# Latest F-35 bang seat* mods will stop them breaking pilots' necks, beams US

The American F-35 Joint Project Office says ejection seat and helmet modifications will stop emergency ejections from breaking petite pilots' necks. Pilots who weigh less than 62kg (9¾ stone, 136lb) are currently banned from flying the state-of-the-art F-35 fighter jet because an emergency ejection using the currently fitted …

1. #### minimum weight

Can't they put adjustable weights in the chair, like a handicapped horse? Or is it that a man who weighs less than 9 stone is going to be flimsy and prone to falling apart?

1. #### Re: minimum weight

Surely it can't be a simple weight switch; what if the pilot is pulling +g?

1. #### Re: minimum weight

Well that's an interesting point.

G applies to the entire mass of the seat. Under +G the seat and pilot are "heavier" for the charge to get moving.

If one ejected under negative g, then the pilot and seat would be "lighter", meaning even the sturdiest pilot would come in "underweight".

One presumes the seat already has a g-meter to deal with such potential variation in ejection conditions, and the weight switch would inform it whether the pilot is lighter than the cut-off at a given g-rating.

1. #### Re: minimum weight

Far simpler - perhaps the seat electronics take the weight of the pilot before takeoff and store that information until the plane has landed again?

2. #### Re: minimum weight

If all the switch does is delay the parachute opening a little to allow the seat to slow down a little, why not just make the delay standard and do away with the switch?

1. #### Re: minimum weight

If you want a parachute to open, then the implication is that you are falling.

But delaying the parachute opening allows the seat to slow down a little??? What laws of physics are in operation here?

Also, bodies of different masses fall with the same acceleration. Some old Italian dude is credited with that one. So what difference does the pilot's weight make?

I suspect that something has been lost in the reporting...

1. #### Re: minimum weight

"But delaying the parachute opening allows the seat to slow down a little??? "

Yes; as ejected, the seat is moving forward through the air at the same speed as the aircraft but is nowhere near as aerodynamically shaped. Hence, it slows down as time goes by. Opening a parachute on a forward moving seat will give a large force that causes the pilot's head to move forwards.

However, I still don't understand what the pilot's weight has to do with it. Unless a lower weight pilot results in a faster ejection (upwards) speed due to a lighter mass load on the ejection mechanism ...... I still don't get it.

1. #### Re: minimum weight

It's probably something to do with design tradeoffs.

The problem is going to be that it's a zero, zero ejection seat. Meaning that should the F35 catchfire on the runway then the pilot can eject from zero altitude whilst stationary. This requires a fairly powerful explosive exit, followed by a very fast parachute deployment.

At a guess, the reason the timer is set to it's current setting is that if it's set to longer then if you do a zero zero eject then the seat could well hit the ground before deploying the chute, a not ideal situation.

If you then eject at speed, kicking out the parachute pretty much immediately is going to cause the ejection seat to go from the aircraft speed to a slow decent very quickly. So quickly that the helmet is going to cause the pilots head to get something like whiplash, which presumably has never been a problem previously because the helmets were just there to protect the pilots head, instead of having a ton of electronics attached.

They probably used a very, very simple fault impervious and time proven system like a burning fuse lit by the initial ejection charge because I suspect the Martin Baker engineers are probably more paranoid about system failure than most of EL Reg's readers. I guess somebody is having to design in a more untested and less fault tolerent workaround at the moment that checks how fast the seat is moving and how far it is from the ground etc.

The weight issue probably doesn't have much to do with weight in the seat per se, but how the pilot is built, ie people with strong neck muscles might get strained muscles, but slightly built pilots get broken necks. As telling people to measure people's neck with a tape measure is probably not an acceptable workaround, and given military fitness standards mean that body fat is not likely to be significant on pilots somebody probably figured that it wouldn't be an issue for >99% of people over \$weight (+\$FudgeFactor) as they probably have substantial enough neck muscles for this not to be an issue. Probably. Just guessing.

1. #### Re: minimum weight

They probably used a very, very simple fault impervious and time proven system like a burning fuse lit by the initial ejection charge

They don't. They use a barostat. This contains a clockwork timer and a diaphragm pressure switch. Deployment is delayed until the timer has expired - so that the seat is clear of the airframe - and until the pressure is high enough. If the pressure is too low, then the seat might be too high, or else it is travelling too fast. In either case, it sits under the drogue until it reaches the correct height & speed, and then a clamp is released which allows the drogue chute cable to pull the main parachute out.

It's quite ingenious really.

Vic.

2. #### Re: minimum weight

Looks to me as it is the hard deceleration when the parachute opens that is the issue. Not the ejection per-se.

2. #### Re: minimum weight

"So what difference does the pilot's weight make?"

My guess is its more to do with the pilots build. A heavier pilot is more likely to have stronger neck muscles that can withstand the forces. Sure a fatty won't, but then they won't have got through the selection process to pilot a fast jet in the first place.

1. #### Re: minimum weight

Pilot build does seem a likely problem, don't forget there's a lot of female fighter pilots out there.

2. #### Re: minimum weight

I believe the issue is due to faster deceleration on the main parachute (same drag less mass pulling it down for lighter folks) while the pilot's head (and heavy helmet) suspended on the (weaker) neck continues down at original velocity (due to its own inertia). So for a moment there's potential for speed difference between the seat (and pilots body) and the head/helmet and resulting injuries. I'd guess that delayed opening of the main parachute let's the pilot-chute decelerate some of velocity though changes to helmet construction and neck brace (or whatever stabilizing device they implemented) would probably be of greater importance.

3. #### Re: minimum weight

You're missing the atmosphere, mate.

Fighter jets travel fatser than the terminal velocity of a dude strapped into a chair, so when he's ejected he'll spend the first seconds slowing down.

Also, bodies of different masses fall with the same acceleration _in a vacuum_, but usually fall with different accelerations in an atmosphere, due to drag.

1. #### Re: minimum weight

fall with different accelerations in an atmosphere, due to drag.

Not very surprising, but I don't expect pilots to wear large billowing dresses very often.

The one with the 'Priscilla, Queen of the desert' DVD in the pocket, ta.

2. #### Re: minimum weight

Fighter jets travel fatser [sic] than the terminal velocity of a dude strapped into a chair, so when he's ejected he'll spend the first seconds slowing down.

Ah, but not if he's flying upside-down when he ejects.

1. #### Re: minimum weight

Even if s/he's upside down his forward velocity will decreasing fairly violently if the aircraft was doing mach 2 when the handle was pulled

It's quite possible that drag will slow down the pilot vertically too - a bang seat will initially be accelerating at 20+G and won't take long to exceed the terminal velocity

4. #### Re: minimum weight

But delaying the parachute opening allows the seat to slow down a little??? What laws of physics are in operation here?

The seat has a two-stage parachute system: as the seat leaves the airframe, a rocket is fired from the top which putts a drogue chute out.The main chute is delayed by a fixed time delay and an air pressure switch (the barostat), preventing the chute from deploying if the seat is too high or travelling too fast.

Prior to the main chute being deployed, the drogue slows the descent of the seat. Once the barostat has fired, it then pulls the main chute out.

Also, bodies of different masses fall with the same acceleration. Some old Italian dude is credited with that one. So what difference does the pilot's weight make?

By the time the main chute deploys, the seat frame has been thrown away, and only the pilot's weight remains in the harness. The force exerted by the parachute is going to be pretty much constant for a given descent speed, and the resulting acceleration is given by Newton's second law. The heavier the pilot, the lower the deceleration.

Vic.

2. #### Re: minimum weight

"There are no UK F-35 pilots affected by this issue"

Does this imply that they are all lard-arses?

1. This post has been deleted by its author

2. #### Re: minimum weight

Worse. It means that there are no F35 aircraft in the UK.

3. #### Re: minimum weight

> Does this imply that they are all lard-arses?

Or that no pilots are affected because they're not doing any flying due to a lack of planes.

3. #### Re: minimum weight

Good idea.

BTW each helmet is apparently tuned to the pilots eyesight and eye motion tracking.

According to The Economist it takes 2 days for a helmet to be calibrated to a pilot.

4. #### Re: minimum weight

"Can't they put adjustable weights in the chair, like a handicapped horse?"

I can see PETA's response now...

"While we applaud the military for not discriminating against handicapped horses, we strongly oppose putting a horse in a fighter jet."

:)

1. #### Re: minimum weight

@Montreal

Damn you. I need a new keyboard.

5. #### Re: minimum weight

This has to do with body mass and build and the spine and neck being able to support the helmet when the seat fires. I guess you've never read or heard about the violence that happens once someone pulled the eject lever?

1. #### Re: minimum weight

Do you really want to delay the opening of the parachute if ejecting from ground level ? Take off and landing being the most dangerous phases of flight etc.

Maybe F1 style helmet brace would work.

1. #### Re: minimum weight

"Maybe F1 style helmet brace would work."

Unlike F1 drivers, pilots are expected to be able to look over their shoulders, etc.

1. #### Re: minimum weight

Unlike F1 drivers, pilots are expected to be able to look over their shoulders, etc.

They could mount, err, wing mirrors. Just have to be careful of the blind spots...

2. #### Re: FOV. F35 doesn't have one.

Could very nearly bolt the helmet to the seat and not affect the pilot's field of view significantly. He's supposed to use his HUD and something akin to Hololens.

2. #### Re: minimum weight

"I guess you've never read or heard about the violence that happens once someone pulled the eject lever?"

I have, enough to know I'd never want to do it unless there's no other choice.

A substantial proportion of pilots who eject spend the rest of their careers flying desks thanks to spinal damage.

The fact that this is related to the mass of the helmet indicates that this is related to the compression forces generated on cervical vertebrae when the eject rocket fires. Ejector seats clamp the pilot's head to the seat back during eject specifically to ensure that forces are vertical and to prevent whiplash injuries when the chutes open.

1. #### Re: minimum weight

I have, enough to know I'd never want to do it unless there's no other choice.

I was reading an article a while back about that way of thinking; apparently, there is a real problem with civilians flying ex-military aircraft in that they really don't want to eject.

A substantial proportion of pilots who eject spend the rest of their careers flying desks thanks to spinal damage.

I think that might have been true for very early seats, but that was a long time ago. There's been lots of development on ejection seats.

The fact that this is related to the mass of the helmet indicates that this is related to the compression forces generated on cervical vertebrae when the eject rocket fires.

It;s the pilot's mass that is important. To my mind, that implies it's the deceleration on deployment that causes the problem.

Ejector seats clamp the pilot's head to the seat back during eject specifically to ensure that forces are vertical and to prevent whiplash injuries when the chutes open.

Errr - you sure about that? Because none of the seats I've played with do that...

Vic.

1. #### Re: minimum weight

"I was reading an article a while back about that way of thinking; apparently, there is a real problem with civilians flying ex-military aircraft in that they really don't want to eject."

In many countries ex-military craft have the ejector seats removed so a civilian pilot can't eject even if (s)he wanted to (explosives being illegal in a non-military craft, etc). There's also the issue that being in the aircraft means that pilots tend to take more care about where it ends up when things go ultimately pear-shaped.

"I think that might have been true for very early seats, but that was a long time ago. There's been lots of development on ejection seats."

Indeed there have, but a 1 in 4 chance of permanent disability is still far too high for my liking. There are quite a few pilots who've ejected once and are still in cockpits but very few have ejected twice and been able to resume active duties.

WRT ejector seats and head clamps: Older ones don't. Newer ones do - along with the also-mentioned airbags to securely clamp the pilot in for the duration of the (short) ride. The issue at point in the F35 is excess helmet mass and I'm pretty sure that the pilot mass requirements are a kludge answer as neck strength and crush/whiplash resistance are wildly variable even for people at the same mass and fitness (Think wrestlers vs footballers)

Presumably the problem could be solved in the short term by moving as much of the mass of the helmet as possible somewhere else but dangling umbilical cables are going to be problematic and it means the ease of dropping a pilot into any available aircraft will be compromised (plus it's something else to go wrong in the field).

Longer term, lighter components will probably be available but by that point piloted craft will probably be obsolete.

In any case the F35 was never designed as an air-combat/air-superiority machine. That's a job for the F22. The F35 is too tubby, too underpowered and with too stubby wings to be an effective fighting machine(*)(**) and by the time it gets into the field its much-vaunted stealth(***) capabilities will be so hopelessly compromised by countermeasures that most of its armaments are likely to be on external hardpoints as there'll be no point hiding itself.

(*) Because the F22 will never be sold to other countries you can expect the Eurofighter and other aircraft to keep working alongside the F35 for a long time to come (assuming it isn't cancelled - and even the SDI got cancelled in the end on cost grounds despite massive multistate pork-barelling)

(**) These same features make it badly compromised as a ground-support aircraft. Short range and low carrying capacity mean it's less capable than what it replaces.

(***) F35 is ONLY stealthy on a 30 degree cone around the nose end of the longitudinal axis(+), ONLY stealthy at currently used SHF radar frequencies(++) and ONLY stealthy with the doors closed(+++)

(+) Networked detection systems can see it clearly from side or rear and transmit to AA batteries located along the flightline. Newer AA missiles can be guided from those side/rear radar systems rather than relying soley on the onboard smarts or controllers near the launch site. F22's role is to eliminate this threat but other countries won't have the F22

(++) Painting with VHF/UHF radar has been shown to work (UK air defence can see B2s even when they're fully stealthed up) and past US stealth tech has failed hoplessly when the wings are wet (which is how the F117 got shot down). Water is a pretty good reflector so all the matte paint in the world may not help much.

(+++) Neither of the above points matter much when you have a "stealth" aircraft so badly designed that the weapons bay (and other) doors need to be opened in flight every 10 minutes or less due to the avionics overheating and needing emergency cooling. At that point it'll cause even the dumbest radar systems to light up like a christmas tree.

The F35 is one of the most expensive clusterfucks the USA has ever engaged on and it's going to fuck their economy even worse than Ronnie RayGun's Star Wars program (which left the USA deeper in debt than it had ever been at any point in history). The best thing that any other country can do is hedge on purchases (many have already cancelled) and try to make as much money out of the program as possible in the meantime.

1. #### Re: minimum weight

In many countries ex-military craft have the ejector seats removed so a civilian pilot can't eject even if (s)he wanted to (explosives being illegal in a non-military craft, etc).

Yes, but there are also countries where that isn't the case. The UK, for example, permits ex-military aircraft to carry original safety equipment.

There's also the issue that being in the aircraft means that pilots tend to take more care about where it ends up when things go ultimately pear-shaped.

If it's time to eject, that's actually a false premise - the pilot has already lost the ability to decide where the aircraft goes. The problem is that civilian pilots often try to fly through this situation - and invariably make the problem worse.

Indeed there have, but a 1 in 4 chance of permanent disability is still far too high for my liking. There are quite a few pilots who've ejected once and are still in cockpits but very few have ejected twice and been able to resume active duties

I suspect your data might be out of date. I fly with several pilots who have ejected many times - being close to ETPS means that several of my acquaintances are former test pilots. I know no-one who has been rendered disabled by ejection. I know several people who have ejected enough times that your 1-in-4 chance should likely have left them so, so I'm afraid I must disbelieve your statistic.

WRT ejector seats and head clamps: Older ones don't. Newer ones do

Do you have a citation for that? I've seen quite a few in-cockpit shots of Typhoon, and I've yet to see anything that could accomplish that.

In any case the F35 was never designed as an air-combat/air-superiority machine. That's a job for the F22.

Well the original description released for the F-35 was that is was a cost-down F-22. Given that the F-22 cost \$150M each, this might still be true[1] - but is is a far inferior aircraft for that price tag.

The F35 is one of the most expensive clusterfucks the USA has ever engaged on and it's going to fuck their economy

It is - but look at what the UK has committed to buy as well. It's not just the US economy that buggered...

Vic.

[1] <a href="https://en.wikipedia.org/wiki/Lockheed_Martin_F-35_Lightning_II>Wikipedia</a> reckons the current F-35A costs \$98M without engines. Whether this will make it cheaper overall than the F-22 is not a calculation I want to make right now...

6. #### Re: minimum weight

I've always wondered if there was an advantage to be "heavy" (which might be called "out of shape" in the military).

I'm around 100kg (15+ stone if I get the conversion right) at the moment, so I guess I'll do.

2. #### Handling the G's

I am surprised that anyone approaching the lower weight limit would be capable of handling the

G-force's that pilots sometime have to endure.

This is based on my personal assumption that the heaver and stronger that you are, the more G's you can handle.. Although I could be completely wrong on this point.

1. #### Re: Handling the G's

IIRC, much to the annoyance of those in charge at the USAF, it was found a number of years ago that those best suited to handling G-forces were small, slightly overweight females. Not quite the all American jutting jaw hero type they try to portray.

1. #### Re: Handling the G's

Same with the Astronauts, women were trained for Mercury Gemini but didn't fly probably for PC reasons :(

1. #### Re: Handling the G's

"Same with the Astronauts, women were trained for Mercury Gemini but didn't fly probably for PC reasons :("

Or maybe they just weren't good enough. I know, a shocking statement but it could just be true.

2. #### Re: Handling the G's

Actually smaller people and women particularly handle excess G better and less likely to black-out.

1. #### Re: Handling the G's

"Actually smaller people and women particularly handle excess G better and less likely to black-out."

Which is more important, the fact that they are women or the fact that they are shorter ?

I can't find any serious article which states clearly that women are actually more capable, a reference anyone ?

1. #### Re: Handling the G's

I can't find any serious article which states clearly that women are actually more capable, a reference anyone ?

You best ask a few women, but give me a moment to buy some popcorn first :)

2. #### Re: Handling the G's

"Which is more important, the fact that they are women or the fact that they are shorter ?"

Both. Women handle G forces better than men do and jet pilots tend to be short legged/long-armed (most male pilots are in the 5'4-5'6 range)

Being long legged is decidedly unhelpful when ejecting. Tales exist of pilots being amputated at the knees by the canopy or instrument panel.

3. #### Re: Handling the G's

Which is more important, the fact that they are women or the fact that they are shorter ?

Shorter.

The pressure difference between the heart and the head is a multiple of the density of the blood, the current acceleration, and the height. The first is pretty much constant, the second is the acceleration we're talking about, and the third is down to the dimensions of the pilot.

The brain requires a certain pressure to maintain consciousness; the smaller the distance from the heart, the less pressure that heart is required to develop. Thus smaller pliots are more able to handle high-g situations.

Vic.

2. #### Re: Handling the G's

It's largely a height issue but there's also a build issue. A short person who is well conditioned resists black-out better because in addition to the G-suit, which effectively squeezes the person, a short person has a shorter distance to pump blood to keep the brain in adequate oxygen supply. Being fat is bad and fit is better because in addition to the lower probability of restricted arteries a fat person isn't as capable of tightening their muscles to push as much blood toward their brain as a slender fit person and it comes down to only the suit squeezing the fat. In the end, your ideal fighter pilot would look a lot like a well toned jockey.

Of course, that isn't what the typical fighter pilot looks like and in order to accelerate the typical amount of beef of the larger pilots and clear the tail it has to be a rather good shove and you want the parachute to deploy quickly because you never know what orientation the plane will be in or how close it is to the ground, yes that would leave a mark. So you get a really healthy shove out followed by a quick jerk back which would likely break our jockey's neck. Delaying the rearward jerk while reducing whiplash will also increase the odds of splatting on the ground in the hopefully rare case of an inverted low altitude ejection. Perhaps a simple1 tether to the back of the helmet that goes taut when ejecting would ease the problem while keeping the quick chute deployment.

1. Simple in concept as I'm fairly sure it would require a bit more than installing a seat belt auto-tensioner since the "gravity" vector can change radically in a fighter aircraft.

1. #### Re: Handling the G's

Perhaps a simple1 tether to the back of the helmet that goes taut when ejecting would ease the problem while keeping the quick chute deployment.

Has anybody done a cost benefit on not having ejector seats at all? Yes, you crash, you bought it, but there's a cost to the extra weight and complexity of ejectors, plus a small but notable number of accidents where poor buggers have been thrown out of serviceable aircraft by ejector related mishaps (and a fair few ejected crew are sufficiently injured that they never fly again).

Some will say that's a bit harsh, given that every hull loss would then mean a pilot loss. But demanding a lifeboat when you fly a ship specifically designed to rain death on people usually without suitable means of defence against your weaponry seems a tad rich, perhaps? Chopper pilots take more risk and have no escape options, why do the fast jet ponces seem to merit this pandering?

A quick scan of aircraft losses suggests that having no ejector seats on fast jets would have cost about ten additional lives in Afghanistan. Compared to the c3,000 allied troops killed (and 1,500 "contractors" about whom you can make your own mind up). Not to mention around 30,000 civilians.

1. #### Re: Handling the G's

"Chopper pilots take more risk and have no escape options, why do the fast jet ponces seem to merit this pandering?"

Why shouldn't they when its possible to do so? Learning to fly a fast jet fighter is a long expensive process - the pilot is actually more valuable in real terms than the plane. Flying a chopper while tricky isn't in the same league and so I'm afraid the life of the pilot is basically worth less since chopper pilots are frankly ten a penny. That and the fact of building an ejector seat that could shoot someone through the rotor blades without turning them into mince is ... tricky.

1. #### Re: Handling the G's / ejection seats for helicopters

There is a little comic by André Franquin about ejection seats for 'choppers'.

2. #### Re: Handling the G's

"That and the fact of building an ejector seat that could shoot someone through the rotor blades without turning them into mince is ... tricky."

But remember the synchronised machine guns on WWI fighters that fired through the propeller.

1. #### Re: Handling the G's

Good for the pilots but what about the crew/passengers? Think door-gunners and medics and wounded...or a load of infantry. The big issue is altitude. Most choppers, if they are about to fall out of the sky, are not at an altitude were parachutes are effective.

*I'm a former door gunner, Vietnam era.

1. #### Re: Handling the G's

> "Altitude" ..."I'm a former door gunner, Vietnam era."

More like 'Attitude': you must have been either extremely brave, or totally reckless. To the FNL* on the ground YOU, yes that body in the doorframe, were the TARGET.

* aka NLF

2. #### Re: Handling the G's

Explosives on the chopper blades worked in bond :p

Also autorotation landing if you are high enough and the pilot is alive, if you are that high I would prefer a parachute!

3. #### Re: Handling the G's

But remember the synchronised machine guns on WWI fighters that fired through the propeller.

Yes, *that's* the solution. We just use pilots that are the size of a bullet and can be ejected at the same speed as one without perishing in the acceleration (in which case you don't need to bother with a parachute either, as landing is just acceleration in reverse).

Glad we finally sorted that one.

:)

4. This post has been deleted by its author

3. #### Re: Handling the G's

"That and the fact of building an ejector seat that could shoot someone through the rotor blades without turning them into mince is ... tricky."

Helicopter ejector seats do exist. There are explosive charges which blow the rotors off before the seats fire. The fact that this turns the "helicopter" into a "rock" means that you don't want to stay onboard after one has been activated.

1. #### Re: Helicopter Ejection

Yes, this: Kamov Ka-50 has the helicopter ejection system. One crashed in 2013 in Moscow after the ejection system activated itself unnecessarily during normal flight.

4. #### Re: Handling the G's

the pilot is actually more valuable in real terms than the plane

I think a lot of the F4 pilots that were rinsed by Mig-17 and 21 opposition in Vietnam spent the rest of the war in the Hanoi Hilton anyway.

5. #### Re: Handling the G's

Learning to fly a fast jet fighter is a long expensive process - the pilot is actually more valuable in real terms than the plane.

This idea that crew are more valuable than planes is a 1940s idea when planes could be mass produced more quickly than pilots could be trained and gain the necessary experience to survive for more than a few sorties. The complexity and specialist components on a modern fast jet mean that your stock of aircraft is essentially fixed, and producing more requires years of supply chain preparation. Certainly at peak production rate you might be knocking one out every two days, but that's based on planning five or more years ahead, and ordering several years before that. All modern air forces train more fast jet pilots than they have fast jets by ratios of about three to one, and then give them non-front line flying jobs and even desk jobs to fill the time. So on that basis the number of aircraft ordered a decade ago is the limiting factor in terms of front line strength, not the crew availability.

Jet jockeys might think they're indispensable, but they clearly are because we're intentionally putting them in harms way. So why make the aircraft heavier, more expensive, more complex to build (and thus less reliable), and trading off the benefits of some crew survival against the admittedly smaller number of ejector seat accidents? And whilst probably not relevant to the very popular "bomb the natives" campaigns that have been the main form of recent warfare, in the air combat roles these jets are designed for, there is a significant maneuverability downside to having an additional half tonne of mass right at the sharp end of the aircraft, added to which that mass requires a heavier airframe and undercarriage, more fuel and/or less weapons...

1. #### Re: Handling the G's

there is a significant maneuverability downside to having an additional half tonne of mass right at the sharp end of the aircraft

Come on, Americans aren't *that* obese..

:)

2. #### Re: Handling the G's

there is a significant maneuverability downside to having an additional half tonne of mass right at the sharp end of the aircraft

Ejection seats aren't anything like that heavy. You can pick one up on your own quite easily.

Vic.

3. "keeping two sets of spares aboard HMS Queen Elizabeth would be a needless duplication." - because we all know that the defence industries are models of efficiency, of course.

4. #### The simulators can be dangerous too ...

I once worked in the US with a pilot who had been invalided out and retrained in IT (courtesy of Uncle Sam) because the simulator he was flying simulated a bad landing on an aircraft carrier a bit *too* well, and broke his back.

Cue obvious arguments about how "real" a simulator should (or needs to) be.

Also interesting to see how the US military are looked after (or were in 1990).

5. Pilots who weigh less than 62kg (9¾ stone, 136lb) are currently banned from flying the state-of-the-art F-35 fighter

Somehow I can't imagine there being many of them in the USA.

1. I can't imagine there are many in the UK either, despite what the article says about the seat in the Hawk, that's on the light side for a grown adult. None of the fast jet pilots I know are anywhere near being that light, although obviously I don't know them all as there's a limit to how much someone talking about themselves you can take.

1. It might be a bit light for a man, but I'd guess 10st (ish) wouldn't be light for a female pilot.

1. "I'd guess 10st (ish) wouldn't be light for a female pilot"

But who's going to tell her? That's worth combat pay right there.

2. obviously I don't know them all as there's a limit to how much someone talking about themselves you can take.

How do you know when a fast jet pilot comes into the bar?

He tells you.

1. #### "How do you know when a fast jet pilot comes into the bar?"

Now what if they are also a Vegan and into Cross-fit?

3. "...that's on the light side for a grown adult."

<cough>

There are these creatures called women, you know. I'm currently 57kg at the age of 52. When I was younger, slimmer, and fitter, I used to regularly struggle to get over 50kg. And I'm not a midget, I'm a bog average 1m 62cm.

2. "Somehow I can't imagine there being many of them in the USA."

There are female fighter pilots who might qualify.

What I had hoped to find out in the article was: How did they find out this was a problem?

And 62KG seems awfully specific.

1. I have two friends who are ex-RAF fighter pilot types and both of them could easily be that weight - they are shorter, tough wiry types. Tall men have issues in jet fighter cockpits...

1. 'I have two friends who are ex-RAF fighter pilot types and both of them could easily be that weight'

I'm sure they could, I'm touching it and have flown in a Hawk. But what do they weigh with all the survival gear on? That adds a few kilos which should slow down the various accelerations to an acceptable level.

2. What I had hoped to find out in the article was: How did they find out this was a problem?

Some of the lighter test sheep didn't make it.

1. "What I had hoped to find out in the article was: How did they find out this was a problem?"

The did tests with dummies, according to The Economist. The Economist also reckons the main problem is the helmet, rather than the seat itself.

http://www.economist.com/news/science-and-technology/21706448-worlds-most-expensive-fighter-jet-helmet-really-good-top-gunu2019s

(might need a subscription)

1. "The did tests with dummies..."

Were their families compensated?

2. They did tests with dummies

I'd say that's a fairly cruel incentive to pass the exams..

3. "And 62KG seems awfully specific."

62kg ==140 pounds == 10 stone

Someone's being overly precise when converting measurements which are plus or minus 10 pounds anyway.

3. Somehow I can't imagine there being many of them in the USA.

I shouldn't laugh, but that was almost my immediate thought as well.

6. Random question to our online military geeks. The latest gen of fighters like F35, Typhoons etc - are these likely to be the last gen of fighters to have a pilot sat in them? My guess is yes. Am I right?

1. #### @Daz555

" the last gen of fighters to have a pilot sat in them?"

Err... Yes, and No. Drones can be remarkably effective in a ground support role. But to gain and keep air superiority you need an aircraft that is able to defend itself and attack others. The delay time for a drone to observe and act upon dogfight conditions would IMHO be too great.

1. #### Re: @Wommit

The delay time for a drone to observe and act upon dogfight conditions would IMHO be too great.

You post that comment on an IT web site? Courageous, sir, if foolhardy and ill informed. Certainly Captain Scott lost his bet of machine over animal, but I'd wager that to claim that no meatsack can outfly a properly configured machine. The sad, sluggish reflexes of the carbon-based won't match the superior silicon, and that's before the weight and performance penalties for the meat.

Of course, if you're talking about crap like Reaper, yes, you're right. But I'd be very surprised if the main defence contractors don't have something they could build now that would kill off the Top Guns of the world. Of course they won't do that, because the top brass buyers of their kit are all former flyboys, still emotionally attached to the idea of the hero on his steed.

1. #### Re: @Wommit

All fighter jets shot down in the last couple of decades were brought down by drones.

You see, by any reasomable definition, guided missiles are a type of drone.

One that can't land and doesn't fly for very long, but still a drone.

1. #### Re: @Wommit

Pilotless fighters would probably deploy in batches of half dozen per enemy human piloted adversary, and loss of a couple would be acceptable. The humans won't stand a chance. It will be most interesting when it is drone versus drone fighting it out. Then air superiority will be down to the geek tech and manufacturing capacity.

2. #### Re: @Wommit @Richard 12

"All fighter jets shot down in the last couple of decades were brought down by drones."

No, a missile is not a drone. Their capabilities are completely different. Missiles have one similarity to drones, they both concentrate their attention forward in a small cone. The drone may see much better forward and down, but that is just a minor difference.

Pilots can look around themselves to see above, to the sides and, to a point behind. Using the Mark ! eye ball the pilots can also make the decision not to fire at what appears to their sensors a valid target. The drone operator only has the drone sensors.

And, while air to air missiles are very good, ask yourself why the US DoD formed the "Top Gun" school to teach air to air combat. The reasoning might surprise you.

7. #### Is there any other type?

I would have thought all ejections are emergencies.

1. #### Re: Is there any other type?

unless your name is Bernard Lynch...

2. #### Re: Is there any other type?

There are two types of ejection, the sort that you can prepare for, and the sort that you cannot.

Preparing involves getting in to the optimum position with feet on the rests, back straight, arms in, etc

It is the unprepared type that not surprisingly causes the worst injuries.

1. #### Re: Is there any other type?

"It is the unprepared type that not surprisingly causes the worst injuries."

Really?

All of the aircraft that I have worked on have had manually initiated ejection systems. The only aircraft in which the seat occupant might not have initiated the ejection himself was in the Sea Vixen. There the pilot may initiate the observers ejection as the observer had to leave first due to a great risk of collision if the pilot went first, or they ejected together.

If you are aware of an aircraft which might summarily eject its occupant(s) please give a link. I would be really interested in reading up on it.

1. #### Re: Is there any other type?

If you are aware of an aircraft which might summarily eject its occupant(s) please give a link.

On an unplanned basis there's a number, as any competent web search will reveal.

1. #### Re: Is there any other type?

Ah like this one you mean https://www.youtube.com/watch?v=OUS9htHp580

2. #### Re: Is there any other type?

If you are aware of an aircraft which might summarily eject its occupant(s) please give a link. I would be really interested in reading up on it.

The first aircraft I found with command ejection is the F-14. I'm sure there are others...

Vic.

2. #### Re: Is there any other type?

There are two types of ejection, the sort that you can prepare for, and the sort that you cannot

So, even top-gun stud fighter pilots can suffer from premature ejection?

8. #### "We believe that .... "

So that's alright then.

By the way I heard many years ago that modern fighter pilots are trained to such a level of intensity over a period of months that if they then stop flying just for a couple of weeks they can never get back to the same level.

Sounds akin to forgetting permanently a sequence of choreographed movements which previously was a no-brainier. Jonathan Edwards (Brit triple jumper) once said he forgot how he jumped to break records and never managed it ever again.

1. #### Re: "We believe that .... "

Dunno about "never" but it does take time to get back up to scratch.

2. #### Re: Time away

I'd heard something in relation to Apache pilots - something like 6 weeks being the maximum time away from flying before being unable to return to role.

1. #### Re: Time away

'- something like 6 weeks being the maximum time away from flying before being unable to return to role.'

Not true, otherwise no one would ever return to flying after a two year staff tour. Normally if you're away from flying more than six months you need a programme of refresher training but that's to be expected due to skill fade.

3. #### Re: "We believe that .... "

"We believe that .... "

Well, it is one step up from "We feel that..."

1. #### Re: "We believe that .... "

I feel like I want to believe, I think.

4. #### Re: "We believe that .... "

"Jonathan Edwards (Brit triple jumper) once said he forgot how he jumped to break records and never managed it ever again."

Remember test pilots aren't young.

Jonathan Edwards' best jumping isn't a great example, he was the best at-doing-his-thing of his generation. Athletes often have a golden period where everything is at its best. The gradual degeneration of the body (from about 18 years old) being overcome by training and increasing experience, after a point the degeneration wins (it always wins eventually). In track and field, the sweet spot is often only a few years. With Edwards, his sweet spot resulted in him jumping longer than anyone had, twice, in the same afternoon. He was still largely untouched for the best part of a decade and went over 18m quite often but didn't again ever jump as far as either of the jumps he did that afternoon. He is still the holder of the longest jump and the world record* a record that has lasted almost 2 decades. He says he forgot, in a sense the inevitable happened but it must have seemed to him like he had just lost the knack.

For fighter pilots, the flying training is intense, partly because there's exams to qualify from and they want to know how someone is in an intense environment (e.g. a war). But to my knowledge the most intense training is long before a pilot gets trained on their specific plane and flying role. So they never really know how good they are. I reckon a lot has to do with the more experienced pilots being quite a bit more efficient with their effort than the talented youngsters. So it must really seem like they aren't as good but they are probably just (unconsciously) wisely doing less.

If you will, Jimmy Anderson was a quicker bowler when young but much more effective when older.

* - the longest jump is farther than the record as it was wind assisted to a degree sufficient to not qualify for the record.

9. #### Feed them

Rather than spending hundreds of millions of dollars on more taxpayer funded pork, why not just stuff the pilots faces with literal pork until they meet the minimum weight? Why are they letting anorexics fly military fighter jets to begin with?

Fucking idiots. But hey, I'm a Brit, so it's not my money.

1. #### Re: Feed them

>But hey, I'm a Brit, so it's not my money.

Umm didn't you all even reconfigure your navy ships because of the ultimate white elephant F-35? If not there is always the constant UK government IT FUBARs on here so don't be smug for long. Government pissing away other people's money knows no national boundries.

2. #### Re: Feed them

"But hey, I'm a Brit, so it's not my money."

Who wants to break the news to AC about the new carrier etc?

10. #### This sounds a bit odd.

This report, whilst saying that the bang seat needs modifying, neglects to say why. I know that it's reported that the seat parachute deployment may be delayed, bit of a bummer if you're ejecting at 0 / 0, but that mod is to allow for less helmet forces on to the pilot.

Most of the things in the article point to the heavier helmet being the problem. That is not an Ejector seat problem. So Martin Baker are being threatened because of a problem that isn't their fault. How is that fair Mr. US DoD?

I'm glad to see that no ones mentioned slowing down the ejection acceleration. These seats have to get out fast and high to save the pilots life in low level and low speed emergencies, re the aforementioned 0 / 0. The pilot, of course, being the most expensive part of the whole system, of course if (s)he wasn't then I doubt that any one in authority would care.

1. #### Re: This sounds a bit odd.

When we're talking about a cost of hundreds of millions of dollars per airframe, the pilot isn't anywhere near the most expensive part of the whole system.

1. #### Re: This sounds a bit odd.

"When we're talking about a cost of hundreds of millions of dollars per airframe, the pilot isn't anywhere near the most expensive part of the whole system."

However the pilots training is.

1. #### Re: This sounds a bit odd.

No it isn't. That's the problem with kids today, they can't arrive at a sensible estimate of anything to within an order of magnitude. No mental common sense filter that screams "this number smells like bullshit, apply some critical thinking here".

Do you -really- think it costs hundreds of millions of dollars to train each pilot?

Care to try to break down where all those costs arise? How much per hour of training that would equate to, and whether that feels reasonable?

1. #### Re: This sounds a bit odd. @AC

No I dont, about 4 million or so for a RAF fast jet pilot. Plus time, times useful, pilots don't get trained up in five minutes. Can you put a value on time when you have a useless jet sitting on the runway especially if you need it now?

2. #### Re: This sounds a bit odd.

When we're talking about a cost of hundreds of millions of dollars per airframe, the pilot isn't anywhere near the most expensive part of the whole system.

It is when you consider the training cost and time, and the fact the aircraft is useless without someone at the stick. In the battle of Britain one of the concerns was lack of trained pilots to send up.

1. #### Re: This sounds a bit odd.

And the Pacific theatre. Turns out training the next pilots is crucial.

The Japanese had two problems: they hadn't enough well-trained experienced pilots after a short while because they kept dying valiantly, and they hadn't a chance of training new pilots because of the first problem. After some time of everyone wanting to be heroes at the front, there were no trainers for the last 2-3 years of the war. No trainers, no more pilots, no air cover, no victory conceivable.

After reading that I finally understood why the services in the West would keep sending their bona fide aces back home. Hey, yes, bond rallies and such on the weekends, but also because training the next pilots was absolutely *vital* to winning a war.

Which countries/services now have enough manpower depth to suck up damage and *replace* the damage? Hey, nobody is even ready to build unmanned drones that fast, much less put enough controllers in seats that don't have rockets under them!

3. #### Re: This sounds a bit odd.

"the pilot isn't anywhere near the most expensive part of the whole system."

The pilot is an officer and is therefore valuable.

Whirlybirds are generally piloted by grunts or noncomms and as such are expendable.

1. #### Re: This sounds a bit odd.

"Whirlybirds are generally piloted by grunts or noncomms and as such are expendable."

You must be USAian. In the Peoples Republic of the UK our Helicopter pilots are officers and / or Royalty.

2. #### Re: This sounds a bit odd.

Whirlybirds are generally piloted by grunts or noncomms and as such are expendable.

In the USA, only the Army uses non-commissioned officers as pilots. Everyone else uses commissioned officers.

3. #### Re: This sounds a bit odd.

"The pilot is an officer and is therefore valuable."

That is, at least to some degree, conflicting with the empirical values I sampled during my time in the military.

2. #### Re: This sounds a bit odd.

If I remember the original reports with lighter pilots the seat might not be orientated close enough to vertical when the chute deployed - this caused the seat (and pilots body) to rapidly re-orientate. The pilots head, being heavy and on a wobbly stick didn't re-orientate as quickly and with the extra weight of the helmet could potentially cause a broken neck.

So the lighter helmet will reduce head inertia, the extra webbing will limit rearward movement of the head before the bottom on the helmet breaks the neck and the chute delay gives the seat more time to steady its orientation.

Part of the problem is that the seat has to be powerful enough to ensure it gets over the vertical lift fan door.

0 / 0 shouldn't be affected - the delay is just a few milliseconds.

1. #### Re: This sounds a bit odd.

The drogue parachute (the only part of the ejector seat relevant to this discussion) fires after the seat starts descending. Any earlier and the seat would just tangle with the drogue before it opened. The seat and occupant need the drogue to deploy to stablise both of them in a feet downwards position. Once stablised, and below a set height, the pilot is detached from the seat and sent on his (her) merry way. Then the main parachute opens and the remains of the pilot float gracefully to earth.

The initial cartridges which start the chair rising are powerful enough to get the seat clear of the airframe. Many twin boom aircraft had high level tail planes and these had to be cleared without the advantages of the rocket assisted ejection seats now used. The extra lift given by the rocket assist is to get the seat occupant up to parachute height, a must if the rest of the seat deployment / pilot separation / main parachute opening is to take place.

1. #### Re: This sounds a bit odd.

The drogue parachute (the only part of the ejector seat relevant to this discussion) fires after the seat starts descending.

No, that's not true.

The seat is lifted from the airframe either by cannon (old-style seat) or rocket (new style, somewhat easier on the pilot). As it lifts, there are two straps (extendible rod-type things) between the seat and the airframe; as they reach full extension, one triggers the barostat to start the chute deployment sequence, and the other fires a rocket which deploys the drogue chute from the headrest.

A cable from the drogue ends in a shackle which is held in a pincer arrangement at the top of the seat. This allows the seat to be suspended from the drogue alone. Once the barostat finishes, the seat chassis is released from the harness (and falls away), and the pincer is released, allowing the drogue to pull out the main parachute.

Any earlier and the seat would just tangle with the drogue before it opened

No. The drogue is fired from the seat (and after the seat has already started moving), and is rocket-powered.

The extra lift given by the rocket assist is to get the seat occupant up to parachute height

Not so. The rocket ejection system is used to spread the total impulse over a longer time period, leading to lower forces acting on the pilot. This makes life easier for the pilot. But the old-style cannon ejectors could get the pilot plenty high enough - just with a risk of damage.

Vic.

3. #### Re: This sounds a bit odd.

Most of the things in the article point to the heavier helmet being the problem. That is not an Ejector seat problem.

That is also my reading of it; the rest seems to detract from the proper identification of the problem. That said I can see how body mass could be a determining factor.

At the risk of stating the obvious an ejection seat works by firing an explosive charge under the seat, after first shattering the canopy (again explosives are used) because unless the canopy is blown the result is a dead pilot. There are other things that happen, such as the pilot's legs being drawn back against the seat, much like car seat belt pretensioners. The seat is firing upwards, and the primary point of contact between seat and pilot is his (or her) derriere. That sudden acceleration is transmitted up the pilot's spine, and if the helmet is heavier that "standard" that heaviness becomes increased inertial mass. That increased mass can only be accelerated by the force transmitted up the spine and neck bones, thus adding to the extreme compression stress to which the entire spine (ncluding the neck) is subjected.

If the pilot and all his (her) component parts survive that, the compression stresses are repeated when the parachute deploys; this time the heavier helmet is forced downwards on to the neck bones and thence to the spine. (I cannot recall - if I ever knew - the point at which the pilot and the seat become separated.)

It is well known that pilots who have had to eject often land about 2" shorter than when they took off because of the compression of all the disks in the spinal column, and IIRC they have a specified number of weeks during which they have to return to within a certain precentage of their previous height; fail to return to "normal" and flying duties are cancelled.

I suspect that the pilot's weight comes into the equation simply because a heavier pilot will have a heavier bone structure that is better able to cope with the severe compression to which the spine and neck will be subjected; lighter pilots will have a lighter spine that is less well able to cope.

Ejection (I had to be careful there!) must come pretty close to the limit of what the human body can tolerate and survive and any additional factors such as increased helmet weight could easily pose a problem. If one answer is to specify a minimum body weight for pilots then that would seem to be perfectly sensible.

So Martin Baker are being threatened because of a problem that isn't their fault seems to be a perfectly fair point to make.

1. #### @Commswonk -- Re: This sounds a bit odd.

Spot on, sir. The only thing I'll take exception to is this: because unless the canopy is blown the result is a dead pilot.

Most current aircraft since the 60's/70's have had a "through the canopy" mode such that there is a projection seat over the helmet to allow this. There were some A/C's where the pilot couldn't eject through the canopy and when the canopy didn't blow off (mechanical or electrical failure) the pilot's seat fired and still tried (and usually succeeded) in going through the canopy. Result was the same.. dead pilot.

1. #### Re: @Commswonk -- This sounds a bit odd.

Most current aircraft since the 60's/70's have had a "through the canopy" mode such that there is a projection seat over the helmet to allow this

The Canberra is slightly odd here. The pilot (or pilots if you had a T4) has an ejection seat as you would expect - but so does the navigator. This is interesting because the navigator sits behind the pilot, and does not have a canopy over him.

I've yet to discover whether the overhead panel has an explosive jettison, or whether the guy is just slung through it...

Vic.

11. Sounds like they could inflate an air bag ring around the bottom of the helmet at the point of ejection, so the shoulders take some of the force off the neck. Of course, if you have a short neck this could pop your noggin off, but them's the breaks, right?

I still think the F-35 big contribution ultimately will be as a famous marker of when US government and cronies could no longer build stuff even with more money than God thrown at it (by the time it is truly ready it will already be obsolete due to drone technology more than likely). The anti Apollo program (results wise) if you wish. The LCS program is just further proof.

13. #### Ejection Seat blues

The old and venerable Phantom F4 had a radar screen that was right over the navigators knees.

I remember being told that several USMC crew had ejected sans legs before they got the mechanism that moves the display out of the way a few mSecs before the ejection took place.

Quite a thought for someone on their first day at work aged 15.

14. #### Simples...

I suggest that they remove their helmet and put on a ball cap before ejecting.

1. #### Re: Simples...

While they're at it, maybe they could change into a ball gown as well.

(Yes, I know, it's only a missing apostrophe:)

15. #### Air bag

Given the level of spending for both the plane and pilot, I wonder if an air bagsystem would help incorporated into the seat and the pilot's pressure suit. A bag designed to deploy as a neck brace tailored to the pilot plus something that could deploy from the seat to brace the spine from the seat to perhaps under the pilot's arms. That's off the top of my head so i am sure I will have missed something but spine and neck support rapidly seems to be part of what is called for. Alternatively an exo skeleton/seat arrangement, cue DARPA.

1. #### Re: Air bag

@Chris G - "Given the level of spending for both the plane and pilot, I wonder if an air bagsystem would help incorporated into the seat and the pilot's pressure suit."

I think the seat already fires airbags that squeeze the pilot firmly into the seat (including pushing the arms close to the body) before launching. Whether there's any scope to extend the system to support the helmet I don't know.

As others have pointed out the simplest solution would be to reduce the weight of the helmet.

16. #### What a petite pilot may look like...

https://fromthepencup.files.wordpress.com/2013/09/p1020665.jpg

1. #### Re: What a petite pilot may look like...

Nah, this is what a petite pilot looks like...

Countered by this “We're three to four weeks away from having all of the data done so that we can finalize the technical assessment, put that into a risk assessment, and then ultimately make a recommendation.”

Obviously, the headline writer has never worked around the defense industry. What the spokesman said is just the start. Once recommendation have been made, they need approved. And the procurement process starts....

This is just the beginning.

18. #### Alternative solutions are also being considered

The DoD has considered cutting physical fitness tests for F-35 pilots and giving them a large wad of McDonalds coupons every month as a way to combat the low-weight pilot problem.

19. #### Airbag Collar

All that is needed is an airbag collar similar to the neck protection devices used by F1 drivers instead of fiddling with weight sensors,real time accelerometers and rocket controls.

1. #### Re: Airbag Collar

"All that is needed is an airbag collar similar to the neck protection devices used by F1 drivers"

F1 drivers don't spend a lot of their time looking up / left / right / down left / down right / behind. Kinda useful in an air combat situation.

While the fighter pilots silk scarf may be a bit of a fashion statement, it does prevent sores developing around the neck from constant rubbing against the flight suit.

20. #### More \$Billleeeeeeoooons

Nothing a few more \$ billleeeeeeeooooon cannot fix. Open wide and say aaaahhhhhhh dear taxpayer. For contractors and politicians, money grows on trees...Troubling is the answer to the question: "Is the US safer with all the gadgets piled and rotting in various locations?" 911 story seems to show NOT. Alternative? How about spending on creating a cabinet post for peace process to encourage peaceful resolution of conflicts under win-win (1+1) instead win-lose (1-1) game? Can we do it for just four years, one US presidential term?

1. #### Re: More \$Billleeeeeeoooons

"How about spending on creating a cabinet post for peace process to encourage peaceful resolution of conflicts under win-win (1+1) instead win-lose (1-1) game? Can we do it for just four years, one US presidential term?"

With the two muppets currently in the lead for the POTUS job, you have to be joking. I know our political twunts are bad (UK of course), but those two really abuse the name of dumb Americans.

P.S. I know that not all Americans are dumb. But really, those two are giving the rest of you a bad name.

21. #### Not so strange, after all

I thought an ejection seat that breaks the pilot's neck was an anti-terrorism measure. You know, a pilot ejecting over hostile territory can't be tortured - sorry, forcefully interrogated - for incriminating information such as the colour of their SO's underwear or the size of their wotsit if they are dead.

Actually it sounds like a rehash of the Imperial Wallies Back In London's view of the importance of parachutes in the First World War, or the importance of not having the bloody thing go up in smoke after it's been hit by incendaries during the Battle of Britain. WWI - don't be such a pussy. You're off to war to die, dontcha know? BoB - Rinse, repeat.

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