Ethernet failure on Swiss business jet prompted emergency descent, warn aviation safety bods
- Reference: 1600944311
- News link: https://www.theregister.co.uk/2020/09/24/pilatus_pc24_software_update/
- Source link:
In a recently issued [1]airworthiness directive , EASA has ordered operators of the Pilatus PC-24 to install new software aboard PC-24 business jets after "a dual Ethernet communication channel failure on a dual-channel data concentration and processing unit".
Like all complex machines in the modern era, jet aircraft are essentially flying servers. Most airliners and business jets contain Ethernet-based internal networks that allow flight control computers to talk to other systems dotted around the airframe, as explained in a previous article [2]about the Boeing 787 . Data concentration units share some similarities with network switches down on terra firma, as detailed [3]here .
When that Ethernet network degrades or fails, things can become unpredictable. So it apparently was when that exact thing happened aboard an unidentified PC-24 flight, according to EASA: "This triggered opening of electronic circuit breakers, which resulted in the degradation of environmental control system functionalities, the deployment of all passenger oxygen masks and the autopilot entering in emergency descent mode."
In addition: "Various crew alerting system messages were shown. The functionality of other systems, e.g. flaps, fuel indication and the ice protection system were significantly degraded."
Such things are unlikely to cause an aeroplane to crash, though they do result in "increased pilot workload" in EASA's words.
The fix for this mildly alarming scenario is simple: install a software update. By the end of October, PC-24 operators must have installed version 7.3 of the onboard Utility Management System software. Software updates to fix aviation problems are relatively common in the cautious world of aviation, where fly-by-wire design philosophies are now embedded for all but the most simple aeroplanes.
Pilatus has been asked for comment. The Swiss firm had accepted orders for 84 PC-24s in an initial run, delivering 30 of those by [4]last summer before reopening its order book. ®
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[1] https://ad.easa.europa.eu/ad/2020-0200
[2] https://www.theregister.com/2020/04/02/boeing_787_power_cycle_51_days_stale_data/
[3] https://www.curtisswrightds.com/applications/aerospace/mission-management/data-concentration.html
[4] https://www.flightglobal.com/pilatus-re-opens-pc-24-orderbook/132768.article
[5] https://whitepapers.theregister.com/
Re: FCS is not new.
You don't need an infinite bucket.
You can get certifiable (i.e. all the certification artefacts are already packaged and can be bought) network and compute systems as COTS (common off the shelf) products, if you go to the correct supplier.
As the aircraft manufacturer, it is then up to you to include this in the aircraft certification.
Network switches in aircraft
I used to supply these to various air frame integrators.
I was rather taken aback when it just popped up in conversation that aboard a major new large aircraft (think Jumbo jet size, but not suggesting any particular manufacturer) as part of their flight trials, they had removed the flight control network switch(es) in flight and swapped for other units they had at hand.
They have bigger dangly bits that I have!!!
My personal feeling is that anything that can be flown manually should have a total overide system, so that in the event of a hijack by gremlins, the pilot/s can take full control of the aircraft.
Pilots ought to be considered a significant part of the redundancy rather than simply redundant.
Well yes, an emergency descent system is only going to help for a short (possibly very short) amount of time isn't it!
(Hopefully this system is just to bring the plane down to a level where masks aren't required)
One reason (but not the only one) for fly by wire is that the aerodynamic forces just get beyond human muscles. See the comments about the [1] 787 Max trim wheel .
[1] https://www.theregister.com/2020/09/23/boeing_737_max_faa_balpa/
Destination Host Unreachable
Hopefully the fact the node in the tail is not responding doesn't mean the tail fell off!
Re: Destination Host Unreachable
Has to be in the tail as that's where the ethernet cable connecting them to the airport unspools from.
Psst - don't tell Apple as they have a trademark on 'Airport Base Station'
Redundant Comment
Didn't I see dual redundant Ethernet in the article? Doesn't that mean that when one fails the other should still work? Or should I take the "fixed by software patch" as an indication that software took out main and redundant symultaneously?
FCS is not new.
Fly-by-wire - where everything is hooked to a computer - is not something new. F-16's have been flying like this for, what, 40 years now?
What's new is not having a McDonnel - Douglas level of budget to exhaustively test everything or having the DoD breathing down your neck to QA the bloody thing properly because you are going to wage war with it.
Trusting your life to a router ain't exactly a good thing, unless you built it for this purpose with infinite budget... so it works right off the bat, and you don't have to wait WINDOWS UPDATE to deploy the landing gear or lower flaps!