Ejection

[Mogus]

Could someone elaborate on what goes on when you eject? What kind of forces are exerted on the body? A USAFA grad spoke to us at Boys State and mentioned that he didn't know anyone that had ejected and not had a screwed-up spine afterwards. Is that true? Just curious. Thanks...

 

[chawbein]

I'ld believe it. I don't relish the thought of having a rocket strapped to my ass.

 

[firstthird]

I didn't fly ejection seat aircraft so am not an expert but I'm pretty darned certain that not "every" person who ever ejected had a screwed up spine.

Basically, I think a lot has to do with whether or not you are in the envelope for ejection, if you are cruising at 600 mph and pull the handle, that probably is outside the envelope for most planes. Some planes you have to have a certain minimum speed since they don't have a 0/0 ejection seat.

I think there is a rule saying that after your 2nd (or 3rd) ejection you are done flying ejection seat aircraft though. I don't have exact numbers but I'm sure there is something like 20 g's or maybe more applied during the ejection cycle. of course, the alternative is likely much worse or you wouldn't be giving that particular plane back to the taxpayers. I think the jet guys have a saying that the PK of the ground is 1.0 (meaning if you impact terra firma it will kill you, PK= percentage kill; used to rate AA systems I'm pretty sure)

I'm an old P-3 bubba though so I'm more knowledgable about per diem and travel claim check cashing.

Actually, here is a paper about it from some Navy Flight Surgeons.

http://www.vnh.org/FSManual/22/04Dynamics.html

It does talk about a high incidence of vertbre injuries mainly resulting from improper body position (maybe if you are out of the envelope survival becomes the problem vs. injuries).

We've got lots of pointy-nose drivers on the board, hopefully they'll enlighten us.

 

[PTWOB]

I have several bud's who have ejected from several different types of airframes with no long term ill effects. To piggyback a little, it has a lot to do with aircraft attitude, speed, proper body position, etc. The newer ejection seat system is the more likely it is to protect the flyer sitting in it through a wider range of parameters. I'm sure that the comment about 100% spinal injuries is a bit of an exageration.

 

[talondriver]

I'ld believe it. I don't relish the thought of having a rocket strapped to my ass.

I'd take the rocket over the alternative. I'm to the point where I'd be uncomfortable flying in a jet without an ejection seat.
As for the effects of ejecting..
I've never had to use the seat (knock on titanium) but it would surely depend on your body position during the sequence as well as the parameters of the jet at the time of ejection. I know guys that have punched and they're fine.

 

[AlbieF15]

As for "screwed up spines", there are more than a few old fighter pilots with holes in their necks from vertebrae surgery even WITHOUT ejecting. My former ANG Det commander is one...and I've met lots more. My former boss was a Viper driver for many years, and from what I here the surgery is not that uncommon. Any Semper Viper types know the surgery?

 

[talondriver]

I know two former Viper dudes who had the "neck" surgery" within then last year (both T-38 IPs). One was an old cranium and the other was fairly young. The younger guy's trying for a stink bug.

 

[CCDiscoB]

I'm to the point where I'd be uncomfortable flying in a jet without an ejection seat.

Same
What about those guys at air shows that fly around in single engine jets, like the F-86 and MiG-21, without ejection seats. Crazy if you ask me. Heck, I wouldn't fly an air show F-4 without a seat.

 

[GumbyDarnit]

I am an old Viper driver and have never heard of the Surgery, but I will say that I could use some kind of help. There is always someone in the squadron walking around with a stiff (STS) neck. I myself would have had to quit flying Vipers several years ago if I could not have gotten help from a Chiroprator. Of course I can only say that now that I've retired because it is almost viewed as self medicating. Now I'm dating a Chiroprator, she rocks!

There is no rule that says you must stop flying an AC with an ejection seat after you had 2 or 3 ejections. On the other hand I have only heard of one guy who had more than one, but Paul Gilcrist wasn't him. When I was flying the stink bug (I prefer to call it the cockroach cause it's really ugly and only comes (STS) out at night) my flight commander ejected from an A-7 over Indianoplis. His back was screwed up until he ejected, the rocket ride "fixed him up". That was the only good thing to come (STS) out of that accident. Getting your back fixed from an ejection certainly wouldn't be the norm though.

About the ejection envelope. Sink rate has the biggest determination for the envelope, therefore how your dive angle and airspeed combine for sink rate will determine the envelope. Air Force guidance for minimum ejection altitudes is 2000 AGL for a controlled flight ejection and 6000 AGL for an out of controlled flight ejection (assumes a very LARGE sink rate, something in the order of 15,000 ft/min). The actual envelope is MUCH more capable then the guidance.

A word about high speed ejections. Current egress equipment in the front line fighters will work up to the placard limit of the aircraft (800 KIAS or MACH 2.05 for the Viper). The problem encountered is flayling injuries. Somewhere above 450 calibrated will produce flayling injuries. Somewhere above 550 cal will really hurt. I've had two former squadron mates go out above 600. They both drowned as a result of their flayling injuries.

As Talondriver said, body position is very important to how your spine will handle the ride.

All that being said, ejection seats are a very very good piece of equipment. I miss having that option a great deal and don't relish the idea of not having a rocket strapped to my a$$.

So to finally answer the question whether it is true that everyone who ejects is going to have a messed up spine. It is not true, I know of scores of guys and gals who have ejected with no ill effects. In fact, I know of no one outside of those who receive flayling injuries who had any problems from their silk letdown experience.

How's that?

I'm Gumby darnit.

 

[Draginass]

It is certainly possible to be injured in an ejection. Many have, but most have not, if the ejection is relatively slow speed and sufficient altitute. One can expect severe flailing injuries at airspeeds above 500 KIAS. Retaining your helmet in a hi-speed ejection is also unlikely.

Given the alternative, ejecting seems like a good risk if needed.