Black boxes put out a sonar ping at about 32kHz. From what I've read, depending on sea conditions the ping will be audible at the surface out to about 16 km, leaving a search area of around 1024 square km. By adding a little complexity to the ping circuit, you could encode within it the last received GPS position of the box, before it hits the water. With average sea depth and average sink angles of less than 45° that information would cut the search area down to about 10 square km. Is there some reason this tech is not used, or is it still in the rigorous testing pipeline these devices must go through?
Current underwater locator beacons (ULBs) have a detection range of only a few km. 16 km would be under exceptionally favourable conditions. So in most cases the GPS data would not be of any additional help. It might tell you where the aircraft was before it hit the water, not exactly where the debris ended up after falling through several Km of water.
An advantage of current ULBs is their extreme simplicity and small size. There's no need for external data-feed and power connections. There are no issues of openings in the casing for waterproof connectors that also need to withstand the g-forces and pressures expected to be endured by a ULB. They are easy to test regularly and relatively easy to maintain.
From what I have read, current proposals for improvements to ULBs mostly focus on
There are trade-offs here - longer duration means bigger batteries. changing the frequency may make it harder to distinguish from other sources of sound in the ocean.
An interesting 2011 dissertation describes the difficulties involved and discusses modulating the beacon signal to include data.
Main reason those signals can be distinguished for what they are is because they have a specific signature. If the signals were to change all the time because you mix in extra information, they'd be impossible to recognise and thus useless.
Combined with the short range of the signal (inevitable consequence of the need to be low power, anything more would mean heavier equipment and/or shorter lifespan), there's just no benefit.
Black boxes put out a sonar ping at about 32kHz. From what I've read, depending on sea conditions the ping will be audible at the surface out to about 16 km, leaving a search area of around 1024 square km. By adding a little complexity to the ping circuit, you could encode within it the last received GPS position of the box, before it hits the water. With average sea depth and average sink angles of less than 45° that information would cut the search area down to about 10 square km. Is there some reason this tech is not used, or is it still in the rigorous testing pipeline these devices must
Why is it that black boxes don't float? From what I gather the answer is: So they will not float away from a water crash site. The ping can be heard underwater with sonar. Finding the ping, finds the site. But why not have two black boxes one that floats and one that stays with the aircraft? That way if a plane is lost at sea, if we find the black box floating, we could use the data to find the other black box and the crash site. Plus the benefits of having a redundancy are enormous.
At a frequency of 37.5 kHz a quarter wavelength is about 2 km long. How does the black box efficiently radiate anything if it is not attached to 2 km of antenna?
This is related to the recent disappearance and the fact that some claim the plane's black box to be deeply under water and that's why it cannot be located
to the Bureau d'Enquêtes et d'Analyses pour la Sécurité de l'Aviation Civile (BEA) in France. It is not clear who developed that black box. Was it the same company that manufactured the airplane? Also, can the buying airline use their own black box or their own security protocols for data encryption or encoding, to avoid having to send the black box out for analysis? ... 202 incident, the black box had to be sent to Germany for data recovery: He stated that the box would be examined by "foreign experts" in Germany or France as Pakistan does not possess
. This is just so we can find plane crashes in the sea when we don't know precisely where they went down (and to get basic data when the black boxes are too deep to get to immediately). Malaysian flight... be distributed around the plane (tail section, along fuselage, etc.). These FDR floaties would be about the size of a seat cushion, but they'd be wrapped in a water soluble cover. When a plane crashes... would help find water crashes sooner, but if you add a simple USB memory stick in the center, then have data similar to the current FDR's being fed into it, then finding one of the floaties would give
I never knew much about airplanes before the tragic incident of Malaysia 370. I have been spending a lot of time on Twitter reading various articles and investigations; in one of the articles I read, they stated that unlike transponders, "black boxes" cannot be turned off. However, each ELT is specifically designed for each aircraft, so it cannot be tampered with. You also cannot turn off the black box, as it runs throughout the flight, recording every 30 to 60 seconds. Is it really impossible to turn off the black boxes from within the plane?
A popular airport near me (KMYF) has two parallel runways, 28/10 R/L and a crosswind runway, 5/23. Almost always, 28R/L is in use. I'm sure they knew that there was generally a sea breeze in the area, and the wind typically will be right down the runway or within 10-20 degrees of centerline. I'm sure they do prevailing wind study for the area, and my questions are about the study: what are there some specifications for the study? Does the study vary in length depending on location? Is there a standard study that they use, and do they test things like average temperature during the study
but also the debris of the plane. If the recorders floated then they could move significant distances from the crash site and other debris, complicating search efforts. It seems that Commander Marks... Fleet, which is taking part in the search, said he expected the plane's flight recorders to be floating in the water. He said the recorders, also known as "black boxes", are fitted with radio... Fleet, which is taking part in the search, says he expects the plane's flight recorders to be floating in the water. "In calm seas, if there were a soccer ball [football] or a basketball floating
Are 40 hours of flight really enough to gain experience to fly a small private plane alone anywhere? The rules state so but from experience off you pilots, is it really enough or should be more hours be clocked with another experienced pilot next to you before venturing out? Today I had my first flight on a 152 from Dar es Salaam International Airport, and the area is quite busy. There were bigger aircraft taking off and approaching and many other taxiing. Putting an inexperienced pilot that has barely 40 hours in an environment like this could cause serious problems even though he has