Air traffic system failure caused by computer memory shortage
reuters.com
reuters.com
(The AAS often appears in software engineering classes as an example of a classic "train wreck" project)
The flight plan did not contain an altitude for the flight, one of the sources said. While a controller entered the usual altitude for a U-2 plane - about 60,000 feet - the system began to consider all altitudes between ground level and infinity.
The conflict generated error messages and caused the system to begin cycling through restarts.
Obviously a hardware problem...
Is there an aircraft of concern to the FAA that flies above FL1000? One or two historic flights have been that high, so raise the ceiling to 150,000'
still not infinite.
A spyplane quietly in flight
At angels great, not infinite
Of course results in filling chips
And vex'd controllers passing slips
The only civil aircraft that ever flew above FL500 were Concorde and the Tu-144, neither of which are in service. But they didn't fly at supersonic speed and high altitude in crowded airspace -- simply because getting an SST up to altitude and speed takes several minutes, a couple of hundred miles, and a prodigious amount of fuel. To say nothing of the sonic boom issue, which basically limited supercruise to over-ocean flight.
While there's been a lot of hot air about supersonic bizjets over the past two decades, so far nothing's escaped from the CAD package much less gone into flight testing.
So what you're asking for is for an FAA system to be retrofitted to handle exotic military requirements, future space shuttles, and a class of commercial aircraft that would not operate in that flight regime within a couple of hundred miles of any airport.
I'm assuming they don't worry over satellites in orbit but they might have some concern if one decides to come back home.
This was made worse by a flight plan that had the plane going in and out of the area, so there were a tremendous number of permutations of possible flight paths.
The computer attempted to allocate memory to calculate every one of them and ran out of memory.
unsigned short int altitude;For example, Here is what the compiler for the 8-bit ATMEL Atmega 328 in an arduino does (on a platform with 32KB for program text and 2KB for RAM.)
sizeof(bool) == 1
sizeof(short) == 2
sizeof(int) == 2
sizeof(long) == 4
sizeof(long long) == 8
sizeof(void *) == 2Such systems should always preallocate fixed-size heapsfor each subsystem, each of which can then dynamically parcel out pieces of their own heaps if necessary. This helps limits the damage of any memory leaks in the system.
The other thing to consider is that some of these systems are rather old and could easily have less than a gig of ram.
Only in the sense of having a broken system, putting in place some procedural constraints and then praying that everyone follows the rules.
As you say, it's a software bug. Until it's been 100% characterised and tested this leaves a huge question mark hanging over the system. Adding memory is a band aid solution.
That sounds more like buffer overrun than OOM. One is a Heartbleed-class vulnerability, the other is a pretty straightforward DoS situation. But of course why would we expect Reuters to be able to distinguish between the two...
And? Consider what this means exactly and how come the system saw the plane but didn't record the altitude.
I thought such a plane would be 100% autonomous and be able to "see" and avoid other planes.
A U2 is not at all stealthy. You must be thinking of some other plane.
> if you have to register a flight plan
It's not a military operation in a foreign country, it's a routine flight in the home country.
> I thought such a plane would be 100% autonomous
The U2 was made long before such computers existed. They do have drones now.
> and be able to "see" and avoid other planes.
It wasn't the plane with the problem, it was ground control.
This must be a world record: A faulty assumption in every single sentence!
For 100% autonomous flight, I wasn't thinking no pilot, but about being able to navigate without any assistance from other radars
Is it worth asking, at all, why we're flying a military reconnaissance aircraft back-and-forth over Los Angeles?
If there's an actual military mission for any military plane that requires it to fly over or through a commercial area, wouldn't you prefer that pilots and ground operators already know how to do that?