Max, do you think it is a good idea for every plane, all the ones sitting on the ground or in hangars, to keep transmitting their GPS coordinates?
Pilots have the ability to turn the transponder off because they don't want it on (and might be required to turn it off) between the time they land the plane, and hours later when another crew takes the plane wheels-up on a different flight.
About losing a 777 airliner ... to paraphrase Douglas Adams: The ocean is big. Really big. You won't believe how vastly, mindboggingly big it is. It just looks small when it is on your CNN screen.
Until fairly recently, HF radio was the norm for all trans-oceanic flights. They had (non-Ham) frequencies which they used to stay in contact with the civilized world when out of VHF contact with ground stations.
Then satellites came into the picture and those HF comms are not used so much anymore. I might be mistaken but I think it is mainly since the 90s that this has happened.
The planes still have HF radios in them, and yes, some pilots who are also licensed ham radio operators, use them to pass the time.
I hear a lot of Air Force jets on HF radio, when approaching the east coast USA.
Depending on the location in the avionics bay there could have been a thermal issue(such as loss of cooling airflow) that caused systems to drop off-line without the pilot knowing it immediately -- another issue that one has to consider is if there was an issue with time-synchronization at the various and scattered ground based sites. Another item to remember is that each of the systems is in a different RF band and due to atmospheric conditions may reach the limits for range imposed by the atmosphere and curvature of the earth at different times (Even a satcom operating in spot beams is affected by this) -- there are many many details like this that do not show up at a first glance -- most things that do cause loss of an aircraft involve multiple things going wrong at the same time -- look at the dehavland comet -- several of these were never found -- it was not until the manufacturer did pressurization fatigue testing to simulate the number of hours and cycles the fleet had reached and the test article failed that they knew they had an issue.
I think I have the answer. Each plane could have a bouyant transponder that pulses laser light and wireless signal both carrying stream of important data. A laser on the satellite would be useful, too, for communications better image capture, and, it only needs to pulse when commanded or on low dutycylce to save energy.
The bouy would detach and tether with a detachable tether. A good BAttery would would permit a long period of laser pulsing and RF transmission plus solar PV could be added to keep it alive for a long time. This is easy to design and more that one at low cost could be atttached to outside of the plane with tamper alarm. In fact many of the them could be attached to the plane with 3M or Berquist adhesive very qucikly and firmly and the laser would be visible for rmany miles. Something like this could work. Lost s data can be put on to a laser light beam!
I think I should put this on Indiegogo right now. Fedback please.
Apparently not a possibility? The BBC was reporting yesterday that ACARS was switched off BEFORE the last message from the airliner, "All right, good night," and that the radar transponder was switched off shortly after that. And there was a third satcom signal that continued to transmit for hours after that. So that's why the catastrophic failure possibility is being discounted.
Just as plausible an explanation is part of the fusalage blew out taking some of the avionics, as well as some of the oxygen system with it over the course of a few minutes -- maybe the pilot can start a turn and descent before blacking out -- after which the plane goes on the new heading out into the middle of the indian ocean and runs out of fuel -- IM apps on phone networks are not really robustly coded, and can leave stale data till the SW timers time out. The other thing to remember is that not as many people in aisa have smart-phones with apps -- due to a variety of reasons -- this may leave fewer bread-crumb trails to follow.
Leading causes of death in the US -- Cancer, Heart Disease, RX Drugs -- all very likely to to die in bed in these scenarios -- maybe a hospital bed, but a bed.
Airliner's are all about managing a large number of risks for a few short hours at a time --we can't even breathe at those altitudes, but given this there are many other risks in building and operating an aircraft. Worker's involved in making parts for the aircraft face many risks that make them more likely to die of cancer -- rare and exotic metals, and materials must be alloyed, forged, and machined and cut -- all of which can cause toxic symptoms in the people doing the work. Automation and technology is helping reduce these very real risks that are a part of every flight's success or failure. These worker's may die in bed after 20-40 years on the job -- basically due to lack of sufficient technology to minimize the myriad of manufacturing and maintenance related risks -- this seldom makes the news, but is a very real risk -- maybe even for those of you living in the same community as manufacturers of high tech aerospace parts -- waste products can find their way into the air, water, and soil and impact everyone in the community.
Max, admittedly there is a GREAT deal of inertia in the "design requirements" portion of avionics for commercial flight, but don't forget that most of the time the "mindset" of the designers of this equipment has served the commercial airline industry, the flying public AND the equipment manufacturers fairly well. But yes it IS slow - I had the privilege of working on a clean-sheet "engine control" (they call it a FADEC) for a brand-new small jet engine design (well actually there were two, but the hardware was pretty similar) and the overall effort ran about FIVE YEARS on the calendar before final signoff (and NONE of the participants felt like they were "dragging their feet")! I think you'd have to look on it more like the "old days" at Western Electric designing equipment for the phone company, in that situation the premise was you wanted to be capable of amortizing any particular piece of equipment over 40 years, the aircarft industry may not look QUITE that far out but it is definitely more of a "long term" view. One of the reasons is in this field neither the hardware nor the software engineers actually "conceives the box", they simply implement the requirements of the RTCA specification for that avionic function, they DO get to pick out the chips and connector pinouts and so forth (subject to a lot of preconditions) but many of the signal definitions and flows and such that will interface with the rest of the aircraft are fairly "cast in concrete". So for example the focus in the wireless protocols tends to be towards narrowband AM because its characteristics are widely known and studied, and also because it uses bandwidth sparingly under high-traffic conditions where we still don't want safety to be compromised.
One of the aspects that I think has served quite well which MAY not have been "fully thought out" in advance is the vast majority of the architectures that get approved for this type of service (particulary at the higher safety levels) are executing code out of flash (or in the prior generation, EPROM) so AT LEAST we won't have to worry too much about "virus-like" issues (because generally program space contains little or no actual RAM that such a creation could be loaded into)! Remember even GPS was originally designed exclusively for military use but it certainly has "worked its way into" the aircraft via standards like DO-229 (for which I wrote the RTOS for the first successful commercial implementation of the airborne receiver, and the company for whom it was designed went on to power Garmin's successful push into avionics). Now no doubt it will be possible to "retrofit" some new concepts into this general "mindset" (like what was done to reinforce the security of cockpit doors after 9/11) but we need to take "all due diligence" before we start making wholesale short-term-minded changes to these systems that have served us so well for so long.
People are notoriously bad at assessing personal risk, letting what they hear color their perceptions. To worry about the 82 planes and not the thousands of people who went missing in the same 65 years for other causes is a typical case in point. Ask a life insurance actuary: disappearing on a phantom airplane isn't even in the top 10. Given that 99.7% of Americans die in bed, maybe we should all give up sleeping. ;)
A Book For All Reasons Bernard Cole1 Comment Robert Oshana's recent book "Software Engineering for Embedded Systems (Newnes/Elsevier)," written and edited with Mark Kraeling, is a 'book for all reasons.' At almost 1,200 pages, it ...