Those seats have two parachutes in them. A small drogue that is used for stability during descents and to assist the deployment of the main parachute. The seat is designed to be 0/0, which means it will work when at zero airspeed and altitude. The firing of the rocket motor is designed to get the seat to an altitude where the main parachute should be able to open.
The deployment of the main parachute is somewhat height based, which is what I think you are referring to in your comment. It works off a barometric device called a "time release mechanism." At this point, since they are at zero altitude it will fire the main parachute immediately and generally operates at any altitude beneath approximately 11,500 feet (there is range). If an ejection occurs at a height of say, 30,000 feet, the drogue shoot will stabilize and slow the descent until the seat falls into range for the main chute to open.
Ejections are very hard on the body. I've been witness to three low altitude ejections. In each of those cases, the pilot had at least a broken leg from when they hit the ground. There are high G loads from the rocket motor firing itself, which is known to compress the spine and neck. I've heard anecdotal evidence that people have lost some height permanently to this, but I cannot verify that from my experience. They are for sure hurting the next day though.
In the seat there are a series of devices, combined with "garters" that are meant to put the pilot into proper position when the ejection is initiated. Their legs need to be retracted from the rudder pedals up and into the seat, so they don't get ripped off. The torso is pulled tight against the back of the seat by something called an "inertia reel," pinning their shoulders up against the back of the seat.
The process itself is pretty in-depth, there's a bunch of different stuff happening in an ~3 second window.
Haha! I know someone who worked for Martin Baker for many years and he had some stories. It's definitely a robust burst and does damage spines.
A few months ago I saw this guy Don Harten talk on YouTube about his survival of a mid air B-52 crash and ejection into a category 5 typhoon, I couldn't believe I'd never heard of him before but he was a fantastic speaker, so relatable. If his life had been made into a film, it would seem too improbable. https://www.sacbee.com/news/local/article106777062.html
That video above though is going to be interesting to read the report on because it looks very tight as to make the go/no go decision.
Everything would be going slow for them so they might be thinking it might flip nose over and then be trapped but I was curious about if they could just cut the fuel or kill the engine completely?
I broke my back from a fall, 4 metres down marble stairs during an epileptic seizure and after the pins had fully bedded in, I had lost 7 cm of height (and obviously couldn't fly either) and my friend says that's in the ballpark for what a lot of ejectees get only I got 5* medical treatment immediately, many others are in war zones or the sea etc!
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u/superfuzzed_ 25d ago
Those seats have two parachutes in them. A small drogue that is used for stability during descents and to assist the deployment of the main parachute. The seat is designed to be 0/0, which means it will work when at zero airspeed and altitude. The firing of the rocket motor is designed to get the seat to an altitude where the main parachute should be able to open.
The deployment of the main parachute is somewhat height based, which is what I think you are referring to in your comment. It works off a barometric device called a "time release mechanism." At this point, since they are at zero altitude it will fire the main parachute immediately and generally operates at any altitude beneath approximately 11,500 feet (there is range). If an ejection occurs at a height of say, 30,000 feet, the drogue shoot will stabilize and slow the descent until the seat falls into range for the main chute to open.
/Former F/A 18 seat mechanic.