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Inflatable CVR/FDR raft.

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Inflatable CVR/FDR raft.

Old 25th Mar 2015, 22:52
  #1 (permalink)  
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Lightbulb Inflatable CVR/FDR raft.

After reading several forums regarding incidents and locating of the CVR/FDR.
Such as the air France flight in the pacific.

Would it not be beneficial to engineer a CVR/FDR inside a inflatable raft device for in the event of an aircraft hitting water, the device floats and possibly adding a EPRIB or similar GPS locator device to it. Thus giving a floating GPS target and a easily retrievable recorder/s.

Food for thought...
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Old 25th Mar 2015, 23:45
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Pacific.......Atlantic........who cares it's all water right!!
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Old 25th Mar 2015, 23:51
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FDRs & CVRs - Solar Powered Floating Locators

I have been advocating a similar idea ever since Malaysian 370 disappeared: a barostatic release of the FDR & CVR deploying when an aircraft descends below a certain depth of water, or after a ground crash, attached to a flotation device/platform, it then uses a simple solar-powered battery to Tx its position and/or send out Sarbe type pings. If the flotation device were large enough and made of Hi-vis, radar reflective material finding it should not be too difficult by radar and then visually and the beacon would keep on and on txing.
Moving the recorders to a more suitable location higher in the tail of more-than-60-mins over-water aircraft would be the biggest expense which one can only assume is too expensive for this idea to catch on. Shame on you aircraft manufacturers. The technology is available : only the incentive is lacking. The cost would be less than installing an aircraft in-flight entertainment system too. One day I will able to say...I told you so!

Last edited by 70plus; 25th Mar 2015 at 23:53. Reason: typo error
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Old 26th Mar 2015, 02:34
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Any time it is suggested that something be automated (such as release of the FDR/CVR from the aircraft) - one always has to think about what would happen if the automation burps and causes an incorrect event.

All automation can fail, and even safety locks on safety locks can fail or be deactivated through error (cf: accidental (and fatal) wing feathering of SpaceShip Two).

So what happens if your system decides to release the FDR/CVR and float into the slipstream during a normal cruise at 38,000 feet and 480 knots? Does it jam or rip off a control surface or fin? Does it compromise the integrity of the pressurized cabin?

Engineering is not "I have a good idea!". Engineering is "I've had an idea - and have investigated every possible failure mode - and can provide evidence that none of them will have a fatal outcome, when (not if) they occur."
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Old 26th Mar 2015, 04:20
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There was a similar thread on this following AF447. Remember an application someone had mentioned on US military aircraft vaguely. My thought was an externally mounted combined unit that would detach sensing high pressure or dissolved by the salt in ocean water.
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Old 26th Mar 2015, 04:39
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dissolved by the salt in ocean water.
Great idea, then we just have to close all airports next to the coast so the aircraft do not get covered in salt spray!
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Old 28th Mar 2015, 18:23
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Engineering is not "I have a good idea!". Engineering is "I've had an idea - and have investigated every possible failure mode - and can provide evidence that none of them will have a fatal outcome, when (not if) they occur."
I think that answers the OP's enquiry.
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Old 31st Mar 2015, 12:11
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Engineering is not "I have a good idea!". Engineering is "I've had an idea - and have investigated every possible failure mode - and can provide evidence that none of them will have a fatal outcome, when (not if) they occur."
So who designs airplanes? Can't be engineers then..
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Old 1st Apr 2015, 00:58
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Originally Posted by ray cosmic View Post
So who designs airplanes? Can't be engineers then..
Unfair. Maybe if the statement was reworded thus:
...every possible failure mode we can think of...
Truth be told, engineers who end up in the aerospace sector tend to be *the* most rigorous and methodical of the breed (which is why I'm not one of them... )
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Old 1st Apr 2015, 10:16
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Originally Posted by Pattern is full
All automation can fail
This is the primary thing that needs to be understood, especially in avionics.
Why re-engineer what I consider to be a 99.9% reliable solution? The essential problem is that of location. FDR/CVRs have been recovered from the most inaccessible places. There is little point in them separating from the airframe as there is always the need to recover bodies and airframe parts and the associated pingers are invaluable.

The real requirement is where to look. This could be addressed by a releasable locator beacon but preferably by real time tracking of aircraft. The latter is already being studied by ITU-R and I expect it will be implemented.

Such real time tracking can be accomplished by a miniature transponder with GPS that is indirectly connected the avionics circuits and is also Intinsically Safe. Being IS means that it is self-protected and no CBs are required in the circuit and it cannot be disarmed.
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Old 3rd Apr 2015, 23:00
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Why do we still have a single FDR and a single CVR? It seems reasonable to have a master recorder that collects and collates all the relevant data streams, but I don't find it so obvious that there should only be a single copy of the data.

With current technology, the weight penalty of having a number of slave recorders, driven from the master FDR and CVR, distributed around the airframe should not be prohibitative.

There must be quite a few locations where a hardened module would have a good chance of surviving fragmentation of the airframe, or could be released when subjected to significant water pressure. Winglets and the top of the fin seem to be reasonably plausible places.

In some locations, the slave recorder could be packaged with radio location features, as suggested by the OP. In others, it might be arranged to release a dye that would spread and help locate the stave (or even the primary recorder) after an accident.
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Old 4th Apr 2015, 02:05
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A floating flight recorder will rapidly drift away from the aircraft wreckage and is more than likely to be run down and sunk by rescue craft or fishing boats attending the scene. The present system where if you find the tail, you will generally find the flight recorders works pretty well.

This appears to be more a case of what can you do to speed up the process of locating the wreckage in the first place in remote locations. The only sensible solution at present would seem to involve using a GPS locator beacon just transmitting a unique aircraft serial number every 15 minutes or so. The power requirements are low enough to be supplied directly from the aircraft batteries with circuit breakers and protection devices located away from areas accessible in flight. A beacon check before take off to check satisfactory operation could be verified by the control tower or ATC. No operating beacon, no flight.

The search area in event of a disappearance would still be potentially very large, but a plot of previous points along the flight path would narrow the initial search area considerably.
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Old 4th Apr 2015, 04:09
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I say again, as I have suggested in the past, I believe a modified form of the airplane locator as installed on the Lockheed P3C is an excellent idea.
Located in the tail, separates when a crash is detected, aerodynamic shape and it floats whilst transmitting. Instant satellite pickup.
So what if it floats away, those things can be calculated!
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Old 7th Apr 2015, 11:35
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The marine industry has a solution to this problem, EPIRBs
What is an EPIRB?

But then again, it's not like there haven't been multiple attempts to solve this. Distress radiobeacon - Wikipedia, the free encyclopedia
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Old 7th Apr 2015, 14:09
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Any locator beacon fitted to the outside of the aircraft would need to be able to withstand temperature changes between +50C and -70C to cope with sitting on the ground in the tropics and flying at altitude in more temperate zones. It would need to withstand acceleration forces of up to 400g during a crash and reliably separate when needed, but never under normal operating conditions.

Such a system would need to be heavy and complex. Additionally power and or data lines would need to be routed through the pressure bulkheads adding additional stress and failure points to the aircraft fuselage.

By contrast, a GPS beacon system can be located within the fuselage with a patch antenna sited in one of the radio frequency transparent panels already mounted on aircraft. The environmental conditions are far more friendly to the electronics, so reliabilty will be better.

Even using off the shelf components costing a couple of hundred dollars, fitting such a device will probably come in at between US$50k and US$100k per aircraft considering engineering costs and lost revenue while the aircraft is being fitted out and tested. I can't see many airlines agreeing to that when existing systems can do the job, assuming they are not sabotaged by the flight crew.

MH370 is a particular case where deliberate efforts were made to hide the aircraft from surveillance. AF447 took a while to locate and recover because of the depth of water at the crash site, although wreckage was quickly found floating on the surface.

External, detatchable floating beacons are not the answer to the problem of locating downed aircraft at sea. If the crash is survivable, then a couple of emergency beacons packaged in the liferafts or emergency slides will suffice to alert rescue crews of the location of possible survivors.

If the aircraft is totally destroyed, then a 15 minute GPS breadcrumb trail along the flight path will narrow down the search area to a maximum of a 150 miles from the last recorded position. A far smaller area than is currently being searched for MH370.

There will always be the chance that an aircraft will totally disappear even when a rough estimate of its final position can be made. The aircraft could crash into mountainous terrain and be buried in an avalanche, or into a remote area of sea where weather conditions are so severe, that floating debris is destroyed or dispersed completely. Eventually something will turn up, but it may take many years of searching or waiting. Sometimes it is just not possible to obtain instant answers, no matter how distasteful this is to the Internet generation. The aviation world is intensely aware of cost management and no airline will fit any additional equipment beyond what is legislated for or will save the company money.
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Old 7th Apr 2015, 19:30
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In the rotocraft realm, there is a device called an ADELT, Automatic Deployable ELT. It is a frisbee sized device,about 6 inches tall mounted through the skin of the aircraft. In the event of a water landing, water sensors detect water in the aircraft and deploy the floating unit.
Several problems with large commecial aircraft, including deployment in flight, and the size of the unit creates alot of drag at high speeds.
In a rotorcraft (like those that transport oil rig crews) even if the tail breaks off and sinks with the ELT, and ADELT will remain near the cabin, that is equipped with emergency floats.
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