Zero/Zero ejection seats vs. safe operating range.

[CH2Tdriver]

In the F-18 crash thread which has been locked already, there was an interesting discussion brewing about what the safe operating range of an ejection seat really is, even though the mfr state that a seat is "Zero/Zero". It was an interesting topic and I figure that I'd post this here.

On the subject of ejection seats, I caught a show on the Military Channel last night called 'Dangerous Jobs: Aircraft Carrier'. It was well done and basically ran down the list of each of the colored shirt deckcrewman positions in detail, as well as including helo pilots and shipboard fire fighters. One thing that made this show stand out was that they used alot of the footage from those onboard B/W video cameras that are used to record flight ops on deck. Most of it has not been seen before. It was amazing to watch and realize how many accidents there are that the general public is not aware of.

One thing I noticed was that there were quite a few zero/zero or low speed ejections recorded on the footage. It seemed that if it appeared to the crew that they might be going over the side, they immediately punched out? In one scene it shows an F-14 on the #4 cat ready to launch. In the background you see the nose of a Tomcat suddenly drop a few feet, and then the crew ejects while the Tomcat stays on the deck. In another an A-6 catches fire on short final....the crew breaks off the approach, flys to the left and then punches out parallel to the deck.

The one scene which I was taken back by was a T-2 flown by a student pilot on short approach. In the camera frame on the left is the island, the tails of 2 Buckeye's and crewmembers standing behind them. The T-2 appears to be waved off but is in an extremely nose high attitude and is wallowing on the fringe of a stall. It then stalls and rolls over to the right on its back and impacts off camera frame on the left. I don't think it hit the parked T-2's but the next thing you notice is both canopies jettisoned off of them.

The show is on again this Sat Dec 13th at 9:00 am on the Military Channel. I got a whole new appreciation for what those guys do after watching that.

Pete

[Randy Haskin]

First off, realize that all that a "zero/zero" seat "guarantees" you is one swing in the chute before your boots hit the ground. Basically the parachute will fully inflate, which starts the pendulum moment of the pilot under it, and as the pilot swings back to the center of the chute area he will impact the ground. It's something like 1/2 to 1 second under an opened canopy. That is not a very safe landing, as after one swing after opening, the parachute hasn't really decelerated you as much as it's going to.

More important to this discussion, the capability of "zero/zero" seats is diminished greatly by a sink rate or downward vector. The #1 most important rule that we brief before every flight is "get out before a sink rate develops". Once the flightpath/flight vector is downward, it greatly shrinks the survivable envelope of an ejection.

Ejection seats are NOT magic by any means, and even the really good ones have pretty significant limitations to the flight envelope.

[Jack Cook]

Randy, does bank angle or pitch figure into it??
My step-dad had a good friend killed in a A-4 crash in the early 70s.
He stayed with it to get it over a unpopulated area then punched out.
The chute opened just in time for the wind to carry him into the exploding wreckage.
I guess a little luck helps also

[RickH]

Thought I would repost since the other thread was locked:

The RAT on the F-4 and A-4 supplies limited electrical power only.

The F-4 primary flight control system was the forerunner of the systems on the F-18, F-15, ie: the mfg refined the systems by adding new technology to the old technology. Servo actuators are very prevalent on the F-4 control surface actuators.

Bold face procedure in several emergency scenarios is simply EJECT !, it is actually written that way in the checklist. The main one is stab failure, the pilot has 0 control in that event. A double PC failure would certainly cause that very failure, as Randy said, the pilot has no control of where the jet will go ( hit the ground).

To folow up on the seat and the MFG website statements, every seat has an envelope that pilots learn. Actuation of the seat within that envelope gives the seat rider a very good chance of having a successful outcome. Out of the envelope? Not so good but not impossible. One of the things that most folks don't look at is sink rate and aircraft attitude. I believe the NACES seat is gyro stabilized. The sink rate is another matter, if the aircraft sink rate is excessive then it reduces the effectiveness of the seat rate of climb, therefore seat/aircraft seperation is degraded which could be put the seat out of it's envelope. 2000ft aint that high when your jet is falling out of the sky ! An awful lot of pilots have been killed simply because they waited too long.

[Randy Haskin]

Randy, does bank angle or pitch figure into it?

Yes, most definitely -- they both figure significantly into the capability of the seat. Any bank angle or downward pitch will also shrink the effective ejection envelope.

Our guidance on what to do if you can control the airplane is, "roll wings level, zoom, and boom!" Zoom means to pitch up and turn any forward speed you have into an upward vector.

[CH2Tdriver]

Thanks Randy, interesting stuff. I guess in the case of carrier operations, if the choice is going over the side strapped in your airplane....the crew would rather chance the one swing and a hard spash into the ocean.

Pete

[Bill Greenwood]

Randy,it is my guess that almost all of us on WIX thought you could reliably get out pretty much zero/zero.
Would you ever consider a belly landing in a F-15 or 18, if you have control but little or no power? Or is ejection about the only way?

That was a hard day for the pilot. The story says the carrier was 50 miles out. He probably came off it feeling pretty good and about 20 min later is sitting in a front yard with destruction and dead all around.

If he was at 1000 feet when he flamed out, and I'd guess with a descent rate around 5000 fpm, then he had 12 sec to do whatever before he hit the ground.

The Father of the dead kids was on TV, in complete agony of course, but with some forgiving words for the pilot. The Father looked Oriental, perhaps even Vietnamese.

[CAPFlyer]

Zero/Zero means just that Pete. It works fine if you're not moving and at zero altitude. The problem you run into is the misconception that if it's Zero/Zero then it must be good at Zero/Negative, which it's not (simple physics and limited rocket fuel).

So, as long as you're moving horizontally or climbing at any speed and relatively upright, you probably have a good chance of getting out and surviving in pretty decent shape. But when you start that "nose dive", you enter a realm that the seat isn't designed to handle fully as you can't just put in a longer impulse rocket or shove more fuel into the tubes at the last second (which would be cool if you could).

Bill, it's interesting that you ask that question. There is a video on YouTube (http://www.youtube.com/watch?v=Zohc7PNP-pw) of a MOANG F-15A pilot who has an engine fire, lands at Whiteman AFB, and then ejects when the plane fails to stop in time and misses the arresting wire. Pilot I think had a broken leg from the landing, but was safe. Funniest thing about the video was the B*tchin' Betty still talking after the plane ran off the end of the runway and breaking up.

[JDK]

A small but important (if I understand correctly) point is that the seat's an emergency escape. Even if everything works like the advert, the rider often faces short-term injury and sometimes worse. It's not a quick way to the 'O Club'.

[warbird1]

A small but important (if I understand correctly) point is that the seat's an emergency escape. Even if everything works like the advert, the rider often faces short-term injury and sometimes worse. It's not a quick way to the 'O Club'.

This is true. The G-forces are extremely hard on the spine, and often create life-long back injuries and disabilities. I read a statistic about it once, and I can't remember the figure, perhaps Randy knows, but ejections are said to make pilots something like a half inch or a full inch shorter in height due to spinal compression after an ejection. Many pilots are permanently grounded after ejections due to the injuries they have sustained. There used to be a rule in the Air Force, I don't know if it's still true, that pilots were permanently grounded after either 2 or 3 ejections due to the detrimental effects it had on the spine and body. Ejections are only used as a last resort and it's not something a pilot wants to have to use unless his life is at stake.

[Jack Cook]

One thing that made this show stand out was that they used alot of the footage from those onboard B/W video cameras that are used to record flight ops on deck. Most of it has not been seen before.

That's called the PLAT ie Pilot Landing Aid Television. I've got hours PLAt from the Forrestal and Saratoga. None from the Nimitz though has it's classified material and VCR were banned from the ship. Watching the PLAT of our flight deck fire knowing I was out there really scared the jeebers out of me. They say crab fishing is the most dangerous occupation. Bull! CV OPS at night is the winner there!!! When I was in VA-128 everyone pulling maintenence of the a/c went through a course of the GRU-7 seat the A-6E used. Somewhere I still have the syllabus.

[Chicoartist]

On that other thread, I picked up on Randy's key word about ejection seat limits: . . . to safely eject from the aircraft. Zero-Zero sounds cool, but there's a bit more to it as he explains above.

Speaking of making use of the seat, here's a neat site:
http://www.ejection-history.org.uk/

Jack - I'd love to see that PLAT footage - have you put it on DVD?

Wade

[Jack Cook]

No I haven't but I should. Since there's np sound it go Country=Western musuc dubbed over it.

[Ztex]

No I haven't but I should. Since there's np sound it go Country=Western music dubbed over it.

How about something like this??

http://www.youtube.com/watch?v=-gb0mxcpPOU

[Randy Haskin]

There used to be a rule in the Air Force, I don't know if it's still true, that pilots were permanently grounded after either 2 or 3 ejections due to the detrimental effects it had on the spine and body.

I don't know that is a rule, per se....but you are correct that ejections come with real physical risk to the pilot and often they end up with serious injuries.

I have several friends who have punched out of F-16s, as well as one who got out of an AT-38. They had minor injuries only.