1 of 5 
Inside the cockpit: mile-high computing
Posted on 25 Jun 2010 at 16:55
What kind of computing power does it take to keep a 747 in the air?
The computers responsible for the take-off and landing of up to 8,000 flights in UK airspace every day are no ordinary computers.
They keep those planes safe and stable through the most punishing weather conditions, and ensure that we get from one continent to another in one piece. They are among the most stringently tested and carefully maintained computers in the world, because if they fail, people die.
And yet many of these computers are significantly less powerful than the laptop PC you have at home. Welcome to the world of 21st-century avionics.
Barring small planes and helicopters, the days of manual flight in civil aviation are long gone. The combination of digital fly-by-wire control, flight-management systems and the autopilot has transformed the pilot’s role to the extent that it’s now popularly believed that the captain has little to do beyond flicking switches and practising his Received Pronunciation over the PA. This is a massive simplification, but not without a grain of truth.
When we fly on a commercial airline, we rely on computers to keep us moving comfortably in the right direction and even, in some circumstances, land us safely on solid ground. In the military sphere, it’s computing power that gives pilots the edge against hostile forces and the information they need to make life or death decisions.
Over the next few pages, we’re going to examine these computers and the tasks they perform. We’ll also look at how they’re evolving to save airlines time and money, reduce emissions and make flying safer.
Period of change
This is a period of change for the aviation industry, as it moves from the old ways of federated systems and proprietary technology into a new age where more familiar, off-the-shelf components are taking to the skies. Get on board, fasten your seatbelt and enjoy the flight.
It was inevitable that the continual evolution of computer technology would eventually affect air travel, but the avionics industry has always been isolated from the fast-moving computing mainstream. Following the introduction of electronic systems in the early 1980s, the computing power in a commercial airliner or military aircraft would have resided in several discrete, dedicated electronic devices, communicating via point-to-point links or – in more recent times – a local network based on the ARINC 420 or ARINC 629 aviation standards.
The most important unit, the Flight Management System (FMS), communicated with various navigational sensors and sent instructions to the autopilot, while giving feedback to the flight crew through dedicated analogue instrument panels or more flexible electronic multifunctional displays.
These weren’t necessarily sophisticated; you’ll still find Airbus 320 or Boeing 777 jets in service today that rely on Intel 80286 or 80486 processors dating back to the late 1980s and early 1990s.
Over the past decade, however, avionics has been transformed. The pilot’s cockpit has been revolutionised by a shift from analogue instrument panels and physical controls to the so-called “glass cockpit”, where programmable multifunction displays provide navigational data and instrument feedback, while touchscreens, trackballs and keyboards control the various systems.
Although text-based menus and simple keypads are still used for the Control Display Units that pilots use to program the FMS, they’ve been added to or supplanted by modern graphical displays and UIs. What’s more, while Boeing retains the classic flight yoke in its cockpits, Airbus long ago replaced it with a smaller “side-stick” similar to the flight sticks used in PC simulations, giving the flight crew more room to interact with the computers.
Yet this is nothing compared to what’s happening behind the scenes.
From around the web
Military aircraft use Redundancy Management
I have in the past been involved in testing the code within the Flight Control Computer for a military aircraft currently in service with the RAF and other countries.
The time taken to complete the project meant that before the end product was delivered, the COTS micro used within the FCC was obsolete and a replacement was being sourced whilst we were in the final stages of the testing!
The FCC was duplicated 4 times within the fuselage and as a result Redundancy Management (RedMan) was built into the code. The rules of RedMan make great bedtime reading, especially if you're an insommniac!
There was also redundancy within the testing - I was a member of one of two different and seperate teams each testing the code in different ways. I was doing system testing, the other team were doing unit testing. We very rarely compared notes.
Now you know why military aircraft cost so much and are usually over budget and late!
By BornOnTheCusp on 25 Jun 2010 
A Flaw in the system
So let me get this strait.If Terrorists really wanted to have an impact.All they would need to do is an Oceans 11 at the Airports.Let off an E.M.P. and all of the planes that have Avionics on board ( That is most of them!) will promptly drop out of the sky
!
By Jaberwocky on 26 Jun 2010
I think that's a little easier said than done there Jaberwocky. For a start, you can't just go and buy a suitably powerful EMP generator from Maplins - even in Hollywood they had to go and nick the make-believe thing from a secure location!
Making a powerful enough, 'weapons-grade' EMP from a non-nuclear devise is pretty difficult.
I should also rather hope that the plane's more sensitive equipment has some form of shielding protecting it. (I say 'hope', I don't know).
If you really want to worry about it, I suspect nefarious new ways of smuggling bombs on board and hand-held rocket launchers near airports are still far more viable threats than EMP attacks to a plane's computers.
Fancy the boat anyone?
By Mr_John_T on 27 Jun 2010
Note: I meant to say 'device', not 'devise'.
By Mr_John_T on 27 Jun 2010
Do we have to give people ideas, Jaberwocky?
For my part, it still puzzles me how the 9/11 hijackers managed to control those fly-by-wire commercial jets so precisely after just a few lessons on a Cessna.
By 0thello on 28 Jun 2010
Nominative determinism
Is it just me, or is there some humour in the fact that a guy who works on computers to keep planes in the air is called Chip Downing...
I'll get my coat
By Mat1971 on 28 Jun 2010
Don't need to go to Maplin!
Many years ago, in an electronics magazine (can't rememember which one) there was an article re EMP and electronic devices. The main point was that an air burst would produce the necessary pulse (killing precisely no-one on the ground directly), but knocking out all electronic equipment not protected for a very large radius. The sort of protection required was either very large power transistors on input stages or valves!
Most military equipment should be protected against EMP, but not COTS of course.
By BornOnTheCusp on 28 Jun 2010
Flying is not so difficult
@0thello
I have worked on flight simulators and can assure you that once the difficult parts of the flight are done by experts (i.e. take off) the flying around is a doddle. Whilst flying a Nimrod MR2 simulator around it was very easy to fly through ships placed at 5,000 feet in the air (produced in the visual model and able to be located at any altitude)
By BornOnTheCusp on 28 Jun 2010
Oops
A friends dad (electronics engineer) worked with a defense contractor a while back, and he was telling me that he wrote code to check the redundant systems on an aircraft only to discover that the result was not in agreement across the systems! (firing systems i think). Apparently someone left a component out of one of the redundant systems!
By GAZZAT5 on 6 Jul 2010
"Redundant" systems are usually identical!
@GAZZAT5, I think you are misremembering the anecdote since a quad redundant system (for example) means ALL four units have identical software loads and the software is written to be aware of the other three units.
By BornOnTheCusp on 6 Jul 2010
For more details about purchasing this feature and/or images for editorial usage, please contact Jasmine Samra on pictures@dennis.co.uk
advertisement
- Windows 8 on ARM to run desktop apps... but only Office
- Windows 8 pauses desktop apps to save energy
- Mobiles boost Apple profits... and there's more to come
- Ubuntu rips up drop-down menus
- RIM founders fall on their swords
- Microsoft to tweak Windows 8 Start screen
- Weak PC sales expected to hit Microsoft's profits
- 802.11ac routers to hit 800Mbit/sec this year
- Asus Transformer Prime gets HD upgrade
- Netgear brings apps to routers for “smart networks”
- Chrome's shine getting lost in translation
- BytePac: the cardboard hard disk enclosure
- How tech loosens our grip on reality
- Hokum watch: Safer Internet Day
- Why I'm deleting Adobe from my PC
- Prepare to be patronised: it's Safer Internet Day
- Dear Sony, Samsung and every other tech company in the world: stop trying to be Apple
- Will Apple's Final Cut Pro X update placate the pros?
- Smartr Contacts for iPhone review
- Switching to Office 365's Outlook Web App
advertisement
Printed from www.pcpro.co.uk