ER-2 causes foobar at the Palmdale FAA center

NBC on the FAA failure

A relic from the Cold War appears to have triggered a software glitch at a major air traffic control center in California Wednesday that led to delays and cancellations of hundreds of flights across the country, sources familiar with the incident told NBC News.

On Wednesday at about 2 p.m., according to sources, a U-2 spy plane, the same type of aircraft that flew high-altitude spy missions over Russia 50 years ago, passed through the airspace monitored by the L.A. Air Route Traffic Control Center in Palmdale, Calif. The L.A. Center handles landings and departures at the region’s major airports, including Los Angeles International (LAX), San Diego and Las Vegas.

The computers at the L.A. Center are programmed to keep commercial airliners and other aircraft from colliding with each other. The U-2 was flying at 60,000 feet, but the computers were attempting to keep it from colliding with planes that were actually miles beneath it.

Looking at the KPMD flights, I would say it was NASA809, an ER-2.
NASA809 flight

Of course the question is now why all of a sudden this plane is a problem since it flies out of KPMD all the time.

a reply to: gariac

It was not a problem with the plane, but software on the ground radar. Happens all the time when software receives parameters that are out of limit. My guess it it was new software, ormamsoftware update.

Probably due to an overflow in a number lets say its an unsigned 16 bit number which gives around 65500 possible combinations so if the planes at a point where it reads lets say 67000 feet it could after doing the maths return a carry flag (it says the number is too big so you need to do something) and the returned number may only be 1500 so it thinks the plane is at 1500ft and thus the panic ensues

Probably someone did a simple change and forgot the system used 16bit instead of 32 bit or maybe he even asked does anything go above 65000 ft and they told him nope

If any one seriously can say they believe that a Palmdale regional air traffic control centre would have a system that cannot handle 67000 elevation, well, I have a boat with no hull to sell you for deep sea fishing.

Goodness me, with the history of the area being steeped in aviation, with plentiful 'unknowns' climbing up out of the area to cross the Atlantic towards Europe (and returning from said journey), not being able to handle 67000 is simply for me, utterly unbelievable.

a reply to: Astr0

Now i don't know what the radar systems actually report back in, it was an example of the basic idea of how its possible for something to report the wrong value due to the number being too high for the system and not checked properly and it seems like 16 bit pdp-11's were popular with air traffic control at one point so who knows if someone slipped passing a 32 bit number into some old code that was expecting a 16 bit number by accident

just fyi, not trying to be rude! but its FUBAR........its an acronym....

Also this really sucks I have to fly throuh LAX tomorrow lol I seriously hope nothing like this happens again!

For the last 50 years, 70 to 96k and ABOVE have crossed those skies and those radar screens. Plenty of 'what the hell was that' gone on and plenty of 'you saw nothing'.

Heathrow airport was a Concorde spotters dream watching that pull away on screen, especially when it was over taken by some thing that left a runway after Concorde had crossed the Welsh coast. Then the unknown climbed higher to really rub salt in the wounds.

originally posted by: ManBehindTheMask
just fyi, not trying to be rude! but its FUBAR........its an acronym....


Also this really sucks I have to fly throuh LAX tomorrow lol I seriously hope nothing like this happens again!

Yeah, I do this fubar foo at screw up all the time. The computer guys use foo a lot, and I mix the fu and foo up often.

Then the auto correct turns foo to food.

Supposedly this FAA memo explains the problem.
FAA memo fubar

a reply to: gariac

The plot thickens...

Air Force: U-2 did not scramble LAX computers

a reply to: dogshark

That's because the ER-2 belongs to NASA.