Airliners carry weather radar, but this is generally not designed to spot other aircraft.
A recent report:
Also reported low incidence of cranial trauma, which unnamed experts said militated away from intact-fuselage impact, as you’d expect most bodies to have massive face/head impact against the seats in front of them.
All right, this is another stupid question, I’m sure. If the commercial jets don’t carry radar to spot other planes, how do they avoid colliding over the ocean if they have no contact with air traffic controllers? I know they have specific routes to follow, but what if they have to divert from those routes due to weather or some other circumstance? Do they not run the risk of running into another plane’s path? You can tell how much I know about all of this…
I know a guy who was an ex-air traffic controller. I asked him about this once. He said, “It’s a big sky out there.”
Then it’s probably best not to read the description of ‘burned beyond recognition’ from Tom Wolfe’s The Right Stuff (about halfway into paragraph 5).
OK, I’m going to spoiler this. It is a very blunt question to this answer. More sensitive readers please pass this answer by, it is really disgusting:
The bodies were floating in the ocean for at least several days, in some cases over a week. In a tropical area. Aside from heat and water causing massive decomposition and bloating which can grossly distort soft tissues, the ocean is full of fish. Most of those fish eat flesh. Most of them aren’t too fussy if the flesh is alive, dead, or dead for a long time when they eat it. Scavengers - those specializing in eating dead things - tend to eat the softest bits first, such as nose, eyes, lips, and yes, genitals. Sharks - of which there are many in the Atlantic - may have chomped bits ranging in size from fingers and toes to major portions of arms and legs off the floating corpses. As it happens, animals teeth and bites leave distinctive marks that can be distinguished from impact trauma, but the end result is that the bodies pulled from the sea after a few days are likely to be missing their crotches and much of their faces.
I trust that has cleared up any remaining confusion.
There has been some discussion that this could have been a partial answer to the question “why would the pilot not deviate more around the storm [assuming he could see it and reliably locate an alternate route]?” There are a good number of defined routing lanes in any given area and, in the dark, the pilots may have had a concern that significant deviation would put them at risk of an incursion. So the default way to avoid incursion is to stick to your assigned route. Other alternatives include visual spotting (not at night in a storm), knowing what aircraft are on similar routes and requesting an update on their position, and in the last resort, the TCAS system which will provide a very brief and emergency-basis collision-avoidance signal (that is the basis for the “pull up!” annunciator).
Coming soon [maybe]:
Well, yes, there’s a lot of sky, the problem is that there are also a lot of airplanes.
I’ll take a stab at this, with the caveat that the airlines may have additional techniques that a general aviation pilot such as myself may not be aware of.
First of all, there is both vertical and horizontal separation of those standard routes you mentioned, as well as separation of traffic going different directions by altitude. So everyone going east is at specified altitudes and everyone going west at another group of specified altitudes. While this does not eliminate all potential problems it does minimize the chances of head-on collisions which, I’m sure, we all agree is an Important Thing.
Second, airplanes have radios. Actually, in the case of airliners, they have a bunch of radios (even most of the small airplanes I fly carry two radios, and I have a spare portable transceiver I carry as well - communication is important to pilots). The best part? They’re two-way radios. Airplanes routinely talk to each other, even in controlled airspace, and in airspace that has no air traffic controllers watching over it they talk to each other even more. In addition, those multiple radios also allow them to monitor multiple frequencies.
In the case of diverting due to weather, a pilot departing the normal route can, and does, let as many people as possible around him or her know what is occuring and where the airplane will be going from that point onward.
Pilots speaking to other pilots in the air is routine. It starts with the beginning of flight training. This is very, very, very routine. Happens ALL the time.
Also, cockpits have windows. I realize they are unsexy, low-tech devices but they do work. Pilots do look out the window, and in addition to admiring sunrises, sunsets, full moons, and other pretty things they monitor the weather and look out for other aircraft. If it looks like they’re getting a little close to the folks in front of them they will take steps to avoid getting too close.
There is also something called a TCAS which, if I understand it correctly, will pick up the transmission from another airplane’s transponder and give a collision warning. Getting close enough to trigger a TCAS isn’t a good thing, it’s a near miss, but it is pretty clear that they have avoided a few collisions over the years. The system tells one airplane to pull up, the other to dive down, thus putting them at different altitudes and avoiding the attempt of two objects to occupy the same space at the same time.
On both of my transatlantic flights (late 70’s-early 80’s), our plane flew in a loose formation with another airliner (perhaps 3 mile separation?).
There’s a misconception here that being out of radar contact means you’re out of contact with air traffic control. These aircraft are flying through controlled airspace under the direct control of various controllers from different countries as the flight progresses. Just because they are not covered by radar does not mean that they are not controlled. Normally they talk to ATC by radio or datalink at nominated reporting points and report their position, altitude, and estimated time at the next reporting point.
If you need to divert around weather then you need a clearance which would normally be something like “AF47 request 50nm right of track due weather”, ATC may respond with a clearance or they may deny the clearance. If the pilots decide they must divert then they say they require clearance for weather diversions. The controller then is pretty much obliged to give the clearance. If they don’t, then the pilots can make broadcast their intentions and divert without a clearance. They should also adjust their altitude by 300 feet if they divert by more than 10miles.
Relevant paragraphs from the Australian AIP:
Air safety is about getting priorities right. The immediate danger of a thunderstorm trumps the possible danger of collision with another aircraft.
Someone said that people might die from the g-forces BEFORE the impact. How exactly does that work? Even assuming that a plane were traveling downward at 5 or 600mph, which is certainly not always the case, they would only have 1 or 2 minutes maximum before impact (depending on their starting altitude). Would that be long enough for such forces to kill someone? If so, how would they actually die before impact? What is the science behind that? I find it hard to believe that many people would actually die just from the speed of descent in a plane. Unconscious perhaps, but dead? Someone please explain. Apologies if this has been discussed and I overlooked it…
G-forces aren’t due to speed - they are due to changes in speed. These could be high when a plane doing 500 knots breaks apart, but they can’t be high for any long period of time.
And note that for g-forces alone to be fatal, the must be really high - something like 12 to 15 g or more. (In planning for crashworthiness, a rule of thumb is that the human body may be able to survive very brief exposure to 40g - so anything in a crashworthy cockpit should stay put when subject to forces equal to 40 times its weight.)
If at 500 kts you are decelerated at 15 g, in less than 2 seconds you’re at zero speed. That’s probably not enough g-force exposure to be fatal. (It’s worth noting that the peak force could be higher.)
They wouldn’t. Trauma as the plane breaks apart (from wind blast, flying objects, etc.) is a much more likely explanation.
I’d say that 15g is nothing like enough to be fatal. Aerobatic pilots can briefly pull 12g and remain conscious, another 3g is not going to kill them.
I seem to recall that for normal people it doesn’t start getting fatal until 20g, and as noted people can withstand 40g very briefly.
However, for the elderly or those with fragile bones 15g might be a problem.
A quote from Red Bull Air Race pilot Matt Hall from a CASA Flight Safety magazine interview:
I expect you are right except possibly in the case of people with heart problems or certain other infirmities. I was trying to choose a number at the low end.
Do you know, I really hate to picture what sounds like a process of trial and error to find that out, with the “error” being his temporarily passing out if he mis-estimated how many seconds or didn’t get the straining technique quite right.
Well, he’s an ex Royal Australian Air Force pilot so I guess he’s had a lot of time and experience to work out what his limits are. At any rate, loss of consciousness due to Gs (GLOC) is normally a gradual process beginning with a loss of peripheral vision followed by a total loss of vision followed by passing out. Under these conditions you have time to recognise the warning signs and back out of what you’re doing. Also any relaxation from the pilot and the g forces drop off as back pressure on the stick is released. A particularly dangerous scenario can occur when you go straight from negative Gs to high positive G. The negative Gs will slow your heart rate and when you follow that with high positive Gs you can go straight to GLOC without getting the warning signs.
Regarding G: The Fastest Man On Earth. It’s a good article (I liked it enough to buy the book, which doesn’t contain much more than the online version) and you should read all of it. But Part 2 says that Paul Stapp withstood 46.2 g.