if you're slow or fast just by looking at the picture as you come in.
9mm is just a .45 set on 'stun.'