a series of interesting observations (to a layman anyway) on Air France 447 - AFR447 - A detailed meteorological analysis - Satellite and weather data
appear to indicate that the storm was not `unusual` in iteself , but might have had unusual properties , being `dry` air turbulence , which wouldn`t be spotted on the radar. |
the A330-200 t.h.s does have a mechanical control chain and cable loop which runs from the pedestal wheels to the input on the t.h.s.actuator. .If the E.F.C.S. has failed then this allows a physical mechanical input but will still need blue and/ or yellow hyd sys .Similarly, the rudder also has a cable system with direct control from the rudder pedals.
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"And perhaps already covered, the pingers on the recorders are distance related from the sonar. So when you consider the possibilities as a three dimensional box including the depth along the debris field in miles, it truly is a needle in a haystack."
Even more daunting when you consider the bottom of the box (i.e. the sea floor) is very unlikely to be flat ... far from it if its anywhere near mid-Atlantic. I imagine this means pinger signals may well be masked by topography and could require a very close pass to pick up. My opinion is that location, not recovery, will be the bigger challenge regarding CVR and FDR ... especially if the tail section experienced significant breakup. Best Ads |
So far the latest info in FMC's thread re AF's release of the 'AIRMAN' ACARS fault info is the most pertinant info avail and this is what we should be looking at.
What sequence of events could cause a Prim Computer to fail causing the AP in cmd to disconnect followed by the other faults 1 minute later is what we need to be looking at. Especially the loss of the Primary flt info provided by the ADRIRU's? And how could this effect the pressn when the packs would still be operating in pneumatic mode if there were a multi elect bus loss with control of the outflow valves still avail in 28 vdc mode.... Lets stick with what we know.. |
Belgique, why would
Cruise captains are likely to be not as well prepared for a sudden coffin corner encounter. Not sure that this has any relevance but it is more than likely that all three crew members were equally proficient at operating the aircraft. It is to me irrelevant who was in what seat given the levels of experience in this cockpit. |
Joe90 wrote:
Conclusion: At times like this always maintain a mental or written note of what headings you would fly and for how long if you suddenly lost the Wx radar. |
I just happen to browsed the Yahoo website and they have released the identity of the flight crews on the downed AF...
List of passengers aboard lost Air France flight - Yahoo! News |
Anyone considered pitot probe contamination or icing? As I said, I think AF should be a lot quieter than it is about this incident but thought people might like to know |
Re no lightning strikes above FL300. I experienced a lightning strike at FL320 while circumnavigating some isolated summer thunderstorms at night over central Texas two years ago in an Airbus 319.
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BlindinG
MD100 wrote - Does anybody know how far can the signal of the ULB (Underwater locator beacon) of the CVR/FDR be detected? Excellent question. Has it been answered here already? Are the CVR and FDR separately enclosed units (i.e. will they be in different locations?). How far will the beeps, or transmissions reach? If it 3600m under the water, but can transmit 10km, then it surely shouldn't be too difficult to find with the correct technology?? |
One very important piece of information is missing though. Was the cabin vertical speed indicating a climb or a descent? If the indication was accurate, it would have almost certainly been a climb. Even if the aircraft was descending at a rapid rate and there was a hull breach, the cabin altitude would have not descended appreciably during that time until they were below 8000 feet. |
A question ...
Can Sonar buoys hear the pinger? Could a maritime patrol aircraft drop a pattern of sonar buoys to start localising the black boxes? (and I can understand if no-one wants to answer) |
Could a maritime patrol aircraft drop a pattern of sonar buoys to start localising the black boxes? Rhino |
FDR and CVR requirements.
TSO C123a (CVR) and C124a (DFDR) Fire (High Intensity) 1100°C flame covering 100% of recorder for 30 minutes. (60 minutes if ED56 test protocol is used) Fire (Low Intensity) 260°C Oven test for 10 hours Impact Shock 3,400 Gs for 6.5 ms Static Crush 5,000 pounds for 5 minutes on each axis Fluid Immersion Immersion in aircraft fluids (fuel, oil etc.) for 24 hours Water Immersion Immersion in sea water for 30 days Penetration Resistance 500 lb. Dropped from 10 ft. with a ¼-inch-diameter contact point Hydrostatic Pressure Pressure equivalent to depth of 20,000 ft. Here are the parameters required to be recorded: http://www.ntsb.gov/Events/symp_rec/...s/Grossi-2.gif I'd rather wait for the professionals to determine the cause. By the way, the results of the investigation are all based on probabilities. This is the most likely event etc. It is not necessarily definitive. In cases especially like this the actual cause may never be known. |
A question ... Can Sonar buoys hear the pinger? Could a maritime patrol aircraft drop a pattern of sonar buoys to start localising the black boxes? Despite being on drug-interdiction duties, they would almost certainly had these buoys at the ready for deployment from their base of operations. |
mickyman
If the airliner went down in one of the deepest parts of the Atlantic - what effect will pressure have on the 'black boxes' and could the data survive in such conditions? Flight Data Recorder Time recorded = 25 hour continuous Number of parameters = 18 - 1000+ Impact tolerance = 3400Gs / 6.5 ms Fire resistance = 1100 degC / 30 min Water pressure resistance submerged = 20,000 ft Underwater locator beacon = 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation Cockpit Voice Recorder Time recorded = 30 min continuous, 2 hours for solid state digital units Number of channels = 4 Impact tolerance = 3400Gs / 6.5 ms Fire resistance = 1100 degC / 30 min Water pressure resistance submerged = 20,000 ft Underwater locator beacon = 37.5 KHz; battery has shelf life of 6 years or more, with 30-day operation capability upon activation Source: www.ntsb.gov The ULB, also known as the "pinger" usually have the following specifications to satisfy TSO-C121 Underwater Locator Beacon (ULB) Operating Frequency:37.5 kHz ± 1 kHz Operating Depth:Surface to 20,000 feet Pulse Length:Not less than 9 milliseconds Pulse Repetition Rate:Not less than 0.9 pulse per second Useful Life:Six years Operating Life:30 days (minimum) Acoustic Output, Initial:1060 dynes/cm2 rms pressure at 1 meter (160.5 dB)Acoustic Output, After 30 days:700 dynes/cm2 rms pressure at 1 meter (157.0 dB) Operating Temperature:28º F to 100º F Actuation:Fresh or salt water, surface to 20,000 feet Radiation Pattern:Rated output over 80 percent of sphere Hope this helps :ok: |
Yes, our Orion anti-sub aircraft are equipped with air-dropped sonobuoys with both passive and active sonar. The active equipment can map the ocean floor... Active sonobuoys are used to localize targets quickly and accurately in extreme environmental conditions, against a very quiet submarine, or in an attack mode. The released acoustic energy enables an accurate location from the sonobuoy in both range and bearing to the submarine. When two or more “fixes” are obtained the speed and the course of the target can be established. Active buoys use a transducer to introduce acoustic energy into the water and to manipulate the return echoes which are amplified and for VHF radio transmission. These buoys are designed for deeper depths than passive buoys. |
Bubbs:
Orion's carry both active and passive buoys. The passive array equipped buoys are fully capable of picking up the DFDR/CVR pingers. Sorry Bubbers, but for clarification I should have mentioned these are two different sonobuoys. |
ADIRU faults
Is it not entirely possible that the same ADIRU fault that caused the airbus on route to Perth to plummet towards the ground ( it took a reading from the fauty unit rather than a reading from the other 2) could have happened here? couple that with flying through severe turbulance/ thunderstorms , and if the plane did dive towards the ground for a number of seconds , would it be recoverable?
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The passive array equipped buoys are fully capable of picking up the DFDR/CVR pingers. |
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