|
Seems there might have been an ejector seat firing while on the ground (and through the canopy) a few hours ago. Pilot serious injuries.
Last edited by: Fenlander on Tue 8 Nov 11 at 16:04
|
>>>The condition of the pilot is said to be "very serious".
Oh dear... ejector seats really are a last resort and they can inflict massive injuries when they go wrong.
|
>> ejector seats really are a last resort and they can inflict massive injuries
>> when they go wrong.
Don't they tend to cause spinal injuries even when they work correctly? Or is that just the old ones?
|
The canopy is supposed to explode or fly off first. (depending on the system.)
Not designed for deployment on the ground.
|
The modern ones like those on the Hawk trainer are 'zero-zero' seats, meaning that they can be used at zero speed and zero height. This is true for all modern fast jets.
You are correct that in older aircraft one would have to eject the canopy (e.g. Lightning).
For the zero-zero capability the pilot is ejected through the canopy. As the seat is deployed and starts moving, it first hits a detonator that fires plastic explosives encased in a lead strip attached to the inside of the canopy. They call this strip a miniature detonating cord or MDC. You can see this strip on close-up photos as a zig-zag pattern. (I believe pattern this is UK patented, so for example, in French fast jets they attach the explosives further down the canopy nearer the base.)
The explosives shatter the canopy (which is around three quarters of an inch thick) and prongs on the top of the seat clear the rest. The pilot's helmet and body have to pass through large fragments of the canopy.
The molten lead from the MDC causes splattering onto the body of the pilot and can cause injury to any exposed skin. Hence they fly visor down with gloves etc.
The actual seat motion is initially propelled by explosives at the base of a piston which pushes the top of the seat clear of the aircraft. You can see this piston sticking out of the cockpit after an ejection. In older seats they simply had a single powerful explosive and it was this huge force that gave rise to the 20+ G force experienced during ejection that injured pilot's spines.
In the newer seats, multiple explosives are detonated sequentially and are just powerful enough to get the seat clear of the aircraft.
Once clear, a wire attached from the bottom of the seat to the cockpit floor pails out and pulls taught. This breaks a firing pin on the bottom of the seat which detonates a rocket pack propelling the seat to around 300ft.
The multiple forces of the piston followed by the rocket pack lowers the overall G forces experienced.
In 2 seater aircraft like the Hawk, the rocket pack is adjusted to send one seat to the right and the other to the left. Survival is lower if you happen to be crashing near to ground and rolling in the direction the seat is set to travel. e.g. when a hovering Harrier over-banks followed by ejection. On some newer seats I understand that the seat can correct for sideways ejections.
Once at 300ft, another explosive sends a drogue shoot out allowing the main parachute to deploy straightaway. (A barometer on the seat determines if the main chute should deploy. At altitude the drogue will stabilise the seat and then at the correct height the main chute is deployed.)
Ejector seats - very clever inventions.
|
.. having said all this and looked at the pictures on the Mail, it looks like it could be a really nasty accident - so we should all spare a thought, prayer etc. for him and his family and friends.
There have been some nasty accidents in the past where a seat has accidentally been left armed and the pilot has snagged the ejection handle with his boot while exiting the cockpit. I hope it isn't one of these...
|
>
>> Ejector seats - very clever inventions.
Clearly not, or we wouldn't be talking about life threatening injuries.
Edit
Death,
Last edited by: Zero on Tue 8 Nov 11 at 17:29
|
That was the older seats with cartridges which gave a nasty jolt, particularly as in some aircraft, the ejectee had to get enough height to clear the tailplane of something like a Victor or Vulcan. Now it is rocket pack which fires for longer and gives a gentler and progressive thrust. Modern seats can be used on the ground and with the aircraft stationary but a fully deployed parachute is not guaranteed
Pilot here ejected after brake failure on a carrier deck; years ago judging by the aircraft
www.youtube.com/watch?v=GGoSCX9V4fo&feature=fvsr
Last edited by: Meldrew on Tue 8 Nov 11 at 16:34
|
|
BBC has just reported that the pilot has died.
|
Very sorry to hear of this , I deal with the major ejector seat manufacturer and have visited their factory and seen the skill and care that goes into their manufacture.
It sounds like a tragic acident and my condolences to the family of the pilot..
Lets wait and see what the enquiry finds before prejudging
|
|
As of the 21st June 2011, Martin-Baker ejection seats had saved 7360 lives. Looks like a result to me (Martin Baker press release).
|
|
Thats a lot of aircraft lost. Even if assume two air crew per loss.
|
That is over 60 years worth of incidents Zeddo....and 93 different airforces.
|
|
In calendar year 1946 the RAF wrote off over 1000 aircraft and over 600 aircrew were killed. Many aircraft were "Written off" as they were so badly damaged that it was easier to get a new one out of the Maintenance Units, where there were huge numbers, than spend money doing a repair.
|
Meldrew,
James Hamilton-Patterson's excellent book 'Empire of the Clouds' makes exactly the same point. He writes of piles of Meteors, Vampires etc stacked in MU yards etc waiting to be broken up.
If you've not got it already add the hardback illustrated edition to your Christmas list!!
Last edited by: Bromptonaut on Tue 8 Nov 11 at 19:23
|
There was a US officer who used his ejection seats 3 times in 4 sorties. One in Vietnam, another on on his next trip a few days later; posted back to USA for a rest, commanding a squadron. Second trip there - out again! I wonder if he took the hint?
I have the Empire of the Clouds - great book! I am going to get Smoke on Go - the history of the RAF aerobatic teams
|
|
Isn't the position of the ejected important to prevent spinal injuries?
|
|
Not as important is it used to be. The strong but steady thrust of the rocket motor is way less damaging than the punch of the cartridges was. Early seats used a face blind attached to the upper firing handle so that the head was forced back into the headrest and the spine was straightened, to a degree. Now there is no top handle! Also restraints are used on the legs, and on some seats, the arms to prevent then flailing during high speed ejections
|
>>>The strong but steady thrust of the rocket motor is way less damaging than the punch of the cartridges was...
True but while the severity of injury from ejection has reduced the numbers injured remain similar.
Some approx stats from 200+ ejections with modern rocket seats...
90% survival... 30% spine injury, 18% lower limb injury, 15% head injury, 11% upper limb injury.
|
|
I am slightly surprised at a survival rate of only 90%. I will hazard a guess that those who died used the seat outside the design limits. In the days of cartridge seats the spine injury rate would have been around 75%.
|
Luftwaffe statistics support your contention that injury numbers are unchanged. Fewer spine injuries but more from flailing limbs and the overall number unchanged. Note their survival rate of 97.6%
"From 1981-1997 there were 86 ejections from 56 aircraft within the German Air Force. Of these, 24 accidents were associated with the F-104 Starfighter, 14 with the PA 200 Tornado, 12 from the F-4 Phantom, 5 from the Alpha Jet and 1 from a MiG 29 Fulcrum. One case involved a front seat pilot, who had already sustained fatal injuries from midair collision, being command ejected by the rear seat pilot. The remaining 85 ejections are the basis of this study. One weapons system officer died from hypothermia after landing in the sea and another from bleeding into the medulla oblongata after flailing; all other participants survived. This is an overall success rate of 97.6%. Of all 85 participants, 12 (14%) were uninjured, 41 (48.2%) were slightly injured, and 30 (35.3%) were severely injured. Typical injuries were those of the spine and lower limbs. The most common severe injury was a vertebral fracture caused by ejection acceleration. This is followed by lower limb injuries received during the parachute landing fall. At the time of ejection, all uninjured crews were flying below 3500 ft altitude and below 260 kn airspeed. Of all ejections from each aircraft type, the percentage of vertebral fractures is highest with the F-4 Phantom (31.8%), followed by the F-104 (16.6%) and the PA 200 Tornado with only 14.8%. The PA 200 is equipped with the most modern type of ejection seat of these aircraft. A conclusion of the gained data is that more modern ejection seat types provide lower injury severity but not fewer total injury numbers, and that the medical data taken during accident investigation should be taken more accurately and in a more standarized fashion to be comparable.
Last edited by: Meldrew on Wed 9 Nov 11 at 09:05
|
>>>I will hazard a guess that those who died used the seat outside the design limits.
Yes a proportion I expect. The stats probably relate to all cases where a seat fired so may include ground accidents like Scampton too.
|
|
It will be interesting to see what the Inquiry finds. If the pilot was properly strapped in and, for whatever reason initiated ejection, he should have survived, The fact that the seat seems to have gone through the intact canopy implies, to me, some malfunction. The canopy should have been shattered by the Miniature Detonating Cord in a premeditated ejection.
|
|
Further consideration tells me that we can see the canopy is shattered but there is no way of telling whether this happened by the MDC cord doing it, which would be the normal procedure, or if it was broken by the seat going through it which is back-up for MDC cord failure. The Inquiry will reveal all, in the fullness of time.
|
I see the initial inquest has reported that...
A post-mortem examination gave the cause of death as multiple injuries due to a fall from height following ejection from an aircraft.
It appears the parachute didn't open and he came back down still in the seat.
Actually on the day there were eyewitness accounts on the net within 30mins of the incident which indicated this was the case but they were quickly taken down out of respect for the family of the pilot as it was way before he'd oficially been declared dead, for the same reason I didn't mention this on my initial post.
How sad for those on site to watch this unfold (quickly obviously) realising there was nothing to be done.
www.telegraph.co.uk/news/uknews/defence/8906375/Red-Arrows-pilot-killed-when-parachute-failed.html
Last edited by: Fenlander on Tue 22 Nov 11 at 12:13
|
Red Arrows Accident? - Meldrew
