Hey Eagl

[Gunslinger]

We discussed this incident in 7 level school as part of the cariculim was briefing a crash investication board on egress matters.

basically I still have to conclude that the "imaculate ejection" as you put it is still impossible.  As you put it there is a chance the guy was pulling Negative Gs at the time wich would have lessend the 40lbs of pressure needed to pull the handles.

The reason I call this BS is because the weight of the handles is not caused by gravity but by spring loaded tension.  Negative G's would not change the amount of pressure needed to pull the handles.

Its kinda like being able to swing a 40 lb wieght by your mask and not notice.

What do you think?

Officials complete F-15 accident investigation
 
9/8/2004 - RANDOLPH AIR FORCE BASE, Texas (AFPN) -- Air Force officials completed their investigation of the F-15 Eagle crash that happened May 21 on the shoreline of St. George Island, Fla.

The accident investigation board determined the accident was caused by a chain of events that led to the pilot’s unintentional ejection, which ultimately led to the crash.

The pilot, Lt. Col. Patrick Marshall, was assigned to the 1st Fighter Squadron at Tyndall Air Force Base, Fla., when the accident happened. He ejected safely.

Colonel Marshall was conducting an air combat training flight when an air-regulating valve detached from his torso harness and became lodged in the ejection seat handle. When Colonel Marshall turned his head to check his position and pulled the control stick toward him, enough tension was put on the detached valve to raise the ejection seat handle, causing him to eject.

The aircraft continued to fly for 1 minute and 49 seconds before it crashed.

The F-15, assigned to the 325th Fighter Wing at Tyndall, was destroyed. It was valued at $36.5 million. (Courtesy of Air Education and Training Command News Service)

[eagl]

I can't discuss safety privledged data, but I will say a few things.  Since my last guess on this mishap, I've seen the report.

First off, the guy was in the process of tightening down a positive G break-turn.  In that situation, a pilot doesn't pull on a darn thing except the control stick.  If he has a hand that isn't on the throttle or stick, it's on the upper canopy handles or rail pushing away so he can get his head and torso twisted around to look backwards, not pulling on anything.

Under 6 or more G's, 40 lbs of weight on the head is NOTHING.  You just probably wouldn't notice that.  When turning your head as you put a good breakturn, a good tug on your personal gear could easily be mistaken as the G loading.

Shxt happens, and the board went over every possibility, everything that could have caused that ejection.  There was some evidence that led them to their conclusion.  I obviously can't go into board deliberation in this forum.

In a defensive breakturn, a lot of things happen quickly and it's by necessity an aggresive and violent maneuver.  I think I blew out my L5-S1 disc at the F-15E RTU, and we were flying the heavier E models and not even the lighter Cs.  So imagine someone resisting and moving around under enough force to blow out the lowest disc in their back, and noticing an additional 40 lbs.  It's just not that much force when you consider your upper torso, harness, helmet, and other equipment weighs upwards of 900 lbs at that point in a 7+ G breakturn.

In the absence of any other data or "proof", I think the board came up with the most likely scenario and I'm inclined to believe them.  We're warned from day one to keep our crap secured in the cockpit so this sort of thing doesn't happen, and there has been more than one T-37 student who flew home sitting on his hands with his handgrips raised because he did something that caused his gear to get tangled up in his seat handgrips.  It's a good thing that the T-37 seats used a dual-action mechanism, otherwise there would have been a whole bunch of inadvertant student "immaculate" ejections over the last couple of decades.

[Gunslinger]

I see what your saying about heavier G loads and not noticing but myself and other Egress types just arent convinced that a hose or regulater could get caught in the handles and yank that much pressure on them especially considering there's a guard on them to prevent just that and that the hose itself is semi rigid.

It was an interesting discussion to say the least and I do try and look at it objectivly.  During the simulated Crash investigation board section I almost failed my PC.  I was going over the innerworkings of an F15 two seater egress system when I called the Canopy piston the "donkey D1ck".  I learned alot in that class and while being grilled by the mock "board".  

Anyhow thanks for further elaborating.