Flt. Lt. Sean Cunningham inquest
The concerns regarding garage forecourts and Cellular devices is related to potential sparking of antenna connections and vapour. - Intrinsically safe RF devices used for example in a bomb dump would have encapsulated circuitry in addition to low power outputs, Cellphones don't however depending on technology and mode the power is not massively over the 500mw (IIRC) that was the IS device power rating.
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Slight thread drift, I know... I think that banning the use of mobile phones on garage forecourts is only prevalent in the UK (and maybe the EU??). Certainly no one in the US cares about this theoretical risk - which is probably the RF equivalent of making everyone on a military flight line wear yellow safety jackets.
From RAC Victoria
Mobile phones and fuel fires | Motoring | RACQ
"Investigations into refuelling fires in the USA conducted by the Petroleum Equipment Institute concluded that, rather than mobile phone radiation, 90 percent of them involved static electricity discharges of some type. In the remaining 10 percent the cause was inconclusive.
The research concluded that while there is theoretically a very slight possibility of a spark being produced by the battery in a mobile phone, the likelihood of a phone-induced fire was negligible."
Back to the topic ...
I met Sean once, many years ago, and have a relative flying aircraft with similar seats, so am interested in the outcomes here.
I've read the thread, and hope I haven't missed this, but is there a timeframe for publishing the coroner's report? A week / month / 6 months?
thanks
layman
Mobile phones and fuel fires | Motoring | RACQ
"Investigations into refuelling fires in the USA conducted by the Petroleum Equipment Institute concluded that, rather than mobile phone radiation, 90 percent of them involved static electricity discharges of some type. In the remaining 10 percent the cause was inconclusive.
The research concluded that while there is theoretically a very slight possibility of a spark being produced by the battery in a mobile phone, the likelihood of a phone-induced fire was negligible."
Back to the topic ...
I met Sean once, many years ago, and have a relative flying aircraft with similar seats, so am interested in the outcomes here.
I've read the thread, and hope I haven't missed this, but is there a timeframe for publishing the coroner's report? A week / month / 6 months?
thanks
layman
All the carts on that seat are percussion fired, a mobile phone would make no difference in this particular case.
Rigga, I have no issue with componants and equipment which are extended due to testing etc. My issue is 'footfall' in and out of the seat which has the potential for damage to the componants on the seat which increases over extended periods. For example the amount of dirt from the underside of boots/shoes that collects in the seatpan can be considerable even after just six months. Also the longer the seat is in the longer it is subject to weather, the canopy does not always get closed before the rain arrives!
The extention to seat servicing and centralised servicing was to save money, lets not kid ourselves it was anything else.
Rigga, I have no issue with componants and equipment which are extended due to testing etc. My issue is 'footfall' in and out of the seat which has the potential for damage to the componants on the seat which increases over extended periods. For example the amount of dirt from the underside of boots/shoes that collects in the seatpan can be considerable even after just six months. Also the longer the seat is in the longer it is subject to weather, the canopy does not always get closed before the rain arrives!
The extention to seat servicing and centralised servicing was to save money, lets not kid ourselves it was anything else.
Re: Night Nurse
Would that perhaps simply have been part of a very general summation of his movements and activities in the hours before the sad event, and nothing more? Is there even a sniff of a suggestion that he was 'drugged' before flying? And are service cynics (I am a civi cynic) really worried he will be found culpable because of it?
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Always provided suitable covering/protection measures are in place and adequate transit arrangements made then I cannot see any great problem in a system of centralized servicing. As a plus, it certainly places a good pool of focused technical expertise in one place. In the early 60’s I remember removing seats from Canberra T4’s (a pig of an installation btw) after which they were transferred a couple of miles to/from the seat bay in the back of a land rover usually resting on the vehicle seat cushions (or whatever else may have been handy); hardly the best way and in all probability the transport arrangements nowadays to/from Marham will be a considerable improvement. Provided appropriate arrangements are in place for the transit, I cannot see a great issue with centralizing the servicing and if a wad of cash can be saved then one should do so. As to time cycles between inspection/life of critical components, I am now a little too remote to comment.
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People seem to be in an awful flap at the mention of meds and mobiles.
A coroners court is like a sponge. It'll soak up all kinds of information and some will be irrelevant, some trivial and some important. Some may even be red herrings.
It's only right that all the details get considered or accusations of a cover up or incompetence will fly.
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A coroners court is like a sponge. It'll soak up all kinds of information and some will be irrelevant, some trivial and some important. Some may even be red herrings.
It's only right that all the details get considered or accusations of a cover up or incompetence will fly.
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Courtney, I think you will find during refueling and using a phone it may be static that is the issue or simply the phone is not intrinsically safe, ll the electric devices in gas stations are protected with explosive containment devices, mobiles will not be.
I remember we used to do rotor turning refuels on Wessex whilst plugged into the intercom, however tests were carried out and it was found that there was so much static floating about because of that, the potential was there to cause a spark, hence the on intercom refuelling was forbidden after that.
I remember we used to do rotor turning refuels on Wessex whilst plugged into the intercom, however tests were carried out and it was found that there was so much static floating about because of that, the potential was there to cause a spark, hence the on intercom refuelling was forbidden after that.
Static! Every time Mrs LB stepped out of our previous car and went to shut the door there was a mighty static spark and a mighty wifely oath [decorous within the total range of possible oaths].
The spark could be SEEN at night. Rather outweighs the moby possibility one would have thought?
The spark could be SEEN at night. Rather outweighs the moby possibility one would have thought?
Dtyke:
"I have no issue with componants and equipment which are extended due to testing etc. My issue is 'footfall' in and out of the seat which has the potential for damage to the componants on the seat which increases over extended periods. For example the amount of dirt from the underside of boots/shoes that collects in the seatpan can be considerable even after just six months. Also the longer the seat is in the longer it is subject to weather, the canopy does not always get closed before the rain arrives!"
I'm not picking on you Dtyke, just answering the post.
If your inspection periodicity covers this exposure to damage and you're still not finding faults then there is no real issue in considering extending the period.
Safety Critical Component inspections can be extended by the right TC holder. e.g. Boeing deleted all the periodic inspections of some 737 APUs from their AMP (including oil changes) as the inspections didn't prevent anything happening.
"I have no issue with componants and equipment which are extended due to testing etc. My issue is 'footfall' in and out of the seat which has the potential for damage to the componants on the seat which increases over extended periods. For example the amount of dirt from the underside of boots/shoes that collects in the seatpan can be considerable even after just six months. Also the longer the seat is in the longer it is subject to weather, the canopy does not always get closed before the rain arrives!"
I'm not picking on you Dtyke, just answering the post.
If your inspection periodicity covers this exposure to damage and you're still not finding faults then there is no real issue in considering extending the period.
Safety Critical Component inspections can be extended by the right TC holder. e.g. Boeing deleted all the periodic inspections of some 737 APUs from their AMP (including oil changes) as the inspections didn't prevent anything happening.
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Is this staffing level shortage indicative of the RAF squadron strength as a whole?
As a Continuing Airworthiness specialist I make two observations:
1. The cause of the ejection is difficult to determine. I do recall the Harrier that flew on over the sea, perfectly trimmed, until it ran out of fuel. The seat and pilot were missing - unintentional ejection?
2. The cause of death in this accident is perfectly clear - once activated, the ejection seat failed to operate as designed.
How was the seat accidentally activated and why did it then fail to function properly? The BoI, when it takes place, should focus firmly on those two points. Self medication, mobile phones and other such distractions have nothing to do with the defect in that seat.
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How was the seat accidentally activated and why did it then fail to function properly? The BoI, when it takes place, should focus firmly on those two points. Self medication, mobile phones and other such distractions have nothing to do with the defect in that seat.
Thread Starter
From yesterdays Lincolnshire Echo:
Here
As important nuts and bolts go, this is an important one. Is it really true there was no torque guidance in the manuals...?
Here
As important nuts and bolts go, this is an important one. Is it really true there was no torque guidance in the manuals...?
Maintenance instructions for Red Arrows ground crew working on ejection seats gave them no proper guidelines on a crucial nut and bolt.
When ejection seats are fired a drogue parachute deploys in order to stabilise the descent.
This mechanism then allows the main parachute to release.
When the pilot activates the seat, a plunger releases the arm of a scissor shackle and in turn releases the drogue shackle the first chute is attached to.
It is crucial that the nut and bolt through shackles is not over-tightened, which could prevent it working properly.
Questions over the bolt's performance were raised during the inquest into the death of Flight Lieutenant Sean Cunningham.
He died on November 8, 2011 after his ejection seat was fired while his plane was on the ground at RAF Scampton.
Reds armourer Sergeant Chris Clarkson, who was present when Flt Lt Cunningham ejected, but has since left the RAF, told the court he understood the drogue nut and bolt should be tightened to a “good positive lock” and showing at least one and a half threads.
He said: “The head of the bolt is very thin.
“It’s difficult to get the spanner on it especially with it’s location on the under side of the drogue.”
Hugh Davies, QC, for Lincolnshire Police, asked: “Did you understand that if the nut was tightened too far it would prevent eventual release?”
Mr Clarkson replied: “I was not aware of that at all.”
Bernard Thorogood, counsel for the Health and Safety Executive, read this extract from the workshop manual that guided the armourers: “Pass the bolt through the drogue and scissor shackles and secure with a lock nut.”
He told the court: “In the absence of any more direct instructions such as torque, that’s the instructions that mechanics or armourers would follow.
“That’s what brings us to think about one and a half turns as a basic engineering principle.
“The problem with that sort of instruction is it involves a subjective amount of judgment by whoever is tightening the bolt.”
The inquest continues.
Mr Clarkson said he did appreciate that when an ejection seat fires the drogue needs to separate from the scissor shackle.
Read more:
When ejection seats are fired a drogue parachute deploys in order to stabilise the descent.
This mechanism then allows the main parachute to release.
When the pilot activates the seat, a plunger releases the arm of a scissor shackle and in turn releases the drogue shackle the first chute is attached to.
It is crucial that the nut and bolt through shackles is not over-tightened, which could prevent it working properly.
Questions over the bolt's performance were raised during the inquest into the death of Flight Lieutenant Sean Cunningham.
He died on November 8, 2011 after his ejection seat was fired while his plane was on the ground at RAF Scampton.
Reds armourer Sergeant Chris Clarkson, who was present when Flt Lt Cunningham ejected, but has since left the RAF, told the court he understood the drogue nut and bolt should be tightened to a “good positive lock” and showing at least one and a half threads.
He said: “The head of the bolt is very thin.
“It’s difficult to get the spanner on it especially with it’s location on the under side of the drogue.”
Hugh Davies, QC, for Lincolnshire Police, asked: “Did you understand that if the nut was tightened too far it would prevent eventual release?”
Mr Clarkson replied: “I was not aware of that at all.”
Bernard Thorogood, counsel for the Health and Safety Executive, read this extract from the workshop manual that guided the armourers: “Pass the bolt through the drogue and scissor shackles and secure with a lock nut.”
He told the court: “In the absence of any more direct instructions such as torque, that’s the instructions that mechanics or armourers would follow.
“That’s what brings us to think about one and a half turns as a basic engineering principle.
“The problem with that sort of instruction is it involves a subjective amount of judgment by whoever is tightening the bolt.”
The inquest continues.
Mr Clarkson said he did appreciate that when an ejection seat fires the drogue needs to separate from the scissor shackle.
Read more:
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and showing at least one and a half threads
For your Info,The US have a different take on the amount required to be showing though, it being less.
It's been so long since I touched a Military Jet, but the Civilian side of things, if a torque is not specifically mentioned, there is normally a chart in the front of the manual with generic torque settings for standard nuts and bolts, however, one suspects the shackle bolt was not a standard item.
Bernard Thorogood, counsel for the Health and Safety Executive, read this extract from the workshop manual that guided the armourers: “Pass the bolt through the drogue and scissor shackles and secure with a lock nut.”
-re torque, on one notorious occasion Boeing didn't specify torque loadings to their own people, never mind the RAF. An avionics rack in a new Mk2 had been over-torqued so badly the honeycomb bulkhead was crushed to nothing, and fully laden with LRUs it toppled onto a UK contractor, minutes after touch down from its delivery flight. MoD denies the incident occurred, despite he and witnesses who reported it retaining their reports.
I also recall MoD denying a critical component was manufactured wrongly, causing multiple deaths. (ZA721, 27/2/87) The AAIB invited anyone interested to speculate where the split pin would be inserted, given no hole had been drilled. MoD ignored the evidence and said cause not determined.
Point being, MoD have form when it comes to protecting certain protected species, both companies and individuals. I hope the Coroner spends his 3 weeks digging deeply, but allowing MoD to withhold SI reports, thus denying informed questions, is not a good sign.
Interesting that the German Air Force chose to pay Aeroflug to replace the MB scissor shackle assy's on their Mk10a Ejection Seats with their own design. The site does not state the reason.
See just over half way down the page.
http://www.ejectionsite.com/frame_sg.htm
See just over half way down the page.
http://www.ejectionsite.com/frame_sg.htm
Having spent 6yrs on Hawk and same on Tornado during a 24 yr career as an Armourer I am very familiar with the Mk10 seat. The statement from the Armourer SNCO from the Reds is correct. The AP used to contain a statement to the effect of 'tighten the stiff nut until 1 1/2 threads are visible through the nut' or words to that effect. This was checked on both the Vital and Independent checks.
I have always felt that the failure to release in this accident must have been caused by this stiff nut being overtightened, as this would prevent the Scissor Shackle from opening correctly.
As for why did the seat fire in the first place? The Seat Pan Firing Unit sits very close to the cockpit floor when the Seat Pan is motored down on its Actuator. A reasonable size loose article (for example a Mobile Phone) could be enough to dislodge the Sear in the Firing Unit and initiate the ejection sequence.
As rightly pointed out by other posters, serious accidents are often caused by several events lining up to cause a disaster (Swiss Cheese Theory). If they were operating at reduced manpower and/or experience levels, that could explain why an otherwise very reliable system has been catastrophically compromised, leading to tragic results.
I am convinced some people in the service will know the cause of this tragedy, I hope it will come out.
I have always felt that the failure to release in this accident must have been caused by this stiff nut being overtightened, as this would prevent the Scissor Shackle from opening correctly.
As for why did the seat fire in the first place? The Seat Pan Firing Unit sits very close to the cockpit floor when the Seat Pan is motored down on its Actuator. A reasonable size loose article (for example a Mobile Phone) could be enough to dislodge the Sear in the Firing Unit and initiate the ejection sequence.
As rightly pointed out by other posters, serious accidents are often caused by several events lining up to cause a disaster (Swiss Cheese Theory). If they were operating at reduced manpower and/or experience levels, that could explain why an otherwise very reliable system has been catastrophically compromised, leading to tragic results.
I am convinced some people in the service will know the cause of this tragedy, I hope it will come out.
A reasonable size loose article (for example a Mobile Phone) could be enough to dislodge the Sear in the Firing Unit and initiate the ejection sequence.
Does anyone know why the Aeroflug mods were done to the German seats? Was it an 'improvement' or a reaction to a perceived weakness in the original design by MBA?
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Beags,
Point taken, but if the firing path is 'mechanically interrupted' as a safety means, there must always be a concern that despite setting the arming mechanism to the correct 'live' position the interrupt remains fully or partially in-place. This situation may or may not deliver a tactile feedback to the operator to warn of the problem. As we are all routinely reminded, the impossible occurs.
Hence, there is a design issue to be considered in terms of minimising any risk that the seat would not fire when needed and MB has opted to keep the primary firing path for their seats open at all times.
lm
Point taken, but if the firing path is 'mechanically interrupted' as a safety means, there must always be a concern that despite setting the arming mechanism to the correct 'live' position the interrupt remains fully or partially in-place. This situation may or may not deliver a tactile feedback to the operator to warn of the problem. As we are all routinely reminded, the impossible occurs.
Hence, there is a design issue to be considered in terms of minimising any risk that the seat would not fire when needed and MB has opted to keep the primary firing path for their seats open at all times.
lm