Inititally it was reported that the US military denied the helicopter which crash-landed and flamed contain radioactive substance, but yesterday's report confirmed the usage.
USMC stated that radioactive substance have been used on multiple components including for example "indicator"s.
USMC said radioactive substance have been removed and the quantity are not sufficient to cause safety concern, Japanese MoD also said that the detected radiation level is same as normal, but these statement cannot comfort residents nearby, as some recall "that's what they said for the Fukushima incident".
The particular helicopter involved in the incident was the same one that have performed emergency landing at Kumejima airport back in June.
The incident occur only a few hundred meters away from residential home.
It is additionally reported that, when US personnel investigating the crash, they have caused further damages to the grassland where the crash occur.
In 2004 when a CH53D fall onto an university campus in Okinawa, Sr90 were detected frorm components like rotor safety device.
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Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
Radium coated dials? Really are the Japanese trying to take the world title in click bait.
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- dragon6172
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Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
Probably talking about the In-flight blade inspection system. Yes, radiation involved, but not a lot. For more info Google: CH-53 IBIS
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- WIederling
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Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
dragon6172 wrote:Probably talking about the In-flight blade inspection system. Yes, radiation involved, but not a lot. For more info Google: CH-53 IBIS
http://www.navair.navy.mil/index.cfm?fu ... CE61273AA9
Radiation source mechanically exposed on pressure loss in the blade.
How old is that system?
US Military imho has a knack for using the most icky solution available.
( you'd use a set of COTS tire pressure RFID sensors today.)
Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
WIederling wrote:http://www.navair.navy.mil/index.cfm?fuseaction=home.download&key=AD8FFC4F-C0CD-4B7A-BD4D-40CE61273AA9
Radiation source mechanically exposed on pressure loss in the blade.
How old is that system?
Late '50s-early '60s design - it's the same basic design on all of Sikorsky's metal-spar MRBs from that timeframe.
US Military imho has a knack for using the most icky solution available.
( you'd use a set of COTS tire pressure RFID sensors today.)
That was Sikorsky's solution to a late '50s-early '60s US military requirement to have an indication of a MRB spar crack in flight..
All-composite MRBs have pretty much taken over on military helicopters; there's no longer a need for pressurized blade spars (and the ability to monitor that pressure).
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- WIederling
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Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
jarheadk5 wrote:All-composite MRBs have pretty much taken over on military helicopters; there's no longer a need for pressurized blade spars (and the ability to monitor that pressure).
Thanks for the background.
Is pressurization functional ( against forex buckling )
or just for the integrity test. ( cracks developing letting the gas out? )
( compare : leak checks on oiltanks via an outer envelope and the interstice evacuated.)
Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
Integrity only. IIRC, the pressure was in the neighborhood of 8psi N2, and a special servicing kit is used to ensure the blades can't be over-pressurized.
Since the pressure is so low, the BIM indicator is quite sensitive, and it's possible to get nuisance BIM indications with rapid weather changes. On a exercise in Norway many years ago, I recall having to check blade pressures and add N2 after we arrived, because of the ambient temperature difference between Southern California winter and Norwegian winter.
Since the pressure is so low, the BIM indicator is quite sensitive, and it's possible to get nuisance BIM indications with rapid weather changes. On a exercise in Norway many years ago, I recall having to check blade pressures and add N2 after we arrived, because of the ambient temperature difference between Southern California winter and Norwegian winter.
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- WIederling
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Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
jarheadk5 wrote:Since the pressure is so low, the BIM indicator is quite sensitive, and it's possible to get nuisance BIM indications with rapid weather changes.
Trigger or toggle style activation ?
i.e. trigger on underpressure and then a manual reset or
on/off corresponding to some passing trigger level pressure?
Re: US Marine Corp helicopter CH53E that was crash-landed a few days ago in Okinawa confrimed to carry radioactive subst
Triggered by underpressure, which exposes the Strontium-90 to the IBIS detector in the fuselage below the root end of the MRBs. A "popped" indicator must be manually reset.
IIRC, an IBIS BIM indication in-flight was a "Land as soon as possible" item; if the BIM would reset and hold, it was considered a nuisance indication and we could continue flying. If the BIM would not reset (continued to pop), further maintenance was required.
IIRC, an IBIS BIM indication in-flight was a "Land as soon as possible" item; if the BIM would reset and hold, it was considered a nuisance indication and we could continue flying. If the BIM would not reset (continued to pop), further maintenance was required.
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