![[Credit: WikiMedia Commons]](jpg/640px-american_airbus_a320_n126u04f3.jpg?width=640&height=337)
The European Union Aviation Safety Agency (EASA) issued an Emergency Airworthiness Directive (AD), mandating immediate software and hardware fixes for a Airbus A320-family aircraft. The move follows an in-flight incident where an A320 experienced an “uncommanded and limited pitch down,” which investigators have linked to data corruption caused by intense solar radiation.
“An Airbus A320 aeroplane recently experienced an uncommanded and limited pitch down event.” the EASA said. “The autopilot remained engaged throughout the event, with a brief and limited loss of altitude, and the rest of the flight was uneventful. Preliminary technical assessment done by Airbus identified a malfunction of the affected ELAC as a possible contributing factor.”
On Friday, Airbus itself released a statement following the discovery of the issue. The aircraft manufacturer acknowledged that a “significant” number of A320s in-service could be impacted and that the subsequent fixes will lead to “operational disruptions to passengers and customers.”
The AD calls for affected aircraft to replace specific Elevator Aileron Computers (ELAC) to be before their next flight. The EASA stated that a ferry flight is permitted to position an aircraft to a location where it can be properly serviced.
American Airlines, which operates around 340 A320s across its fleet, said that it expects some operational disruptions, but that the majority of its aircraft will be updated today and tomorrow.
United Airlines said that they remained unaffected by the Airbus announcement, a spokesperson for the company told USA Today.
Usually when a cause is identified there is hard factual evidence. Like the 737-Max problems that were the MCAS system. Saying “solar radiation” is pretty weak, I would like to see how they proved it. In an aircraft known to be “fly-by-wire”, there are many microcontrollers with embedded logic. That means tiny computers placed all over the plane. Unless they rad-harden the plane this same “solar radiation” data corruption can occur again and again. Maybe this is just a pacifying “finding” so people think there is little to worry about for Airbus?If the cause is unknown, the fleet would be grounded, just like the Max.
I agree that a lot of this just don’t pass the smell test. First, as is usually the case, the Airbus solution is a quick software update. In this case the fix is actually replacing a previous update with a prior version. Some older airframes actually need hardware updates. That doesn’t sound like a software issue to me. Nobody wants to know how the flawed update made it into the aircraft? It is said a “line of code” was missing that “protects” the system from radiation. It would be very interesting to see how that is works. After the MAX issues, we were led to believe by the FAA and EASA that all software updates needed to be validated by a second independent source. If so, how did that missing line of code escape them also. And just who are they?
What this really says and nobody wants to say out loud, is that the FAA and EASA really has little capability to keep us as safe as they would like us to believe. It might also say that Airbus learned a lot after the Max issue as to how best bury an issue. How many more gremlins are hiding in all of those computers with the millions of lines of code that make it all work? How can we be assured that any simple future update won’t induce even more dangerous bugs? Or, what was in the flawed update that apparently wasn’t all that important in the first place? Must be something the previous version didn’t have. Or, dummer yet, when the sun decides to throw us another “solar radiation” burst.
I think a lot of people are really gullible here. I just watched a TV reporter ask “an airline expert” some of these questions. The answer? We should be so thankful for the smart engineers that discovered this so quickly". Well, it wouldn’t have been quick enough if that Jet Blue decided to take a quick 500 foot dive during a 400 foot approach.
I used to work for Boeing Satellite Systems. We made satellites and radiation hardening is real. But it was pervasive, not a point solution. It had to be. I cannot believe that “smart engineers” are basically saying their guess is good. Boeing proved that the MCAS would fail when sensor input was unavailable and they included a hardware change to always have at least 2 sensors in case one is not providing input. I used to be a professional software engineer, Fringe and error cases are the major parts of any good software. I think an airline expert is the wrong person for the assessment of coding issues.
It’s just like the new cars they’re making nowadays, filled with too many computers and modules that nobody can fix anything without expensive readers. It is making it hard for most mechanics to deal with. This computer age is going to kill people especially when AI comes in.
Who led you to believe that? Who is that second independent source and what exactly are they providing?
No, Boeing didn’t prove anything of the sort. When AOA sensor data is unavailable or invalid the ADIRU sends a “No data computed” for airspeed and altitude and those parameters are blanked on the displays.
The hardware change to utilize two AOA sensors didn’t provide redundancy if one is not working. A discrepancy between the two does not allow a determination as to which one is erroneous. Thus the scheme provides integrity monitoring; a discrepancy indicates AOA sensing is unreliable and neither value is used.
True parametric redundancy would require three or more sources and a source-select mechanism that compares the source outputs, determines whether the number of outputs that mutually match meets or exceeds the minimum functional assurance criterion (2/3, 5/7, 5/9, 7/9, etc.) and then selects one of them to be the source for the consuming system(s). If the minimum functional assurance is not met the source-select has to send a “parameter not computed” or equivalent message instead.