Author Topic: WTF!!! (French Airforce FUBAR)  (Read 3502 times)

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Offline jmelson

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Re: WTF!!! (French Airforce FUBAR)
« Reply #50 on: April 15, 2020, 05:54:54 pm »

They probably use something like C4 for the pyrotechnic lines so the chances of it going off on its own after the line has been severed are basically nonexistent but i wouldn't trust it if i was sitting on a armed ejection seat.
The pyrotechnic lines use hexanitrostilbene, I think.  It is very heat resistant, and needs a strong initiator to start the shock wave.

Jon
 

Online jogri

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Re: WTF!!! (French Airforce FUBAR)
« Reply #51 on: April 15, 2020, 09:41:34 pm »
I only know sim aircraft, but the F18, A10, Harrier and F14 ALL have a "Seat Arm" lever, either where the armrest would be or on the side of the seat.  In rafale cockpit photos you can see a flat yellow and black chevron's lever beside the pilots thigh.  I think that's the same thing.

That's not the handle of the ejection seat, that handle is there in case the ejection seat doesn't separate from the pilot after he ejected himself (it should be marked "manual release"). I don't think that it will initiate the ejection sequence if you pull on it.
 

Offline wasyoungonce

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Re: WTF!!! (French Airforce FUBAR)
« Reply #52 on: April 15, 2020, 11:37:36 pm »
.......They probably use something like C4 for the pyrotechnic lines so the chances of it going off on its own after the line has been severed are basically nonexistent ...

SMDC...Shielded Mild Detonating Cord.......https://psemc.com/products/shielded-mild-detonating-cord/.
Used for the Canopy initiator.  The seats have more than one charge.   I don't know what they use but they look like large blanks.  Usually 2 in each seat.  2 are for ejection then solid rocket motor initiates .... I think....sometimes a small SMDC for automatic sear of the harness release.
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Offline paulca

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Re: WTF!!! (French Airforce FUBAR)
« Reply #53 on: April 16, 2020, 06:48:53 am »
I only know sim aircraft, but the F18, A10, Harrier and F14 ALL have a "Seat Arm" lever, either where the armrest would be or on the side of the seat.  In rafale cockpit photos you can see a flat yellow and black chevron's lever beside the pilots thigh.  I think that's the same thing.

That's not the handle of the ejection seat, that handle is there in case the ejection seat doesn't separate from the pilot after he ejected himself (it should be marked "manual release"). I don't think that it will initiate the ejection sequence if you pull on it.

No it arms the ejection seat.  Or disarms it, so the handle will not fire the seat.  I expect it is more of a safety interlock thing, with that handle raised the seat will not and cannot fire.

http://www.ejectorseats.co.uk/martin%20baker%20sju5a.html

This describes it as the "Safe/Arm handle"

We were talking about accidental firing of the seat.  Consider getting into a powered on plane in a hangar.  One does NOT want the seat armed.  The seat is armed in the taxi checklist or after leaving the hangar and closing the canopy.  Before the canopy is closed the pilot can get out of the aircraft in case of fire and be safer than a 0 foot ejection.
« Last Edit: April 16, 2020, 06:57:07 am by paulca »
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Offline Gixy

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Re: WTF!!! (French Airforce FUBAR)
« Reply #54 on: April 16, 2020, 07:15:43 am »
Yes, and those levers are secured by "remove before flight" pins which must be shown by the mecanics to the pilot(s) once on board.
 

Online langwadt

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Re: WTF!!! (French Airforce FUBAR)
« Reply #55 on: April 16, 2020, 07:25:47 am »
I only know sim aircraft, but the F18, A10, Harrier and F14 ALL have a "Seat Arm" lever, either where the armrest would be or on the side of the seat.  In rafale cockpit photos you can see a flat yellow and black chevron's lever beside the pilots thigh.  I think that's the same thing.

That's not the handle of the ejection seat, that handle is there in case the ejection seat doesn't separate from the pilot after he ejected himself (it should be marked "manual release"). I don't think that it will initiate the ejection sequence if you pull on it.

No it arms the ejection seat.  Or disarms it, so the handle will not fire the seat.  I expect it is more of a safety interlock thing, with that handle raised the seat will not and cannot fire.

http://www.ejectorseats.co.uk/martin%20baker%20sju5a.html

This describes it as the "Safe/Arm handle"

We were talking about accidental firing of the seat.  Consider getting into a powered on plane in a hangar.  One does NOT want the seat armed.  The seat is armed in the taxi checklist or after leaving the hangar and closing the canopy.  Before the canopy is closed the pilot can get out of the aircraft in case of fire and be safer than a 0 foot ejection.

Looks like the Rafale uses a newer seat, http://martin-baker.com/wp-content/uploads/2017/05/mk16_rafale.pdf

but I'm sure it also has some safety lock out for maintenance and before you are strapped in
 

Offline paulca

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Re: WTF!!! (French Airforce FUBAR)
« Reply #56 on: April 16, 2020, 10:06:05 am »
Yes, and those levers are secured by "remove before flight" pins which must be shown by the mecanics to the pilot(s) once on board.

Yes and no.  The pins are shown to the pilot by the crew chef when he/she hands the plane over to the pilot.  The pilot will conduct a walk around while all the panels are open, then check them again when they are closed.  He will then accept the aircraft.  The pins are out long before he climbs aboard.

There may well be a pin in the arm/disarm handle, but I'm 99% sure that is out when the pilot boards the plane.

Here is an awesome video (F/A-18) uncut video showing the full sequence.


And here is a commentary video on the above.


The safe/arm handle is clearly visible at 6:00

At 07:00 other yellow/black chevron's items to note, from left to right.  Canopy jetison (lever).  Weapons Jetison (Round button, Admiral's doorbell) and on the right, the spin recovery mode switch.
« Last Edit: April 16, 2020, 10:17:12 am by paulca »
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Online jogri

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Re: WTF!!! (French Airforce FUBAR)
« Reply #57 on: April 16, 2020, 10:59:42 am »
The safe/arm handle is clearly visible at 6:00

At 07:00 other yellow/black chevron's items to note, from left to right.  Canopy jetison (lever).  Weapons Jetison (Round button, Admiral's doorbell) and on the right, the spin recovery mode switch.

That yellow/black handle at 6:00 is not the safe/arm switch, that's the manual relase... You can see the safe/arm under the papers, it is at the same height as the joystick and it is white as the seat isn't armed yet (you can see that the black/yellow "armed" side is tilted forwards).

The Rafale uses a slightly different system but since the manufacturer is the same i'd guess that the safe/arm is still in the same position although it has a different design.

I marked the manual relase handles red and the safe/arm switches blue in both pictures.

Here is a quote from that manual about the functions of both handles:
Quote
EJECTION SEAT SAFE/ ARM HANDLE.- To prevent inadvertent seat ejection, an ejection seat safe/ arm handle (18) is installed. To safety the seat, you must rotate the handle up and forward. To arm the seat, you rotate the handle down and aft. When in the ARMED position, the portion of the handle that is visible to the pilot is coloured yellow and black with the word ARMED showing. In the SAFE position, the visible portion of the handle is coloured white with the word SAFE showing. By placing the handle to the SAFE position, it causes a pinto be inserted into the ejection firing mechanism. This prevents withdrawal of the sears from the dual seat initiators.

MANUAL OVERRIDE HANDLE.- The manual override handle (17) is located on the right side of the seat bucket. The handle is connected to the lower restraint mechanism. It is also connected to the manual override initiator.

MANUAL OVERRIDE INITIATOR.- The manual override initiator (19) is mounted in a covered compartment in the lower aft right side of the seat bucket. A linkage connects the sear to the manual override handle. Pulling the handle releases the lower restraints. Full upward movement of the handle is prevented by the pin puller. However, during ejection, the pin puller is automatically retracted. This allows the manual override handle to pull the sear from the manual override initiator, which will override the automatic sequencing. This is accomplished by routing gas pressure to the time-release mechanism and the secondary cartridge of the drogue gun.
 

Offline MK14

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Re: WTF!!! (French Airforce FUBAR)
« Reply #58 on: April 18, 2020, 10:27:31 am »
I didn't realise, BOTH ejector seats were actually activated (one ejected, the other partly did). But, the pilots seat, stopped, part way through its sequence. So, the canopy top, was explosively released (injuring the pilot, slightly), but then it stopped (malfunctioned).
So, it was not that easy for the pilot to return to base. Details in video.
Also, the dingy failed to inflate and all the fighter planes in the fleet (of that type) had to be grounded from flying for a few weeks, until the issues were processed (cleared for flying again). Some time later.

« Last Edit: April 18, 2020, 10:31:24 am by MK14 »
 

Online jogri

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Re: WTF!!! (French Airforce FUBAR)
« Reply #59 on: April 18, 2020, 11:28:59 am »
So, it was not that easy for the pilot to return to base. Details in video.

That's quite the understatement given that the pilot had to deal with:
-a changed center of mass of his airplane (okay, we are talking about ~150kg on a 15 ton jet)
-a massively changed airfoil: losing the canopy meant that the plane suddenly produced a metric sh*tton of drag, ruining the normal airflow and drastically reducing the lift the plane generated
-a plane that is aerodynamically unstable under normal conditions and requires aid from a computer to be flown ->i don't think the computer has programs for a "the ejection sequence kinda worked/how about flying a cabriolet" situation, meaning that the pilot had to fly it with reduced help from the flight computer
 
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Offline MK14

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Re: WTF!!! (French Airforce FUBAR)
« Reply #60 on: April 18, 2020, 12:22:48 pm »
So, it was not that easy for the pilot to return to base. Details in video.

That's quite the understatement given that the pilot had to deal with:
-a changed center of mass of his airplane (okay, we are talking about ~150kg on a 15 ton jet)
-a massively changed airfoil: losing the canopy meant that the plane suddenly produced a metric sh*tton of drag, ruining the normal airflow and drastically reducing the lift the plane generated
-a plane that is aerodynamically unstable under normal conditions and requires aid from a computer to be flown ->i don't think the computer has programs for a "the ejection sequence kinda worked/how about flying a cabriolet" situation, meaning that the pilot had to fly it with reduced help from the flight computer

That makes sense.
Plus the risk, that the pilot, could have been ejected, at any time. He had to depart it very quickly, because of the risk of it suddenly deciding to work properly. Which is why the pilot (correctly), immediately moved safely away from any built up areas, before heading back to the military airport.
Apparently, they left the plane for 24 hours, after landing, without going near it. In case the ejector seat went off, if they went near it.
 

Offline Alphaprot

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Re: WTF!!! (French Airforce FUBAR)
« Reply #61 on: April 18, 2020, 01:22:12 pm »
I have no clue about fighter jet systems, but if I was the French Air Force, I would investigate why a system designed to engage both ejection seats once one is activated simply fails and leaves one seat in a somewhat superposition state where it is technically engaged but physically nothing has happened so far. That appears to me to be a risk which should be mititigated.

Imagine a fighter pilot on the rear seat (aren't they used for targetting and controlling the aircraft's weapon system?) loses consciousness in mid-air in a combat situation. Plane gets problems and both pilots SHOULD immediately exit via their ejection seats. The conscious front-seated pilot engages his seat's handle and saves his life, but the other pilot won't survive as his seat won't autoactivate (but it should by design, as the article says).

EDIT:
Quote
a changed center of mass of his airplane (okay, we are talking about ~150kg on a 15 ton jet)
I'm not sure, but don't the Rafale's have autotrim (pretty standard in newer fly-by-wire systems)? So a slightly altered CG shouldn't add that much trouble.
« Last Edit: April 18, 2020, 01:26:55 pm by Alphaprot »
 
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Online langwadt

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Re: WTF!!! (French Airforce FUBAR)
« Reply #62 on: April 18, 2020, 01:57:48 pm »
I have no clue about fighter jet systems, but if I was the French Air Force, I would investigate why a system designed to engage both ejection seats once one is activated simply fails and leaves one seat in a somewhat superposition state where it is technically engaged but physically nothing has happened so far. That appears to me to be a risk which should be mititigated.

Imagine a fighter pilot on the rear seat (aren't they used for targetting and controlling the aircraft's weapon system?) loses consciousness in mid-air in a combat situation. Plane gets problems and both pilots SHOULD immediately exit via their ejection seats. The conscious front-seated pilot engages his seat's handle and saves his life, but the other pilot won't survive as his seat won't autoactivate (but it should by design, as the article says).

EDIT:
Quote
a changed center of mass of his airplane (okay, we are talking about ~150kg on a 15 ton jet)
I'm not sure, but don't the Rafale's have autotrim (pretty standard in newer fly-by-wire systems)? So a slightly altered CG shouldn't add that much trouble.

it can carry 9500kg of ordinance and fuel on the outside, I suspect dropping that causes bigger changes in CG and handling.

an ejection seat that doesn't eject and a life raft that doesn't deploy on plane that is still used in active service has go to cause some serious
questions to maintenance

 
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Offline Ground_Loop

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Re: WTF!!! (French Airforce FUBAR)
« Reply #63 on: April 18, 2020, 01:59:05 pm »
I think one of the worst moments for the pilot was getting out of his seat after he landed: If the ejector seat goes off while you're strapped in you are relatively safe, but it could be rather nasty if it goes off while you are removing your seat straps.

It's a shame it didn't go off at that point, it would have been a bit of a lesson for him after inflicting that flight on his passenger.
Those idiots (different air base) are flying over me daily, if I catch an ejected one in my garden he'll be getting my best sympathy for his kind.
I must think of getting a heavy dog just in case...

Fighter pilots are known to be fairly intelligent.  What do you base your term "idiot" on?  When I ask about idiot, my reference is the general usage here in the states which is simply someone with a different opinion than yours.
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Offline paulca

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Re: WTF!!! (French Airforce FUBAR)
« Reply #64 on: April 18, 2020, 05:33:18 pm »
I can't find the videos now, but a female pilot of the F14 tomcat experienced an engine failure on approach to the carrier.  Instinctively she opened the throttle to the remaining engine to avoid stall, abort and climb out.  In the original Tomcat this was a coffin corner on the graphs.  So close to stall on the final to a carrier an engine loss needed nearly full power from the other engine to not stall, but full power from the other engine induced a yaw moment so close to stall that it spun.  Keeled over and headed straight to the water. 

The RIO in the back seat seen the situation go critical and pulled the handle, ejecting both pilot and RIO.
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Offline MK14

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Re: WTF!!! (French Airforce FUBAR)
« Reply #65 on: April 18, 2020, 06:16:27 pm »
I can't find the videos now, but a female pilot of the F14 tomcat experienced an engine failure on approach to the carrier.  Instinctively she opened the throttle to the remaining engine to avoid stall, abort and climb out.  In the original Tomcat this was a coffin corner on the graphs.  So close to stall on the final to a carrier an engine loss needed nearly full power from the other engine to not stall, but full power from the other engine induced a yaw moment so close to stall that it spun.  Keeled over and headed straight to the water. 

The RIO in the back seat seen the situation go critical and pulled the handle, ejecting both pilot and RIO.

It seems to be this one:

 
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Offline SeanB

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Re: WTF!!! (French Airforce FUBAR)
« Reply #66 on: April 18, 2020, 07:25:15 pm »
I heard of one pilot being killed by a malfunctioning ejection seat, that did an uncommanded eject over the ocean. His body was recovered, but the plane never was, as it went down in about 6km of water, in a very rough sea area. I had actually met that pilot a few times, but at that time was more than a year out of that base. I never liked climbing into a cockpit with the seat still there, both because it is incredibly cramped for a tall person ( pilots tend to the short side, to fit the aircraft) and also because of those two yellow black handlkes, with the only thing keeping you safe being the 2 ball detent release pins.

I still use one as a tool box latch, as the armourers always had plenty of used ones around.
 
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Offline jmelson

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Re: WTF!!! (French Airforce FUBAR)
« Reply #67 on: April 19, 2020, 03:15:44 am »

Imagine a fighter pilot on the rear seat (aren't they used for targetting and controlling the aircraft's weapon system?) loses consciousness in mid-air in a combat situation. Plane gets problems and both pilots SHOULD immediately exit via their ejection seats. The conscious front-seated pilot engages his seat's handle and saves his life, but the other pilot won't survive as his seat won't autoactivate (but it should by design, as the article says).
Nope.  When both seats are occupied, the ejection selector is set to "both" by the pilot.  In that case, if EITHER pilot pulls his ejection handle the system blows the canopy, then the rear seat ejects first, then the front seat.  If the canopy fails to jettison, then the seats are ejected through the canopy after a slight additonal delay.

The rear seat has to go first, as the rocket motor from the front seat would fry the rear seat guy if he was still there.

There is a "single" position on the ejection sequence selector so that the front seat guy can eject faster if there's nobody in the back seat.

As for the center of gravity, the complete seat system with all the pyrotechnics, parachute, survival kit, oxygen and radio generally weighs more than the pilot.  But then, a few missles and bombs weigh a lot more than that.  Anyway, for rapid maneuvering, the control surfaces on the fighter jets are QUITE large, and can produce PLENTY of force to overcome a little change in CG.  Note the F-15 that had a midair in Israel 20-some years ago, and was flown back to the base with one wing
COMPLETELY sheared off! 

Jon

Jon
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Offline jmelson

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Re: WTF!!! (French Airforce FUBAR)
« Reply #68 on: April 19, 2020, 03:19:30 am »
I can't find the videos now, but a female pilot of the F14 tomcat experienced an engine failure on approach to the carrier.  Instinctively she opened the throttle to the remaining engine to avoid stall, abort and climb out.  In the original Tomcat this was a coffin corner on the graphs.  So close to stall on the final to a carrier an engine loss needed nearly full power from the other engine to not stall, but full power from the other engine induced a yaw moment so close to stall that it spun.  Keeled over and headed straight to the water. 

The RIO in the back seat seen the situation go critical and pulled the handle, ejecting both pilot and RIO.

It seems to be this one:


Yes.  The RIO (rear seat) goes first, then the front seat later, to spare the rear seat of the flame from the ejection rocket motor.
By the time the sequence system fired the front seat, the plane was upside down, and she was fired straight down into the water at high speed.

Jon
 
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Offline MK14

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Re: WTF!!! (French Airforce FUBAR)
« Reply #69 on: April 19, 2020, 03:30:54 am »
Yes.  The RIO (rear seat) goes first, then the front seat later, to spare the rear seat of the flame from the ejection rocket motor.
By the time the sequence system fired the front seat, the plane was upside down, and she was fired straight down into the water at high speed.

Very sad incident.

On the other hand, this is an amazingly good one (for the F15), video below:

Note the F-15 that had a midair in Israel 20-some years ago, and was flown back to the base with one wing
COMPLETELY sheared off! 

 

Offline EEVblog

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Re: WTF!!! (French Airforce FUBAR)
« Reply #70 on: April 19, 2020, 06:06:33 am »
So, it was not that easy for the pilot to return to base. Details in video.

That's quite the understatement given that the pilot had to deal with:
-a changed center of mass of his airplane (okay, we are talking about ~150kg on a 15 ton jet)
-a massively changed airfoil: losing the canopy meant that the plane suddenly produced a metric sh*tton of drag, ruining the normal airflow and drastically reducing the lift the plane generated
-a plane that is aerodynamically unstable under normal conditions and requires aid from a computer to be flown ->i don't think the computer has programs for a "the ejection sequence kinda worked/how about flying a cabriolet" situation, meaning that the pilot had to fly it with reduced help from the flight computer

Plus the hug mental situation knowing full well that his seat was supposed to eject too, and it could have done so at any instant.
 
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Online jogri

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Re: WTF!!! (French Airforce FUBAR)
« Reply #71 on: April 19, 2020, 04:03:52 pm »
You can also look at it the other way round: He knew that his ejection seat was supposed to go off, but didn't. That means he can't be sure if it will eject him in case something goes wrong during the landing, which he has to do in a badly damaged plane that was never supposed to be flown in that condition. If he stalls it, he is probably dead.

On the other hand, the ejection seat will probably kill him if it goes off (either accidentally or if he has to use it during landing): The harness tensioner charge was already activated when his passenger left the jet, meaning that their is no way for him to be properly secured if the rocket motor of his seat fires up. The main function of the harness tensioner is to align his head+spine with the thrust vector of the rocket motor (by forcing him back into his seat) to minimize the risk of his spine collapsing under the immense acceleration, he might snap his neck if he remains leaned forward (normal flight position) when it goes off.
 
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Offline paulca

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Re: WTF!!! (French Airforce FUBAR)
« Reply #72 on: April 21, 2020, 07:28:36 am »
"What could possibly go wrong?"
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